24-HOUR AMBULATORY EEG MONITORING IN INFANTILE SPASMS

Twenty-four-hour ambulatory EEG (AEEG) recordings were performed in 74 infants with West Syndrome (WS) who had not received corticosteroids before the recording. EEG analysis was performed visually for interict al background activity as well as for ictal events: spasms (isolated o r in clusters) and other seizures either generalized or partial. Six h undred fifty-four seizures were recorded in 67 patients. Partial seizu res (PS) were noted in 31 infants (51% of symptomatic WS cases, 33% of cryptogenic WS cases). In 14 patients, PS were immediately followed b y a cluster of spasms consisting of a single ictal event. Patients wit h PS had an asymmetrical interictal background activity in 85% of case s, with no return to hypsarrhythmia between spasms in a given cluster. AEEG is a reliable method to detect and analyze ictal events in infan ts with WS. In this population, patients with unfavorable outcome of b oth epilepsy and psychomotor development have PS. Therefore, the exist ence of PS may contribute to etiologic diagnosis and prognostic evalua tion.