title: Concordance of polysomnographic and actigraphic measurement of sleep and wake in older women with insomnia.
abstract: OBJECTIVE
  The objective of this secondary analysis was to evaluate concurrent validity of actigraphy and polysomnography (PSG) in older women with insomnia.
  
  
  METHODS
  Concurrent validity of actigraphy and PSG was examined through (1) comparison of sleep outcomes from each recording method; (2) calculation of sensitivity, specificity, accuracy, and predictive values from epoch-by-epoch data; and (3) statistical and graphical exploration of the relationship between sleep disturbance severity and concordance of actigraphy and PSG. Subjects were 16 community-dwelling older women (mean age 69.4 ± 8.1) with insomnia who underwent 8 nights of concurrent actigraphy and PSG.
  
  
  RESULTS
  Sleep efficiency reflected much greater sleep disturbance on PSG (66.9%) than actigraphy (84.4%). Based on generalized linear models, the parameter estimates for agreement between actigraphy and PSG were statistically significant (p < 0.05) for total sleep time and sleep latency, verged on significance for WASO (p = 0.052), but was not significant for sleep efficiency (p = 0.20). Epoch-by-epoch analysis showed high sensitivity (96.1%), low specificity (36.4%), and modest values on agreement (75.4%) and predictive values of sleep (74.7%) and wake (80.2%). Generalized linear models showed that overall accuracy of actigraphy declined as sleep efficiency declined (unstandardized Beta = 0.741, p < 0.001). Based on this model, sleep efficiency of 73% was the point at which accuracy declined below an acceptable accuracy value of 80%.
  
  
  CONCLUSIONS
  Actigraphy offers a relatively inexpensive and unobtrusive method for measuring sleep, but it appears to underestimate sleep disturbance, particularly at sleep efficiency levels below 73%, in older women with insomnia.
authors.affiliation: Departments of Biobehavioral Nursing & Health Systems, University of Washington, School of Nursing, Seattle, WA 98195-7262, USA. dmtaibi@uw.edu
authors.forename: Diana M
authors.initials: DM
authors.lastname: Taibi
authors.forename: Carol A
authors.initials: CA
authors.lastname: Landis
authors.forename: Michael V
authors.initials: MV
authors.lastname: Vitiello
mesh_terms: D056044:Actigraphy; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008875:Middle Aged; D017286:Polysomnography; D015203:Reproducibility of Results; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis / Q000503:physiopathology*; D014851:Wakefulness / Q000502:physiology*
keywords: Actigraphy; aging; insomnia; sleep; sleep initiation and maintenance disorders