Evaluation of morning bradykinesia in Parkinson's disease in a United States cohort using continuous objective monitoring.

Introduction: Bradykinesia in Parkinson's disease is a marker for clinical levodopa responsiveness, with persistent bradykinesia reflecting suboptimal response. We objectively measured prevalence and severity of morning bradykinesia using the Personal KinetiGraph® (PKG®). Methods: Retrospective evaluation of a large global database of de-identified PKG assessments from individuals (N=12,840) in routine clinical care in the United States (US; n=3288). Median bradykinesia scores (mBKS) and median dyskinesia scores (mDKS) were calculated using a validated algorithm and previously established targets to evaluate percent time in bradykinesia, levodopa responsiveness, and prevalence and severity (0-5; 5=highest severity) of morning bradykinesia. Results: mBKS was above target (≥26) in 65% of all individuals, and mDKS was above target (≥7) in 3%. Elevated percent time in bradykinesia occurred in 79%. Among individuals where levodopa responsiveness could be evaluated (n=1933), 31% had a significant response (≥1.15 postdose decrease in severity). Morning bradykinesia was identified in 85% of individuals with available morning data (1298/1524), and 64% (954/1501) experienced continued bradykinesia after the first daily levodopa dose. Morning bradykinesia was severe (4.0-4.7) in levodopa-responsive individuals regardless of percent time spent in bradykinesia. Conclusion: Elevated mBKS was very common in the US. Most individuals taking levodopa had morning bradykinesia that persisted even after the first daily dose, and severity was high, indicating a need for additional treatment options.