ABRET R.EEG.T. Exam — Questions and Answers

Question 1: Intravenous drip artifact may appear on EEG as:

Continuous 60 Hz noise across all channels
High-amplitude polyspikes in the frontal region
Periodic, rhythmic slow transients corresponding to the drip rate, typically at one or a few channels near the IV site (Correct answer)
Generalized burst suppression pattern

Correct answer: Periodic, rhythmic slow transients corresponding to the drip rate, typically at one or a few channels near the IV site

IV drip artifact produces periodic transients at the frequency of the drip rate, typically affecting electrodes near the IV site. Each drop creates a small electrical potential change detected by nearby electrodes.

Question 2: Which EEG finding is considered a non-epileptiform abnormality that reflects cortical dysfunction ipsilateral to a structural lesion?

Sleep spindles
Focal polymorphic delta slowing (Correct answer)
Occipital dominant rhythm at 10 Hz
Lambda waves

Correct answer: Focal polymorphic delta slowing

Focal polymorphic delta activity indicates underlying structural or physiologic disruption of cortical neurons in that region and is not epileptiform.

Question 3: A unilaterally prolonged P100 latency on visual evoked potential testing is most characteristically associated with which condition?

Demyelinating optic neuritis (multiple sclerosis) (Correct answer)
Retinal detachment
Cataracts
Glaucoma

Correct answer: Demyelinating optic neuritis (multiple sclerosis)

Demyelinating optic neuritis, most commonly seen in multiple sclerosis, slows conduction along the optic nerve, resulting in a prolonged P100 latency that may persist even after clinical recovery.

Question 4: During hyperventilation, if the patient has an underlying brain tumor, you would most likely expect to see:

Focal or lateralized slow-wave abnormality that increases in prominence (Correct answer)
High-frequency gamma activity over the tumor site
Suppression of all EEG activity
Bilateral synchronous generalized slowing

Correct answer: Focal or lateralized slow-wave abnormality that increases in prominence

Focal structural lesions such as tumors typically produce focal or lateralized slow-wave abnormalities that are accentuated by hyperventilation-induced hypocapnia.

Question 5: Temporal intermittent rhythmic delta activity (TIRDA) is significant because it:

Indicates brainstem dysfunction
Is caused by electrode artifact at temporal sites
Is always a normal variant in elderly patients
Has a strong association with temporal lobe epilepsy even in the absence of spikes (Correct answer)

Correct answer: Has a strong association with temporal lobe epilepsy even in the absence of spikes

TIRDA (temporal intermittent rhythmic delta activity) has a high correlation with temporal lobe epilepsy and is considered an epileptiform-equivalent pattern, even when no spikes or sharp waves are present.

Question 6: An EEG performed on a patient with an acute left-hemispheric stroke shows stereotyped sharp waves recurring every 1-1.5 seconds, confined to the left cerebral hemisphere. This pattern is best described as:

Generalized Periodic Discharges (GPDs)
Burst-Suppression
Triphasic Waves
Periodic Lateralized Discharges (PLEDs) (Correct answer)

Correct answer: Periodic Lateralized Discharges (PLEDs)

This pattern fits the definition of Periodic Lateralized Discharges (PLEDs), which are stereotyped, periodic complexes that are restricted to one hemisphere. They are often associated with acute structural lesions like stroke or encephalitis. GPDs are bilateral, not lateralized.

Question 7: Which action by an EEG technologist during a video-EEG monitoring session could constitute a HIPAA violation?

Storing the recording on the facility's encrypted server with access restricted to the care team
Posting an anonymized educational clip on a social media platform without explicit patient authorization (Correct answer)
Documenting behavioral events in the patient's medical record
Reviewing the recording with the supervising neurologist on a secure workstation

Correct answer: Posting an anonymized educational clip on a social media platform without explicit patient authorization

Posting any patient recording — even anonymized — to social media without specific written HIPAA authorization is a privacy violation.

Question 8: What is the minimum recommended sampling rate for routine digital EEG recording?

1024 Hz
64 Hz
256 Hz (Correct answer)
128 Hz

Correct answer: 256 Hz

A sampling rate of at least 256 Hz is recommended for routine EEG to adequately capture frequencies up to 70-100 Hz according to the Nyquist theorem (sampling rate must be at least twice the highest frequency of interest).

Question 9: Generalized voltage attenuation (low-voltage EEG) with amplitudes below 20 µV throughout may be caused by:

Caffeine ingestion in the last hour
Hyperventilation artifact
Scalp edema, subdural fluid, or certain medications such as barbiturates (Correct answer)
Photic driving response

Correct answer: Scalp edema, subdural fluid, or certain medications such as barbiturates

Generalized low voltage can result from physical barriers between brain and electrodes (scalp edema, subdural effusions, thick skull) or from cortical suppression by medications like barbiturates, hypothermia, or severe diffuse brain injury.

Question 10: Which electrode placement system uses 10% and 20% distances from skull landmarks to determine electrode positions?

The American Clinical Neurophysiology Society (ACNS) system
The Modified Combinatorial Nomenclature
The Queen Square system
The International 10-20 system (Correct answer)

Correct answer: The International 10-20 system

The International 10-20 system divides skull circumference into intervals of 10% and 20% from fixed bony landmarks to standardize electrode placement.

Question 11: Approximately how many stimulus repetitions (averages) are typically needed to obtain a reliable, reproducible BAEP waveform?

50–200
300–500
5000–10000
1000–2000 (Correct answer)

Correct answer: 1000–2000

Because the BAEP signal amplitude is only about 0.1–1 µV, averaging 1000–2000 responses is required to achieve an adequate signal-to-noise ratio and clearly resolve all five waves.

Question 12: In a bipolar longitudinal (anterior-posterior) montage, a phase reversal at C3 indicates:

An artifact at the C3 electrode
The C3 electrode has high impedance
Maximum negativity or positivity at C3 (Correct answer)
Activity originating from the contralateral hemisphere

Correct answer: Maximum negativity or positivity at C3

A phase reversal occurs where adjacent channels sharing an electrode deflect in opposite directions, indicating the electrode at the reversal point has the maximum voltage for that event.

Question 13: Generalized periodic discharges (GPDs) are most classically associated with which condition?

Acute ischemic stroke
Herpes simplex encephalitis
Creutzfeldt-Jakob disease (CJD) (Correct answer)
Hypoxic-ischemic encephalopathy

Correct answer: Creutzfeldt-Jakob disease (CJD)

GPDs (formerly called generalized PLEDs or BiPLEDs) with a triphasic morphology are classically associated with CJD, though they also appear in metabolic encephalopathies.

Question 14: What precaution should be taken when performing EEG on a patient with a suspected skull fracture or recent craniotomy?

Avoid placing electrodes over or applying pressure to the affected area, and consult with the clinical team (Correct answer)
Only use subdermal needle electrodes at the affected site
No special precautions are needed — standard application applies
EEG is absolutely contraindicated in these patients

Correct answer: Avoid placing electrodes over or applying pressure to the affected area, and consult with the clinical team

Electrode application over skull fractures or recent craniotomy sites requires avoiding direct pressure on the area, using alternative electrode positions, and coordinating with the clinical team to prevent complications.

Question 15: During an ambulatory EEG, a patient calls to report they removed the electrodes themselves because of discomfort. What is the technologist's primary ethical obligation?

Document the incident and attempt to retrieve the equipment
Immediately dispatch a technologist to reapply electrodes without discussing with the patient
Respect patient autonomy, document the removal, and notify the ordering physician (Correct answer)
Report the patient to the billing department for equipment misuse

Correct answer: Respect patient autonomy, document the removal, and notify the ordering physician

Patients have the right to discontinue testing; the technologist must respect autonomy, document thoroughly, and inform the physician.

Question 16: Rhythmic delta activity (RDA) in the ICU that shows an evolution in frequency or distribution should prompt the clinician to consider:

Possible seizure activity requiring further evaluation (Correct answer)
Medication effect from benzodiazepines
Calibration error
Normal sleep architecture

Correct answer: Possible seizure activity requiring further evaluation

Evolving RDA may represent ictal activity on the ictal-interictal continuum, and evolution is a key feature that raises concern for seizures rather than a static encephalopathic pattern.

Question 17: Electrographic seizure activity on EEG is defined by which characteristic evolution?

Evolving pattern with change in frequency, morphology, or spatial distribution over time (Correct answer)
Random isolated spikes without pattern
Only generalized tonic-clonic movements on video
Static, unchanging repetitive discharges

Correct answer: Evolving pattern with change in frequency, morphology, or spatial distribution over time

Electrographic seizures are defined by evolution — a progressive change in frequency, amplitude, morphology, and/or spatial distribution over at least 10 seconds, distinguishing them from brief interictal discharges.

Question 18: What is the primary advantage of using an average reference montage?

It reduces bias from any single reference electrode location (Correct answer)
It reduces the number of electrodes required
It eliminates the need for impedance checks
It best localizes focal epileptiform discharges

Correct answer: It reduces bias from any single reference electrode location

The average reference montage uses the average of all electrodes as the reference, which reduces the distortion that can occur when a single reference electrode is near active brain tissue.

Question 19: Sleep spindles are a hallmark of which stage of sleep?

Stage N1 (drowsiness)
Stage N2 sleep (Correct answer)
Stage N3 (deep slow wave sleep)
REM sleep

Correct answer: Stage N2 sleep

Sleep spindles (11-16 Hz bursts lasting 0.5-2 seconds) are the defining feature of Stage N2 sleep. They are generated by thalamic reticular nucleus oscillations and are best seen over central regions.

Question 20: Neonatal seizures on EEG differ from adult seizures in that they:

Are often focal, brief, fragmentary, and may migrate between regions without clear generalization (Correct answer)
Always show generalized 3 Hz spike-and-wave patterns
Have the same patterns and distribution as adult seizures
Are always accompanied by obvious clinical convulsions

Correct answer: Are often focal, brief, fragmentary, and may migrate between regions without clear generalization

Neonatal seizures are characteristically focal (reflecting immature interhemispheric connections), brief, may migrate between brain regions, and frequently occur without visible clinical manifestation (subclinical seizures).

Question 21: A technologist notices intermittent square-wave transients isolated to a single electrode that disappear when the electrode impedance is rechecked and re-gelled. This is most consistent with:

Muscle artifact
EKG artifact
Electrode pop (Correct answer)
Sweat artifact

Correct answer: Electrode pop

Electrode pops are caused by intermittent loss of contact or impedance instability at a single electrode and typically resolve with re-application.

Question 22: Which waveform is considered a normal variant and is characteristically seen at the vertex during stage N1 sleep?

Vertex sharp wave (Correct answer)
Sleep spindle
Lambda wave
K-complex

Correct answer: Vertex sharp wave

Vertex sharp waves (V-waves) are normal, high-amplitude transients maximal at Cz that appear during drowsiness and stage N1 sleep.

Question 23: What minimum area of synchronously active cortex is typically required to produce a detectable signal on scalp EEG?

6 cm² (Correct answer)
100 cm²
25 cm²
1 cm²

Correct answer: 6 cm²

Approximately 6 cm² (some estimates range from 6-10 cm²) of synchronously active cortex is needed to generate sufficient electrical potential to be detected through the skull, meninges, and scalp by surface electrodes.

Question 24: The blood-brain barrier's role in EEG is primarily related to:

Filtering EEG signals before they reach the scalp
Directly generating electrical potentials recorded on the scalp
Producing artifact from cerebral blood flow
Maintaining the ionic environment necessary for proper neuronal electrical activity (Correct answer)

Correct answer: Maintaining the ionic environment necessary for proper neuronal electrical activity

The blood-brain barrier maintains the precise ionic composition of the extracellular fluid (particularly Na+, K+, Ca2+, and Cl- concentrations) essential for proper neuronal membrane potentials and synaptic transmission that generate EEG signals.

Question 25: Modified neonatal montages differ from standard adult montages primarily by:

Using only midline electrodes
Recording at higher paper speeds exclusively
Using the same 10-20 system without any modifications
Using fewer electrodes with adjusted placement for the smaller head size and including polygraphic channels for behavioral state assessment (Correct answer)

Correct answer: Using fewer electrodes with adjusted placement for the smaller head size and including polygraphic channels for behavioral state assessment

Neonatal montages use fewer electrodes (typically 9-11 EEG channels) adapted for the small head, modified placement to cover areas of clinical importance, and include polygraphic channels (EMG, EOG, ECG, respiration) essential for state assessment.

Question 26: Inhibitory postsynaptic potentials (IPSPs) on apical dendrites of cortical pyramidal neurons generate which polarity at the overlying scalp electrode?

Negative deflection
No detectable signal
Biphasic spike
Positive deflection (Correct answer)

Correct answer: Positive deflection

IPSPs at apical dendrites create a current sink deeper in the cortex and a source near the surface, resulting in a positive polarity at the scalp electrode above.

