EEG Abnormal Epileptiform Patterns 3

Question 1

Lennox-Gastaut syndrome is characterized by which EEG pattern during wakefulness?

Accepted Answer

Slow spike-and-wave complexes at 1.5-2.5 Hz

Answer

3 Hz generalized spike-and-wave

Answer

Focal temporal sharp waves

Answer

Normal background with occasional vertex waves

Question 2

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

Accepted Answer

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

Answer

Polyspike-and-wave is always focal rather than generalized

Answer

Polyspike-and-wave occurs only during REM sleep

Answer

Polyspike-and-wave has a slower frequency than single spike-and-wave

Question 3

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

Accepted Answer

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

Answer

Static, unchanging repetitive discharges

Answer

Random isolated spikes without pattern

Answer

Only generalized tonic-clonic movements on video

Question 4

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

Accepted Answer

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

Answer

Is always a normal variant in elderly patients

Answer

Indicates brainstem dysfunction

Answer

Is caused by electrode artifact at temporal sites

Question 5

The centrotemporal spikes seen in benign childhood epilepsy with centrotemporal spikes (BECTS) have which typical characteristic?

Accepted Answer

They show a horizontal dipole with negativity at centrotemporal and positivity at frontal electrodes, activated by sleep

Answer

They are maximal at occipital electrodes and occur during photic stimulation

Answer

They are continuous during wakefulness and suppressed by sleep

Answer

They are bilateral synchronous without a dipole field

Question 6

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

Accepted Answer

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

Answer

Always require immediate anticonvulsant treatment

Answer

Are only seen in outpatient EEG recordings

Answer

Indicate the patient is about to have a tonic-clonic seizure