Polygraphic study on the clinical seizures induced during nocturnal sleep

The subjects of this study consisted of 17 epileptic patients with clinical seizures during all-night sleep recording (the seizure group) and another 17 epileptic patients without clinical seizures (the control group). The results obtained were as follows: 1) The 50-90% out of total clinical seizures were induced in non-REM sleep, while a few clinical seizures were induced in REM sleep. The number of clinical seizures in sleep stage of higher activity level increased as the incidence of clinical seizure during all-night grew. 2) In the seizure group REM sleep could not be detectable during all-night in five cases out of 17 cases, while we could not find cases lacking REM sleep in the control group. This difference between two subject groups was statistically significant (P less than 0.025). 3) As to focal spike group, the spike discharge incidence of total sleeping time and of each sleep stage was higher respectively in the seizure group than that in the control group, and particularly in St.1, St.2 and REM sleep the figure of the discharge incidence was found significantly higher in the seizure group than that in the control group (P less than 0.05). We discussed on above-mentioned results, and we emphasized particularly that REM-sleep suppresses clinical seizures, although non-REM sleep induces clinical seizures.