Question 27: A 68-year-old patient with a history of a craniotomy for a meningioma resection presents for a routine EEG. The recording shows a focal area of high-amplitude, sharp, and at times spiky-appearing 6-11 Hz activity directly over the surgical site. This activity is persistent across both awake and drowsy states. Which feature would most strongly differentiate this as Breach Rhythm rather than an epileptiform abnormality?

The absence of an after-going slow wave. (Correct answer)
Its focal and asymmetric nature.
The presence of intermixed beta frequencies.
The high amplitude of the activity compared to the contralateral side.

Correct answer: The absence of an after-going slow wave.

A key distinguishing feature between Breach Rhythm and a true epileptiform discharge is that Breach Rhythm consists of sharp or spiky transients that are not followed by a slow-wave component. [3, 7] While increased amplitude, focal asymmetry, and intermixed faster frequencies are all characteristic of Breach Rhythm, the lack of an associated slow wave is the most definitive feature to rule out an epileptiform spike or sharp wave. [3, 6, 7]

Question 28: A patient undergoing an EEG displays rhythmic 8-13 Hz activity over the occipital regions that attenuates with eye-opening. This activity is primarily modulated by which subcortical structure?

Thalamus (Correct answer)
Hippocampus
Basal Ganglia
Cerebellum

Correct answer: Thalamus

The posterior dominant alpha rhythm, an 8-13 Hz activity seen in relaxed wakefulness, is generated through corticothalamic circuits. The thalamus acts as a pacemaker and gatekeeper, synchronizing cortical activity to produce these characteristic rhythms. The hippocampus is involved in memory, the basal ganglia in motor control, and the cerebellum in coordination; they are not the primary modulators of the alpha rhythm.

Question 29: What feature best distinguishes a benign epileptiform transient of sleep (BETS) from a pathological epileptiform discharge?

BETS are typically small, isolated, and lack an after-going slow wave (Correct answer)
BETS have a duration greater than 200 milliseconds
BETS occur only during REM sleep
BETS always appear in the frontal regions

Correct answer: BETS are typically small, isolated, and lack an after-going slow wave

BETS (also known as small sharp spikes or SSS) are low-amplitude, brief, isolated transients without after-going slow waves, occurring during drowsiness and light sleep, and are considered benign normal variants.

Question 30: During a routine EEG, how long should a standard hyperventilation activation procedure last?

10 minutes
3 minutes (Correct answer)
5 minutes
1 minute

Correct answer: 3 minutes

Standard hyperventilation during routine EEG lasts 3 minutes, followed by at least 1 minute of continued recording.

Question 31: The N20 component of the median nerve SSEP is primarily generated by which brain structure?

Primary somatosensory cortex (Area 3b, S1) (Correct answer)
Supplementary motor area
Parietal association cortex (Area 7)
Thalamus (ventral posterior lateral nucleus)

Correct answer: Primary somatosensory cortex (Area 3b, S1)

N20 reflects the initial thalamocortical volley arriving at primary somatosensory cortex (Brodmann area 3b) on the posterior bank of the central sulcus.

Question 32: Which of the following describes the typical, normal response to hyperventilation in a healthy 8-year-old child's EEG?

Development of focal sharp waves over the temporal regions.
The appearance of generalized 3 Hz spike-and-wave discharges.
A buildup of generalized, rhythmic, high-amplitude delta and theta slowing. (Correct answer)
Attenuation of the posterior dominant rhythm with no other changes.

Correct answer: A buildup of generalized, rhythmic, high-amplitude delta and theta slowing.

A normal response to HV, especially prominent in children and adolescents, is the development of generalized, often high-amplitude, rhythmic slowing in the delta and theta frequency ranges. This is known as a "buildup" response and should resolve shortly after HV is discontinued. Generalized spike-and-wave or focal sharps would be abnormal findings.

Question 33: In continuous EEG monitoring, what is the recommended minimum duration of recording to detect the majority of seizures in high-risk ICU patients?

6 hours
48 hours
2 hours
24 hours (Correct answer)

Correct answer: 24 hours

Studies show that 24 hours of continuous EEG monitoring captures approximately 80–90% of seizures in high-risk ICU patients.

Question 34: Which medication commonly produces diffuse beta activity as a non-epileptiform EEG abnormality?

Benzodiazepines (Correct answer)
Levetiracetam
Haloperidol
Phenytoin

Correct answer: Benzodiazepines

Benzodiazepines and barbiturates classically increase diffuse beta activity (>13 Hz), which is a drug effect rather than a pathological finding.

Question 35: Which of the following EEG findings is most characteristic of a patient performing lateral eye movements to the right?

High-amplitude, synchronous slow waves in all frontal channels.
A slow positive deflection at F8 and a slow negative deflection at F7. (Correct answer)
Rhythmic 8 Hz sinusoidal waves in the Fp1 and Fp2 channels.
A sharp positive deflection at F7 and a sharp negative deflection at F8.

Correct answer: A slow positive deflection at F8 and a slow negative deflection at F7.

Due to the corneoretinal potential, the cornea of the eye is positively charged relative to the retina. When the eyes move to the right, the positive cornea moves closer to the F8 electrode, creating a positive deflection, and further from the F7 electrode, creating a negative deflection. This results in a characteristic out-of-phase potential between the two electrodes.

Question 36: A technologist observes rhythmic, sharp-appearing transients that are most prominent in the left temporal channels and perfectly time-locked with the QRS complex on the EKG monitor. What is the most likely artifact and the best initial step to resolve it?

EKG artifact; attempt to reposition the M1/A1 or T3 electrode slightly. (Correct answer)
60 Hz interference; ensure the notch filter is enabled.
Pulse artifact; increase the low-frequency filter to 2 Hz.
IV drip artifact; check the patient's infusion pump for electrical noise.

Correct answer: EKG artifact; attempt to reposition the M1/A1 or T3 electrode slightly.

The artifact's morphology and perfect correlation with the EKG are classic signs of EKG artifact. This artifact is often most prominent on the left side because the heart's electrical field is strongest there. Slightly moving an electrode can change its orientation relative to the heart's electrical field, often reducing the artifact without altering the cerebral data.

Question 37: Which neonatal EEG pattern is considered highly abnormal and suggests severe encephalopathy?

Burst-suppression with interburst intervals showing isoelectric or near-isoelectric activity (Correct answer)
Activité moyenne (continuous medium-voltage mixed pattern)
Tracé alternant
Delta brushes in the temporal regions

Correct answer: Burst-suppression with interburst intervals showing isoelectric or near-isoelectric activity

Burst-suppression is a severely abnormal neonatal EEG pattern with bursts of high-voltage mixed activity separated by nearly isoelectric periods, indicating severe diffuse cerebral dysfunction from hypoxic-ischemic injury, metabolic disorders, or other causes.

Question 38: What is the standard low-frequency filter (LFF) setting used in routine clinical EEG?

10 Hz
1 Hz (Correct answer)
5 Hz
0.1 Hz

Correct answer: 1 Hz

A low-frequency filter of 1 Hz (high-pass filter) is the standard setting for routine EEG to reduce slow baseline drift.

Question 39: Which antiepileptic drug effect on the EEG may be mistaken for a pathological finding if the technologist is unaware of the patient's medication list?

Phenytoin toxicity causing rhythmic beta activity indistinguishable from normal
Lamotrigine causing prominent mu rhythm enhancement
Valproate at therapeutic levels causing diffuse slowing that mimics metabolic encephalopathy (Correct answer)
Carbamazepine causing bifrontal spike-and-wave discharges

Correct answer: Valproate at therapeutic levels causing diffuse slowing that mimics metabolic encephalopathy

Valproate, even at therapeutic serum levels, can produce diffuse background slowing that resembles a mild encephalopathy. Without knowing the patient is on valproate, the EEG reader could incorrectly diagnose a metabolic or structural abnormality. This is a common source of interpretation error and underscores the importance of obtaining a complete medication history before interpreting any EEG.

Question 40: During photic stimulation, the technologist notices the patient becoming agitated and the EEG shows generalized spike-and-wave activity outlasting the flash trains. The appropriate action is to:

Immediately stop photic stimulation and continue recording the after-discharge (Correct answer)
Switch to hyperventilation immediately
Continue stimulation to determine the full extent of the response
Increase the flash frequency to get a better sample of the response

Correct answer: Immediately stop photic stimulation and continue recording the after-discharge

A photoparoxysmal response that outlasts the stimulus (Type 4) is clinically significant and stimulation should be stopped immediately to prevent triggering a clinical seizure, while continuing to record the EEG.

Question 41: Electrode bridging occurs when:

An electrode falls off and makes contact with a metal surface
Two nearby electrodes are electrically connected by excess conductive gel, producing nearly identical waveforms (Correct answer)
The ground electrode fails during recording
Digital filters create artificial similarities between channels

Correct answer: Two nearby electrodes are electrically connected by excess conductive gel, producing nearly identical waveforms

Electrode bridging occurs when excessive conductive gel spreads between adjacent electrodes, creating a low-resistance pathway that makes both electrodes record essentially the same signal, reducing spatial resolution.

Question 42: An EEG recording of a relaxed, awake adult with eyes closed shows a prominent 8-13 Hz rhythm in the occipital regions. This rhythm attenuates with eye opening. Which of the following best identifies this waveform?

Theta rhythm
Alpha rhythm (Correct answer)
Beta rhythm
Mu rhythm

Correct answer: Alpha rhythm

The posterior dominant alpha rhythm is the hallmark of a normal, relaxed, awake adult EEG with eyes closed. It is characterized by its frequency of 8-13 Hz, posterior location (maximal in the occipital regions), and its attenuation or blocking with eye opening or mental effort.

Question 43: During a routine EEG, the technologist observes the patient staring blankly and becoming unresponsive. The appropriate action is to:

Wait until the episode ends to note it in the report
Disconnect the electrodes to examine the patient
Immediately stop the recording and call a code
Continue recording while testing the patient's responsiveness and documenting observations (Correct answer)

Correct answer: Continue recording while testing the patient's responsiveness and documenting observations

The technologist should keep recording to capture the EEG correlate of the clinical event while simultaneously testing responsiveness (speaking to the patient, presenting objects) and carefully documenting all observations with timestamps.

Question 44: What is the typical frequency range of theta activity in EEG?

0.5-4 Hz
8-13 Hz
13-30 Hz
4-8 Hz (Correct answer)

Correct answer: 4-8 Hz

Theta activity ranges from 4-8 Hz. In adults, mild theta activity is normal during drowsiness but persistent theta during wakefulness suggests encephalopathy. In children, more theta activity is normal.

Question 45: In a bipolar transverse montage, the electrode chains run in which direction?

Left to right across the head (coronal) (Correct answer)
Diagonally from frontal to contralateral occipital
Front to back (anterior-posterior)
In a circular pattern around the head

Correct answer: Left to right across the head (coronal)

Bipolar transverse montages chain electrodes from left to right across the head in coronal rows, complementing the longitudinal (anterior-posterior) montage and helping lateralize epileptiform discharges.

Question 46: A compressed spectral array (CSA) displays EEG information by showing:

Amplitude envelope of the raw EEG plotted as a single line per channel
Spike-and-wave discharge counts per epoch displayed as a histogram
Power spectral density plotted over time, with frequency on one axis and time on the other (Correct answer)
Raw EEG waveforms compressed to fit on a single page per hour

Correct answer: Power spectral density plotted over time, with frequency on one axis and time on the other

A CSA (also called a density spectral array or DSA depending on color coding) uses Fast Fourier Transform (FFT) to decompose the EEG into its component frequencies and plots the power at each frequency band over time. This allows hours of EEG to be reviewed at a glance for trends in frequency content, making it useful for detecting delayed cerebral ischemia, seizures, and drug effects.

Question 47: In a normal adult EEG, what is the expected effect of opening the eyes on the posterior alpha rhythm?

Alpha amplitude increases
Alpha spreads to frontal regions
Alpha frequency increases by 4 Hz
Alpha is attenuated or blocked (Correct answer)

Correct answer: Alpha is attenuated or blocked

Eye opening causes alpha blocking (Berger effect), suppressing posterior alpha due to visual cortex activation.

Question 48: Lambda waves in the EEG are best elicited by which condition?

Eye closure in a dark room
Auditory stimulation
Voluntary limb movement
Active visual scanning of a patterned surface (Correct answer)

Correct answer: Active visual scanning of a patterned surface

Lambda waves are positive occipital transients that occur during active visual scanning (saccadic eye movements) of a patterned scene.

Question 49: What is the physiological mechanism by which hyperventilation activates epileptiform activity?

Increased oxygen delivery stabilizes neuronal membranes
Respiratory alkalosis suppresses inhibitory interneurons permanently
Hypocapnia causes cerebral vasoconstriction, reducing cerebral blood flow and causing neuronal hyperexcitability (Correct answer)
Hypercapnia causes cerebral vasodilation and increased ICP

Correct answer: Hypocapnia causes cerebral vasoconstriction, reducing cerebral blood flow and causing neuronal hyperexcitability

Hyperventilation lowers CO2 (hypocapnia), causing cerebral vasoconstriction, reduced perfusion, and subsequent neuronal hyperexcitability that can provoke epileptiform discharges.

