1 Submitted: 5 March, 2019; Revised: 6 June, 2019 © Sleep Research Society 2019. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com. Original Article Sleep and wake are shared and transmitted between individuals with insomnia and their bed-sharing partners Elizabeth M. Walters 1 , Andrew J. K. Phillips 1 , Alix Mellor 1 , Kellie Hamill 1 , Melissa M. Jenkins 2 , Peter J. Norton 1 , Donald H. Baucom 3 and Sean P. A. Drummond 1, * , 1 School of Psychological Sciences and Turner Institute for Brain and Mental Health, Monash University, Melbourne, Victoria, Australia, 2 Center for Stress and Anxiety Management, San Diego, CA and 3 Department of Psychology and Neuroscience, University of North Carolina, Chapel Hill, NC *Corresponding author. Sean P. A. Drummond, Monash Institute for Cognitive and Clinical Neurosciences, School of Psychological Sciences, Monash University, 18 Innovation Walk, Clayton, Victoria 2300, Australia. Email: sean.drummond@monash.edu Abstract Patients with insomnia frequently report disturbing, or being disturbed by, their bedpartner. We aimed to (1) characterize how individuals with insomnia and their bedpartners influence each other’s sleep and (2) identify characteristics predicting vulnerability to wake transmission. Fifty-two couples (aged 19–82 years), where one individual was diagnosed with insomnia, participated. Sleep/wake patterns were monitored via actigraphy and sleep diaries for seven nights. Minute-by-minute sleep and wake concordance (simultaneous sleep/wake epochs), number of wake transmissions received (awakenings immediately preceded by wakefulness in the bedpartner), percent wake transmissions received (percentage of total awakenings that were transmitted), and percent of bedpartner’s wake minutes resistant to transmission (ability to sleep through bedpartner wakefulness) were calculated. Mixed-effects modeling assessed within-couple bedtime and chronotype differences as predictors of dyadic sleep. We described rates of sleep concordance (M Patient  = 63.8%, M Partner  = 65.6%), wake concordance (M Patient  = 6.6%, M Partner  = 6.6%), total transmissions received (M Patient  = 5.5, M Partner  = 6.9 per night), percent transmissions received (M Patient  = 18.5%, M Partner  = 23.4% of total awakenings), and percent minutes resistant (M Patient  = 56.4%, M Partner  = 58.6% of bedpartner’s wake time). Partners received wake transmissions at 1.25 times the rate of patients. Percent transmissions received was increased in couples with concordant bedtimes and individuals with later chronotype than their bedpartner. Patterns of chronotype and bedtime order predicting percent minutes resistant to transmission differed across the length of the rest interval. Transmission provides a novel characterization of how bedpartners influence sleep and provide insight into mechanisms of insomnia generation and maintenance. Understanding modifiable risk factors may provide ways to personalize insomnia treatments. Clinical Trial: Researching Effective Sleep Treatments (Project REST), ANZCTR Registration: ACTRN12616000586415 Key words: couples; insomnia; concordance; wake transmission; relationships; sleep disorders; dyad Statement of Significance Recent research suggest that sleep problems in an individual can precipitate sleep problems in their bedpartner, but ways to systematically assess this process do not exist. Here, we quantify a novel metric in bed-sharing couples comprising one individual with insomnia and their partner: transmission of wake between bedpartners (awakenings occurring immediately after wake in the bedpartner). Partners of in- somnia patients receive more frequent wake transmissions than those with insomnia, indicating that having a bedpartner with insomnia is disruptive to sleep. Individual sleep timing and chronotype characteristics predict the degree of bedpartner disruption. Understanding modifiable risk factors related to dyadic sleep has implications for preventing the development of insomnia and improving insomnia therapies. SLEEPJ, 2020, 1–12 doi: 10.1093/sleep/zsz206 Advance Access Publication Date: 25 September 2019 Original Article Downloaded from https://academic.oup.com/sleep/article/43/1/zsz206/5573656 by guest on 21 November 2023