Increasing the yield of EEG.

The EEG is the most common neurodiagnostic test performed to evaluate patients with suspected seizures. The majority of EEGs are requested in patients because of suspected seizures or for seizure management. It is unlikely that the patient's usual spell will be recorded during a routine EEG. Therefore, several activation techniques have been used in clinical EEG to help increase the occurrence of interictal epileptiform abnormalities, which are highly correlated with the diagnosis of a seizure disorder. EEG laboratories have long employed these techniques, which include hyperventilation, intermittent photic stimulation, sleep, and sleep deprivation. However, despite being utilized in routine clinical EEGs for decades, a number of differing views on the usefulness and indications for these procedures exist. This review will evaluate these procedures and review their history, technique, effectiveness, controversies, and unanswered questions.