The influence of environmental factors on sleep during recovery from acquired brain injury: Update from a systematic review...34th Australasian Rehabilitation Nurses' Association (ARNA) Annual Conference, October 23-24, 2025, Melbourne, Victoria

Abstract

Background Nightingale's Environmental theory (1860) describes the importance of quiet nights and strong daylight during wake for patients in hospital. The current World Health Organisation recommended noise levels are ≤30 decibels overnight in hospital, and recommended light levels are <1 lux during sleep and >250 lux during wake. People with acquired brain injury (ABI) commonly report trouble sleeping. Sleep problems and ABI during admission can cause delayed recovery and hospital discharge, exacerbation of pain and psychological distress. Post discharge, children with ABI and sleep problems report higher rates of depression and anxiety, and poor cognitive function. Aim The research question was 'How do environmental factors effect sleep for children and adults with an acquired brain injury?' The study followed the Cochrane methodology, was registered on PROSPERO and conducted according to PRISMA guidelines. Methods Five databases (PubMed, Embase, CINAHL, PsycINFO, Cochrane) were searched for studies published before January 2025. Inclusion criteria focused on human studies of ABI populations with documented environmental exposures and sleep outcome measurements. Results The review identified 1302 articles, a final seven studies met the inclusion criteria, with a combined 414 adult participants. Overnight noise was ≥ 50dB and mean light levels 1.74-9 lux. There were 5-6 episodes of nursing care overnight. Sleep quality was poor. Clustering cares and safeguarding sleep times were considered protective factors. Discussion Few studies have explored the environmental influence on sleep after ABI and none measured sleep with polysomnography, therefore the proportions of change in sleep stages remained unexamined in this population. Most concerning was the absence of paediatric studies, when children are a key population at risk for ABI and for whom long term improvement may cross the lifespan.