A Preliminary Evaluation of the Physiological Mechanisms of Action for Sleep Restriction Therapy

Sleep disorders 11/2013; 2013(1):726372. DOI: 10.1155/2013/726372
Source: PubMed


Our objective was to investigate the physiological mechanisms involved in the sleep restriction treatment of insomnia. A multiple baseline across subjects design was used. Sleep of five participants suffering from insomnia was assessed throughout the experimentation by sleep diaries and actigraphy. Ten nights of polysomnography were conducted over five occasions. The first two-night assessment served to screen for sleep disorders and to establish a baseline for dependent measures. Three assessments were undertaken across the treatment interval, with the fifth and last one coming at follow-up. Daily cortisol assays were obtained. Sleep restriction therapy was applied in-lab for the first two nights of treatment and was subsequently supervised weekly. Interrupted time series analyses were computed on sleep diary data and showed a significantly decreased wake time, increased sleep efficiency, and decreased total sleep time. Sleepiness at night seems positively related to sleep variables, polysomnography data suggest objective changes mainly for stage 2, and power spectral analysis shows a decrease in beta-1 and -2 powers for the second night of treatment. Cortisol levels seem to be lower during treatment. These preliminary results confirm part of the proposed physiological mechanisms and suggest that sleep restriction contributes to a rapid decrease in hyperarousal insomnia.

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Available from: Celyne Bastien, Feb 18, 2014
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    ABSTRACT: Behavioural therapies are recommended as the first-line treatment of insomnia; however, sedatives and hypnotics constitute the main treatment modality used in primary care. Community pharmacies provide a unique conduit for identifying and providing appropriate treatment for those with insomnia either purchasing prescription sedatives or seeking over-the-counter treatments. A feasibility study using a cluster-randomized controlled trial, testing the efficacy of trained pharmacists providing behavioural interventions such as stimulus control and sleep restriction to patients with insomnia, in improving insomnia severity was conducted. The intervention involved three pharmacy visits (baseline, 1 and 3 months follow-up). The control group received usual care and information sheets on insomnia. The primary outcome was the Insomnia Severity Index. Twelve community pharmacists (five control, seven intervention) in New South Wales, Australia were recruited and trained. These pharmacists, in turn, recruited 46 patients (22 control, 24 intervention (mean age 53.7 ± 18.4, 72% females) and delivered a brief behavioural therapy intervention. The overall decrease in Insomnia Severity Index from baseline to the 3-month follow-up in the intervention group, n = 17 (7.6 ± 4.3 points), was significantly greater than for the control group, n = 19 (2.9 ± 8.8 points) (mean difference 4.6, 95% confidence interval: 0.005-9.2, P = 0.05). However, when the effect of clustering was taken into account using a mixed-effects model, the estimated difference in Insomnia Severity Index (change from baseline to visit 3) between the intervention and control groups was not significant (group difference in Insomnia Severity Index change = 3.78, 95% confidence interval: -0.81 to 8.37, P = 0.11; intracluster correlation = 0.18). The study highlights the use of a novel venue to deliver brief behavioural therapies for insomnia using trained non-psychologist health professionals. Although, when cluster effect was taken into account, the difference in Insomnia Severity Index reduction between the intervention versus control groups was non-significant, the results highlight that reductions in insomnia severity can be gained using trained pharmacists providing brief behavioural interventions. Future research in this area is warranted, with appropriately sized studies using the conventional, robust randomized trial design. © 2015 European Sleep Research Society.
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