The start-stop-start phenomenon of subdurally recorded seizures.

Defined as a pair of sequential ictal potentials separated by complete or almost complete cessation of seizure activity, the start-stop-start (SSS) phenomenon was found on subdural recordings in 23 (23%) of 98 patients. The two phases were morphologically similar. Thirty-six (58%) of 62 SSS seizures showed a complete stop, a return to interictal morphology being more common than a postictal pattern. Twenty-two (35%) of 62 seizures in 8 (35%) of 23 patients restarted in a different location than the first start. When in different locations, the start, not the restart, correlated with non-SSS origin. SSS seizures arose in the same region as non-SSS seizures in 22 of 23 patients.