Effects of a Tailored Lighting Intervention on Sleep Quality, Rest-Activity, Mood, and Behavior in Older Adults With Alzheimer Disease and Related Dementias: A Randomized Clinical Trial

Abstract

Study objectives: We investigated the effectiveness of a lighting intervention tailored to maximally affect the circadian system as a nonpharmacological therapy for treating problems with sleep, mood, and behavior in persons with Alzheimer disease and related dementias (ADRD).

Methods: This 14-week randomized, placebo-controlled, crossover design clinical trial administered an all-day active or control lighting intervention to 46 patients with ADRD in 8 long-term care facilities for two 4-week periods (separated by a 4-week washout). The study employed wrist-worn actigraphy measures and standardized measures of sleep quality, mood, and behavior.

Results: The active intervention significantly improved Pittsburgh Sleep Quality Index scores compared to the active baseline and control intervention (mean ± SEM: 6.67 ± 0.48 after active intervention, 10.30 ± 0.40 at active baseline, 8.41 ± 0.47 after control intervention). The active intervention also resulted in significantly greater active versus control differences in intradaily variability. As for secondary outcomes, the active intervention resulted in significant improvements in Cornell Scale for Depression in Dementia scores (mean ± SEM: 10.30 ± 1.02 at baseline, 7.05 ± 0.67 after active intervention) and significantly greater active versus control differences in Cohen-Mansfield Agitation Inventory scores (mean ± SEM: -5.51 ± 1.03 for the active intervention, -1.50 ± 1.24 for the control intervention).

Conclusions: A lighting intervention tailored to maximally entrain the circadian system can improve sleep, mood, and behavior in patients with dementia living in controlled environments.

Clinical trial registration: Registry: ClinicalTrials.gov, title: Methodology Issues in a Tailored Light Treatment for Persons With Dementia, URL: https://clinicaltrials.gov/ct2/show/NCT01816152, identifier: NCT01816152.

Keywords: Alzheimer’s disease; circadian system; dementia; lighting intervention; mood; rest–activity; sleep.

Figure 1. The study protocol.

The 14-week protocol was composed of two 1-week baseline measurement periods and two 4-week counterbalanced lighting interventions (active versus control), separated by a 4-week washout period. Data were collected during the baseline measurement weeks (weeks 1 and 10) prior to each 4-week intervention and once again during the final week of each intervention (weeks 5 and 14).

Figure 2. Geometric mean raw and difference CS values for the active and control interventions.

The mean CS value after the active intervention was significantly greater than baseline (A), and the differences in mean CS values were significantly greater after the active intervention compared to the control intervention (B). The error bars represent standard error of the mean. ** represents P < .01 and * represents P < .05. CS = circadian stimulus.

Figure 3. Mean raw and difference scores for measures of sleep quality, depression, and agitation behavior for the active and control interventions.

Mean raw and difference scores for measures of (A, B) sleep quality (primary aim), (C, D) depression (secondary aim), and (E, F) agitation (secondary aim) for the active and control interventions. The raw scores for sleep quality (PSQI) and depression (CSDD) improved significantly after the active TLI compared to baseline. The sleep quality, depression, and agitation behavior difference (baseline–intervention) scores were significantly greater after the active TLI compared to the control TLI. The results of the post hoc analysis are provided in Table 3 and Table 5. The error bars represent standard error of the mean. *** represents P < .001 and * represents P < .05. CMAI = Cohen-Mansfield Agitation Inventory, CSDD = Cornell Scale for Depression in Dementia, PSQI = Pittsburgh Sleep Quality Index.