Difference of motor overflow depending on the impaired or unimpaired hand in stroke patients

Yushin Kim, Woo Sub Kim, Jae Kun Shim, Dong Won Suh, Tae Yeong Kim, Bum-Chul Yoon

Research output: Contribution to journalArticle

6 Citations (Scopus)


The aim of this study was to investigate the patterns of contralateral motor overflow (i.e. mirror movement) between the homologous body parts on the right and left side, in stroke patients during single-finger and multi-finger maximum force production tasks. Forty subjects, including stroke (. n=. 20) and normal subjects (. n=. 20), participated in this study. The stroke subjects maximally pressed force sensors with their fingers in a flexed position using a single (index, middle, ring, or little) or all fingers (all 4 fingers) using the impaired (IH) or unimpaired (UIH) hand, while the non-patient subjects used their right hands for the same tasks. The maximal voluntary forces in the ipsilateral and unintended pressing forces of each contralateral finger were recorded during the tasks. The magnitude of motor overflow to the contralateral side was calculated using the index of contralateral independence (CI). During the single finger tasks, the finger CI was significantly decreased in the UIH (91%) compared with that in the IH (99%) or normal hands (99%). Likewise, the multiple finger tasks showed that the CI was significantly lower in the UIH (84%) compared with that in the IH (96%) or normal hands (99%). However, the maximal forces were significantly lower in the IH relative to those in the UIH and normal hands. These data demonstrate that stroke patients have greater motor overflow from the UIH to the IH.

Original languageEnglish
Pages (from-to)154-162
Number of pages9
JournalHuman Movement Science
Publication statusPublished - 2015 Feb 1



  • Associated reaction
  • Force independence
  • Hand
  • Mirror movement
  • Motor overflow
  • Stroke

ASJC Scopus subject areas

  • Biophysics
  • Orthopedics and Sports Medicine
  • Experimental and Cognitive Psychology

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