Question 50: What is the purpose of the ground electrode in an EEG recording?

To serve as the primary reference
To reduce common-mode noise and electrical interference (Correct answer)
To detect eye movement artifacts
To measure impedance across the scalp

Correct answer: To reduce common-mode noise and electrical interference

The ground electrode helps the amplifier reject common-mode noise and electrical interference by providing a reference point for the differential amplifier.

Question 51: Which behavioral state in neonates is associated with continuous low-to-moderate amplitude mixed-frequency EEG activity?

Deep quiet sleep
Awake crying state
Active sleep (REM) (Correct answer)
Quiet sleep (NREM)

Correct answer: Active sleep (REM)

Active (REM) sleep in neonates is characterized by continuous, relatively low-amplitude mixed-frequency activity similar to wakefulness.

Question 52: In juvenile myoclonic epilepsy (JME), the EEG hallmark is polyspike-and-wave discharges typically at which frequency?

1–2 Hz
4–6 Hz (Correct answer)
10–12 Hz
3 Hz

Correct answer: 4–6 Hz

JME is characterized by generalized polyspike-and-wave complexes at 4–6 Hz, typically maximal in the morning and activated by sleep deprivation.

Question 53: In healthy young adults, what percentage of total sleep time is typically spent in REM sleep?

45–55%
5–10%
30–35%
20–25% (Correct answer)

Correct answer: 20–25%

REM sleep constitutes approximately 20–25% of TST in healthy young adults, decreasing with advancing age.

Question 54: Which EEG finding is the ictal correlate of epilepsia partialis continua (Kojewnikow syndrome)?

Bilateral independent periodic discharges (BIPDs)
Periodic lateralized epileptiform discharges (PLEDs) at 1–2 Hz
Continuous focal rhythmic delta activity with embedded spikes over the motor cortex (Correct answer)
Generalized 3-Hz spike-and-wave

Correct answer: Continuous focal rhythmic delta activity with embedded spikes over the motor cortex

Epilepsia partialis continua produces continuous or near-continuous focal rhythmic discharges, often with embedded spikes, localized to the contralateral motor cortex.

Question 55: A double banana montage is another name for which standard montage?

Bipolar transverse montage
Laplacian source derivation
Bipolar longitudinal (anterior-posterior) montage with temporal and parasagittal chains (Correct answer)
Average reference montage

Correct answer: Bipolar longitudinal (anterior-posterior) montage with temporal and parasagittal chains

The 'double banana' is the colloquial name for the standard bipolar longitudinal montage featuring two parasagittal chains and two temporal chains running anterior to posterior, resembling two banana shapes on the page.

Question 56: In normal neonatal EEGs, which activity pattern is considered developmentally appropriate but would be abnormal in a healthy adult?

Prominent lambda waves
Persistent 14 Hz spindles
Trace alternant (burst-suppression-like) pattern during quiet sleep (Correct answer)
Continuous alpha rhythm

Correct answer: Trace alternant (burst-suppression-like) pattern during quiet sleep

Trace alternant, characterized by alternating bursts and interburst intervals during quiet sleep, is a normal pattern in full-term neonates up to about 44 weeks conceptional age.

Question 57: A technologist notices a phase reversal at F7 in a bipolar montage. What does this indicate?

Minimum electrical activity at F7
F7 is the reference electrode
The montage chain is incorrectly ordered
Maximum electrical activity at F7 (Correct answer)

Correct answer: Maximum electrical activity at F7

In a bipolar montage, phase reversal at a specific electrode indicates that the maximum (or focus of) electrical activity is located at that electrode.

Question 58: Spectral edge frequency (SEF95) is defined as the frequency below which what percentage of the total EEG spectral power is contained?

95% (Correct answer)
75%
50%
90%

Correct answer: 95%

SEF95 is the frequency at or below which 95% of the total spectral power lies. It is a single-number summary of the 'upper edge' of EEG activity and is used in anesthesia monitoring and ICU trend analysis to track shifts in dominant frequencies over time. A falling SEF95 indicates slowing of brain activity.

Question 59: Which EEG feature differentiates true electrocerebral inactivity from a technical artifact producing an isoelectric-appearing record?

Recording for exactly 20 minutes
Performing a photic stimulation test
Switching to referential montage only
Increasing interelectrode distances, confirming low impedances, and testing reactivity with painful stimuli (Correct answer)

Correct answer: Increasing interelectrode distances, confirming low impedances, and testing reactivity with painful stimuli

Confirming ECI requires technical verification including electrode impedances <10 kΩ, interelectrode distance ≥10 cm, high sensitivity settings, and absence of reactivity to stimulation.

Question 60: Which electrode placement is standard for detecting eye movements during sleep staging PSG?

F7-F8 bipolar pair
Fp1-Fp2 bipolar pair
C3-A2 and C4-A1
E1-M2 and E2-M2 (outer canthi referenced to contralateral mastoid) (Correct answer)

Correct answer: E1-M2 and E2-M2 (outer canthi referenced to contralateral mastoid)

EOG channels placed at the outer canthi (E1, E2) referenced to mastoids capture horizontal and vertical eye movements needed for sleep staging.

Question 61: A patient has recurrent brief lapses with 3-Hz spike-and-wave that are abruptly terminated by photic stimulation. This response pattern is called:

Photomyogenic response
Scotosensitivity
Fixation-off sensitivity
Photoparoxysmal response (Correct answer)

Correct answer: Photoparoxysmal response

A photoparoxysmal response refers to generalized epileptiform discharges (spike-and-wave) triggered by intermittent photic stimulation, distinct from the non-epileptiform photomyogenic response.

Question 62: What does a referential montage compare each electrode to?

A common reference electrode (Correct answer)
The opposite hemisphere electrode
The adjacent electrode
The ground electrode

Correct answer: A common reference electrode

In a referential montage, each active electrode is compared to a single common reference electrode, often placed at the ear or linked mastoids.

Question 63: Which of the following statements is true regarding beta activity in a normal adult EEG?

It is often enhanced fronto-centrally by drowsiness or certain medications like benzodiazepines. (Correct answer)
It is defined as activity in the 4-7 Hz frequency range.
It is always considered an abnormal finding in an awake adult.
It is typically highest in amplitude in the occipital regions.

Correct answer: It is often enhanced fronto-centrally by drowsiness or certain medications like benzodiazepines.

Beta activity (>13 Hz) is a normal rhythm, typically low in amplitude and most evident in the frontal and central regions. Its amplitude can be enhanced by a state of drowsiness or by the use of sedative-hypnotic drugs, such as benzodiazepines and barbiturates.

Question 64: The high-frequency filter (low-pass filter) in EEG recording at a typical setting of 70 Hz will:

Attenuate frequencies above 70 Hz while passing lower frequencies (Correct answer)
Block all frequencies below 70 Hz
Amplify frequencies above 70 Hz
Only display the 70 Hz component

Correct answer: Attenuate frequencies above 70 Hz while passing lower frequencies

The high-frequency (low-pass) filter attenuates signals above its cutoff frequency. At 70 Hz, it progressively reduces muscle artifact and electrical noise above 70 Hz while preserving brain activity which is predominantly below 70 Hz.

Question 65: What is the purpose of recording a period of wakefulness with eyes open and eyes closed before activation procedures?

To establish the baseline EEG background including posterior dominant rhythm frequency, reactivity, and symmetry (Correct answer)
To calibrate the photic stimulator
To reduce the total recording time needed
To test the patient's visual acuity

Correct answer: To establish the baseline EEG background including posterior dominant rhythm frequency, reactivity, and symmetry

Baseline awake recording with eyes open and closed establishes the posterior dominant rhythm (frequency, amplitude, symmetry, reactivity), identifies any focal or generalized abnormalities, and provides comparison for interpreting changes during activation procedures.

Question 66: Impedance testing of EEG electrodes should ideally be performed using:

Visual inspection of electrode gel application
A direct current (DC) impedance meter
An alternating current (AC) impedance meter at a frequency similar to the signals of interest (Correct answer)
A standard multimeter in resistance mode

Correct answer: An alternating current (AC) impedance meter at a frequency similar to the signals of interest

AC impedance measurement at frequencies relevant to EEG (typically 10-30 Hz) is preferred because it accounts for the capacitive and resistive components of electrode impedance and avoids DC polarization that could affect recording quality.

Question 67: Which epileptiform pattern consists of high-amplitude, chaotic, multifocal spikes and slow waves seen in infantile spasms?

Hypsarrhythmia (Correct answer)
Focal cortical dysplasia pattern
Electrical status epilepticus in sleep
Generalized polyspike-and-wave

Correct answer: Hypsarrhythmia

Hypsarrhythmia is the classic interictal EEG pattern of infantile spasms (West syndrome), characterized by high-amplitude disorganized slow waves with multifocal spikes.

Question 68: K-complexes are characterized by which of the following features?

Continuous monomorphic theta activity in frontal regions
Low-amplitude fast activity in temporal regions during REM sleep
A biphasic wave with initial sharp negative component followed by a positive slow wave, maximal at the vertex during N2 sleep (Correct answer)
Bilateral occipital alpha bursts during drowsiness

Correct answer: A biphasic wave with initial sharp negative component followed by a positive slow wave, maximal at the vertex during N2 sleep

K-complexes are large biphasic waves with an initial sharp negative deflection followed by a slower positive component, maximal at Fz/Cz, occurring spontaneously or in response to stimuli during Stage N2 sleep.

Question 69: FIRDA (Frontal Intermittent Rhythmic Delta Activity) is most commonly associated with which condition?

Focal cortical lesion
Normal variant in elderly
Temporal lobe epilepsy
Diffuse encephalopathy or deep midline dysfunction (Correct answer)

Correct answer: Diffuse encephalopathy or deep midline dysfunction

FIRDA reflects diffuse cerebral dysfunction or deep midline/diencephalic disturbance and is not a focal or epileptiform finding.

Question 70: The standard recommended duration of the hyperventilation activation procedure in adults is:

3 minutes (Correct answer)
5 minutes
2 minutes
1 minute

Correct answer: 3 minutes

ACNS guidelines recommend 3 minutes of hyperventilation followed by at least 1 minute of post-HV recording to capture delayed responses.

Question 71: Excitatory postsynaptic potentials (EPSPs) at the apical dendrites of cortical pyramidal neurons produce which electrical field at the scalp?

A surface-negative potential directly over the active cortex (Correct answer)
A bipolar field that cancels itself out
A surface-positive potential directly over the active cortex
No measurable potential at the scalp

Correct answer: A surface-negative potential directly over the active cortex

EPSPs at the apical dendrites create a current sink (negative extracellular field) near the cortical surface, producing a surface-negative potential at the overlying scalp electrode.

Question 72: What distinguishes a polyspike-and-wave complex from a single spike-and-wave complex?

Polyspike-and-wave is always focal rather than generalized
Polyspike-and-wave has a slower frequency than single spike-and-wave
Polyspike-and-wave occurs only during REM sleep
Polyspike-and-wave contains multiple spikes (2 or more) preceding the slow wave component (Correct answer)

Correct answer: Polyspike-and-wave contains multiple spikes (2 or more) preceding the slow wave component

Polyspike-and-wave complexes contain a burst of two or more spikes before the slow wave, and are particularly associated with juvenile myoclonic epilepsy and other generalized epilepsies with myoclonic seizures.

Question 73: Triphasic waves with anterior-to-posterior phase lag are most classically associated with which metabolic condition?

Hepatic encephalopathy (Correct answer)
Hyperthyroidism
Hyponatremia
Hypoglycemia

Correct answer: Hepatic encephalopathy

Triphasic waves — high-amplitude, anteriorly dominant complexes with three phases and an anterior-to-posterior time lag — are the classic EEG hallmark of hepatic (portosystemic) encephalopathy, though they can also appear in renal failure and other toxic-metabolic states. Recognizing this pattern and its metabolic context is essential for accurate reporting.

Question 74: A patient with uremic encephalopathy undergoes EEG. Which pattern would be an expected non-epileptiform abnormality in this setting?

Diffuse theta-delta slowing with possible triphasic waves (Correct answer)
Well-organized posterior dominant rhythm
Persistent beta spindle activity
Prominent alpha activity at 10–12 Hz

Correct answer: Diffuse theta-delta slowing with possible triphasic waves

Uremic encephalopathy typically produces diffuse background slowing into the theta and delta ranges, sometimes with triphasic morphology similar to hepatic encephalopathy.

Question 75: In the 10-20 system, which electrode is located at the vertex of the skull?

Cz (Correct answer)
Pz
C3
Fz

Correct answer: Cz

Cz is located at the vertex (top) of the skull at the intersection of the midline and a line connecting the two ears.

