Original articleComparison of actigraphic, polysomnographic, and subjective assessment of sleep parameters in sleep-disordered patients
Introduction
Actigraphy, a method used to estimate sleep-wake schedules by measurement of activity, has been used by researchers to study sleep disturbances in a variety of populations, most frequently for the evaluation of insomnia, sleep state misperception and circadian rhythm disorders. The American Academy of Sleep Medicine recognizes it as a useful adjunct in the clinical assessment of sleep disorders [1]. An actigraph, worn on the wrist or ankle allows estimation of sleep and wakefulness based on motor activity. It provides a low-cost, non-invasive, objective, and longitudinal method for the diagnostic and post-treatment evaluation of patients with sleep disorders in the ambulatory setting.
Prior studies have used a variety of methods and algorithms to validate actigraphy. Comparison of actigraphy with the ‘gold standard’ of polysomnography (PSG) has typically yielded agreement rates in the range of 78–95% [2]. However, systematic review of earlier studies revealed smaller sample sizes (mean n=42±25) compared to the present study, and these studies were conducted on primarily normal subjects without sleep disorders [2]. Also, few studies have compared subjective sleep parameter values to the ones obtained from actigraphy and PSG. In the present study, PSG data in the form of sleep parameters such as number of awakenings, total sleep time, and sleep efficiency were compared to actigraphy as well as subjective data for 100 consecutive patients. We also performed an epoch-by-epoch comparison between PSG and actigraphic data to determine the sensitivity, specificity and accuracy of actigraphy.
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Subjects
The subject population consisted of 100 consecutive patients who had an initial sleep study in our sleep laboratory. Of these 100 subjects, 69 were men and 31 were women with a mean age of 49±14.7 years. Our university's panel on human subjects in medical research approved the study, and informed consent was obtained from every subject following full explanation of the study.
Procedures
Actigraphy and PSG were simultaneously performed for one night for each of the 100 consecutive subjects. Bedtimes and
Results
The data for number of awakenings, total sleep time, and sleep efficiency as obtained from PSG, actigraphic (low-threshold algorithm), and subjective questionnaire data are depicted in Table 2. After review of these data, we observed that total sleep time and sleep efficiency were overestimated by actigraphy by means of 1.0–1.8 h and 12.1–29.1%, respectively, but to a lesser degree by the subjects (means of 0.3 h and 2.5%, respectively). Upon further analysis, total sleep time and sleep
Discussion
The results from our study were comparable with those obtained from an earlier independent study (sensitivity, 0.95; specificity, 0.36; accuracy, 0.80) using the same device on a group of 30 consecutive sleep-disordered patients [8]; however, these statistics were obtained in a different manner compared to that of our study. In other earlier studies, the overall agreement rates between actigraphy and PSG for sleep and wakefulness in normal subjects have been very high (>90%) [2]. The agreement
Acknowledgements
Special thanks to Rolfe LaForge, Ph.D., Jeff Hindman, Luciana Palombini, M.D., and Seung Chul Hong, M.D., for their contributions to this study.
References (17)
An American Sleep Disorders Association Report. Practice parameters for the use of actigraphy in the clinical assessment of sleep disorders
Sleep
(1995)- et al.
The role of actigraphy in the evaluation of sleep disorders
Sleep
(1995) Validation with polysomnography of the Sleepwatch sleep/wake scoring algorithm used by the Actiwatch activity monitoring system. Technical Report to Mini Mitter Co., Inc.
(1997)International classification of sleep disorders, revised: diagnostic and coding manual
(1997)Activity and sleep
Act Measure Psychol Med
(1991)Robust locally weight regression and smoothing scatterplots
J Am Statist Assoc
(1979)- et al.
Determining sleep-wake activity using Actiwatch®
Sleep Res
(1997)
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