Background and objective: Levodopa off/on testing is frequently performed to assess medication response in patients with Parkinson's disease (PD) as an aid in determining best medical management or potential surgical candidacy. The Parkinson's Kinetigraph (PKG) is a wearable device which generates tremor, bradykinesia (BKS) and dyskinesia (DKS) scores representing motor symptoms over a six-day period. In this study, we compared off/on testing with PKG motor scores.
Methods: Patients were enrolled as part of an observational study: Assessing the Longitudinal Signs in PD, a three-year study evaluating clinical and biomarker evolution in patients with PD taking levodopa. Patients underwent off/on testing at baseline and 6-month visits. A greater than 30% improvement between off and on MDS-Unified Parkinson's Disease Rating Scale scores was considered a robust response. After each visit, patients wore the PKG for 6 days. A bradykinesia score (BKS) greater than 26 and dyskinesia score (DKS) greater than 9 were considered poorly controlled bradykinesia and dyskinesia, respectively.
Results: The median BKS at the baseline and 6-month visits were 27.15 and 27.55, respectively, despite a robust median off/on improvement at both visits. In addition, 10/18 (66%) and 7/13 (53.8%) patients with robust off/on improvement at the baseline and 6-month visits, respectively, demonstrated a BKS > 26 or DKS > 9.
Conclusion: A robust off/on response during a clinic visit does not necessarily reflect adequately controlled motor symptoms. The PKG, by virtue of its continuous recording of motor movements, may provide additional clinically relevant data on motor symptoms which may be useful for prospective observational studies.
Keywords: Deep brain stimulation; Levodopa response testing; Parkinson’s disease; Parkinson’s kinetigraph; Wearable devices.
Published by Elsevier B.V.