A Comparison of Actigraphy and Polysomnography in Older Adults Treated for Chronic Primary Insomnia

STUDY OBJECTIVES: The present study explores the accuracy and clinical utility of actigraphy compared with polysomnography in older adults treated for chronic primary insomnia. DESIGN: Polysomnographic and actigraphic data were collected before and after treatment. SETTING: A university-based outpatient clinic for adults and elderly. PARTICIPANTS: Thirty-four participants with chronic primary insomnia. Mean age was 60.5 years. INTERVENTIONS: Participants received either a manualized treatment package based on cognitive-behavior therapy and sleep management or hypnotic-drug treatment (7.5 mg zopiclone) for 6 weeks (these findings are reported elsewhere). MEASUREMENTS AND RESULTS: Although the sensitivity of actigraphy to detect sleep was very high (95.2%), actigraphy performed poorly in detecting wakefulness (specificity: 36.3%), yielding on an overall level of accuracy of 83.1%. However, the level of actigraphy accuracy was dependent upon polysomnography-registered sleep efficiency. Actigraphy underestimated total wake time and sleep-onset latency and consequently overestimated total sleep time and sleep efficiency. Compared with polysomnography, actigraphy captured only part of the treatment effects on total wake time and sleep-onset latency and failed to detect significant changes in sleep efficiency. CONCLUSIONS: The present findings suggest that the clinical utility of actigraphy is still suboptimal in older adults treated for chronic primary insomnia and should, hence, be used in this clinical setting with the concurrent use of supplementary assessment methods.