In children, (1) sensitivity was 58.7% and (2) specificity was 69.6%. In adults, (1) sensitivity was 17.3% and (2) specificity was 94.7%. Abnormal EEG activity is also seen in some normal persons, and one paper reported that epileptiform discharges were recorded in 0.5% (69/13,658) of normal persons 3).Ī recent systematic review of 15 articles with a total of 1,799 patients presenting with a first unprovoked seizure analyzed the (1) sensitivity (percentage of patients with epileptiform discharges on routine EEG among those who had repeated seizures during one-year follow-up and hence were diagnosed with epilepsy) and (2) specificity (percentage of patients finally diagnosed with epilepsy among those who were found to have epileptiform discharges on routine EEG) separately in children and adults 4).

However, even if epileptic discharges are recorded in EEG, unless the discharges can explain the seizure symptom, this finding alone does not necessarily lead to a diagnosis of epilepsy. Especially, it has been reported that during sleep, the epileptic discharges detection rate is higher in children than in adults, and higher for partial epilepsy than for generalized epilepsy. In patients in whom no epileptic discharges are detected in awake recordings, epileptic discharges are often detected by sleep EEG 3). In addition, the diagnostic value of sleep EEG is high. However, some reports indicate that the more EEG examinations are repeated, the higher is the epileptic discharges detection rate on EEG 3). Regarding the question of how many EEG examinations are needed to exclude a diagnosis of epilepsy, there is no solid evidence-based answer. In a systematic review of 12 articles with evidence levels of classes I and II comprising 1,766 adult patients, approximately 50% of the patients with epilepsy had normal EEG 2).

However, in a considerable number of patients, seizure discharges cannot be detected by a single routine EEG examination.

Regarding the EEG recording methods, it is desirable to follow the guidelines of the Japanese Society of Clinical Neurophysiology 1). Thus, EEG findings are essential in addition to clinical seizure types and neurological symptoms. Commentĭiagnosis of epilepsy is conducted in accordance with the International League Against Epilepsy (ILAE) classification of epileptic seizure types (1981) as well as classification of epilepsies, epileptic syndromes and related seizure disorders (1989). In a considerable number of patients, however, epileptic discharges cannot be detected by only a single routine EEG examination, and multiple EEG recordings including sleep or sleep-deprived EEG are required. How useful is EEG for the diagnosis of epilepsy? SummaryĮlectroencephalography (EEG) is the most useful clinical examination for the diagnosis of epilepsy.

Eeg of epilepsy vs normal