Narcoleptic syndrome and paradoxical sleep.

Abstract

SummaryIn order to elucidate the mechanism of the narcoleptic syndrome, the course of all‐night sleep was investigated by means of poly graphic methods or by using inducing stimuli. Further study on each symptom was performed in relation to the sleep mechanism using similar methods. Thirty‐three cases of typical narcolepsy were examined. The results from these studies are summarized as follows.1. The paradoxical phase of sleep occurs immediately after sleep onset in the natural nocturnal sleep of narcoleptics. The proportion of sleep time spent in the paradoxical phase (30%) in narcoleptics is higher than in normals, whereas that of the deep sleep stage is lower.2. In narcolepsy, hypnagogic hallucination and sleep paralysis appear mostly during the paradoxical phase. During these episodes the level of cerebral vigilance ascends temporarily but slight differences are found between these two episodes. The responses to the stimuli (auditory evoked response, the H reflex and the knee jerk) are similar to those in normals in each stage of sleep.3. Chlorpromazine, being effective against hypnagogic hallucination and sleep disturbance, stabilizes a night's sleep and prolongs the duration of deep sleep and the paradoxical phase. Imipramine with a suppressing action on cataplectic attack, inhibits the occurrence of the paradoxical phase at sleep onset and diminishes the following paradoxical phases, accompanied by a decrease of hypnagogic hallucination.4. The level of wakefulness tends to descend easily in narcoleptics. In sleep attacks, the subjects fall rapidly into the paradoxical phase from alert or drowsy state. Both sleep attacks and a tendency to fall asleep are apt to occur periodically in the daytime with lucid intervals.5. A cataplectic attack closely relates to the paradoxical phase. During the episode, a great discrepancy is found between hypofunction of the arousal system and function of the motor and autonomic systems. Cataplectic occur frequently concomitant with the sleeping‐waking rhythm.6. Fundamental disorders of narcolepsy are considered as follows: the abnormal occurrence of the paradoxical phase of sleep, the tendency to fall asleep easily, the sleep cycle through night and day and the remarkable dissociation of the arousal system from the motor or autonomic systems. Accordingly, disorders in the sleep‐wakefulness regulating mechanisms are found. Dysfunction of the brain stem reticular formation, especially in the pons, and disturbances of the interrelationship among them are discussed.