Non-Epileptiform Abnormalities Flashcards
6 cards from real EEG practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Non-Epileptiform Abnormalities flashcards as text
Breach rhythm is a normal consequence of a skull defect that appears as:
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.
Occipital intermittent rhythmic delta activity (OIRDA) in a child is most commonly associated with:
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.
Continuous generalized slowing to the theta range (5-7 Hz) in an awake adult with no focal features most likely represents:
Answer: Mild to moderate diffuse encephalopathy
Continuous generalized theta slowing in an awake adult suggests mild to moderate diffuse cerebral dysfunction (encephalopathy) from metabolic, toxic, infectious, or degenerative causes, with severity proportional to the degree of slowing.
Post-ictal slowing on EEG following a focal seizure is clinically useful because it:
Answer: Helps lateralize and localize the seizure onset zone by showing regional slowing in the post-ictal period
Post-ictal regional slowing (focal delta or theta) provides lateralizing and localizing information about the seizure onset zone, as the area of maximal slowing typically corresponds to the ictal onset region.
Periodic discharges on the ictal-interictal continuum are challenging because:
Answer: They exist between clearly interictal and clearly ictal patterns, with uncertain clinical significance regarding ongoing brain injury
Patterns on the ictal-interictal continuum (periodic discharges, rhythmic delta) share features of both interictal and ictal patterns, creating diagnostic uncertainty about whether they represent ongoing seizure activity causing brain injury or a non-ictal irritative pattern.
Alpha coma is an EEG pattern characterized by:
Answer: Widespread, unreactive alpha-frequency activity in a comatose patient, typically following cardiac arrest or brainstem lesion
Alpha coma is a paradoxical pattern where widespread, unreactive alpha-frequency activity (8-13 Hz) is present in a comatose patient, most commonly seen after cardiopulmonary arrest or brainstem lesions, and generally carries a poor prognosis.