Polysomnographic Characteristics of Sleep in Stroke: A Systematic Review and Meta-Analysis

Abstract

Background: Research on sleep after stroke has focused mainly on sleep disordered breathing. However, the extend to which sleep physiology is altered in stroke survivors, how these alterations compare to healthy volunteers, and how sleep changes might affect recovery as well as physical and mental health has yet to be fully researched. Motivated by the view that a deeper understanding of sleep in stroke is needed to account for its role in health and well-being as well as its relevance for recovery and rehabilitation, we conducted a systematic review and meta-analysis of polysomnographic studies comparing stroke to control populations.

Method: Medline and PsycInfo databases were searched using "stroke" and words capturing polysomnographic parameters as search terms. This yielded 1692 abstracts for screening, with 15 meeting the criteria for systematic review and 9 for meta-analysis. Prisma best practice guidelines were followed for the systematic review; the Comprehensive Meta-Analysis software was used for random effects modelling.

Results: The meta-analysis revealed that patients with stroke have poorer sleep than controls. Patients had lower sleep efficiency (mean 75% vs 84%), shorter total-sleep-time (309.4 vs 340.3 min) and more wake-after-sleep-onset (97.2 vs 53.8 min). Patients also spend more time in stage 1 (13% vs 10%) and less time in stage 2 sleep (36% vs 45%) and slow-wave-sleep (10% vs 12%). No group differences were identified for REM sleep. The systematic review revealed a strong bias towards studies in the early recovery phase of stroke, with no study reporting specifically on patients in the chronic state. Moreover, participants in the control groups included community samples as well as other patients groups.

Conclusions: These results indicate poorer sleep in patients with stroke than controls. While strongly suggestive in nature, the evidence base is limited and methodologically diverse, and hands a clear mandate for further research. A particular need regards polysomnographic studies in chronic community-dwelling patients compared to age-matched individuals.

Fig 1. Prisma chart for search flow.

Fig 2. Graphical representation of meta-analysis data.

Top half shows the results for all studies (with hospitalized and non-hopitalized control groups). The bottom half shows the results for studies with non-hospitalized healthy control groups.

Fig 3. Schematic representation of the how sleep changes in stroke might interact with stroke recovery.

Having a stroke induces physiological and psychological changes that are likely to trigger sleep problems. Sleep on the other hand is associated with mental and physical health, influences memory and plasticity processes, and is an important mediator of daytime functioning and performance. It is therefore plausible to assume that poor sleep impacts negatively on all of these aspects and may therefore directly or indirectly be detrimental to the rehabilitation process and longterm outcome.