SUMMARYThe availability of a reliable system to record sleep stage measures easily and automatically in ambulatory settings could be of utility for research and clinical work. The aim of this study was to evaluate a novel wireless system (WS) that does not require skilled preparation for the automatic collection and scoring of human sleep. Twenty-nine healthy adults underwent concurrent sleep measurement via the WS, polysomnography (PSG) and an actigraph (ACT) in a sleep laboratory for one assessment night preceded by an acclimation night. The PSG recordings were scored by two experienced trained technicians from separate laboratories. Each recording was scored by both technicians to Rechtschaffen and Kales (R&K) criteria. The WS and ACT were compared with each of the PSG scores and a consensus PSG score, and the PSG scores were compared with each other. Inter-rater agreement was assessed for each pair over all pooled epochs by percentage agreement, CohenÕs kappa and intraclass correlation coefficient. The WS agreement with each of the two PSG scores for sleep stages was 75.8 and 74.7%, respectively. WS agreement with each of the two PSG scores for sleep ⁄ wakefulness was 92.6 and 91.1%, ACT agreement with PSG was 86.3 and 85.7%. The PSG scorersÕ agreement with each other for sleep stages was 83.2%, and for sleep ⁄ wakefulness was 95.8%. The findings from the current study indicate that the WS may provide an easy to use and accurate complement to other established technologies for measuring sleep in healthy adults. INTRODUC TIONThe ability to investigate the sleep of individuals is of scientific and clinical interest. Sleep patterns have most commonly been examined with polysomnography (PSG), wrist actigraphy and subjective self-report instruments. Each method of measuring sleep has strengths and limitations. PSG is the gold standard assessment methodology for sleep and it provides detailed information on sleep staging, latencies to sleep and specific sleep stages, as well as the number of arousals from sleep.Actigraphy is an alternative to PSG as an objective indirect measurement of sleep and wakefulness (Ancoli-Israel et al., 2003;Paquet et al., 2007). Actigraphy has the advantages that it is less costly and less intrusive than PSG, is relatively easy to use in ambulatory settings, and utilizes automated scoring algorithms that reduce the need for manual interpretation of the recordings. These advantages enable its use for multiple nights in longitudinal studies of sleep ⁄ wakefulness patterns. However, there is no set standard for the collection or scoring of sleep using actigraphy, making interpretation of data from different systems difficult (Acebo and LeBourgeois, 2006). In addition, because actigraphy uses movement as a surrogate for wakefulness, it is limited almost exclusively to the detection of sleep and wakefulness, and its correlation with PSG is moderate. Moreover, actigraphy tends to overestimate total sleep time (TST) in healthy and sleepdisordered subjects because actigraphy is prone to misint...

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A laboratory simulation has been devised for use in developing and testing physiologic monitoring systems' performance in the presence of electrosurgical interference. This facilitated the development through iterative optimization of an EEG based parameter whose performance is improved during electrosurgery. The system was found to have an improvement of 94% in response to electrosurgery interference in the laboratory simulation. It was found to be improved 78% from all interference sources when tested clinically during actual surgery. This demonstrates the efficacy of the simulation.

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