Abstract: Objective To study the effects of different light intensity of phototherapy on the sleep quality of the elderly patients with Parkinson’s disease and insomnia. Methods A total of 136 elderly patients with Parkinson’s disease and insomnia at the First Affiliated Hospital with Nanjing Medical University from July 2022 to January 2024 were enrolled in this study. They were randomly divided into high-intensity light group, moderate-intensity light group, low-intensity light group and control group. The control group received routine treatment and nursing, and the three phototherapy groups received 10 000 Lux, 5 000 Lux and 1 000 Lux phototherapy from 16:30 to 17:00 every day additionally. The score of Parkinson’s Disease Sleep Scale(PDSS) and the polysomnography(PSG) parameters were compared among the four groups 1 week, 2 weeks and 1 month after intervention. Results After one week of intervention, there was no significant difference in PDSS score and PSG paramenters between the high-intensity light group and the moderate-intensity light group(P>0.05), but the PDSS scores and the sleep efficiency, wake time and wake frequency were significantly different compared with the low-intensity light group and the control group(P<0.05). There was no significant difference in PDSS score and PSG parameters between the low-intensity light group and the control group(P>0.05). After two weeks of intervention, there was no significant difference in PDSS score and PSG parameters between the moderate-intensity light group and the low-intensity light group(P>0.05), but the PDSS scores and the sleep efficiency, wake time and wake frequency were different compared with the control group(P<0.05); The PDSS scores and the sleep efficiency, wake time of the high-intensity light group were significant different compared with the moderate-intensity light group, the low-intensity light group and the control group(P<0.05). One month after intervention, there was no significant difference in PDSS scores and PSG among the three phototherapy groups(P>0.05),but the sleep efficiency, wake time and wake frequency were significant different compared with the control group (P<0.05). Conclusions Phototherapy with higher intensity(5 000 Lux and above) can achieve good therapeutic effect in the elderly patients with Parkinson’s disease and insomnia in a short period of time(1 week), and the greater the light intensity in the short term, the greater the effect size. Long-term adherence to 30 min daily phototherapy, 1 000 Lux and above light intensity can improve sleep quality.

Key words: bright light therapy, aged, Parkinson’s disease, insomnia, sleep quality