Different cortical involvement pattern of generalized and localized spasms: a magnetoencephalography study.

We report successful magnetoencephalography (MEG) recording in a child who had generalized epileptic spasms (ESs) as well as ESs involving the legs only during the recording. MEG source localization results demonstrated that (1) the interictal epileptiform discharges and both types of ESs had the same origin, that is, the right parietal region, and (2) the two types of ESs had different cortical spread patterns, that is, epileptic involvement localized to the right parietal region in spasms of the legs and rapid diffuse involvement in generalized spasms. In this case, MEG provided new insight into the mechanisms underlying the two types of ESs: both types were generated from the same focus, and in generalized ESs, abnormal excitation spread to cortical areas diffusely. Copyright Â