Sleep cycle organization in narcoleptic and normal dogs

Abstract

The normal sleep-wake patterns of four narcoleptic and four normal dogs were recorded electrographically for 48 hours in a laboratory setting. The amount of the various stages of vigilance (wake, light slow wave sleep, deep slow wave sleep and REM sleep) were similar for both sets of dogs except that narcoleptic dogs has significantly less REM sleep and had an additional state scored as cataplexy. Mean episode durations and the number of episodes per 48 hr were not significantly different except that narcoleptic dogs had fewer REM episodes and a trend toward more waking episodes. There was a significant difference in the state progression between normal and narcoleptic dogs before and after REM episodes. Narcoleptic dogs had an increase in LSWS and a decrease in DSWS during the last 5 min before REM sleep onset in comparison to the reverse pattern in controls. In the stages following REM there was a marked elevation of wakefulness in narcoleptic dogs. These data support the notion that narcolepsy is a sleep disorder characterized by a disruption of the normal sleep-wake cycle. These results parallel similar findings in humans and provide strong evidence that this disease entity is similar in man and dog.