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April 1970

Primary and Secondary Bilateral Synchrony in Epilepsy: A Clinical and Electroencephalographic Study

Author Affiliations

From the Seizure Unit and Division of Neurophysiology, Department of Neurology, Children's Hospital Medical Center, and the Department of Neurology, Harvard Medical School, Boston. Dr. Erba is now at the Department of Neurology, Montreal General Hospital, Montreal.

Arch Neurol. 1970;22(4):321-334. doi:10.1001/archneur.1970.00480220035006

THE MECHANISMS underlying human seizures generalized from the start and those that become so secondarily have not been clearly elucidated. The experimental data accumulated in the last two decades still seem to weigh in favor of a subcortical integrating system as the main agent involved,1,2 despite the arguments based on electrographic observations3,4 and on findings of depth electrography and stimulation in man,5,6 as well as those based on findings in free cortical slabs or on cortical-callosal preparations in animals.7,8

While waiting for further clarification of the mechanisms, the clinician, whenever confronted by electroencephalograms with bilaterally synchronous discharges of the spike and wave variety, associated or not with focal features, is faced with the task of distinguishing between "primary" and "secondary bilateral synchrony." The latter term was first introduced by Penfield9 and Tuckel and Jasper10 to protect the integrity of the "centrencephalic" hypothesis