The Effects of Light Therapy on Sleep, Depression, Neuropsychiatric Behaviors, and Cognition Among People Living With Dementia: A Meta-Analysis of Randomized Controlled Trials.
Study Goal
The researchers aimed to evaluate the effects of light therapy on sleep, depression, neuropsychiatric behaviors, and cognition in people living with dementia (PLWD).
Results Summary
Light therapy showed small-to-medium improvements in sleep parameters, reduced depression, and improved cognition, with medium-to-large effects on specific subscales like agitation, affective symptoms, and mood-related signs. It also demonstrated benefits in reducing neuropsychiatric behaviors.
Population
People living with dementia (PLWD)
Effective Dosage
Not specified
Duration
Not specified
Interactions
None mentioned
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
light therapy | increase | total sleep time | people living with dementia (PLWD) | Hedges' g = 0.19 | demonstrated small-to-medium effects on improving | #1 |
light therapy | decrease | wake after sleep onset | people living with dementia (PLWD) | Hedges' g = 0.24 | demonstrated small-to-medium effects on improving | #2 |
light therapy | increase | sleep efficiency | people living with dementia (PLWD) | Hedges' g = 0.31 | demonstrated small-to-medium effects on improving | #3 |
light therapy | decrease | sleep latency | people living with dementia (PLWD) | Hedges' g = 0.35 | demonstrated small-to-medium effects on improving | #4 |
light therapy | increase | circadian rhythm (acrophase) | people living with dementia (PLWD) | Hedges' g = 0.36 | demonstrated small-to-medium effects on improving | #5 |
light therapy | increase | circadian rhythm (amplitude) | people living with dementia (PLWD) | Hedges' g = 0.43 | demonstrated small-to-medium effects on improving | #6 |
light therapy | decrease | number of night awakenings | people living with dementia (PLWD) | Hedges' g = 0.37 | demonstrated small-to-medium effects on improving | #7 |
light therapy | decrease | sleep disturbance | people living with dementia (PLWD) | Hedges' g = 0.45 | demonstrated small-to-medium effects on improving | #8 |
light therapy | increase | sleep quality | people living with dementia (PLWD) | Hedges' g = 0.60 | demonstrated small-to-medium effects on improving | #9 |
light therapy | decrease | depression | people living with dementia (PLWD) | Hedges' g = -0.46 | showed small-to-medium effect on reducing | #10 |
light therapy | decrease | cyclical function subscale | people living with dementia (PLWD) | Hedges' g = -0.68 | showed medium-to-large effect on reducing | #11 |
light therapy | decrease | mood-related signs and symptoms subscale | people living with dementia (PLWD) | Hedges' g = -0.84 | showed medium-to-large effect on reducing | #12 |
light therapy | decrease | neuropsychiatric behaviors | people living with dementia (PLWD) | Hedges' g = -0.34 | demonstrated small effect on reducing | #13 |
light therapy | decrease | agitation subscale | people living with dementia (PLWD) | Hedges' g = -0.65 | demonstrated medium-to-large effect on reducing | #14 |
light therapy | decrease | affective symptom subscale | people living with dementia (PLWD) | Hedges' g = -0.70 | demonstrated medium-to-large effect on reducing | #15 |
light therapy | decrease | psychosis subscale | people living with dementia (PLWD) | Hedges' g = -0.72 | demonstrated medium-to-large effect on reducing | #16 |
light therapy | decrease | melancholic behavior subscale | people living with dementia (PLWD) | Hedges' g = -0.91 | demonstrated medium-to-large effect on reducing | #17 |
light therapy | increase | cognition | people living with dementia (PLWD) | Hedges' g = 0.39 | improved | #18 |
OBJECTIVE: Alterations in the suprachiasmatic nucleus due to underlying pathologies disrupt the circadian rhythms in people living with dementia (PLWD). Circadian rhythms significantly impact sleep, emotional, and cognitive functions, with its synchronization depending on light exposure. We performed a meta-analysis to evaluate the effects of light therapy on sleep, depression, neuropsychiatric behaviors, and cognition among PLWD. METHODS: A systematic search was conducted in Cochrane, ClinicalTrials.gov, Embase, EBSCOhost, Ovid-MEDLINE, PubMed, Scopus, Web of Science, and CINAHL databases. The pooled effect size was calculated using the Hedges' g with random-effects model adopted in comprehensive meta-analysis software. The Cochrane risk of bias (RoB 2.0) tool evaluated the quality of studies, while Cochrane's Q and I² tests assessed heterogeneity. RESULTS: A total of 24 studies with 1,074 participants were included. Light therapy demonstrated small-to-medium effects on improving sleep parameters: total sleep time (Hedges' g = 0.19), wake after sleep onset (Hedges' g = 0.24), sleep efficiency (Hedges' g = 0.31), sleep latency (Hedges' g = 0.35), circadian rhythm (acrophase: Hedges' g = 0.36; amplitude: Hedges' g = 0.43), number of night awakenings (Hedges' g = 0.37), sleep disturbance (Hedges'g = 0.45), and sleep quality (Hedges' g = 0.60). Light therapy showed small-to-medium effect on reducing depression (Hedges' g = -0.46) with medium-to-large effect on cyclical function (Hedges' g = -0.68) and mood-related signs and symptoms (Hedges' g = -0.84) subscales. Light therapy also demonstrated small effect on reducing neuropsychiatric behaviors (Hedges' g = -0.34) with medium-to-large effect on agitation (Hedges' g = -0.65), affective symptom (Hedges' g = -0.70), psychosis (Hedges' g = -0.72), and melancholic behavior (Hedges' g = -0.91) subscales. Additionally, light therapy also improved cognition (Hedges' g = 0.39). CONCLUSION: Light therapy could be used as a supportive therapy to improve sleep, depression, cognition, and neuropsychiatric behaviors among PLWD.