Q: On the average, are grand mal seizures more frequent during waking or sleeping hours?
A: Many patients report that their tonic-clonic ("grand mal") seizures are more likely to occur, or only occur, during sleep. A paper published this month in the journal, Epilepsia, verifies this observation. The authors reviewed data on patients with partial-onset seizures who were admitted for monitoring to their epilepsy unit to determine when tonic-clonic seizures occur. 35% of complex partial seizures during sleep evolved into tonic-clonic seizures, whereas only 18% did during wakefulness. Thus, the tonic-clonic seizures were almost twice as common during sleep.
Reference: C.W. Bazuk and T.S. Walczak. "Effects of sleep and sleep stage on epileptic and non-epileptic seizures." Epilepsia (1997), 38:56-62.