Transcranial magnetic stimulation as a provocation for epileptic seizures in multiple sclerosis.

Epileptic seizures may be of a provoked origin in acute phases of multiple sclerosis (MS), while chronic epilepsy typically occurs in advanced stages of the disease. A case of seizure provocation during diagnostic transcranial magnetic stimulation (TMS) is described here with a corresponding central nervous system (CNS) lesion in cranial magnetic resonance imaging. A subsequent chronic epileptogenesis originating from the opposite cerebral hemisphere was observed without further TMS influence after several years. The case in its clinical rarity demonstrates that standard single pulse TMS may trigger epileptic seizures only under limited conditions. Single pulse TMS is still regarded a safe procedure in MS.