The effects of bright light treatment on affective symptoms in people with dementia: a 24-week cluster randomized controlled trial

BackgroundThe majority of people with dementia have behavioral and psychological symptoms of dementia (BPSD), including depression, anxiety and agitation. These may be elicited or aggravated by disrupted circadian rhythms. Bright light treatment (BLT) is a promising non-pharmacological approach to the management of BPSD, but previous research has yielded mixed results.MethodsEight nursing home dementia units (1 unit=1 cluster) with 78 patients were invited to participate in a cluster randomized controlled trial from September 2017 to April 2018 investigating the effects of BLT on sleep and circadian rhythms (primary outcome) and BPSD (secondary outcome). Ceiling mounted LED-panels were installed in the intervention group (four units), providing light at 1000lx and 6000K (vertically at 1.2m) between 10a.m. and 3p.m., with lower values in the mornings and evenings. Standard indoor light was used in the control group (four units). BPSD were assessed with The Cornell Scale for Depression in Dementia (CSDD) and the Neuropsychiatric Inventory Nursing Home Version (NPI-NH). Data collection took place at baseline and after 8, 16 and 24weeks. Multilevel regression models with and without false discovery rate correction were used for the analysis, with baseline values and dementia stage entered as covariates.ResultsSixty-nine patients were included in the study at baseline. Compared to the control group, the intervention group had a larger reduction on the composite scores of both the CSDD (95% CI=-6.0 - -0.3) and the NPI-NH (95% CI=-2.2 - -0.1), as well as on the NPI-NH Affect sub-syndrome, and the CSDD Mood related signs sub-scale at follow-up after 16weeks. With FDR correction, the group difference was significant on the CSDD Mood related signs sub-scale (95% CI=-2.7 - -0.8) and the NPI-NH Affect sub-syndrome (95% CI=-1.6 - -0.2). No differences were found between conditions at weeks 8 or 24.ConclusionCompared to the control condition, affective symptoms were reduced after 16weeks in the group receiving BLT, suggesting BLT may be beneficial for nursing home patients with dementia.Trial registrationClinicalTrials.gov Identifier: NCT03357328. Retrospectively registered on November 29, 2017.

Automated summary

The study showed that bright light treatment can reduce affective symptoms in nursing home patients with dementia, with significant effects observed after 16 weeks of use.