TY - JOUR
T1 - Weakness Is the Primary Contributor to Finger Impairment in Chronic Stroke
AU - Kamper, Derek G.
AU - Fischer, Heidi C.
AU - Cruz, Erik G.
AU - Rymer, William Z.
N1 - Funding Information:
Supported by the Department for Veterans Affairs (merit review grant no. 537D46088).
PY - 2006/9
Y1 - 2006/9
N2 - Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairment in chronic stroke. Objective: To assess the relative contributions of several neurologic and biomechanic impairment mechanisms to overall finger and hand impairment in chronic hemiparetic stroke survivors. Design: Repeated-measures design. Setting: Clinical research laboratory. Participants: Thirty stroke survivors with chronic hemiparesis. Fifteen subjects had severe hand motor impairment and 15 had moderate impairment, as measured with the Chedoke-McMaster Stroke Assessment. Interventions: Not applicable. Main Outcome Measures: The biomechanic factors stiffness and resting flexion torque, together with the neurologic factors spasticity, strength, and coactivation, were quantified by using a custom hand manipulator, a dynamometer, and electromyographic recordings. Both passive and active rotations of the metacarpophalangeal joints of the fingers were examined. Results: Although subjects in the severely impaired group exhibited statistically greater passive stiffness and resting flexion torque than their moderately impaired counterparts (P<.05), the overall effect of these biomechanic changes appeared small in relation to the deficits attributable to neurologic changes such as spasticity and, especially, weakness. In fact, weakness in grip strength and isometric extension accounted for the greatest portion of the variance between the 2 groups (η2=.40 and η2=.23, respectively). Conclusions: Thus, deficits in hand motor control after stroke seem to derive mainly from weakness, which may be attributable to the loss of descending corticospinal pathway activation of motoneurons.
AB - Kamper DG, Fischer HC, Cruz EG, Rymer WZ. Weakness is the primary contributor to finger impairment in chronic stroke. Objective: To assess the relative contributions of several neurologic and biomechanic impairment mechanisms to overall finger and hand impairment in chronic hemiparetic stroke survivors. Design: Repeated-measures design. Setting: Clinical research laboratory. Participants: Thirty stroke survivors with chronic hemiparesis. Fifteen subjects had severe hand motor impairment and 15 had moderate impairment, as measured with the Chedoke-McMaster Stroke Assessment. Interventions: Not applicable. Main Outcome Measures: The biomechanic factors stiffness and resting flexion torque, together with the neurologic factors spasticity, strength, and coactivation, were quantified by using a custom hand manipulator, a dynamometer, and electromyographic recordings. Both passive and active rotations of the metacarpophalangeal joints of the fingers were examined. Results: Although subjects in the severely impaired group exhibited statistically greater passive stiffness and resting flexion torque than their moderately impaired counterparts (P<.05), the overall effect of these biomechanic changes appeared small in relation to the deficits attributable to neurologic changes such as spasticity and, especially, weakness. In fact, weakness in grip strength and isometric extension accounted for the greatest portion of the variance between the 2 groups (η2=.40 and η2=.23, respectively). Conclusions: Thus, deficits in hand motor control after stroke seem to derive mainly from weakness, which may be attributable to the loss of descending corticospinal pathway activation of motoneurons.
KW - Hand
KW - Human
KW - Muscle spasticity
KW - Muscle weakness
KW - Rehabilitation
KW - Stroke
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U2 - 10.1016/j.apmr.2006.05.013
DO - 10.1016/j.apmr.2006.05.013
M3 - Article
C2 - 16935065
AN - SCOPUS:33747780737
VL - 87
SP - 1262
EP - 1269
JO - Archives of Physical Medicine and Rehabilitation
JF - Archives of Physical Medicine and Rehabilitation
SN - 0003-9993
IS - 9
ER -