title: Effects of Between- and Within-Subject Variability on Autonomic Cardiorespiratory Activity during Sleep and Their Limitations on Sleep Staging: A Multilevel Analysis.
abstract: Autonomic cardiorespiratory activity changes across sleep stages. However, it is unknown to what extent it is affected by between- and within-subject variability during sleep. As it is hypothesized that the variability is caused by differences in subject demographics (age, gender, and body mass index), time, and physiology, we quantified these effects and investigated how they limit reliable cardiorespiratory-based sleep staging. Six representative parameters obtained from 165 overnight heartbeat and respiration recordings were analyzed. Multilevel models were used to evaluate the effects evoked by differences in sleep stages, demographics, time, and physiology between and within subjects. Results show that the between- and within-subject effects were found to be significant for each parameter. When adjusted by sleep stages, the effects in physiology between and within subjects explained more than 80% of total variance but the time and demographic effects explained less. If these effects are corrected, profound improvements in sleep staging can be observed. These results indicate that the differences in subject demographics, time, and physiology present significant effects on cardiorespiratory activity during sleep. The primary effects come from the physiological variability between and within subjects, markedly limiting the sleep staging performance. Efforts to diminish these effects will be the main challenge.
authors.affiliation: Department of Personal Health, Philips Research, 5656 AE Eindhoven, Netherlands ; Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands.
authors.forename: Xi
authors.initials: X
authors.lastname: Long
authors.affiliation: Department of Personal Health, Philips Research, 5656 AE Eindhoven, Netherlands.
authors.forename: Reinder
authors.initials: R
authors.lastname: Haakma
authors.affiliation: Department of Behavior, Cognition & Perception, Philips Research, 5656 AE Eindhoven, Netherlands.
authors.forename: Tim R M
authors.initials: TR
authors.lastname: Leufkens
authors.affiliation: Department of Personal Health, Philips Research, 5656 AE Eindhoven, Netherlands ; Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands.
authors.forename: Pedro
authors.initials: P
authors.lastname: Fonseca
authors.affiliation: Department of Personal Health, Philips Research, 5656 AE Eindhoven, Netherlands ; Department of Electrical Engineering, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands.
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Aarts
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001341:Autonomic Nervous System; D002320:Cardiovascular Physiological Phenomena; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007206:Individuality; D008297:Male; D008875:Middle Aged; D055361:Multilevel Analysis / Q000379:methods*; D012119:Respiration; D012143:Respiratory Physiological Phenomena; D012737:Sex Factors; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology; D013997:Time Factors; D055815:Young Adult