Overnight polygraphic study of Lennox-Gastaut syndrome.
Nine children with Lennox-Gastaut syndrome, aged 2-14 years, were studied by overnight polygraphy for one night. Percentage of sleep period time (SPT) for stage rapid eye movement (REM) and REM density during REM sleep decreased in Lennox-Gastaut syndrome as compared with control. Alpha rhythm was seen in only 3 cases and sleep spindles in only 6 cases. The effect of sleep-wake or REM-non-REM (NREM) sleep rhythm on the rate of generalized epileptiform discharges varied with the individual. Ictal discharges with or without clinical tonic seizures observed in 5 children appeared during NREM sleep and awakening in the morning, and in 2 of these cases they also occurred frequently during the NREM sleep of the first sleep cycle. Subclinical ictal discharges were also seen during REM sleep in the early morning in one case who was 2 years old. The Lennox-Gastaut syndrome is assumed to involved a considerable degree of brain stem dysfunction.