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. Author manuscript; available in PMC: 2008 Jun 1.
Published in final edited form as: Sleep Med. 2007 Apr 30;8(4):373–399. doi: 10.1016/j.sleep.2007.03.008

Fig. 2. Percent of Time Spent in, Mean Frequency of, and Mean Duration for Each Vigilance State of Narcoleptic and Control Canines during Daytime 6-Hour Recordings (10:00 to 16:00).

Fig. 2

(a, b) No significant difference was found in the percentage of time spent in each vigilance state between narcoleptic and control dogs. However, the mean duration of wake, drowsy, and deep sleep episodes were significantly shorter in the narcoleptics, suggesting a fragmentation of the vigilance states (wake and sleep) in these animals. To compensate for the influence of cataplectic episodes on wake and drowsiness, those episodes interrupted by the occurrence of cataplexy were excluded. (c) Mean latency (min) to each sleep stage and occurrences (number/total sessions) of cataplexy and sleep onset REM periods (SOREMPs) during the multiple sleep latency test (MSLT) in narcoleptic and control Dobermans. Drowsy and light sleep occurred in all sessions. Deep sleep, REM sleep or cataplexy (for narcoleptic dogs) occurred in some sessions, and the number of sessions where each state occurred/total number of sessions is shown in parentheses. Narcoleptic dogs exhibited cataplexy in 9 out of 100 sessions, and these events were differentiated from REM sleep episodes. Narcoleptic dogs show a significantly shorter latency to drowsy and light sleep in overall sessions. Note that narcoleptic dogs exhibited SOREMPs (i.e., REM sleep occurring within 15 min of sleep onset) significantly more often than control animals, although both narcoleptic (36.0 % of total session) and control dogs (21.7 %) showed REM sleep during the MSLT.