Morning lighting intervention reduces fatigue and improves sleep in Parkinson disease

Fatigue and sleep disturbances are common in Parkinson Disease (PD) and significantly reduce quality of life, yet effective pharmacological treatments are limited. Light therapy offers a promising non-pharmacologic approach, but most lighting interventions have focused on improving sleep. Using a novel and easily administered morning lighting intervention, we previously demonstrated improvement in sleep duration. We have now extended the prior study through the addition of 23 individuals to investigate the intervention's effect on fatigue and sleep. In this single-arm intervention study, participants received morning light for 4 consecutive weeks from table or floor luminaires designed to deliver circadian-effective ambient light at home. Objective sleep was measured with wrist-worn actigraphy and subjective sleep, fatigue and mood were assessed using standardized questionnaires. Analysis of pre and post intervention data for the current cohort was performed separately as well as in combination with the 20 participants from the previously reported pilot study. For the 23 current participants, fatigue on the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) scale improved by 3.9 ± 1.00 points (p = 0.0026). While sleep duration increased by mean 21.3 ± 14.4 min, it was not statistically significant (p = 0.082). When combined with the 20 participants from the prior pilot study, significant improvement in fatigue by 2.8 ± 0.85 points (p = 0.0033) was observed and sleep duration was also significantly increased by 24.7 ± 10.4 min (p = 0.012). These findings support morning light as a novel intervention for fatigue in PD.