Induced microseizures in West syndrome.

Induced microseizures (IMS) were observed in a 5-month-old girl with symptomatic West syndrome. The seizures occurred following the suppression of infantile spasms with adrenocorticotropic hormone therapy and disappeared following the cessation of clonazepam administration. The ictal manifestations consisted of periods of irregular respiration, and respiratory arrest lasting for several seconds which often involved opening of the eyes and mild extension of the neck corresponding with the diffuse fast wave bursts in EEG activity observed during sleep. These seizures were thought to be equivalent to the IMS in Lennox-Gastaut syndrome, which have never been reported before in patients with West syndrome.