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Volume 13 No. 11
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Accepted Papers

Scientific Investigations

Night-to-Night Sleep Variability in Older Adults With Chronic Insomnia: Mediators and Moderators in a Randomized Controlled Trial of Brief Behavioral Therapy (BBT-I)

Wai Sze Chan, PhD1; Jacob Williams, MA2; Natalie D. Dautovich, PhD3; Joseph P.H. McNamara, PhD4; Ashley Stripling, PhD5; Joseph M. Dzierzewski, PhD3; Richard B. Berry, MD6; Karin J.M. McCoy, PhD7; Christina S. McCrae, PhD8
1Department of Psychiatry, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire; 2TIRR Memorial Hermann, Houston, Texas; 3Psychology Department, Virginia Commonwealth University, Richmond, Virginia; 4Department of Psychiatry, University of Florida, Gainesville, Florida; 5College of Psychology, Nova Southeastern University, Fort Lauderdale, Florida; 6College of Medicine, University of Florida, Gainesville, Florida; 7Neuropsychology Service, South Texas Veterans Health Care System, San Antonio, Texas; 8Department of Health Psychology, University of Missouri-Columbia, Columbia, Missouri

Study Objectives:

Sleep variability is a clinically significant variable in understanding and treating insomnia in older adults. The current study examined changes in sleep variability in the course of brief behavioral therapy for insomnia (BBT-I) in older adults who had chronic insomnia. Additionally, the current study examined the mediating mechanisms underlying reductions of sleep variability and the moderating effects of baseline sleep variability on treatment responsiveness.


Sixty-two elderly participants were randomly assigned to either BBT-I or self-monitoring and attention control (SMAC). Sleep was assessed by sleep diaries and actigraphy from baseline to posttreatment and at 3-month follow-up. Mixed models were used to examine changes in sleep variability (within-person standard deviations of weekly sleep parameters) and the hypothesized mediation and moderation effects.


Variabilities in sleep diary-assessed sleep onset latency (SOL) and actigraphy-assessed total sleep time (TST) significantly decreased in BBT-I compared to SMAC (Pseudo R2 = .12, .27; P = .018, .008). These effects were mediated by reductions in bedtime and wake time variability and time in bed. Significant time × group × baseline sleep variability interactions on sleep outcomes indicated that participants who had higher baseline sleep variability were more responsive to BBT-I; their actigraphy-assessed TST, SOL, and sleep efficiency improved to a greater degree (Pseudo R2 = .15 to .66; P < .001 to .044).


BBT-I is effective in reducing sleep variability in older adults who have chronic insomnia. Increased consistency in bedtime and wake time and decreased time in bed mediate reductions of sleep variability. Baseline sleep variability may serve as a marker of high treatment responsiveness to BBT-I.

Clinical Trial Registration:, Identifier: NCT02967185


Chan WS, Williams J, Dautovich ND, McNamara JP, Stripling A, Dzierzewski JM, Berry RB, McCoy KJ, McCrae CS. Night-to-night sleep variability in older adults with chronic insomnia: mediators and moderators in a randomized controlled trial of brief behavioral therapy (BBT-I). J Clin Sleep Med. 2017;13(11):1243–1254.

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