Light therapy for managing sleep, behaviour, and mood disturbances in dementia

Rest-activity and sleep-wake cycles are controlled by the endogenous circadian rhythm generated by the suprachiasmatic nuclei (SCN) of the hypothalamus. Degenerative changes in the SCN appear to be a biological basis for circadian disturbances in people with dementia, and might be reversed by stimulation of the SCN by light.

The review assesses the efficacy of bright light therapy (BLT) in managing sleep, behaviour, mood, and cognitive disturbances associated with dementia.

The trials were identified from a search of the Specialized Register of the Cochrane Dementia and Cognitive Improvement Group on 27 January 2004 using the terms "bright light*", "light box*", "light visor*", "dawn-dusk*", phototherapy (MESH), phototherapy, "photo therapy", "light therapy" "light treatment", light*.

All relevant, randomized controlled trials in which BLT, at any intensity and duration, was compared with a control group for the effect on managing sleep, behavioural, mood, and cognitive disturbances (as well as changes in institutionalization rates and cost of care) on people with dementia of any degree of severity.

Three reviewers independently assessed the retrieved articles for relevance, methodological quality, and extracted data from the selected studies. The statistically significant differences in changes in outcomes from baseline to end of treatment and from baseline to follow-up between the light therapy and control groups were examined. Each study was summarized using a measure of effect (e.g. mean difference). Owing to lack of homogeneity between studies, their results were not combined.

Five studies met the inclusion criteria. However, only three were included in the analyses because of inappropriate analyses reported or inability to retrieve the required data from the investigators. This review revealed no adequate evidence of the effectiveness of BLT in managing sleep, behaviour, and mood disturbances associated with dementia.

There is insufficient evidence to assess the value of BLT for people with dementia. The available studies are of poor quality and further research is required.