Question 76: The cyclic alternating pattern (CAP) in NREM sleep is significant because it:

Indicates Stage REM entry
Marks the onset of Stage N3
Reflects sleep instability and arousal fluctuations (Correct answer)
Confirms absence epilepsy diagnosis

Correct answer: Reflects sleep instability and arousal fluctuations

CAP is a periodic EEG activity during NREM that reflects cyclic arousal oscillations, and elevated CAP rates are associated with fragmented, non-restorative sleep.

Question 77: Which EEG frequency band is most prominent during deep NREM sleep (stage N3)?

Theta (4–8 Hz)
Delta (0.5–4 Hz) (Correct answer)
Beta (13–30 Hz)
Alpha (8–13 Hz)

Correct answer: Delta (0.5–4 Hz)

Stage N3 (slow-wave sleep) is defined by high-amplitude delta waves occupying at least 20% of the epoch.

Question 78: Which electrode placement system is MOST commonly used for ambulatory EEG studies in the United States?

Bipolar longitudinal strip only
Laplacian montage
Queen Square System
10-20 International System (Correct answer)

Correct answer: 10-20 International System

The 10-20 International System is the standard electrode placement system used for ambulatory EEG in the US and most international centers.

Question 79: A patient is in a coma due to a severe metabolic disturbance. The EEG shows generalized, high-amplitude (>70 µV), periodically repeating waves at 1-2 Hz. Each wave has a distinct morphology: a small initial negative deflection, a large surface-positive sharp wave, and a following slow negative wave. This pattern is most consistent with:

Generalized Periodic Discharges (GPDs)
Frontal Intermittent Rhythmic Delta Activity (FIRDA)
Burst-Suppression
Triphasic Waves (Correct answer)

Correct answer: Triphasic Waves

The described morphology—a negative-positive-negative sequence with a dominant surface-positive phase, high amplitude, and periodic recurrence at 1-2 Hz—is the classic definition of triphasic waves. [4, 5] This pattern is strongly associated with metabolic encephalopathy, among other conditions causing altered mental status. [16, 31] While they can be considered a subset of GPDs, the specific triphasic morphology is the most precise answer. FIRDA is typically restricted to the frontal regions and lacks this specific three-phase shape. Burst-suppression consists of periods of high-voltage activity alternating with profound attenuation.

Question 80: What is the modified combinatorial nomenclature (MCN) designation for the traditional T3 electrode position?

T7 (Correct answer)
TP7
FT7
T9

Correct answer: T7

In the modified combinatorial nomenclature system, the traditional T3 position is redesignated as T7, following the logic that odd numbers indicate left hemisphere and the '7' indicates the temporal row position.

Question 81: Which technical factor most directly degrades SSEP and BAEP signal quality by introducing 60 Hz noise and poor signal-to-noise ratio?

Slow stimulus repetition rate
High electrode impedance (Correct answer)
High patient body temperature
Low number of trials averaged

Correct answer: High electrode impedance

High electrode impedance increases susceptibility to capacitively coupled electrical interference (60 Hz), which obscures the small far-field potentials and cannot be fully corrected by averaging.

Question 82: A patient's ambulatory EEG diary notes going to sleep at 22:30. The technologist should expect to see which EEG pattern shortly after this time?

Vertex sharp waves and sleep spindles (Correct answer)
Continuous 10 Hz alpha rhythm
Generalized paroxysmal fast activity
High-amplitude delta with sharp transients suggesting seizure

Correct answer: Vertex sharp waves and sleep spindles

Normal sleep onset is marked by vertex sharp waves (V waves) and sleep spindles (12–14 Hz) during NREM stage N2 sleep.

Question 83: Beta activity (13-30 Hz) on the normal EEG is typically maximal over which brain region?

Parietal regions only
Temporal regions
Occipital regions
Frontal and central regions (Correct answer)

Correct answer: Frontal and central regions

Normal beta activity is most prominent over frontal and central regions, reflecting the activity of frontal cortical networks during alertness and cognitive processing.

Question 84: Anterior dysrhythmia (frontal sharp transients) in a premature neonate at 34 weeks conceptional age is considered:

Always pathological requiring treatment
A normal developmental feature (encoches frontales) expected at this age (Correct answer)
An artifact from eye movements
Evidence of frontal lobe seizure activity

Correct answer: A normal developmental feature (encoches frontales) expected at this age

Anterior dysrhythmia (encoches frontales or frontal sharp transients) is a normal developmental pattern in premature neonates from approximately 34-36 weeks conceptional age, appearing as bilateral frontal sharp waves during quiet sleep.

Question 85: In a bipolar longitudinal montage, what is the typical chain order for the left hemisphere?

Fp1-F7-T3-T5-O1
F3-C3-P3-T3-O1
O1-P3-C3-F3-Fp1
Fp1-F3-C3-P3-O1 (Correct answer)

Correct answer: Fp1-F3-C3-P3-O1

The standard longitudinal bipolar (double banana) chain runs from front to back: Fp1-F3-C3-P3-O1 for the left parasagittal chain.

Question 86: What impedance level is considered acceptable for EEG electrodes before starting a recording?

Below 5,000 ohms (5 kΩ) (Correct answer)
Below 500 ohms
Below 50,000 ohms
Below 100 kΩ

Correct answer: Below 5,000 ohms (5 kΩ)

Electrode impedances should be below 5 kΩ (and ideally matched between electrodes) to ensure low-artifact, high-quality recordings.

Question 87: During a routine EEG, the standard display sensitivity is set to:

7 µV/mm (Correct answer)
50 µV/mm
3 µV/mm
15 µV/mm

Correct answer: 7 µV/mm

The standard display sensitivity for routine EEG is 7 µV/mm, which provides adequate visualization of normal brain rhythms. Sensitivity may be adjusted for high-amplitude (increase µV/mm) or low-amplitude (decrease µV/mm) activity.

Question 88: What EEG response is termed 'photoparoxysmal' during intermittent photic stimulation?

Focal theta slowing over the occipital region
Generalized spike-and-wave or polyspike-and-wave discharges time-locked to flashes (Correct answer)
Posterior dominant rhythm attenuation
Increased beta activity frontally

Correct answer: Generalized spike-and-wave or polyspike-and-wave discharges time-locked to flashes

A photoparoxysmal response consists of generalized epileptiform discharges (spike-wave or polyspike-wave) that are provoked by and time-locked to photic stimulation.

Question 89: Which EEG feature is pathognomonic of N2 sleep and must be present for stage scoring?

Vertex sharp waves
Delta waves >75 µV
Sawtooth waves
Sleep spindles or K-complexes (Correct answer)

Correct answer: Sleep spindles or K-complexes

N2 sleep requires the presence of sleep spindles (12–14 Hz bursts) or K-complexes; delta waves define N3, sawtooth waves occur in REM, and vertex sharps mark N1.

Question 90: A technologist notices the patient begins breathing very slowly and shallowly during hyperventilation. The best action is to:

Increase the flash rate on the photic stimulator simultaneously
Verbally coach the patient to breathe more deeply and consistently (Correct answer)
Stop the test immediately and call a physician
Document it and continue without intervention

Correct answer: Verbally coach the patient to breathe more deeply and consistently

Verbal coaching helps the patient maintain adequate depth and rate of breathing to achieve the desired hypocapnic effect.

Question 91: An artifact appearing as a rhythmic, 1–3 Hz broad, high-amplitude slow-wave pattern that correlates with the patient's assisted ventilation rate is called:

Tremor artifact
Movement artifact
Cardiac artifact
Ventilator artifact (Correct answer)

Correct answer: Ventilator artifact

Ventilator artifact is caused by rhythmic chest and head movement from mechanical ventilation, producing slow waves at the ventilation rate.

Question 92: Informed consent for EEG should include information about which potential discomfort or risk?

Radiation exposure during the recording
Risk of electric shock from the EEG machine
Risk of permanent brain damage from the recording
Skin irritation from electrode adhesive and small possibility of seizure provocation during activation procedures (Correct answer)

Correct answer: Skin irritation from electrode adhesive and small possibility of seizure provocation during activation procedures

Informed consent should cover possible skin irritation from electrode paste or adhesive (collodion), mild discomfort from skin preparation, and the small risk that activation procedures could provoke a seizure in susceptible individuals.

Question 93: Wave with a single deviation from the baseline, either up or down.

Epileptiform
Paroxysmal
Monophasic (Correct answer)
Polyphasic

Correct answer: Monophasic

Monophasic waves have only one deflection from the baseline, either up or down. This indicates that there is just one phase or direction of deflection for the wave. Unlike the other alternatives, it does not contain many phases or deflections (transient, polyphasic, paroxysmal, epileptiform).

Question 94: What is the purpose of the notch filter in EEG recording?

To selectively attenuate 60 Hz (or 50 Hz) power line interference while preserving surrounding frequencies (Correct answer)
To amplify signals at a specific frequency
To eliminate all frequencies above 30 Hz
To boost low-frequency signals for better visualization

Correct answer: To selectively attenuate 60 Hz (or 50 Hz) power line interference while preserving surrounding frequencies

The notch filter is a band-reject filter designed to selectively remove power line interference (60 Hz in North America, 50 Hz in other regions) while minimally affecting adjacent frequencies.

Question 95: An EEG amplifier has a CMRR of 100 dB. This means the amplifier rejects common-mode signals by a factor of approximately:

100,000 times (Correct answer)
100 times
1,000 times
10,000 times

Correct answer: 100,000 times

100 dB CMRR means common-mode signals are rejected by a factor of 10^(100/20) = 100,000 times relative to the differential signal.

Question 96: Which peripheral nerve is most commonly stimulated at the ankle when performing lower extremity somatosensory evoked potential (SSEP) testing?

Posterior tibial nerve (Correct answer)
Common peroneal nerve
Femoral nerve
Sciatic nerve

Correct answer: Posterior tibial nerve

The posterior tibial nerve at the medial ankle is the standard lower extremity stimulus site because it is superficial, easily palpated, and activates large-diameter sensory fibers with reliable cortical responses.

Question 97: What does the '10' and '20' refer to in the International 10-20 system?

Frequency bands measured at each site
Millimeters between electrodes
Number of electrodes in each region
Percentage of total skull distance between electrode sites (Correct answer)

Correct answer: Percentage of total skull distance between electrode sites

The 10 and 20 refer to the percentage of the total front-to-back or left-to-right skull distance used as the spacing between electrode positions.

Question 98: Which EEG pattern in a neonate is characterized by high-amplitude bursts separated by periods of relative quiescence and is considered normal in premature infants?

Delta brushes
Hypsarrhythmia
Trace alternant (Correct answer)
Burst suppression

Correct answer: Trace alternant

Trace alternant is a normal sleep pattern in term and preterm neonates consisting of high-amplitude bursts alternating with lower-amplitude inter-burst intervals.

Question 99: Stimulus-induced rhythmic, periodic, or ictal-looking discharges (SIRPIDs) are important to recognize because they:

Are only seen in outpatient EEG recordings
Indicate the patient is about to have a tonic-clonic seizure
Always require immediate anticonvulsant treatment
May represent a cortical irritability pattern that mimics seizures but occurs in response to stimulation in critically ill patients (Correct answer)

Correct answer: May represent a cortical irritability pattern that mimics seizures but occurs in response to stimulation in critically ill patients

SIRPIDs are rhythmic or periodic patterns triggered by alerting stimuli (suctioning, turning, examination) in critically ill patients. They may mimic seizures but are stimulus-provoked and their treatment significance remains debated.

Question 100: A patient on high-dose phenobarbital for status epilepticus shows a burst-suppression pattern on EEG. Which feature is most characteristic of drug-induced burst suppression compared to anoxic burst suppression?

Bursts are consistently asymmetric between hemispheres
Burst suppression is dose-dependent and reverses as the drug is metabolized (Correct answer)
Suppression periods are always longer than 10 seconds
Delta activity is absent during burst periods

Correct answer: Burst suppression is dose-dependent and reverses as the drug is metabolized

Drug-induced burst suppression (from barbiturates, propofol, or benzodiazepines) is dose-dependent and will improve as serum drug levels fall. Anoxic burst suppression following cardiac arrest is not dose-dependent and carries a far worse prognosis. This distinction is clinically critical for EEG interpretation in the ICU.

Question 101: Delta activity (0.5-4 Hz) in a normal awake adult EEG is considered abnormal because it typically indicates:

Normal arousal response
Cortical dysfunction from structural or metabolic causes (Correct answer)
Enhanced attention and concentration
Increased alpha variant activity

Correct answer: Cortical dysfunction from structural or metabolic causes

In awake adults, delta activity is abnormal and suggests cortical or subcortical dysfunction. Focal delta suggests structural lesion; generalized delta suggests diffuse encephalopathy or deep midline dysfunction.

Question 102: What EEG finding during photic stimulation represents a normal physiological response?

Generalized spike-and-wave complexes
Photic driving response in occipital regions (Correct answer)
Frontal intermittent rhythmic delta activity
Photoparoxysmal response

Correct answer: Photic driving response in occipital regions

Photic driving is a normal response where occipital rhythms entrain to the flash frequency. It represents normal visual cortex reactivity and should not be confused with pathological photoparoxysmal responses.

