[Kinesigenic supplementary motor seizure? A case report]

Supplementary motor seizure (SMS) and paroxysmal kinesigenic choreoathetosis (PKC) appear similar, but are generally considered to represent different disease entities. We report a case that shared the clinical features of both disorders. A 62-year-old woman presented with attacks consisting of brief tonic posturing of four limbs, more prominent on the right side. The attack started at age 59 and subsequently began to occur about 20 times daily. Her consciousness was preserved during the attack. The attack lasted 5-15 sec. The attacks were often evoked by sudden initiation of movement, but also occurred spontaneously and even during sleep. She had never experienced generalized convulsion. Ictal scalp EEG showed high amplitude beta activity appearing a few seconds before the attacks around the vertex. Otherwise EEG was within normal limits. The response to anti-convulsant medication was poor and a combination of three kinds of drugs was needed. An almost identical case was reported as "PKC" by Lombroso. His case showed unequivocal epileptiform discharges arising from the supplementary motor area. Accordingly, our case is considered kinesigenic SMS. It seems important to examine similar cases to elucidate the relationship between SMS and PKC, or between the kinesigenic and non-kinesigenic types of these disease entities.