The electroencephalogram during spontaneous night sleep in epileptic patients

Abstract

Recent advances in the electroencephalographic studies of normal sleep have modified the older hypothesis of the sleep mechanisms by newer interpretations, which explain sleep as the result of an inhibitory activity originating from specific hypnogenic centers 7 -14 . The great importance of the sleep was stressed by Gibbs and Gibbs 6 '20 years ago, when these authors stated that epileptic patients show more than twice seizure discharges in their EEG recorded during sleep than in the waking state. The five well known fundamental stages of sleep with especific electroencephalographic findings were established by Dement and Kleitman 2 in 1957.These reports have presently focused the attention of the electroencephalographers upon the value of the sleep record as a useful tool for studying the electroencephalographic patterns of epileptic patients.Our study was carried out in order to investigate the brain function of epileptic patients on the basis of electroencephalographic information during spontaneous night sleep. MATERIAL AND METHODSFor the purposes of the present study, 5 patients with the chief complaint of convulsive disorders were investigated. The EEGs were taken first at day time as a routine procedure and have show sharp waves in the temporal leads in 4 cases, and bilateral spike and slow waves and synchronic discharges in one case. A second record was taken during spontaneous night sleep. The EEGs were recorded on an 8 channel model VI Grass instrument, the electrodes being placed as usually in the 1Q/20 system; monopolar and bipolar techniques were used 15 . Eye movements, snoring and reactivity to auditory stimuli were also recorded. RESULTSThe EEG findings in the 5 experiments indicate that the focal sharp waves, when recorded during the 1st and 2nd stages of spontaneous night sleep, are characterized by a slight elevation of the frequency of the discharges. On the same way, the qualitative aspects of the bioelectrical activity of subcortical