0503 Reductions in Sleep and Daily Rhythm Variability Following Brief Behavioral Treatment for Insomnia

Abstract

Introduction: Brief behavioral treatment for insomnia (BBTI) is efficacious for insomnia symptoms. Here we examine whether BBTI reduces sleep and daily rhythm variability and whether reductions in variability result in improved functioning and quality of life. Methods: Ninety-one Veterans with insomnia (49.3±18.7yrs; 18.7% female) were randomized to one of two treatment conditions: BBTI or progressive muscle relaxation training (PMRT; control condition). Variability was assessed using sleep diaries and actigraphy. The sleep diary outcome variables included bedtime variability, wake time variability, and total sleep time variability; actigraphy variables included interdaily stability, intradaily variability, and total sleep time variability. Functioning was assessed using the Work and Social Adjustment Scale. Quality of life was assessed using the Hotel Dieu-16 Scale. Results: Compared to PMRT, BBTI resulted in a greater reduction in subjective total sleep time variability (F1,90=6.61, p<0.01, partial η2=0.13) and a greater increase in interdaily stability (F1,78=12.41, p<0.01, partial η2=0.25). There was a greater decrease in intradaily variability following PMRT (F1,78=27.96, p<0.01, partial η2=0.42). Across the entire sample, reductions in subjective wake time variability were associated with improved functioning (F1,88=4.43, p=0.04, η2=0.05) and reductions in subjective total sleep time variability were associated with improved quality of life (F1,89=4.91, p=0.03, partial η2=0.05). Conclusion: There was significant improvement in the stability of sleep-wake rhythms following BBTI, suggesting that BBTI not only treats insomnia, but also may stabilize circadian rhythms. Interestingly, PMRT resulted in greater intradaily variability reductions than BBTI. One explanation is that due to BBTI stimulus control guidelines, individuals were getting out of bed in the middle of the night more frequently and thus, these awakenings were better captured by actigraphy. Reductions in wake time and total sleep time variability were associated with improved functioning and quality of life, further demonstrating the importance of stable sleep-wake rhythms.