SUMMARY In our retrospective study 27 narcoleptic patients were divided into two groups: Group A comprised 14 patients (10 male, 4 female) with a history of REM behaviour disorder (RBD) and Group B comprised 13 age- and sex-matched patients (10 male, 3 female) without a history of RBD. Polygraphic and videometry data, medical history, medication, blood chemistry, psychological and neuroradiological data of the two groups of patients were compared.
The narcoleptic patients with a history of RBD differed from the narcoleptic control group without history of RBD in that they had: (a) a higher frequency of parasomnias in their history; (b) a higher percentage of stage 1 REM (P < 0.01); (c) a lower number of arousals during REM sleep; (d) fewer sleep stage changes. Compared to the heterogenous RBD patient group of Mahowald and Schenck, the REM behaviour of most of our narcoleptic patients was less violent.
Thus it can be speculated that the motor disorder in REM sleep might still be in the process of developing towards a full-blown REM sleep behaviour disorder. In a possible lifelong development of a motor disorder starting in NREM sleep, the onset of narcolepsy might represent the turning point for its intrusion into REM sleep.