title: Automatic sleep/wake scoring from body motion in bed: validation of a newly developed sensor placed under a mattress.
abstract: The purpose of this study was to formulate a "sleep/wake" scoring algorithm for processing activity measurements obtained using a newly developed nonwear actigraphy (NWA) device, and to test its validity. The NWA device has a highly sensitive pressure sensor and is placed under a mattress. It can continuously record the activity of a person lying on the mattress and identify an "in-bed/out-of-bed" state from the vibrations of the mattress. We formulated the sleep/wake scoring algorithm by using data obtained simultaneously by wrist actigraphy (Act) and the NWA device in 33 healthy participants. Agreement rate, sensitivity, and specificity with Act were 95.7%, 97.6%, and 75.8% (33 healthy people); the corresponding values were 85.9%, 89.1%, and 79.8% for 12 nursing home residents and 93.7%, 97.2%, and 60.8% for 60 nights for 6 healthy persons who slept 10 nights on their futons. Agreement rate, sensitivity, and specificity with polysomnography were in almost perfect agreement with Act (12 nights; 6 healthy persons who slept 2 nights). All our validation results indicate that the NWA device, placed under a mattress or a futon, can produce almost identical sleep/wake scores to Act. It is expected that the NWA device, a nonwear device for scoring sleep/wake and in-bed/out-of-bed, enables convenient long-term sleep-related evaluation in various fields, including hospital settings, home-care settings, and care facility settings such as nursing homes.
authors.affiliation: Paramount Bed Sleep Research Laboratory, Paramount Bed Co., Ltd., Tokyo, Japan. t.kogure@paramount.co.jp
authors.forename: Takamasa
authors.initials: T
authors.lastname: Kogure
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Shirakawa
authors.forename: Masato
authors.initials: M
authors.lastname: Shimokawa
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hosokawa
mesh_terms: D056044:Actigraphy / Q000295:instrumentation*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001513:Beds; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes; D017286:Polysomnography / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012890:Sleep / Q000502:physiology*; D018709:Statistics, Nonparametric; D014851:Wakefulness / Q000502:physiology; D055815:Young Adult