Chronotype, sleep, and sleepiness in Parkinson's disease

We aimed to determine the distribution of chronotypes in a cohort of PD patients and to evaluate the relationships between chronotype and PD characteristics, and self-reported metrics of sleep and sleepiness. Chronotype was characterized using the Horne-Ostberg Morningness-Eveningness Questionnaire (MEQ). PD participants were categorized as Evening Types (ET), Neither Types (NT), or Morning Types (MT). Sleepiness was assessed by the Epworth Sleepiness Scale. Sleep metrics included self-reported sleep times and latency. 186 participants with PD, age 65.5 ± 9.8 yrs, disease duration 6.17 ± 6.7 yrs completed the MEQ. Most participants were classified as MT (63.4%). Participants in the ET group were younger than those in the NT and MT groups (57.6 ± 6.3 vs 67.3 ± 10.2 vs 64.9 ± 9.5). The mean disease duration was not different among chronotypes. No significant relationship between chronotype and sleepiness was found. MT participants woke up and went to bed significantly earlier than NT participants. There was no significant difference between chronotypes and PD medications. Further studies should examine if PD severity and progression affect the chronotype, and whether certain chronotype differentially affects the quality of life, symptom control, and medication effectiveness in the PD population.