OBJECTIVE: While there are a number of observations/quantifications indicating a greater proportion of REM sleep without atonia (RWA) in narcolepsy, the intra-night distribution of this parameter has not been evaluated.
MATERIALS AND METHODS: Thirty-four patients (15 men and 19 women; mean age 44.9 +/- 18.9) with narcolepsy-cataplexy were included in this retrospective study. The clinical diagnosis was confirmed by MSLT, video-polysomnography and HLA typing. Polysomnographic recordings were scored with particular regard to REM sleep without atonia (RWA) across all the nocturnal REM periods. RWA scoring was done according to a standard method.
RESULTS: The analysis showed a significant increase in the proportion of REM sleep without atonia during successive nocturnal REM periods in narcoleptic patients (p<0.01). No correlation was found between the percentage of RWA and the severity or duration of the disease, no age effect was documented.
CONCLUSION: The study demonstrates for the first time an increasing amount of RWA during the night suggesting enhanced nocturnal REM sleep motor disturbance.