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; Jacob Williams; Natalie D Dautovich; Joseph P H McNamara; Ashley Stripling; Joseph M Dzierzewski; Richard B Berry; Karin J M McCoy; Christina S McCrae

doi:10.5664/jcsm.6790

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 Nov 15;13(11):1243-1254. doi: 10.5664/jcsm.6790.

Authors

Wai Sze Chan¹, Jacob Williams², Natalie D Dautovich³, Joseph P H McNamara⁴, Ashley Stripling⁵, Joseph M Dzierzewski³, Richard B Berry⁶, Karin J M McCoy⁷, Christina S McCrae⁸

Affiliations

¹ Department of Psychiatry, Geisel School of Medicine, Dartmouth College, Hanover, New Hampshire.
² TIRR Memorial Hermann, Houston, Texas.
³ Psychology Department, Virginia Commonwealth University, Richmond, Virginia.
⁴ Department of Psychiatry, University of Florida, Gainesville, Florida.
⁵ College of Psychology, Nova Southeastern University, Fort Lauderdale, Florida.
⁶ College of Medicine, University of Florida, Gainesville, Florida.
⁷ Neuropsychology Service, South Texas Veterans Health Care System, San Antonio, Texas.
⁸ Department of Health Psychology, University of Missouri-Columbia, Columbia, Missouri.

Abstract

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.

Methods: 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.

Results: 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).

Conclusions: 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: ClinicalTrials.gov, Identifier: NCT02967185.

Keywords: CBT-I; insomnia; mechanisms of change; older adults; sleep variability; treatment efficacy moderator.

Publication types

Randomized Controlled Trial

MeSH terms

Aged
Chronic Disease
Cognitive Behavioral Therapy / methods*
Female
Follow-Up Studies
Geriatric Assessment / methods
Geriatric Assessment / statistics & numerical data
Humans
Male
Polysomnography
Sleep / physiology
Sleep Initiation and Maintenance Disorders / physiopathology
Sleep Initiation and Maintenance Disorders / psychology
Sleep Initiation and Maintenance Disorders / therapy*
Time Factors

Associated data

ClinicalTrials.gov/NCT02967185

Grants and funding

K23 AG049955/AG/NIA NIH HHS/United States