TY - JOUR
T1 - Deficits in grasp versus reach during acute hemiparesis
AU - Lang, Catherine E.
AU - Wagner, Joanne M.
AU - Bastian, Amy J.
AU - Hu, Qingli
AU - Edwards, Dorothy F.
AU - Sahrmann, Shirley A.
AU - Dromerick, Alexander W.
N1 - Funding Information:
Acknowledgements We thank R. Birkenmeier and the research team for their assistance with patient recruitment and scheduling during this project. This project is supported by NIH R01 NS 41261 and the James S. McDonnell Foundation 21002032.
PY - 2005/9
Y1 - 2005/9
N2 - We studied how acute hemiparesis affects the ability to perform purposeful movements of proximal versus distal upper extremity segments. Given the gradient of corticospinal input to the spinal motoneuron pools, we postulated that movement performance requiring distal segment control (grasping) should be more impaired than movement performance requiring proximal segment control (reaching) in people with hemiparesis. We tested subjects with acute hemiparesis and control subjects performing reach and reach-to-grasp movements. Three characteristics of movement performance were quantified for each movement: speed, accuracy, and efficiency. For the reach, we calculated peak wrist velocity, endpoint error, and reach path ratio. For the grasp, we calculated peak aperture rate, aperture at touch, and aperture path ratio. To evaluate the relative deficits in reaching versus grasping, performance measures were converted to z-scores using control group means and standard deviations. For both the movements, movement times were longer and performance was more variable in the hemiparetic group compared to the control group. Hemiparetic z-scores indicated that relative deficits in movement speed were small in the two movements, with deficits in grasp being slightly greater than deficits in reach. Relative deficits in accuracy showed a trend for being larger in the reach compared to the grasp, but this difference did not reach statistical significance. In contrast, relative deficits in efficiency were larger in the grasp compared to the reach, with reaching efficiency near the range of normal performance. When considering data across all three movement characteristics, the ability to perform a purposeful movement with the distal segments was not clearly more disrupted than the ability to perform a purposeful movement with the proximal segments in people with acute hemiparesis.
AB - We studied how acute hemiparesis affects the ability to perform purposeful movements of proximal versus distal upper extremity segments. Given the gradient of corticospinal input to the spinal motoneuron pools, we postulated that movement performance requiring distal segment control (grasping) should be more impaired than movement performance requiring proximal segment control (reaching) in people with hemiparesis. We tested subjects with acute hemiparesis and control subjects performing reach and reach-to-grasp movements. Three characteristics of movement performance were quantified for each movement: speed, accuracy, and efficiency. For the reach, we calculated peak wrist velocity, endpoint error, and reach path ratio. For the grasp, we calculated peak aperture rate, aperture at touch, and aperture path ratio. To evaluate the relative deficits in reaching versus grasping, performance measures were converted to z-scores using control group means and standard deviations. For both the movements, movement times were longer and performance was more variable in the hemiparetic group compared to the control group. Hemiparetic z-scores indicated that relative deficits in movement speed were small in the two movements, with deficits in grasp being slightly greater than deficits in reach. Relative deficits in accuracy showed a trend for being larger in the reach compared to the grasp, but this difference did not reach statistical significance. In contrast, relative deficits in efficiency were larger in the grasp compared to the reach, with reaching efficiency near the range of normal performance. When considering data across all three movement characteristics, the ability to perform a purposeful movement with the distal segments was not clearly more disrupted than the ability to perform a purposeful movement with the proximal segments in people with acute hemiparesis.
KW - Corticospinal tract
KW - Human
KW - Motor cortex
KW - Prehension
KW - Stroke
KW - Upper extremity
UR - http://www.scopus.com/inward/record.url?scp=26844547056&partnerID=8YFLogxK
U2 - 10.1007/s00221-005-2350-6
DO - 10.1007/s00221-005-2350-6
M3 - Article
C2 - 16021431
AN - SCOPUS:26844547056
VL - 166
SP - 126
EP - 136
JO - Experimental Brain Research
JF - Experimental Brain Research
SN - 0014-4819
IS - 1
ER -