1022 Changes in The Sleep Quality And Caregiver Burden by Timed Blue Light in Alzheimer`s Disease

Abstract

Introduction: Sleep‐wake disturbances are prevalent in patients with Alzheimer's disease(AD), burdening distress for their caregivers. Therapeutic exposure to light has been shown to alter sleep‐wake rhythms. However, previous studies on the light therapy(LT) for sleep‐wake disturbances in AD failed to yield consistent findings due to methodological issues. We aimed to examine the effect of timed blue‐enriched light on subjective and objective sleep in AD patients and to evaluate changes in their caregiver burden. Methods: We recruited patients with mild to moderate AD who had the Pittsburgh Sleep Quality Index(PSQI) score of 5 or greater and/or complained insomnia symptoms more than 3 times a week. The patients were randomly assigned to the treatment group(TG) or control group(CG). The dim light melatonin onset(DLMO) was determined from seven hourly saliva samples obtained before sleep onset measured by actigraphy(Actiwatch 2;Respironics, USA) for 5 days. Home‐based one‐hour blue‐enriched light intervention(Litebook®EDGE™;Litebook, Canada) for 2 weeks was applied between 9 to 10 h after DLMO. The CG was to wear blue‐blocked glasses during timed LT. The neuropsychiatric inventory(NPI) was used for assessing the neuropsychiatric symptoms of patients(NPI‐S) and caregiver distress (NPI‐D). Six patients(77.3 ± 3.3years) of TG and four patients(76.0 ± 10.7years) of CG were included. Changes in the values before and after timed LT were analyzed for each group. Results: The PSQI scores of TG after timed LT were significantly decreased, compared to those before timed LT(p<0.05) while there were no significant changes between sleep parameters before and after timed LT in both groups. The scores of NPI‐S and NPI‐D in TG were reduced after timed LT(11.0 ± 4.5 to8.5 ± 4.9;13.3 ± 9.1 to9.0 ± 8.1), but these were not significant. Conclusion: After timed LT, AD patients did not show a significant improvement in objective sleep, but did in subjective sleep quality. Our finding also indicates timed LT might have a beneficial effect on the behavior disturbance of AD patients and their caregiver distress.