Effectiveness of Light Therapy in Cognitively Impaired Persons: A Metaanalysis of Randomized Controlled Trials.

OBJECTIVES

To explore the effects of light therapy on behavioral disturbances (BDs), sleep quality, and depression.

DESIGN

Meta-analysis of randomized controlled trials.

SETTING

PubMed, Cochrane Library, Medline, EMBASE, Web of Science, and clinicaltrials.gov of selected randomized controlled trials and previous systematic reviews were searched.

PARTICIPANTS

Cognitively impaired persons.

MEASUREMENTS

Information was extracted on study characteristics, quality assessment, and outcomes. Outcome measures included BDs, sleep quality, and depression.

RESULTS

Nine randomized controlled trials were examined. The results showed that light therapy has a moderate effect on BD (g = -0.61) and depression (g = -0.58) and a small effect on total sleep time at night (g = 0.25). Subgroup analysis indicated that a light intensity of 2,500 lux or greater has a greater effect on depression than an intensity of less than 2,500 lux (P = .03), and the low risk of bias in blinding was superior to the RCTs deemed to be of high or unclear risk of bias in blinding in terms of BD (P = .02).

CONCLUSION

Light therapy can relieve BD, improve sleep quality, and alleviate symptoms of depression for cognitively impaired persons.