Question 103: What is the purpose of biological calibration at the beginning of an EEG recording?

To test the patient's cognitive function
To warm up the amplifier circuits
To establish the patient's seizure threshold
To verify that electrodes are properly placed and functioning by observing known physiological signals like alpha blocking (Correct answer)

Correct answer: To verify that electrodes are properly placed and functioning by observing known physiological signals like alpha blocking

Biological calibration uses known physiological signals (alpha rhythm with eye opening/closing, eye movements, muscle artifact) to verify that each electrode is properly placed, has good contact, and is recording genuine brain signals.

Question 104: What is the most effective method for reducing 60 Hz electrical interference artifact?

Increasing the high-frequency filter to 100 Hz
Increasing the recording sensitivity
Ensuring all electrode impedances are balanced and below 5 kOhm (Correct answer)
Switching to a bipolar montage

Correct answer: Ensuring all electrode impedances are balanced and below 5 kOhm

Balanced, low impedances (below 5 kOhm) allow the differential amplifier to effectively reject common-mode 60 Hz noise. Impedance imbalance between electrodes is the primary cause of excessive 60 Hz artifact.

Question 105: TIRDA (Temporal Intermittent Rhythmic Delta Activity) is considered a non-epileptiform abnormality but is clinically significant because it is associated with which condition?

Frontal lobe tumors
Temporal lobe epilepsy (Correct answer)
Metabolic alkalosis
Normal aging

Correct answer: Temporal lobe epilepsy

TIRDA, while not epileptiform itself, is strongly associated with temporal lobe epilepsy and should prompt clinical correlation for seizure disorder.

Question 106: Which of the following must be documented and excluded before an EEG can be interpreted as confirming electrocerebral inactivity?

Electrode impedances below 100 Ω at all sites
Core body temperature above 32°C, absence of CNS depressants, and no severe metabolic disturbance (Correct answer)
Presence of burst suppression for at least 30 minutes
Absence of alpha-frequency activity in posterior regions

Correct answer: Core body temperature above 32°C, absence of CNS depressants, and no severe metabolic disturbance

Before ECI can be considered confirmatory for brain death, reversible causes must be excluded: core temperature must be ≥32°C (hypothermia suppresses EEG), CNS depressant drugs must be absent or below therapeutic levels, and severe metabolic disturbances (e.g., extreme hypoglycemia) must be ruled out.

Question 107: Which neurotransmitter released by basal forebrain neurons desynchronizes the EEG and promotes wakefulness by depolarizing cortical neurons?

Acetylcholine (Correct answer)
Serotonin
Glycine
GABA

Correct answer: Acetylcholine

Basal forebrain cholinergic neurons release acetylcholine onto cortical neurons, causing depolarization and EEG desynchronization characteristic of wakefulness and REM sleep.

Question 108: In a comatose patient, the presence of sleep architecture elements such as sleep spindles or K-complexes on EEG suggests which prognostic implication?

Imminent seizure activity
Relatively preserved thalamocortical function and potentially better prognosis (Correct answer)
Certain poor outcome
Electrocerebral inactivity

Correct answer: Relatively preserved thalamocortical function and potentially better prognosis

Preservation of sleep architecture in coma indicates intact thalamocortical circuitry and generally correlates with a more favorable neurological prognosis.

Question 109: An average reference montage calculates each channel's display by:

Comparing left hemisphere electrodes to right hemisphere
Subtracting the computed average of all electrode voltages from each electrode (Correct answer)
Subtracting the voltage of the nearest neighbor electrode
Using a weighted sum based on electrode distance

Correct answer: Subtracting the computed average of all electrode voltages from each electrode

The average reference uses the arithmetic mean of all active electrodes as the reference point. Each channel displays the difference between one electrode and this common average, providing a relatively neutral reference.

Question 110: A patient's EEG shows slow (1–2.5 Hz) spike-and-wave complexes during sleep alongside atonic and tonic seizures. Which syndrome does this pattern most suggest?

Dravet syndrome
Angelman syndrome
Lennox-Gastaut syndrome (Correct answer)
West syndrome

Correct answer: Lennox-Gastaut syndrome

Lennox-Gastaut syndrome is defined by slow (1–2.5 Hz) spike-and-wave, multiple seizure types including atonic and tonic, and intellectual disability.

Question 111: Which epileptiform feature specifically distinguishes a true spike from a sharp wave on EEG?

Duration less than 70 ms vs. 70–200 ms (Correct answer)
Presence of a following slow wave
Occurrence only during NREM sleep
Amplitude greater than 200 µV

Correct answer: Duration less than 70 ms vs. 70–200 ms

By convention, a spike has a duration of less than 70 ms, whereas a sharp wave has a duration of 70–200 ms; both may be followed by a slow wave.

Question 112: An 8-year-old child presents with frequent staring spells. The EEG recording shows bursts of generalized, synchronous, and symmetric 3 Hz spike-and-wave discharges that are easily provoked by hyperventilation. What is the most likely clinical correlation?

Juvenile myoclonic epilepsy
Benign Rolandic epilepsy
Childhood absence epilepsy (Correct answer)
Lennox-Gastaut syndrome

Correct answer: Childhood absence epilepsy

The classic EEG signature for typical childhood absence epilepsy is generalized, symmetric 3 Hz spike-and-wave discharges, often induced by hyperventilation, which correlates clinically with brief staring spells. Lennox-Gastaut syndrome presents with slow (<2.5 Hz) spike-and-wave, Benign Rolandic epilepsy shows focal centrotemporal spikes, and Juvenile myoclonic epilepsy typically has faster (>3 Hz) polyspike-and-wave discharges.

Question 113: Signal averaging in evoked potential recording improves waveform clarity primarily because:

It eliminates biological noise by randomizing it across trials
It increases the stimulation frequency proportional to the number of averages
It amplifies the stimulus artifact to improve timing reference
The evoked response is time-locked to the stimulus while background EEG cancels out with repeated averaging (Correct answer)

Correct answer: The evoked response is time-locked to the stimulus while background EEG cancels out with repeated averaging

The neural response to each stimulus occurs at a fixed latency (time-locked), so it adds coherently across averages; random background EEG noise is uncorrelated and averages toward zero, improving signal-to-noise ratio.

Question 114: The wicket rhythm is a benign normal variant that can be confused with:

Frontal intermittent rhythmic delta activity
Temporal sharp waves or epileptiform discharges (Correct answer)
Sleep spindles
Occipital spikes

Correct answer: Temporal sharp waves or epileptiform discharges

Wicket spikes (or wicket rhythm) are arch-shaped 6-11 Hz waveforms over the temporal regions that can resemble temporal sharp waves, potentially leading to misdiagnosis of temporal lobe epilepsy if not recognized as benign.

Question 115: The 'N13' potential recorded at the cervical spine (Cv5 or Cv7 electrode) during median nerve SSEP is generated by which structure?

Brachial plexus Erb's point
Primary somatosensory cortex
Dorsal horn/dorsal column nuclei at the cervicomedullary junction (Correct answer)
Ventral posterior lateral thalamus

Correct answer: Dorsal horn/dorsal column nuclei at the cervicomedullary junction

N13 is a stationary far-field potential reflecting synaptic activity at the dorsal column nuclei (cuneate nucleus) in the cervicomedullary junction, serving as an important reference point for central conduction.

Question 116: The K-complex is a normal EEG feature of stage N2 sleep. What is its characteristic morphology?

A high-frequency, low-amplitude spindle
A monophasic positive deflection at the vertex
A negative sharp wave followed by a positive slow component, often superimposed by a spindle (Correct answer)
A series of positive occipital transients

Correct answer: A negative sharp wave followed by a positive slow component, often superimposed by a spindle

A K-complex is a well-delineated negative sharp component followed by a positive slow wave, lasting ≥0.5 s, often with a superimposed sleep spindle.

Question 117: An electrode pop artifact on EEG is characterized by:

Bilateral synchronous sharp waves
Rhythmic activity at 14 Hz
Abrupt, high-amplitude deflection confined to a single channel (Correct answer)
Gradual onset sinusoidal waveform

Correct answer: Abrupt, high-amplitude deflection confined to a single channel

Electrode pop appears as a sudden, high-amplitude spike-like deflection isolated to one channel, caused by abrupt impedance change at a single electrode due to drying gel, poor contact, or mechanical disturbance.

Question 118: What is the standard stimulus rate used when performing pattern reversal visual evoked potentials (VEPs) in a clinical setting?

10–15 reversals/second
0.1–0.5 reversals/second
1–2 reversals/second (Correct answer)
5–8 reversals/second

Correct answer: 1–2 reversals/second

A reversal rate of approximately 1–2 per second (1–2 Hz) is standard for pattern reversal VEPs; faster rates can cause habituation and distort the P100 latency.

Question 119: In a referential montage, an artifact that appears identical in amplitude and polarity on ALL channels simultaneously most likely originates from:

Eye blinks
The reference electrode (Correct answer)
A single scalp electrode
Muscle activity

Correct answer: The reference electrode

When artifact appears on all channels equally in a referential montage, it is localized to the common reference electrode, not the active electrodes.

Question 120: On a neonatal EEG, which feature best distinguishes a seizure discharge from a normal sharp transient?

Amplitude exceeding 100 µV
Presence of a post-ictal suppression lasting 1 second
Occurrence during active sleep
Evolution in frequency, amplitude, or spatial distribution over time (Correct answer)

Correct answer: Evolution in frequency, amplitude, or spatial distribution over time

Neonatal seizures are defined by electrographic evolution — a clear change in frequency, morphology, or field — rather than by a fixed amplitude or sleep-state rule.

Question 121: An EEG technologist discovers that a colleague has been omitting seizure events from written reports to speed up throughput. What is the most appropriate course of action?

Confront the colleague privately and ask them to stop
Begin correcting the colleague's reports without disclosure
Ignore it since the interpreting physician will catch any errors
Report the concern through the facility's established chain of command or compliance channel (Correct answer)

Correct answer: Report the concern through the facility's established chain of command or compliance channel

Omitting clinical data is an ethical and potentially legal violation requiring formal reporting through proper institutional channels.

Question 122: What is the most appropriate low-frequency filter setting when recording neonatal EEG to capture slow cerebral activity?

30 Hz
5 Hz
1 Hz (Correct answer)
10 Hz

Correct answer: 1 Hz

A low-frequency filter of 1 Hz (or lower) is used in neonatal EEG to preserve slow background activity that is characteristic of the immature brain.

Question 123: A technologist is reviewing an EEG on a digital system and wants to enhance the visualization of a very localized, focal discharge while minimizing the influence from distant, widespread activity. Which montage would be the most appropriate choice?

Laplacian montage (Correct answer)
Longitudinal bipolar montage
Contralateral ear reference montage
Average reference montage

Correct answer: Laplacian montage

The Laplacian montage, also known as a source derivation or local average reference, is specifically designed to highlight focal activity. It calculates the voltage at each electrode relative to a weighted average of its immediate surrounding electrodes. This technique enhances localized events and reduces the effect of widespread or distant electrical fields.

Question 124: According to the 10-20 International System nomenclature, which electrode would be located over the left mid-temporal region?

C3
T4
Pz
T3 (Correct answer)

Correct answer: T3

In the 10-20 system, the letter indicates the underlying brain region ('T' for Temporal) and the number indicates the hemisphere. Odd numbers are used for the left hemisphere and even numbers for the right hemisphere. 'z' denotes the midline. Therefore, T3 is the electrode over the left mid-temporal region.

Question 125: Photomyogenic (photomyoclonic) response, which can mimic a photoparoxysmal response, differs in that it:

Outlasts the stimulus train
Consists of generalized spike-wave discharges
Begins with a posterior predominance
Is frontally predominant muscle artifact time-locked to each flash (Correct answer)

Correct answer: Is frontally predominant muscle artifact time-locked to each flash

Photomyogenic response is a muscle artifact (frontalis/orbicularis) synchronized to each photic flash, whereas photoparoxysmal response is a true cerebral epileptiform discharge that may outlast the stimulus.

Question 126: Which of the following best describes the neurophysiological basis for why a minimum cortical area of approximately 6-20 cm² must be synchronously activated to generate a detectable scalp EEG signal?

The requirement for bilateral hemispheric involvement for any recordable potential
The specific firing frequency of pyramidal neurons
The high electrical impedance of the cerebrospinal fluid
The filtering effect of the skull and scalp, which attenuates small or asynchronous signals (Correct answer)

Correct answer: The filtering effect of the skull and scalp, which attenuates small or asynchronous signals

The skull, dura, and scalp act as low-pass filters and have high electrical resistance, a process known as volume conduction. This significantly attenuates the electrical potentials generated by the brain. Therefore, a large area of cortex with thousands of neurons firing synchronously is required to produce a signal strong enough to overcome this impedance and be detected by scalp electrodes.

