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

Lennox-Gastaut syndrome features slow (<3 Hz) generalized spike-and-wave complexes during wakefulness and generalized paroxysmal fast activity during sleep, along with multiple seizure types.

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 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 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

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 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

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 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

BECTS spikes show a characteristic tangential dipole with maximum negativity at C3/C4-T3/T4 and simultaneous positivity at frontal electrodes. They are markedly activated by drowsiness and NREM sleep.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Abnormal Epileptiform Patterns 3