Although Alzheimer's disease (AD) mainly affects cognitive function, it is often accompanied by sleep disorders and psycho-behavioural symptoms. In a new study published in the journal PloS One, Chinese researchers from the School of Nursing at Weifang Medical University evaluated the efficacy of light therapy in improving sleep disorders and psycho-behavioural symptoms in people with AD. They conducted a meta-analysis by identifying randomised controlled studies on light therapy for AD in the literature up to December 2022.
They found 15 studies involving 598 people with AD, perfomed in 7 countries and selected them for further analysis. In the case of sleep disorders, the meta-analysis revealed that light therapy significantly improved sleep efficiency, increased interdaily stability (a measure of the strength of circadian rhythms) and reduced intradaily variability (a measure of how frequently someone transitions between rest and activity during the day). Light therapy also alleviated depression and reduced agitation and caregiver burden. Given the limited sample sizes in studies included in this meta-analysis, the authors advocate for larger future studies. They conclude that light therapy could lead to significant improvement in sleep and psycho-behavioural symptoms and is associated with relatively fewer side effects in people with AD.
