Electroencephalographic Abnormalities during Sleep as Related to the Temporal Distribution of Seizures

Abstract

SUMMARY The sleep and awake EEG's of 90 epileptics and 30 normal controls were evaluated. The epileptics were divided into three groups: (1) Nocturnal seizures predominately, (2) Diurnal seizures predominately, (3) Mixed diurnal and nocturnal seizures. Patients with nocturnal seizures showed greater numbers and degrees of abnormalities during sleep EEG's. In patients with diurnal seizures abnormalities appeared about equally in sleep and awake EEG's. The stage of sleep most useful for detecting abnormalities was drowsiness‐light sleep. Depriving the patient of anticonvulsant medication for 24 hours did not increase the chance of abnormalities occurring during sleep recordings. The sleep recordings were conducted on a 16 channel electroencephalograph using bipolar and monopolar recording techniques simultaneously. Except that bipolar recordings seemed to detect foci better, these techniques appeared to be equal in their ability to display abnormalities associated with epilepsy. RÉSUMÉ Les E.E.G. enregistrés en sommeil ou en veille chez 90 épileptiques et 30 témoins normaux ont étéétudiés. Les épileptiques avaient été répartis en trois groupes: (1) Crises nocturnes prédominantes, (2) Crises diurnes prédominantes et (3) Crises diurnes et nocturnes mélangées. Les malades ayant des crises nocturnes ont donné dans ľE.E.G. en sommeil des anomalies en chiffres et en dégres plus élevés. Chez les malades souffrant de crises diurnes, les anomalies se sont manifestées à peu prés également dans ľE.E.G. pendant le sommeil et pendant la veille. La phase du sommeil la plus favorable à la détection ďanomalies a été celle ďun sommeil léger. La privation de médicament anticonvulsif infligée au malade pendant 24 heures n'a pas augmenté la chance des anomalies se produisant lors de ľenregistrement pendant le sommeil. Les E.E.G. pris pendant le sommeil ľont été avec électroencéphalographe à 16 canaux faisant un usage simultané de techniques bipolaires et monopolaires ďenregistrement. Exception faite du fait que ľenregistrement bipolaire a semblé mieux révéler les foci, ces techniques se sont montrées de valeur égale dans la détection des anomalies associées àľépilepsie.

Sleep and Epilepsy: What We Know, Don’t Know, and Need to Know

“…They also noted that seizures were more likely to be activated by sleep or sleep deprivation in patients with IGE than with partial epilepsy. The yield of sleep recordings may be greater in patients with nocturnal seizures versus awake or randomly distributed seizures (White et al, 1962) and in untreated patients with epilepsy (Aguglia et al, 1994).…”

The temporal relation between seizure onset and arousal-awakening in temporal lobe seizures

“…Epilepsy also changes the organization and microstructure of sleep [4]. Since patients with epilepsy have seizures during sleep, this reciprocal interaction has led researchers to investigate the relationship between the pathologic processes underlying seizures and the physiological structures of sleep [5][6][7][8][9]. Arousal or awakening systems that separate sleep and wakefulness are characterized by excitability and increased electrical activity of sensory and motor systems.…”

Sleep and Epilepsy

“…34 This is in contrast to an older study by White et al that reported more prominent interictal abnormalities during lighter stages of sleep. 35 The scarcity of abnormal interictal activity during REM sleep is also seen in childhood epileptic syndromes, such as those of West, 36,37 Landau-Kleffner, 38 and Lennox-Gastaut. 39 Although interictal discharges are less prevalent in REM sleep, when they are present they carry more localizing value for the seizure focus.…”