Question 127: During the transition from wakefulness to drowsiness, the expected EEG changes include:

Attenuation of the posterior dominant rhythm with appearance of diffuse theta activity and slow rolling eye movements (Correct answer)
Increase in alpha amplitude and frequency
Increase in beta activity throughout
Appearance of generalized sharp waves

Correct answer: Attenuation of the posterior dominant rhythm with appearance of diffuse theta activity and slow rolling eye movements

The wake-to-drowsiness transition is marked by progressive attenuation of the posterior dominant rhythm (alpha dropout), replacement by diffuse low-amplitude theta activity, slow lateral eye movements, and eventually vertex sharp waves marking Stage N1.

Question 128: Which activation procedure is most effective for provoking absence seizures during a routine EEG?

Sleep deprivation
Intermittent photic stimulation
Cold water caloric testing
Hyperventilation (Correct answer)

Correct answer: Hyperventilation

Hyperventilation is the most effective provocative maneuver for absence seizures, eliciting 3 Hz spike-and-wave discharges in approximately 80-90% of patients with untreated typical absence epilepsy.

Question 129: Which of the following non-epileptiform patterns is characterized by its location over the sensorimotor cortex, a frequency of 8-10 Hz, an arciform or comb-like morphology, and its attenuation with contralateral limb movement or the thought of movement?

Mu Rhythm (Correct answer)
Rhythmic Mid-Temporal Theta of Drowsiness (RMTD)
Posterior Dominant Rhythm (Alpha)
Lambda Waves

Correct answer: Mu Rhythm

The Mu rhythm is the idling rhythm of the sensorimotor cortex. It is defined by its central location (C3, Cz, C4), alpha-range frequency (typically 8-10 Hz), arc-like shape, and its unique reactivity—it blocks or attenuates with contralateral motor activity, imagined motor activity, or tactile stimulation, but not with eye-opening. [21, 29, 39]

Question 130: AAN guidelines recommend that ECI be recorded for a minimum duration of how many minutes of technically satisfactory tracing?

60 minutes
20 minutes
30 minutes (Correct answer)
10 minutes

Correct answer: 30 minutes

A minimum of 30 minutes of technically adequate recording is required. This duration helps ensure that any intermittent low-amplitude cerebral activity is not missed due to sampling too brief a window, and it provides a sufficient record for independent clinical review.

Question 131: In a healthy, awake adult, the presence of excessive, generalized, and persistent theta activity (4-7 Hz) would most likely be interpreted as:

Evidence of cerebral dysfunction. (Correct answer)
A normal variant during hyperventilation.
A normal posterior dominant rhythm.
An indicator of deep relaxation.

Correct answer: Evidence of cerebral dysfunction.

While small amounts of theta activity can be normal, especially during drowsiness, excessive and persistent generalized theta activity in an awake adult is considered abnormal. It is a nonspecific indicator of generalized cerebral dysfunction or encephalopathy.

Question 132: Slow, sinusoidal, high-amplitude waves that wax and wane over frontal electrodes in a drowsy, diaphoretic patient are most characteristic of:

Eye movement artifact
Sweat artifact (Correct answer)
Muscle artifact
Delta slowing

Correct answer: Sweat artifact

Sweat artifact produces slow (< 1 Hz), large-amplitude sinusoidal waves predominantly over frontal regions due to sweat gland activity.

Question 133: According to the American Clinical Neurophysiology Society (ACNS) guidelines, interelectrode impedances should be within what range for a standard EEG recording?

Exactly 5,000 Ohms (5 kOhms)
Below 100 Ohms
Above 50,000 Ohms (50 kOhms)
Between 100 Ohms and 10,000 Ohms (10 kOhms) (Correct answer)

Correct answer: Between 100 Ohms and 10,000 Ohms (10 kOhms)

ACNS guidelines state that interelectrode impedances should be under 10,000 Ohms (10 kOhms) but over 100 Ohms. Impedances that are too high can lead to increased noise and artifact, while impedances below 100 Ohms may suggest a salt bridge or short circuit between electrodes. While values under 5 kOhms are often recommended, the acceptable range is up to 10 kOhms.

Question 134: The synchronization of cortical neurons necessary to produce normal resting rhythms and abnormal discharges like generalized spike-and-wave is heavily dependent on the integrity of:

Corticospinal tracts
The fornix and limbic pathways
Corticothalamic circuits (Correct answer)
Corpus callosum pathways

Correct answer: Corticothalamic circuits

Corticothalamic circuits, the reciprocal connections between the cortex and the thalamus, are fundamental for synchronizing neuronal activity across large brain regions. These circuits are responsible for pacing normal rhythms like sleep spindles and the alpha rhythm, and their dysfunction is implicated in the generation of widespread, synchronized discharges seen in generalized epilepsies.

Question 135: The posterior dominant rhythm (PDR) in a healthy 8-year-old child is expected to have a frequency of approximately:

6-7 Hz
11-12 Hz
4-5 Hz
9 Hz (Correct answer)

Correct answer: 9 Hz

The frequency of the posterior dominant rhythm matures with age. It starts around 3-4 Hz in infants, reaches 8 Hz by about age 3, and typically achieves a frequency of 9 Hz by age 8. It stabilizes in the adult alpha range of 8-13 Hz in the early teen years.

Question 136: The posterior dominant rhythm (alpha rhythm) in a normal awake adult is generated primarily by which brain structure interaction?

Basal ganglia output to frontal cortex
Thalamocortical circuits involving the thalamus and occipital cortex (Correct answer)
Hippocampal-entorhinal connections
Brainstem reticular formation alone

Correct answer: Thalamocortical circuits involving the thalamus and occipital cortex

The alpha rhythm arises from synchronized oscillations in thalamocortical loops, with the thalamic relay nuclei (particularly the pulvinar and lateral geniculate) pacing cortical neurons in the occipital visual cortex.

Question 137: The time constant of an EEG amplifier determines:

The number of channels that can record simultaneously
How quickly the amplifier reaches maximum gain
The maximum amplitude the amplifier can display
The rate at which a DC-shifted signal decays back to baseline through the low-frequency filter (Correct answer)

Correct answer: The rate at which a DC-shifted signal decays back to baseline through the low-frequency filter

The time constant represents the time it takes for a DC-shifted square wave calibration signal to decay to 37% of its initial value. It is directly related to the low-frequency filter setting.

Question 138: During a routine EEG on a 25-year-old patient, the technologist observes intermittent bursts of 7-11 Hz, arch-shaped waves over the central head regions (C3, C4, Cz). This activity disappears when the patient is asked to make a fist. What normal EEG variant is being described?

Sleep spindles
Posterior slow waves of youth
Mu rhythm (Correct answer)
Lambda waves

Correct answer: Mu rhythm

The Mu rhythm is a normal variant found in the alpha frequency range (typically 7-11 Hz) with a characteristic arch-like or comb shape. It is located over the central regions (sensorimotor cortex) and is uniquely blocked or attenuated by contralateral motor activity, the thought of movement, or tactile stimulation, but not by eye opening.

Question 139: The common mode rejection ratio (CMRR) of an EEG differential amplifier measures its ability to:

Maintain constant impedance across all electrodes
Amplify all signals equally across the frequency spectrum
Reject signals that are identical at both inputs while amplifying their difference (Correct answer)
Filter out frequencies above 70 Hz

Correct answer: Reject signals that are identical at both inputs while amplifying their difference

CMRR quantifies how effectively the differential amplifier rejects common-mode signals (those appearing equally at both inputs, such as 60 Hz noise) while preserving the differential signal (brain activity).

Question 140: During a recording of a 25-year-old patient in light sleep, the technologist observes trains of 6-11 Hz arc-shaped (arciform), monophasic waves in the left temporal region. They occur without disrupting the background and are not followed by a slow wave. They sometimes appear as single transients that resemble sharp waves. This pattern is best described as:

Benign Small Sharp Spikes (BSSS/BETS)
Lambda Waves
Wicket Spikes (Correct answer)
Mu Rhythm

Correct answer: Wicket Spikes

Wicket spikes are defined as 6-11 Hz, arc-shaped (arciform), monophasic waves that occur in the temporal regions, especially during drowsiness and light sleep. [2, 35] They can appear in trains or as single transients, which can be easily mistaken for epileptiform sharp waves, but they lack an after-going slow wave and do not disturb the background activity. [33, 35] Mu rhythm is found over the central region and is related to motor activity. [21, 29] BSSS/BETS are lower in amplitude and shorter in duration. [12] Lambda waves are occipital and occur during wakefulness with visual scanning. [1, 38]

Question 141: The lambda wave is a positive sharp transient that occurs in the occipital region during:

Active visual scanning of a complex image or environment (Correct answer)
Eye closure in a dark room
Hyperventilation
Deep sleep stage N3

Correct answer: Active visual scanning of a complex image or environment

Lambda waves are positive sharp transients over the occipital regions that occur during visual scanning with saccadic eye movements. They represent cortical responses to visual input during active looking.

Question 142: When performing EEG on a patient with an implanted cardiac defibrillator (ICD), the technologist should:

Refuse to perform the study as it is absolutely contraindicated
Only use 4 electrodes to minimize electromagnetic interference
Proceed with the study using standard technique, as EEG does not interfere with ICDs, but be aware the ICD may produce artifact on the ECG channel (Correct answer)
Deactivate the ICD before starting the recording

Correct answer: Proceed with the study using standard technique, as EEG does not interfere with ICDs, but be aware the ICD may produce artifact on the ECG channel

EEG is safe to perform on patients with ICDs as EEG equipment does not generate electromagnetic fields that could interfere with the device. The ICD may produce artifact on the ECG channel that should be recognized.

Question 143: What should an ambulatory EEG patient do when experiencing a suspected seizure or event?

Press the event marker button and keep an event diary (Correct answer)
Disconnect and reconnect the recording device
Call the EEG technologist to come verify the recording
Remove the electrodes immediately

Correct answer: Press the event marker button and keep an event diary

Patients are instructed to press the event marker button on the ambulatory device and record the event details (time, symptoms, activity) in their diary, enabling correlation of clinical events with EEG data.

Question 144: Gamma oscillations (>30 Hz) in the normal EEG are most associated with which cognitive state?

REM sleep only
Deep sleep
High-level cognitive processing and sensory binding (Correct answer)
Drowsiness

Correct answer: High-level cognitive processing and sensory binding

Gamma oscillations are linked to higher cognitive functions such as attention, working memory, and cross-modal sensory binding.

Question 145: Which VEP component is most commonly used clinically to detect demyelinating disease of the optic nerve?

P200
N145
P100 (Correct answer)
N75

Correct answer: P100

The P100 component of the VEP is the most clinically relevant peak; a delayed latency (>115 ms) strongly suggests optic nerve demyelination.

Question 146: Which electrode placement best captures activity from the temporal lobe?

T3/T4 (T7/T8) (Correct answer)
P3/P4
F3/F4
O1/O2

Correct answer: T3/T4 (T7/T8)

T3/T4 (now called T7/T8 in the revised system) are positioned over the temporal lobes and best capture temporal lobe activity.

Question 147: Sweat artifact on EEG typically presents as:

Very slow, undulating baseline shifts in the delta or sub-delta frequency range (Correct answer)
High-frequency beta activity over central regions
Sharp spike-like transients at all electrodes simultaneously
Rhythmic 14 Hz activity at temporal electrodes

Correct answer: Very slow, undulating baseline shifts in the delta or sub-delta frequency range

Sweat artifact produces slow, rolling baseline undulations (typically <1 Hz) caused by changes in skin potential and electrode impedance from perspiration, often appearing as very slow waves that can obscure underlying EEG activity.

Question 148: What is the typical duration criterion for an EEG spike?

Less than 20 milliseconds
20 to 70 milliseconds (Correct answer)
70 to 200 milliseconds
200 to 500 milliseconds

Correct answer: 20 to 70 milliseconds

By IFCN definition, a spike has a duration of 20 to 70 milliseconds, distinguishing it from sharp waves which last 70 to 200 milliseconds.

Question 149: When a cEEG technologist notes an abrupt change from background suppression to high-amplitude rhythmic activity during routine care in an ICU patient, what is the FIRST appropriate step?

Immediately administer IV lorazepam
Discontinue cEEG and obtain an urgent CT head
Increase the high-frequency filter to remove artifact
Notify the interpreting neurologist and document the clinical state at onset (Correct answer)

Correct answer: Notify the interpreting neurologist and document the clinical state at onset

The technologist's immediate responsibility is to alert the interpreting neurologist and document concurrent clinical findings; treatment decisions are made by the physician after EEG review.

Question 150: What is the standard calibration signal used to verify EEG amplifier function?

A 50 µV square wave at 1 Hz (Correct answer)
A 200 µV sine wave at 60 Hz
A 100 µV triangle wave at 5 Hz
A 10 µV sine wave at 10 Hz

Correct answer: A 50 µV square wave at 1 Hz

The standard calibration signal is a 50 µV square wave at 1 Hz. This verifies amplifier gain accuracy, frequency response, and channel matching across the system.

