Background: Several small-scale studies have shown that motor performance in Parkinson's disease (PD) fluctuates throughout the day. Studies specifically focusing on de novo patients are, however, lacking. Objective: To evaluate the effect of clock time on motor performance in de novo drug-naïve patients with PD. Methods: We retrieved MDS-UPDRS III scores for 421 de novo PD patients from the PPMI cohort and stratified them into three groups based on time of assessment: group 1) 7:00-10:00; group 2) 10:00-13:00, and group 3) 13:00-18:00. Groups were compared using Kruskal-Wallis test and results corrected for multiple testing. In addition, we obtained 27 wearable sensor reports, objectively capturing bradykinesia scores in a home setting over a 6-day continuous period, in 12 drug-naïve patients from the Parkinson's Kinetigraph Registry held at King's College Hospital London. Time spent in severe bradykinesia scores were broken down into five daytime (06:00-21:00) three-hourly epochs and scores compared using the Friedman test. Results: There were no group differences in demographic or other clinical variables for the cross-sectional analysis. MDS-UPDRS III total scores worsened significantly during the course of the day (median 18 (group 1); 20 (group 2); and 23 (group 3); p=0.001). In the longitudinal wearable sensor cohort, diurnal variations were present in percentage of time spent in severe bradykinesia (p<0.001) with the lowest percentage during the 09:00-12:00 epoch (69.56±16.68%), when most patients are awake and start daily activity, and the highest percentage during the 18:00-21:00 epoch (73.58±16.35%). Conclusion: This exploratory study shows the existence of a diurnal pattern of motor function in patients with de novo PD. The results obtained were corroborated by objective measurements in a small longitudinal cohort confirming a similar diurnal motor score variation.

Original languageEnglish
Pages (from-to)695-702
Number of pages8
JournalJournal of Parkinson's Disease
Issue number2
Publication statusPublished - 2021


  • bradykinesia
  • circadian rhythm
  • diurnal rhythm
  • motor
  • Parkinson's disease


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