Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2009 Nov;47(13):2953-66.
doi: 10.1016/j.neuropsychologia.2009.06.025. Epub 2009 Jun 30.

Hemispheric Specialization and Functional Impact of Ipsilesional Deficits in Movement Coordination and Accuracy

Affiliations
Free PMC article
Comparative Study

Hemispheric Specialization and Functional Impact of Ipsilesional Deficits in Movement Coordination and Accuracy

Sydney Y Schaefer et al. Neuropsychologia. .
Free PMC article

Erratum in

  • Neuropsychologia. 2010 Mar;48(4):1178-80

Abstract

Previous studies have demonstrated that following unilateral stroke, motor impairment occurs both contralateral, as well as ipsilateral, to the lesion. Although ipsilesional impairments can be functionally limiting, they can also provide important insight into the role of the ipsilateral hemisphere in controlling movement and the lateralization of specific motor control mechanisms, given that unilateral arm movements are thought to recruit processes in each hemisphere. The purpose of this study was to examine whether left and right hemisphere damage following stroke produces different ipsilesional deficits, and whether our dynamic dominance model of motor lateralization can predict such deficits. Specifically, the dynamic dominance model attributes control of multijoint dynamics to the left hemisphere, and control of steady-state position to the right hemisphere. Chronic stroke patients with either left or right hemisphere damage (LHD or RHD) used their ipsilesional arm, and the control subjects used either their left or right arm (LHC or RHC), to perform targeted reaching movements in different directions within the workspace ipsilateral to their reaching arm. We found that the LHD group showed deficits in controlling the arm's trajectory due to impaired multijoint coordination, but no deficits in achieving accurate final positions. In contrast, the RHD group showed deficits in final position accuracy but not in the ability to coordinate multiple joints during movement, thereby providing additional evidence for the hemisphere-specific nature of motor deficits. Furthermore, while both the LHD and RHD groups were functionally impaired to the same degree on the Jebsen Hand Function Test (JHFT), our results suggest that the underlying mechanisms for such impairment may be hemisphere-dependent.

Figures

Figure 1
Figure 1
Lesion locations were traced on 11 axial slices (see inset for slice level) from MRI or CT scans for each LHD (1-7) and RHD (1-7) patient. Slices are displayed left-to-right from inferior to superior (i-xi) for both groups of patients. Arrows in top row indicate location of central sulcus.
Figure 2
Figure 2
A, Lateral and top view of experimental apparatus are shown. B, Experimental task required movement of cursor from start circle to 1 of 3 target circles located (C) in the medial, center, or lateral direction relative to the starting position. All targets were presented in the ipsilateral hemispace relative to the arm.
Figure 3
Figure 3
The minor and major axes of the hand’s trajectory for an example trial are schematically represented. The minor axis divided by the major axis is used a measure of handpath curvature for a given trajectory.
Figure 4
Figure 4
A, Mean reaction time B, Mean movement time C, Mean absolute error and D, Mean peak tangential velocity for each target is displayed for the left and right arms of control subjects (LHC,RHC) (solid line) and the ipsilesional arms of left- and right-hemisphere-damaged patients (LHD,RHD) (dashed line). Bars indicate standard error of mean.
Figure 5
Figure 5
A, Handpaths of individual trials to each target are shown for a representative subject from each group. B, Mean handpath curvature for each target is displayed for the left and right arms of control subjects (LHC,RHC) (solid line) and the ipsilesional arms of left- and right-hemisphere-damaged patients (LHD,RHD) (dashed line). Bars indicate standard error of mean.
Figure 6
Figure 6
A. Handpaths of two trials to the medial target for a LHD and RHD patient are shown. These handpaths correspond to the trials initiated in the most positive, or clockwise (CW) (gray), and most negative, or counter-clockwise (CCW) (black), directions for each patient relative to a right-arm coordinate system. The cross-hairs indicate the location of the fingertip 100 ms following movement onset. B, Mean standard deviation (SD) of initial movement direction for the medial target is displayed for the left and right arms of control subjects (LHC,RHC) (solid line) and the ipsilesional arms of left- and right-hemisphere-damaged patients (LHD,RHD) (dashed line). Bars indicate standard error of mean. C, The profiles of corresponding shoulder muscle (top), elbow interaction (middle), and elbow muscle (bottom) torque are displayed for the first 100 ms of each trial. Arrows indicate initial peak elbow muscle torque, as defined as the maximum torque (flexor or extensor) generated during the first 100 ms. D, Mean coefficient of variation (CV) of initial peak shoulder muscle (top), elbow interaction (middle), and elbow muscle (bottom) torque for the medial target is displayed for the left and right arms of control subjects (LHC,RHC) (solid line) and the ipsilesional arms of left- and right-hemisphere-damaged patients (LHD,RHD) (dashed line). Bars indicate standard error of mean.
Figure 7
Figure 7
A, The location of the hand at peak velocity (+) and movement end (●) for each trial of an LHD patient and RHD patient are shown. Ellipses represent the 99% confidence interval of the data from each target for each patient. B, Mean ratio of variable error at peak velocity relative to movement end collapsed across targets is displayed for the left and right arms of control subjects (LHC,RHC) (solid) and the ipsilesional arms of left- and right-hemisphere-damaged patients (LHC,RHD) (lined). Bars indicate standard error of mean.
Figure 8
Figure 8
Jebsen Hand Function test score is plotted as a function of mean handpath curvature (top) and mean reaction time (bottom) collapsed across targets for each subject in each group (dot). Corresponding r2 values are displayed in the bottom left corner of each scatterplot.

Similar articles

See all similar articles

Cited by 68 articles

See all "Cited by" articles

Publication types

Feedback