title: Difference of motor overflow depending on the impaired or unimpaired hand in stroke patients.
abstract: 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.
authors.affiliation: Department of Physical Therapy, Korea University, South Korea.
authors.forename: Yushin
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Department of Rehabilitation Medicine, VHS Medical Center, South Korea.
authors.forename: Woo-Sub
authors.initials: WS
authors.lastname: Kim
authors.affiliation: Department of Kinesiology, University of Maryland, United States; Department of Mechanical Engineering, Kyung Hee University, South Korea.
authors.forename: Jae Kun
authors.initials: JK
authors.lastname: Shim
authors.affiliation: Department of Rehabilitation Medicine, Barunsesang Hospital, South Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Suh
authors.affiliation: Department of Physical Therapy, Korea University, South Korea.
authors.forename: TaeYeong
authors.initials: T
authors.lastname: Kim
authors.affiliation: Department of Physical Therapy, Korea University, South Korea. Electronic address: yoonbc@korea.ac.kr.
authors.forename: BumChul
authors.initials: B
authors.lastname: Yoon
mesh_terms: D000368:Aged; D005260:Female; D005385:Fingers / Q000502:physiology*; D007839:Functional Laterality; D006225:Hand / Q000502:physiology*; D018737:Hand Strength; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills; D009068:Movement; D009119:Muscle Contraction; D011597:Psychomotor Performance; D020521:Stroke / Q000503:physiopathology*
keywords: Associated reaction; Force independence; Hand; Mirror movement; Motor overflow; Stroke