Sleep stage dynamics differ between children with and without obstructive sleep apnea.
OBJECTIVE
Analysis of sleep dynamics--distributions of contiguous sleep and sleep stage durations--reveal exponential distributions and potential clinical utility in adults. We sought to examine these polysomnographic variables for the first time in children, and in the context of childhood sleep disordered breathing (SDB).


METHODS
Analysis of polysomnographic data available from the Washtenaw County Adenotonsillectomy Cohort.


METHODS
Selected subjects were 48 children aged 5-12 years with SDB (pediatric apnea/hypopnea index > or = 1.5) who were scheduled for adenotonsillectomy and 20 control subjects of similar ages without SDB. Subjects were studied at enrollment and again one year later in almost all cases.


RESULTS
Durations of sleep and specific sleep stage bouts generally followed exponential distributions. At baseline, the number of sleep stage changes, proportion of total sleep time occupied by stage 1 sleep, proportion stage 2 sleep, mean stage 2 duration, and mean stage REM duration each distinguished subjects with and without SDB (P < 0.05), but only mean stage 2 duration did so independently after accounting for the other variables (P = 0.03). At one-year follow-up, changes in total sleep time, mean stage 2 duration, and mean stage REM duration distinguished SDB from control subjects, but again only changes in mean stage 2 duration did so independently (P = 0.01).


CONCLUSIONS
Durations of uninterrupted sleep and specific sleep stages appear to follow exponential distributions in children with or without SDB. Parameters that describe these distributions--particularly mean duration of stage 2 sleep periods--may provide useful additions to standard sleep stage analyses.
Chervin
Ronald D
RD
Sleep Disorders Center and Department of Neurology, University ofMichigan, Ann Arbor, MI 48109-0845, USA. chervin@umich.edu
Fetterolf
Judith L
JL
Ruzicka
Deborah L
DL
Thelen
Brian J
BJ
Burns
Joseph W
JW
D000233:Adenoidectomy; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004569:Electroencephalography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D017286:Polysomnography / Q000379:methods / Q000706:statistics & numerical data; D011446:Prospective Studies; D012891:Sleep Apnea Syndromes / Q000503:physiopathology / Q000601:surgery; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology* / Q000601:surgery; D012894:Sleep Stages; D013997:Time Factors; D014068:Tonsillectomy