Evaluation of tremor interference with control of voluntary reaching movements in patients with Parkinson's disease.
Zixiang Hu, Manzhao Hao, Shaoqing Xu and 2 others
PMID 30866977WHAT IT FOUND
People with Parkinson's disease and tremor began reaching later and took longer to complete movements than controls.
Measured tremor intensity tracked the delay in starting, but clinical tremor scores did not.
Key findings
01In ten people with Parkinson's disease and tremor and ten controls, the Parkinson's group took 43.4% longer to start and 79.5% longer to complete reaches.
02Measured tremor intensity was correlated with reaction time, but clinical tremor, bradykinesia, and rigidity scores were not significantly associated with reaction time or movement time.
03Voluntary reaching was followed by a temporary reduction in tremor intensity.
STILL TO COME
How it was doneWhat they foundWhat it means for OTs
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What it does not show
Very small group of participants. People with Parkinson's disease also had bradykinesia and rigidity, so the study cannot separate the contribution of tremor alone. Clinical symptom scores were not sensitive enough to explain movement timing. The study did not test a treatment, so it cannot show that reducing tremor improves reaching. The task was performed in a laboratory with a custom arm support, so everyday function may differ.
Declared interests
Funded by the National Natural Science Foundation of China. The supplied text reports no other conflicts of interest.
The easy way to misread this
Do not conclude that resting tremor alone caused the slower reaching. The participants also had bradykinesia and rigidity, and the clinical scores for these symptoms did not significantly explain reaction time or movement time. The study did not test a treatment that suppresses tremor.