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Characterization of the influence of the dominant tract on hand closing post stroke based on the Fugl-Meyer score
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  • Raziyeh Baghi ,
  • Dongwon Kim ,
  • Kyung Koh ,
  • Li-Qun Zhang
Raziyeh Baghi
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Dongwon Kim

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Kyung Koh
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Li-Qun Zhang
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While stroke survivors with moderate or mild impairment are typically able to open their hand at will, those with severe impairment are not. Abnormal synergies govern the arm and hand in stoke survivors with severe impairment, so hand opening, which is required to overcome the working synergy, is a task extremely difficult for them to achieve. It is universally accepted that alternative tracts including the cortico-reticulospinal tract (CRST), employed in the case that the corticospinal tract (CST) is damaged by stroke, brings about such abnormal synergies. Here we note that hand closing is enabled by alternative tracts as well as the CST, and raise a research question: does motor characteristics while closing the hand depend on the integrity of the CST? In this study, we evaluate the ability of 17 stroke survivors to flex and relax the metacarpophalangeal (MCP) joints and investigate whether motor characteristics can be distinguished based on CST integrity which is estimated using upper-extremity Fugl-Meyer (UEFM). UEFM scores have been perceived as an indirect indicator of CST integrity. We found that participants with the UEFM score above a certain value, who are assumed to use the CST, moves the MCP joints more smoothly (p<0.05) and activates the flexor to flex the joints faster (p<0.05), in comparison to participants with low UEFM scores, who are assumed to use alternative tracts. The results present evidence that use of alternative tracts (i.e. the CRST) results in a degradation in movement smoothness and slow activation of the MCP flexor.
14 Feb 2023Published in Scientific Reports volume 13 issue 1. 10.1038/s41598-023-28290-z