Objective Impact on Sleep and Daytime Functioning of Sleep Restriction Therapy

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Project title Objective Impact on Sleep and Daytime Functioning of Sleep Restriction Therapy: a Brief Behavioural Intervention for Persistent Insomnia.
Funding body Chief Scientist Office of the Scottish Government Health Directorates
Total funding £49,505
  • Professor Colin Espie, University of Glasgow Sleep Centre (Chief Investigator)
  • Dr Simon Kyle, Psychological Sciences, University of Manchester
  • Christine Salveta, University of Glasgow Sleep Centre
  • Professor Niroshan Siriwardena, School of Health & Social Care, University of Lincoln.
Overarching aim The study aimed to:

  • Rigorously test sleep restriction (SR), and so to provide an objective evidence base for its impact on sleep and daytime functioning
  • Evaluate the relationship between subjective and objective sleep and establish the optimal regime for adherence and the minimisation of adverse side-effects when advising on its use.
Objectives  The study sought to test the following hypotheses:

  • Sleep restriction therapy leads to objective improvements in sleep parameters, namely polysomnographic (PSG)-defined sleep-onset latency (SOL), wake-time after sleep-onset (WASO), and sleep efficiency (SE)
  • Sleep restriction modifies homeostatic pressure as measured by delta power during NREM sleep. And these changes relate to subjective improvements in sleep parameters
  • Sleep restriction impairs vigilance levels (as measured by psychomotor RT tasks) and higher cognitive abilities during acute implementation.
Methods A within subjects repeated measures design with major in-lab sleep evaluations, included:

  • Neuro-cognitive testing, conducted at baseline, and at three points during SR treatment
  • Self-report data on sleep and daytime functioning, along with a log of treatment experiences including side-effects gathered continuously over the experimental period
  • Exit interviews three months after completion of the acute treatment phase to gather follow-up data.
  • Primary outcomes related to changes to objectively defined sleep continuity and architecture and objective daytime functioning (neuropsychological performance)
  • Secondary outcomes related to subjective sleep and daytime functioning/quality of life variables.

Peer reviewed publications:

The research paper fromthis study has been cited over 50 times.

Kyle Simon D, Miller, Christopher B, Rogers, Zoe,  Siriwardena A. NiroshanMacMahon Kenneth M, and Espie Colin A. (2014)Sleep Restriction Therapy for Insomnia is associated with reduced objective total sleep time, increased daytime somnolence, and objectively-impaired vigilance: implications for the clinical management of Insomnia Disorder. Sleep, 37 (2). pp. 229-237. ISSN 0161-8105 Item availability may be restricted.


This work has helped us understand the therapeutic action of SR, potential adverse effects and how to deliver treatment in a safe and effective manner.

The impact from our research on insomnia is summarised at the REST project website, was presented in a case study to REF2014, Improving the primary care management of insomnia, and publicised in the university research showcase, ‘Improving treatment for insomnia sufferers‘.

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