A method for measuring time spent in bradykinesia and dyskinesia in people with Parkinson's disease using an ambulatory monitor.
Hamid Khodakarami, Navid Shokouhi, Malcolm Horne
PMID 34271971WHAT IT FOUND
Wrist-worn monitoring quantifies time spent above bradykinesia and dyskinesia targets, correlating with clinical scales and showing larger changes than those scales after treatment.
This offers a continuous objective measure for tracking motor fluctuations and therapy response in Parkinson's disease.
Key findings
01Percent time in bradykinesia (PTB) and dyskinesia (PTD) correlated significantly with UPDRS III, UPDRS Total, and PDQ39 scores, confirming they track with established clinical severity measures.
02Following treatment for bradykinesia, PTB decreased by 20.6%, a larger percentage change than the 13.9% decrease seen in the UPDRS III motor score.
03The method categorises patients into fluctuator types based on levodopa response and target ranges, revealing that 44.8% of the Parkinson's cohort were fluctuators.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTsWhat it means for SLPs
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What it does not show
The study relied on data from a single wrist sensor, which may underreport bradykinesia or dyskinesia if it primarily affects the face, trunk, or lower limbs. The analysis of wearing-off was limited to the period after the first dose of the day, potentially underestimating fluctuations that occur later. The cohort was drawn from mixed clinics and may underrepresent late-stage Parkinson's disease. There were no direct comparisons with patient diaries in this dataset, so the relationship between these objective signs and patient-reported symptoms remains to be fully clarified.
Declared interests
The study uses the Parkinson's KinetiGraph (PKG) system developed by Global Kinetics Corporation. The text does not explicitly state funding sources or author conflicts of interest regarding the company, but the method is proprietary to the device manufacturer.
The easy way to misread this
Do not interpret the larger percentage change in PTB compared to UPDRS III as proof that the device is a superior clinical outcome measure. The study validates the metric's sensitivity to change, but does not yet prove that guiding therapy by these numbers improves patient quality of life more than standard care.