Ipsilesional motor performance following stroke: Evidence for motor lateralization
Open Access
- Author:
- Schaefer, Sydney Yoshie
- Graduate Program:
- Kinesiology
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 03, 2008
- Committee Members:
- Robert L Sainburg, Committee Chair/Co-Chair
Mark Latash, Committee Member
Jonathan T Mordkoff, Ph D, Committee Member
Karl Maxim Newell, Committee Member - Keywords:
- hemispheric specialization
motor control - Abstract:
- Cerebrovascular accidents (CVA) are a leading cause of serious, long-term disability in the United States, with 780,000 individuals per year suffering a stroke (Rosamond et al., 2008). Roughly half of stroke survivors regain some functional independence, but 15% to 30% are permanently disabled (Asplund et al., 1998). Contralateral hemiparesis, or weakness opposite to the damaged hemisphere, is the primary source of functional limitation in stroke patients. However, motor deficits are also present in the arm on the same side of, or ipsilesional to, the damaged hemisphere, which previously had been thought to be “unaffected.” Such deficits suggest that both contra- and ipsilateral hemispheres are involved in the control of unilateral movement, and our work in healthy subjects supports that the hemispheres may be specialized for controlling specific yet separate features of movement. In a series of three experiments, we tested whether ipsilesional motor deficits following stroke would be 1) different in patients with left and right hemisphere damage and 2) predictable based on our model of motor lateralization, which describes a left hemisphere specialization for coordination of limb and task dynamics, and a right hemisphere specialization for achieving steady-state positions through limb impedance. Specifically, we predicted that left but not right stroke patients would demonstrate impairment in mechanisms underlying the control of limb coordination, and that right but not left stroke patients would demonstrate impairment in impedance or position-based control mechanisms. We believe that this work is important not only for understanding the role of ipsilateral hemisphere in control of movement, but also for providing insight into why ipsilesional motor deficits can substantially impact functional performance of activities of daily living. The impact of such deficits is of particular concern for those stroke survivors who must use the ipsilesional arm as their primary controller due to severe contralesional hemiparesis.