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

J Am Geriatr Soc. 2017 Oct;65(10):2227-2234. doi: 10.1111/jgs.14990. Epub 2017 Jul 22.


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.

Keywords: behavioral disturbance; cognitively impaired; depression; light therapy; sleep quality.

Publication types

  • Meta-Analysis

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cognitive Dysfunction / physiopathology
  • Cognitive Dysfunction / psychology
  • Cognitive Dysfunction / therapy*
  • Depression / physiopathology
  • Depression / psychology
  • Depression / therapy
  • Female
  • Humans
  • Male
  • Middle Aged
  • Phototherapy / methods*
  • Randomized Controlled Trials as Topic
  • Sleep / physiology
  • Treatment Outcome