Trunk Compensation During Bimanual Reaching at Different Heights by Healthy and Hemiparetic Adults

ABSTRACT

The authors explored how trunk compensation and hand symmetry in stroke survivors and healthy controls were affected by the distance and height of virtual targets during a bimanual reaching task. Participants were asked to reach to 4 different virtual targets set at: 90% of their arm length at shoulder, xiphoid process, and knee height, and 50% of their arm length at xiphoid process height. For the stroke group, for all targets, the hands’ movements were more asymmetrical than those of the healthy group, with more asymmetry observed in the direction of gravity, and trunk forward displacement values were larger and more variable. The knee targets had the largest trunk displacement values; index of curvature and trunk displacement were strongly correlated with participants’ impairment scores. A strong correlation was found between the hands’ asymmetry in the anterior or posterior direction for the shoulder targets, and the impairment scores. The results suggest that target height influences the degree of trunk compensation and hand symmetry during bimanual reaching by hemiparetic participants.

Keywords:

• bimanual movement
• compensatory movement
• kinematics
• stroke
• trunk

ACKNOWLEDGMENTS

The authors would like to thank all of the participants and their families, Abilities Neurological Rehabilitation Clinic, the Stroke Recovery Association, and the Heart and Stroke Foundation of British Columbia, as well as colleagues Elizabeth Croft, Alison Hoens, Kim Miller, Jenny Sullivan, Navid Shirzad, Tina Hung, Brandon Kim, Austin Wallace, and Brendan Sexton for their assistance.

FUNDING

This work was supported by the Peter Wall Solutions Initiative (11-079), Vancouver, Canada; and CONACYT (Consejo Nacional de Ciencia y Tecnología, México; 311462).