Objective measurements of sleep for non-laboratory settings as alternatives to polysomnography--a systematic review

Sleep disturbance influences human health. To examine sleep patterns, it is advisable to utilize valid subjective and objective measures. Laboratory-based polysomnography (PSG) is deemed the gold standard to measure sleep objectively, but is impractical for long-term and home utilization (e.g. resource-demanding, difficult to use). Hence, alternative devices have been developed. This study aimed to review the literature systematically, providing an overview of available objective sleep measures in non-laboratory settings as an alternative to PSG. To identify relevant articles, a specific search strategy was run in EMBASE, PubMed, CINAHL, PsycInfo and Compendex (Engineering Village 2). In addition, reference lists of retrieved articles were screened and experts within this research field were contacted. Two researchers, using specified in/exclusion criteria, screened identified citations independently in three stages: on title, abstract and full text. Data from included articles were extracted and inserted into summarizing tables outlining the results. Of the 2217 electronically identified citations, 35 studies met the inclusion criteria. Additional searches revealed eight papers. Psychometric characteristics of nine different objective measures of sleep pattern alternatives to PSG [(bed) actigraphy, observation, bed sensors, eyelid movement- and non-invasive arm sensors, a sleep switch and a remote device] were evaluated. Actigraphy is used widely and has been validated in several populations. Alternative devices to measure sleep patterns are becoming available, but most remain at prototype stage and are validated insufficiently. Future research should concentrate on the development and further validation of non-invasive, inexpensive and user-friendly sleep measures for non-laboratory settings.