Chronotypes, Nocturnal Melatonin Level and Excessive Daytime Sleepiness in Parkinson's Disease (PD) (P4.280)

Objective: To determine whether subjective propensity towards morningness or eveningness is associated with a specific nocturnal melatonin profile in persons with Parkinson9s disease (PD). Background: Circadian dysrhythmia may underlie several sleep-wake cycle associated symptoms in PD. Effective strategies to address this derangement require better understanding of melatonin secretion patterns, and identification of subjective markers that may predict these patterns in persons with PD. Methods: 26 Veterans with PD completed Horn and Ostberg9s Morningness-Eveningness questionnaire, 14 day sleep diary and provided hourly saliva samples from 8pm to 3am at the facility Sleep Lab for melatonin assay. Comparisons were made by chronotype for the peak melatonin level and collection hour (the hour at which the assay showed the highest level of melatonin). Additionally, the total collection hours were grouped as quartiles and compared [8-9pm, 10-11pm, 12-1am, and 2-3am] for the chronotypes. Chronotype groups were also compared for depression (Standardized Zung), excessive sleepiness (Epworth Sleepiness Scale), age at the time of questionnaire completion, disease severity (H&Y), cognition (UPDRS Mentation score), median bedtime and median rise time. (SPSS, Kruskal-Wallis Test) Results There was no difference between the chronotype groups for the peak melatonin hour, (STATA, Fishers exact test) or the peak melatonin level. The chronotype groups did not differ for melatonin levels (STATA, Kruskal-Wallis Test) at any of the 8 hourly collection times. There was no correlation of the peak melatonin time with the subject9s median rise time. However, the Morningness-Eveningness score was negatively correlated with the rise time. (SPSS, Spearmans Rho = -0.344, p-value= 0.019) There was no difference between the chronotypes with respect to depression, excessive sleepiness, PD severity, cognition, age, gender and ethnicity. Conclusion: Subjective propensity towards morningness and eveningness is not predictive of a particular nocturnal melatonin profile or a tendency towards daytime sleepiness in Veterans with Parkinson9s disease. Disclosure: Dr. Sarwar has nothing to disclose. Dr. Moore has nothing to disclose. Dr. Hirshkowitz has nothing to disclose.