Antiseizure Medication and EEG Abnormalities Quiz

What is the duration of each transient required for a discharge to qualify as an interictal epileptiform discharge (IED)?

Which type of EEG abnormalities are associated with epilepsy at rates sufficient to be clinically useful?

What is the previous name for lateralized periodic discharges (LPDs)?

Which of the following conditions have been associated with IEDs, even in the absence of accompanying seizures?

Which of the following drugs is NOT associated with IEDs, even in the absence of accompanying seizures?

What can inexperienced interpreters of EEG potentially do that can limit the specificity of the findings?

Which of the following is a characteristic of sharp waves?

What is a distinguishing feature of most IEDs at the scalp?

What is the sensitivity of an IED finding on a first 'routine' EEG?

What is the probability of seizure recurrence in patients with normal EEGs after a first unprovoked seizure?

Which epilepsy syndrome is almost invariably associated with the presence of IEDs?

What technique can be used to increase the yield of IEDs on an interictal EEG?

What is the prevalence of IEDs in healthy children?

What is the specificity of IEDs in patients without a history of seizures?

Interictal Epileptiform Discharges (IEDs)

Duration of transients for a discharge to qualify as IED is typically 20-70 milliseconds.
Epileptiform abnormalities in EEG commonly associated with epilepsy include spikes, sharp waves, and spike-and-wave discharges.

Lateralized Periodic Discharges (LPDs)

Previous name for LPDs is "lateralized periodic lateralized epileptiform discharges" (LPLEDs).

Conditions Associated with IEDs

Conditions linked to IEDs, even without seizures, include brain injury, infections, and metabolic disturbances.

Drugs Without Association to IEDs

Certain drugs, like lithium, are not associated with IEDs in the absence of seizures.

EEG Interpretation Limitations

Inexperienced EEG interpreters may misidentify normal variations as pathologic findings, potentially reducing diagnostic specificity.

Characteristics of Sharp Waves

Sharp waves are characterized by a quick transition from a baseline to a peak, distinct from slower waves in frequency.

Distinguishing Features of IEDs

Most IEDs at the scalp present as high-voltage spikes or sharp waves, often localized to specific regions of interest.

Sensitivity and Probability Measures

The sensitivity of finding an IED on a first routine EEG is approximately 60-70%.
Probability of seizure recurrence in patients with normal EEGs after a first unprovoked seizure is about 30-50%.

Epilepsy Syndrome and IEDs

Childhood epilepsy syndromes, particularly those like Landau-Kleffner syndrome, are almost invariably associated with IEDs.

Techniques to Increase IED Yield

Sleep deprivation can enhance the yield of IEDs on interictal EEG recordings.

Prevalence and Specificity of IEDs

Prevalence of IEDs in healthy children is around 2-5%.
Specificity of IEDs in patients without a history of seizures is relatively low, causing potential misdiagnosis.

Test your knowledge on the impact of antiseizure medication on IEDs and EEG abnormalities in epilepsy syndromes with this informative quiz. Keywords: Diazepam, phenobarbital, IEDs, chronic therapy, antiseizure medication, withdrawal, EEG, epilepsy syndromes.