Prolonged assessment of sleep and daytime sleepiness in unrestrained Macaca mulatta.
OBJECTIVE
To establish a method for the prolonged recording of electrophysiologic variables of sleep in freely moving nonhuman primates. To establish and validate means for scoring nocturnal sleep and quantifying daytime alertness in these subjects.


METHODS
Four animals (M. mulatta) were permanently instrumented for the recording of electroencephalograms, electrooculograms, and electromyograms. A telemetry unit housed in a backpack transmitted these variables for several overnight periods to establish normal sleep. During the day, a modified Multiple Sleep Latency Test protocol was followed to quantify daytime alertness. High-quality recordings were maintained from a minimum of 8 months to a maximum of 5.5 years.


RESULTS
Across 6 to 7 nights per animal, average total sleep time was 522 minutes, with a sleep latency of 20 minutes. The proportion of total sleep spent in the various stages of sleep was 10.8%, stage 1; 56.4%, stage 2; 20.0%, stages 3-4; and 12.7%, rapid eye movement sleep. Mean sleep latency across testing sessions for each monkey was 12.5 minutes, 20 minutes (no daytime sleep), 14.6 minutes, and 8.6 minutes for animals 1 to 4, respectively. Intrarater and interrater reliabilities were high and similar to those obtained when the same scorers evaluated human sleep and Multiple Sleep Latency Tests.


CONCLUSIONS
Similarities in sleep architecture between M. mulatta and humans make this an excellent animal model for investigations of normal and pathologic human sleep. This study confirms and extends previous findings in nonhuman primates. Stable, high-quality data were obtained for months to years using a telemetric system capable of long-term data collection.
Department of Neurology, Emory University, Atlanta, GA, USA.
Joseph T
JT
Daley
Robert S
RS
Turner
Amanda
A
Freeman
Donald L
DL
Bliwise
David B
DB
Rye
D000818:Animals; D001143:Arousal / Q000502:physiology; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005260:Female; D008253:Macaca mulatta; D008297:Male; D015588:Observer Variation; D017286:Polysomnography; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D013686:Telemetry / Q000379:methods; D013997:Time Factors