[Narcolepsy and sudden onset of REM periods after nocturnal awakenings].

The objective of this study was to evaluate polysomnographic data, and especially the sudden onset of REM periods that occur after spontaneous awakenings during the night as characteristics of narcolepsy. We evaluated 148 consecutive patients with excessive daytime somnolence, except for those with sleep apnea. After clinical evaluation, all-night polysomnographic recording and multiple sleep latency test, 55 were diagnosed as narcoleptics and 93 were grouped as non-narcoleptics. The mean age of narcoleptics was 42.9 +/- 14.4 years old and the non-narcoleptics were 40.3 +/- 13.5 years old. Polysomnographic variables were compared between both samples using unpaired t test. Non-significant differences were found for: sex; total time in bed; total sleep time; time in stages 3, 4 and REM; number of arousals (less than 30 sec); number of body movements; REM density. The following significant differences were found: number of sleep onset REM periods during the night was higher for narcoleptics (p less than 0.001); total sleep time was lower for narcoleptics (p = 0.02); sleep latency was shorter for narcoleptics (p less than 0.001); REM latency to stage 1 was shorter for narcoleptics (p less than 0.001); time in stage 1 was higher for narcoleptics (p less than 0.001); time in stage 2 was lower for narcoleptics (p less than 0.001); number of full awakenings (greater than 30 sec) was higher for narcoleptics (p less than 0.001); number of awakenings longer than 5 minutes was higher for narcoleptics (p = 0.002). In conclusion, there were marked differences in the sleep architecture between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)