Bimanual coordination deficits in hands following stroke and their relationship with motor and functional performance.
Chien-Hung Lai, Wen-Hsu Sung, Shang-Lin Chiang and 4 others
PMID 31375122WHAT IT FOUND
Stroke patients showed unstable grip-force transfer to the paretic hand, with sudden force rebounds.
Shorter transfer times from the paretic hand correlated with better motor and functional scores, suggesting this specific timing metric may track recovery progress.
Key findings
01Stroke patients exhibited significantly higher variation (instability) in grip-force transfer when moving force from the non-paretic to the paretic hand compared to healthy controls.
02Shorter alternating time (speed of grip-force transfer) from the paretic to the non-paretic hand was moderately correlated with better motor and functional performance scores (FMA-UE, WMFT, BI).
03The study observed sudden rebounds in resultant force when the paretic hand initiated grip, likely due to muscle weakness and delayed reaction times.
STILL TO COME
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
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What it does not show
The sample size was small (22 stroke patients), limiting the generalizability of the findings. The healthy control group and stroke group were not matched for age or sex, which could influence coordination metrics. The stroke group had a wide range of severity (Brunnstrom stages 3-6), making it difficult to pinpoint if specific deficits relate to specific stages of recovery. The study was cross-sectional, so it cannot prove that improving alternating time causes better functional outcomes, only that they are associated.
Declared interests
The study was supported by the Ministry of Science and Technology. The authors declared no conflicts of interest.
The easy way to misread this
Do not assume that a faster grip transfer from the paretic hand indicates a better outcome in isolation. The study notes this speed may be a compensatory movement resulting from the patient's inability to modulate force smoothly, rather than true motor recovery. The correlation with functional scores was moderate, not strong.