Normal EEG Waveforms 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 Normal EEG Waveforms flashcards as text
What is the normal frequency range of the posterior dominant rhythm (alpha rhythm) in a healthy awake adult?
Answer: 8-13 Hz
The normal adult posterior dominant rhythm falls within the alpha frequency band of 8-13 Hz, typically with a mean frequency around 10 Hz. It is best seen over the occipital regions with eyes closed.
Sleep spindles are a hallmark of which stage of sleep?
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.
Vertex sharp waves (V waves) during drowsiness are maximally recorded at which electrode position?
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.
The lambda wave is a positive sharp transient that occurs in the occipital region during:
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.
K-complexes are characterized by which of the following features?
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.
Positive occipital sharp transients of sleep (POSTS) are a normal finding seen during which sleep state?
Answer: NREM light sleep (N1-N2)
POSTS are surface-positive sharp transients over the occipital regions that appear during light NREM sleep (N1 and N2). They are a normal variant and should not be confused with occipital epileptiform discharges.