Question 151: A technologist is reviewing an EEG from an awake patient who was asked to scan a complex image. The recording shows bilateral, positive, sharply contoured waves in the occipital channels that occur only during the visual scanning task. These waveforms are most likely:

Lambda waves (Correct answer)
Positive Occipital Sharp Transients of Sleep (POSTS)
Epileptiform discharges
Vertex waves

Correct answer: Lambda waves

Lambda waves are normal, waking phenomena that are time-locked to saccadic eye movements, such as those that occur during visual scanning or reading. They are characteristically positive in polarity, have a sharp or triangular shape, and are located in the occipital regions.

Question 152: Vertex sharp waves (V waves) during drowsiness are maximally recorded at which electrode position?

T3 and T4
Fp1 and Fp2
O1 and O2
Cz (Correct answer)

Correct answer: Cz

Vertex sharp waves are high-amplitude, surface-negative sharp transients maximal at the vertex (Cz electrode) that appear during drowsiness and Stage N1 sleep as a normal finding.

Question 153: The 'mu rhythm' seen over the central scalp in a relaxed, awake subject has a frequency overlapping with which other rhythm?

Delta
Theta
Alpha (Correct answer)
Gamma

Correct answer: Alpha

The mu rhythm (8–13 Hz) overlaps the alpha frequency band but is maximal over central (C3/C4) rather than occipital electrodes.

Question 154: Breach rhythm is a normal consequence of a skull defect that appears as:

Focal delta slowing at the site of the defect
Higher-amplitude, sharper-appearing activity over the skull defect due to reduced signal attenuation by bone (Correct answer)
Generalized voltage attenuation across all electrodes
Loss of all electrical activity over the affected area

Correct answer: Higher-amplitude, sharper-appearing activity over the skull defect due to reduced signal attenuation by bone

Breach rhythm occurs when a skull defect (craniotomy, fracture) removes the attenuating and filtering effect of bone, allowing higher-amplitude, faster, sharper-appearing activity to be recorded from the overlying electrode.

Question 155: When a square wave calibration signal shows 'ringing' or oscillations after the rising edge, this most likely indicates:

The amplifier gain is set too high
The electrode impedance is too low
The high-frequency filter cutoff is set too high, allowing high-frequency resonance (Correct answer)
The low-frequency filter cutoff is set too high

Correct answer: The high-frequency filter cutoff is set too high, allowing high-frequency resonance

Ringing after the rising edge of a square wave indicates the high-frequency filter cutoff is set too high, allowing the amplifier to pass and amplify resonant high-frequency components at the step transition.

Question 156: Which artifact appears as a regular, rhythmic waveform at the same frequency as the patient's heart rate?

Pulse artifact (ECG artifact) (Correct answer)
Eye blink artifact
Electrode pop
Glossokinetic artifact

Correct answer: Pulse artifact (ECG artifact)

Pulse artifact appears as rhythmic waveforms synchronous with the cardiac cycle, caused by electrode placement over a pulsating blood vessel or by ballistocardiographic effect.

Question 157: In childhood absence epilepsy, the typical ictal EEG discharge consists of:

Focal theta with phase reversal
Fast (>10 Hz) rhythmic activity
2 Hz spike-and-wave
3 Hz spike-and-wave (Correct answer)

Correct answer: 3 Hz spike-and-wave

Childhood absence epilepsy is characterized by generalized, symmetric 3 Hz (2.5–4 Hz) spike-and-wave complexes that are abrupt in onset and termination.

Question 158: What is the typical voltage (amplitude) range of normal alpha waves recorded from the scalp?

500–1000 µV
5–10 µV
20–200 µV (Correct answer)
200–500 µV

Correct answer: 20–200 µV

Alpha waves normally range from about 20 to 200 µV in amplitude when recorded from scalp electrodes.

Question 159: Which artifact would most likely appear as a high-amplitude, low-frequency deflection time-locked to the R-wave on ECG?

Sweat artifact
Chewing artifact
Electrode pop
Pulse artifact (Correct answer)

Correct answer: Pulse artifact

Pulse artifact is caused by scalp vessel pulsations under electrodes and appears as slow deflections synchronous with the cardiac cycle.

Question 160: Occipital intermittent rhythmic delta activity (OIRDA) in a child is most commonly associated with:

Medication effect from stimulants
Normal aging
Frontal lobe lesion
Childhood absence epilepsy or posterior fossa pathology (Correct answer)

Correct answer: Childhood absence epilepsy or posterior fossa pathology

OIRDA in children is most commonly associated with childhood absence epilepsy (where it may be an early finding before typical 3 Hz spike-and-wave develops) or with posterior fossa structural lesions.

Question 161: What is the maximum recommended electrode impedance for routine EEG recording according to ACNS guidelines?

1 kOhm
10 kOhm
5 kOhm (Correct answer)
20 kOhm

Correct answer: 5 kOhm

The American Clinical Neurophysiology Society recommends electrode impedances be below 5 kOhm and balanced across all electrodes to optimize signal quality and common-mode rejection.

Question 162: Which electrode site is used as the nasion landmark in the 10-20 measurement system?

The tip of the nose
The center of the forehead
The bridge of the nose between the eyes (Correct answer)
The glabella above the nose

Correct answer: The bridge of the nose between the eyes

The nasion is the depression at the bridge of the nose between the eyes and serves as the anterior skull landmark for 10-20 measurements.

Question 163: During an EEG-recorded absence seizure, the 3 Hz spike-and-wave discharge is generated by abnormal oscillations between the cortex and which structure?

Hippocampus
Thalamus (Correct answer)
Cerebellum
Basal ganglia

Correct answer: Thalamus

Absence seizures arise from abnormal thalamocortical resonance, with cortical and thalamic circuits entraining at ~3 Hz spike-and-wave frequency.

Question 164: Benzodiazepine administration typically produces which EEG change that a technologist should recognize and document?

Suppression of all activity below 1 Hz
Prominent generalized theta slowing without faster activity
Increase in frontocentral beta activity (14–30 Hz) (Correct answer)
Appearance of triphasic waves over frontal regions

Correct answer: Increase in frontocentral beta activity (14–30 Hz)

Benzodiazepines (and other GABA-A agonists such as barbiturates at sub-anesthetic doses) characteristically increase fast-frequency beta activity, most prominent over frontocentral regions. Recognizing drug-induced beta prevents misinterpretation as normal or abnormal endogenous activity.

Question 165: In the International 10-20 system, what do the numbers 10 and 20 represent?

The number of electrodes used
The percentage of distance between skull landmarks for electrode placement (Correct answer)
The amplifier gain settings
The impedance levels required in kilohms

Correct answer: The percentage of distance between skull landmarks for electrode placement

The 10-20 system places electrodes at 10% and 20% intervals of the measured distances between standardized skull landmarks (nasion, inion, preauricular points).

Question 166: Which filter setting should be used to reduce sweat artifact (very slow baseline drift) without significantly affecting EEG frequencies of interest?

Enable the 60 Hz notch filter
Increase the high-frequency filter cutoff to 70 Hz
Decrease the time constant (increase the low-frequency filter cutoff) (Correct answer)
Decrease the sensitivity to 10 µV/mm

Correct answer: Decrease the time constant (increase the low-frequency filter cutoff)

Sweat artifact is a very low-frequency (sub-1 Hz) drift; decreasing the time constant (raising the low-frequency filter) attenuates these slow potentials while preserving standard EEG frequencies.

Question 167: Which scenario represents an appropriate use of physical restraint during a pediatric EEG?

Using a papoose board with parental consent and physician order when medically necessary and less restrictive methods have failed (Correct answer)
Restraining a cooperative child simply to shorten setup time
Applying wrist restraints routinely to prevent electrode displacement in all children under age 5
Using restraints whenever a child cries during electrode application

Correct answer: Using a papoose board with parental consent and physician order when medically necessary and less restrictive methods have failed

Restraint requires a physician order, parental consent, documented failure of alternatives, and must be the least restrictive option necessary.

Question 168: Which of the following flash frequencies used in intermittent photic stimulation (IPS) is most likely to elicit a photoparoxysmal response in photosensitive individuals?

1–2 Hz
3–5 Hz
15–20 Hz (Correct answer)
50 Hz

Correct answer: 15–20 Hz

Frequencies between approximately 15–20 Hz are the most common range for provoking photoparoxysmal responses in photosensitive patients.

Question 169: Positive occipital sharp transients of sleep (POSTS) are a normal variant that appear during which sleep stage?

REM sleep only
Stage N2 and N3
Stage N2, N3, and sometimes REM (Correct answer)
Stage N1 only

Correct answer: Stage N2, N3, and sometimes REM

POSTS are surface-positive sharp transients over the occipital regions seen in stage N2, N3, and sometimes REM sleep.

Question 170: An EEG recording shows a sudden, very high-amplitude, brief transient that is strictly confined to a single channel. The transient does not have a physiological field and is not time-locked to any other event. What is the most likely cause?

An electrode artifact ('pop') (Correct answer)
An epileptiform spike
A photic driving response
An EKG artifact

Correct answer: An electrode artifact ('pop')

The key features are its confinement to a single electrode and the lack of a physiological field (i.e., it doesn't appear in adjacent channels). This is the classic presentation of an electrode artifact, often called an 'electrode pop,' which is caused by a sudden, unstable change in impedance at that one site.

Question 171: In a longitudinal bipolar montage, often called a 'double banana', how are the electrodes connected?

To a single common reference electrode, such as the vertex (Cz).
In chains running from anterior to posterior regions of the head. (Correct answer)
In chains running from the left to the right side of the head.
Each electrode is compared to a weighted average of its surrounding electrodes.

Correct answer: In chains running from anterior to posterior regions of the head.

The longitudinal bipolar montage, or 'double banana', consists of chains of electrodes linked from front to back. For example, a temporal chain might connect Fp1-F7, F7-T3, T3-T5, and T5-O1. This arrangement is excellent for identifying phase reversals, which help localize the source of an abnormality between two adjacent electrodes.

Question 172: The perisylvian language network includes Broca's area (IFG) and Wernicke's area connected by the arcuate fasciculus. EEG-based language mapping uses which technique to identify these regions before epilepsy surgery?

Photic driving response analysis
Routine scalp EEG with hyperventilation
Electrocorticography (ECoG) with cortical stimulation mapping (Correct answer)
Z-score normalization of alpha power

Correct answer: Electrocorticography (ECoG) with cortical stimulation mapping

Electrocorticography with direct cortical stimulation (extraoperative or intraoperative) is the gold-standard EEG-based method to map language-eloquent cortex before resection.

Question 173: During an EEG recording, a technologist notices significant 60 Hz artifact across all channels. Which of the following instrument settings should be adjusted to specifically target and reduce this type of interference?

Low-Frequency Filter
High-Frequency Filter
Sensitivity
Notch Filter (Correct answer)

Correct answer: Notch Filter

The Notch Filter is specifically designed to attenuate a very narrow band of frequencies. In North America, this is set to 60 Hz to eliminate interference from the AC electrical power lines. It should be used judiciously as it can sometimes distort clinically relevant activity near that frequency.

Question 174: Stimulus-induced rhythmic, periodic, or ictal discharges (SIRPIDs) are significant in cEEG monitoring because they:

Indicate electrode malfunction
May represent seizures triggered by external stimulation and affect care decisions (Correct answer)
Are always benign and require no intervention
Occur only in patients with prior epilepsy

Correct answer: May represent seizures triggered by external stimulation and affect care decisions

SIRPIDs are pathological EEG discharges provoked by external stimuli (tactile, auditory) and their clinical significance — whether ictal or interictal — must be assessed to guide treatment.

Question 175: What is the primary safety concern when performing EEG on a patient in the ICU with external ventricular drains?

Risk of photic-induced seizures
Need for sedation during the recording
Risk of infection or displacement of the drain during electrode application (Correct answer)
Interference from the drain's electrical signal

Correct answer: Risk of infection or displacement of the drain during electrode application

Electrode application near external ventricular drains (EVDs) poses risks of infection (introducing pathogens near the surgical site) and mechanical displacement of the drain. Careful coordination with nursing and neurosurgery is essential.

Question 176: Which of the following is a contraindication for performing hyperventilation during an EEG?

History of febrile seizures
Recent cerebrovascular accident (Correct answer)
History of generalized tonic-clonic seizures
Age over 40 years

Correct answer: Recent cerebrovascular accident

Recent stroke is a contraindication for hyperventilation because the resulting hypocapnia and cerebral vasoconstriction could worsen ischemia in vulnerable brain tissue.

Question 177: Generalized rhythmic delta activity (GRDA) persisting despite stimulation is most suggestive of which condition compared to GRDA that attenuates with stimulation?

GRDA that persists is more benign; GRDA that attenuates indicates seizure
GRDA that persists is more likely ictal; GRDA that attenuates is more likely non-ictal (Correct answer)
Both have identical clinical significance
Persistence indicates artifact only

Correct answer: GRDA that persists is more likely ictal; GRDA that attenuates is more likely non-ictal

GRDA that does not attenuate with stimulation (non-reactive) raises concern for ictal or peri-ictal activity, while stimulus-induced attenuation suggests non-epileptiform encephalopathy.

