Integrated robotics platform with haptic control differentiates subjects with Parkinson's disease from controls and quantifies the motor effects of levodopa.
Pauline Gaprielian, Stephen H Scott, Catherine Lowrey and 3 others
PMID 31655612WHAT IT FOUND
A robot arm test separated Parkinson's disease from controls.
People off medication moved 41% slower and hit 25% fewer targets. After medication, motor and robot scores improved, but rigidity measures did not track the clinical change.
Key findings
01In the OFF medication state, participants with Parkinson's disease had mean hand speed 41% slower and hit 25% fewer targets than controls on the object hit task, and mean hand speed 47% slower and hit 23% fewer targets on the object hit and avoid task.
02After dopamine replacement therapy, the total UPDRS Part III score decreased from 32 to 16 in the 20 subjects who met the minimal clinical improvement criterion, but end total torque in the passive stretch rigidity task did not change.
03The combined robotic score in the 20 subjects with minimal clinical improvement decreased from 4.5 OFF medication to 3.8 ON medication, and it correlated with the combined UPDRS score across all 26 subjects.
STILL TO COME
How it was doneWhat they foundWhat it means for OTs
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What it does not show
Only 26 people with Parkinson's disease were studied, and they were recruited from one movement disorders clinic. Healthy control numbers differed by task (250, 174, 27, and 38), so the same control group was not used for every comparison. The neurologists were not blinded to medication state, so UPDRS changes after medication may be biased. Medication states were not randomized, and medication regimens varied, including levodopa plus other drugs, so the effect of any single medication cannot be separated. The robot could not measure tremor or dyskinesia because of the exoskeleton arm constraints. The combined robot score could not be directly compared with controls because control subjects did not all perform the same tasks. One subject with Parkinson's disease could not complete the passive stretch task with one arm in the OFF state and was excluded from rigidity analyses; that subject also did not perform the unloading task. Distractor hits after medication did not correlate with MoCA scores, levodopa dose, or years with Parkinson's disease.
Declared interests
The supplied funding statement names Southeastern Ontario Academic Medical Organization. BKIN Technologies supplied the KINARM device and helped screen healthy controls.
The easy way to misread this
Do not read this as proof that dopamine replacement therapy improves rigidity or as a validated diagnostic test. The study included 26 people with Parkinson's disease, medication regimens varied, the neurologists were not blinded to medication state, and the robotic rigidity measure did not change after medication.