Is it time for individualized testing in the electroencephalogram (EEG) laboratory?

Area of Science:

• Neurology
• Clinical Neurophysiology

Background:

• The interictal electroencephalogram (EEG) is crucial for epilepsy diagnosis and management.
• Current recommendations for EEG recording length consume valuable laboratory resources.
• Understanding the time to the first interictal epileptiform discharge (IED) can inform optimized EEG protocols.

Purpose of the Study:

• To investigate the time to the first IED in both standard and sleep-deprived EEGs.
• To analyze factors influencing IED latency, including EEG type and patient status.

Main Methods:

• Retrospective review of 684 standard and sleep-deprived EEG recordings over a 2-year period.
• Exclusion of bedside and long-term video-EEG recordings.
• Analysis of IED latency using the Kaplan-Meier estimator, stratified by EEG type, age, and inpatient/outpatient status.

Main Results:

• Ninety percent of IEDs occurred within 18.5 minutes.
• IEDs appeared significantly earlier in standard EEGs (14.6 min) compared to sleep-deprived EEGs (21.3 min).
• Inpatient EEGs showed earlier IEDs (14 min) than outpatient EEGs (21.3 min); age did not affect latency.

Conclusions:

• EEG type and inpatient status are significant factors in determining the optimal duration for EEG recordings.
• Consideration should be given to reducing EEG recording times, particularly for inpatients, to improve resource efficiency.