The electroclinical and neuroimaging features, and response to antiepileptic drugs in 12 children with seizures involving the supplementary sensory motor area (SSMA) are reported from the British Columbia’s Children’s Hospital, Vancouver, BC, Canada. SSMA seizures were characterized by bilateral tonic posturing of upper or lower extremities, preserved consciousness, and no postictal confusion. Sensory auras, speech arrest, and abnormal vocalization were frequent symptoms. Ictal EEGs showed abrupt generalized attenuation of background activity and diffuse beta activity, followed by theta or delta frontal activity or generalized rhythmic midline slowing. Interictal recordings were normal in 50%. Delayed cognitive development occurred in 3 patients. One patient had tuberous sclerosis and one had a hypothalamic hamartoma. Brain imaging was normal in the remaining 10 patients. Seizures were responsive to AEDs in 50% of cases. [1]

COMMENT. Supplementary SM seizures in adults with surgical lesions are described by Penfield W and Jasper H in their classic “Epilepsy and the Functional Anatomy of the Human Brain,” Boston, Little Brown, 1954. In one patient with a scar in the right posterior frontal region adjacent to the longitudinal sinus, attacks were ushered in by a sensation in the left foot. This was followed by turning of the head and eyes to the left, raising of the left hand and tonic posturing of both legs. Clonic movements followed. There was no loss of consciousness unless a generalized seizure occurred. Attacks in children are similar to those described in adults. Diagnosis is often difficult because of frequent normal interictal EEG and subtle ictal EEG abnormalities. Repeated video/EEG recordings may be required to establish a clear electroclinical pattern.