Question 178: What is the upper limit of normal for the interpeak latency I–V (IPL I–V) in BAEPs recorded from a typical adult?

Less than 2.0 ms
Less than 3.0 ms
Less than 4.4 ms (Correct answer)
Less than 6.0 ms

Correct answer: Less than 4.4 ms

The IPL I–V, representing total brainstem conduction time, normally does not exceed approximately 4.4 ms; values beyond this suggest central conduction slowing.

Question 179: A high-amplitude, sharply contoured discharge that appears only in a single channel and does not violate the "neighbor rule" of field spread is most likely:

A breach rhythm
An electrode artifact (Correct answer)
A vertex sharp wave
A focal interictal epileptiform discharge

Correct answer: An electrode artifact

True cerebral discharges have plausible electrical fields involving neighboring electrodes, so an isolated single-channel transient without field spread is likely artifactual.

Question 180: The recommended minimum number of EEG channels for a routine clinical recording is:

64 channels
32 channels
8 channels
16 channels (plus ECG, EOG) (Correct answer)

Correct answer: 16 channels (plus ECG, EOG)

The ACNS recommends a minimum of 16 EEG channels for routine clinical recording, derived from 21 electrodes in the 10-20 system, plus additional channels for ECG, EOG, and other polygraphic recordings.

Question 181: An EEG showing continuous generalized polymorphic delta slowing with no clear faster frequencies in a patient with altered consciousness most likely indicates what?

Severe diffuse cortical dysfunction (Correct answer)
REM sleep
Normal drowsiness pattern
Stage 3 NREM sleep

Correct answer: Severe diffuse cortical dysfunction

Continuous generalized polymorphic delta without faster activity in a wakeful patient indicates severe diffuse encephalopathy affecting cortical function.

Question 182: An ambulatory EEG recording shows a sudden onset of 3 Hz spike-and-wave discharges lasting 12 seconds, coinciding with the patient pressing the event button. This is MOST consistent with:

A typical absence seizure (Correct answer)
A generalized tonic-clonic seizure
A psychogenic non-epileptic seizure
A focal onset impaired awareness seizure

Correct answer: A typical absence seizure

Classic 3 Hz generalized spike-and-wave lasting approximately 10–15 seconds with preserved consciousness is the hallmark of typical absence seizures.

Question 183: During polysomnography, the minimum duration of a K-complex to be scored as such is:

1.0 second
2.0 seconds
0.25 seconds
0.5 seconds (Correct answer)

Correct answer: 0.5 seconds

Per AASM scoring rules, a K-complex must have a duration of ≥0.5 seconds to be distinguished from other sharp transients.

Question 184: During a routine EEG, the patient closes his eyes and 10 Hz activity appears posteriorly. When he opens his eyes this activity disappears. This is consistent with:

Normal alpha rhythm with eye-opening attenuation (Correct answer)
Posterior slow waves of youth
Breach rhythm
Occipital seizure activity

Correct answer: Normal alpha rhythm with eye-opening attenuation

Alpha rhythm (8–13 Hz) generated in the occipital cortex is reactive to eye opening and represents a normal, awake, relaxed EEG finding.

Question 185: In VEP testing, what is the main reason each eye is tested separately with the other eye patched?

To prevent binocular rivalry artifacts
To isolate each optic nerve's conduction independently (Correct answer)
To improve signal averaging efficiency
To reduce electrical interference between eyes

Correct answer: To isolate each optic nerve's conduction independently

Monocular testing isolates the optic nerve pathway anterior to the chiasm, allowing detection of unilateral demyelination or compressive lesions of a single optic nerve.

Question 186: An EEG technologist notes that a patient's EEG shows generalized high-amplitude rhythmic delta with superimposed faster frequencies. The patient's chart indicates a blood glucose of 28 mg/dL. The MOST likely explanation for this EEG pattern is:

Nonconvulsive status epilepticus
Benzodiazepine overdose
Hypoglycemic encephalopathy producing diffuse metabolic slowing (Correct answer)
Subcortical ischemia from a posterior circulation stroke

Correct answer: Hypoglycemic encephalopathy producing diffuse metabolic slowing

Severe hypoglycemia deprives neurons of their primary energy substrate, producing diffuse encephalopathy with EEG slowing ranging from theta to delta frequencies, often with high amplitude. This metabolic encephalopathy reverses rapidly with glucose correction. The clinical context (blood glucose 28 mg/dL) makes this the most parsimonious explanation.

Question 187: A patient's EEG recording shows a focal discharge. To best define the point of maximum electronegativity and pinpoint the origin of the activity, which type of montage is most effective?

Transverse bipolar montage
Laplacian montage
Referential montage (Correct answer)
Bipolar 'double banana' montage

Correct answer: Referential montage

Referential montages compare the voltage of each scalp electrode to a single, common reference point. This configuration is particularly useful for determining the electrode with the highest amplitude abnormality, which helps to clarify the point of maximal electronegativity when it might be unclear on a bipolar view.

Question 188: In a BAEP recording, absent Wave I with relatively preserved Waves III and V most likely indicates pathology at which level?

Cochlea or cochlear nerve peripheral to the brainstem (Correct answer)
Cochlear nucleus in the lower brainstem
Inferior colliculus
Superior olivary complex

Correct answer: Cochlea or cochlear nerve peripheral to the brainstem

Wave I reflects the distal cochlear nerve action potential; its absence with central waves preserved indicates peripheral auditory dysfunction (cochlea or nerve), not brainstem pathology.

Question 189: Which cortical cell type is the primary generator of EEG signals recorded at the scalp?

Pyramidal neurons in cortical layers III and V (Correct answer)
Motor neurons of the precentral gyrus
Stellate interneurons
Purkinje cells of the cerebellum

Correct answer: Pyramidal neurons in cortical layers III and V

Pyramidal neurons are the primary generators of scalp EEG because their elongated apical dendrites are oriented perpendicular to the cortical surface, creating open electrical fields that summate and can be detected at the scalp.

Question 190: What infection control measure is required when applying reusable EEG electrodes between patients?

Electrodes only need cleaning if visible contamination is present
Rinsing electrodes with tap water is sufficient
Electrodes must be disinfected or sterilized according to facility protocol between each patient (Correct answer)
Alcohol wipe of the electrode surface is the only requirement

Correct answer: Electrodes must be disinfected or sterilized according to facility protocol between each patient

Reusable EEG electrodes must undergo proper disinfection or sterilization between patients to prevent transmission of infections, following facility-specific protocols and manufacturer guidelines.

Question 191: During a routine outpatient EEG, a patient discloses they are currently experiencing active suicidal ideation. What is the technologist's first action?

Do not engage further to avoid worsening distress
Immediately alert clinical staff or a supervisor and ensure the patient is not left alone (Correct answer)
Complete the EEG as planned, then document the disclosure at the end of the session
Ask the patient to contact their own therapist after leaving the facility

Correct answer: Immediately alert clinical staff or a supervisor and ensure the patient is not left alone

Active suicidal ideation is a psychiatric emergency requiring immediate notification of clinical staff and continuous patient supervision.

Question 192: AAN guidelines for ECI recordings require a minimum interelectrode distance of at least how many centimeters to avoid missing low-amplitude activity between nearby electrodes?

10 cm (Correct answer)
15 cm
20 cm
5 cm

Correct answer: 10 cm

A minimum interelectrode distance of 10 cm is mandated so that small potential differences across brain tissue are not masked by electrodes placed too closely together. Shorter distances increase the risk of amplitude cancellation and may falsely suggest ECI.

Question 193: Which of the following activities is MOST likely to produce muscle artifact that obscures the EEG during an ambulatory recording?

Writing in a patient diary
Reading a book while seated
Chewing food during a meal (Correct answer)
Sleeping in a supine position

Correct answer: Chewing food during a meal

Chewing activates the temporalis and masseter muscles, generating high-amplitude EMG artifact that directly overlies temporal EEG electrodes.

Question 194: An EEG technologist is performing a biological calibration. The patient is asked to open and close their eyes, look left and right, and clench their jaw. What is the primary purpose of this procedure?

To verify the integrity of the recording system by generating physiological artifacts and confirming correct channel derivations. (Correct answer)
To warm up the EEG amplifiers and ensure they are functioning.
To assess the patient's level of cooperation before starting the recording.
To measure the baseline impedance of the scalp electrodes.

Correct answer: To verify the integrity of the recording system by generating physiological artifacts and confirming correct channel derivations.

Biological calibration (bio-cal) is essential to ensure the entire recording pathway is functioning correctly. By having the patient perform specific actions that are known to create distinct physiological artifacts (like eye movements and muscle tension), the technologist can confirm that electrodes are correctly placed and connected to the appropriate channels in the montage, and that the amplifiers are displaying these signals as expected.

Question 195: Amplitude-integrated EEG (aEEG) is most commonly used in which clinical setting?

Outpatient ambulatory studies in adults with suspected absence epilepsy
Adult outpatient epilepsy monitoring units for seizure localization
Neonatal intensive care units for continuous cerebral monitoring of high-risk newborns (Correct answer)
Intraoperative monitoring during spinal cord surgery

Correct answer: Neonatal intensive care units for continuous cerebral monitoring of high-risk newborns

aEEG was developed specifically for continuous cerebral function monitoring in neonates. It compresses and amplitude-integrates the EEG into a single trend channel, making it practical for bedside nurses and neonatologists to monitor brain activity, detect seizures, and assess background continuity in premature and term newborns with hypoxic-ischemic encephalopathy.

Question 196: During ambulatory EEG data review, a technologist identifies a train of rhythmic sharp waves in the right temporal region lasting 45 seconds without a diary entry or event button press. The appropriate action is to:

Immediately contact emergency services
Re-record the study with additional electrodes
Discard the segment as artifact due to absence of patient report
Flag the segment and note it in the report as a possible subclinical seizure (Correct answer)

Correct answer: Flag the segment and note it in the report as a possible subclinical seizure

Subclinical seizures can occur without patient awareness; the technologist should flag and document the finding for the interpreting physician's review.

Question 197: Which normal EEG feature is defined as a 12–14 Hz waxing-and-waning burst lasting 0.5–3 seconds, maximal over central-parietal regions?

Sleep spindle (Correct answer)
Positive occipital sharp transient (POST)
K-complex
Vertex sharp wave

Correct answer: Sleep spindle

Sleep spindles are 12–14 Hz (sigma band) bursts with a characteristic spindle shape appearing in stage N2 sleep.

Question 198: For a patient who cannot perform volitional hyperventilation (e.g., young child), an alternative activation method may include:

Applying cold water to the face
Having the child blow on a pinwheel or blow bubbles (Correct answer)
Bilateral carotid massage
Administering IV benzodiazepines

Correct answer: Having the child blow on a pinwheel or blow bubbles

Having young children blow on a pinwheel or blow bubbles is a standard pediatric technique to elicit sustained hyperventilation without requiring volitional cooperation.

Question 199: Bilateral prolongation of SSEP cortical latencies with normal peripheral nerve and plexus responses most strongly suggests pathology at which level?

Bilateral carpal tunnel syndrome
Bilateral peripheral neuropathy
Bilateral brachial plexopathy
Cervical spinal cord (myelopathy) (Correct answer)

Correct answer: Cervical spinal cord (myelopathy)

Normal peripheral potentials with delayed cortical responses imply a central conduction abnormality; bilateral symmetric involvement points to the cervical cord rather than unilateral brain pathology.

Question 200: Rhythmic midtemporal theta of drowsiness (RMTD) is characterized by:

Continuous high-amplitude slow waves during deep sleep
Irregular polymorphic delta activity during wakefulness
Sharply contoured 5-7 Hz rhythmic theta bursts over the midtemporal regions during drowsiness, with a characteristic notched appearance (Correct answer)
Focal beta activity in the temporal region

Correct answer: Sharply contoured 5-7 Hz rhythmic theta bursts over the midtemporal regions during drowsiness, with a characteristic notched appearance

RMTD (formerly called psychomotor variant) consists of rhythmic, sharply contoured 5-7 Hz theta activity over one or both midtemporal regions during drowsiness, with a distinctive notched or flat-topped morphology.

Question 201: A technologist uses a short-time constant (high-pass filter increase) to reduce which type of artifact?

Slow sweat artifact (Correct answer)
60 Hz line noise
Muscle artifact
Electrode pop

Correct answer: Slow sweat artifact

Increasing the high-pass (low frequency) filter shortens the time constant and attenuates slow, DC-shift sweat artifact.

ABRET R.EEG.T. Exam

The ABRET R.EEG.T. (Registered Electroencephalographic Technologist) exam certifies competency in performing and interpreting electroencephalographic recordings, covering electrode placement, normal and abnormal waveform recognition, instrumentation, patient safety, and neuroanatomy.

200

Questions

180 min

Time Limit

70%

To Pass

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