Blom S, Heijbel J
Epilepsia. 1975 Mar;16(1):133-40. doi: 10.1111/j.1528-1157.1975.tb04730.x.
The discharge rate (the number of spikes/min) was determined in the awake state and during different stages of induced sleep in 17 children with "benign epilepsy of childhood with centro-temporal EEG foci". Ten patients had seizures only during sleep. The discharge rate of Rolandic spikes was significantly higher during sleep than during the awake state, and 5 patients had Rolandic discharges only during sleep. For diagnostic purposes, EEG recordings during sleep are indicated when children suspected of having this seizure type have a normal EEG when awake. Brief induced sleep is usually adequate. REM sleep was not studied.