A systematic review on the effect of light therapy in sundowning behavior of patients with dementia

Dementia is a cognitive disorder that affects daily living of the individual. According to DSM V criteria, it is defined as the evidence of significant cognitive decline from a previous level of performance in one or more cognitive domains which interferes in everyday activity with no other structural, metabolic or psychiatric cause. However, during the course of dementia, 90% of patients suffer from behavioral and psychological symptoms of dementia (BPSD). The sundowning or nocturnal delirium is a form of BPSD which can affect patients with dementia particularly those of advanced stage. Presently, there are no established guidelines for the management of symptoms of sundowning in patients with dementia and efficacy of pharmacologic and nonpharmacologic treatments are not yet established. One of the nonpharmacologic treatment is bright light therapy. We performed a systemic review of published literature on the effects of bright light therapy on sundowning in patients with dementia. We found only two randomized controlled trials utilizing the standard 10,000 lux lamp among dementia patients. Based on the two studies, bright light therapy had no significant beneficial effect on the sundowning behavior.