Abnormal joint torque patterns in the paretic upper limb of subjects with hemiparesis

TLDR

Abnormal torque patterns in hemiparetic limbs may arise from neural and biomechanical factors, affecting functional use. This study presents the results of a novel paradigm for characterizing abnormal coordination in subjects with hemiparesis. Subjects performed maximum voluntary torques in eight elbow and shoulder directions while a 6‑DOF load cell recorded primary and secondary joint torques, enabling multijoint pattern analysis. Paretic limbs showed distinct torque patterns compared to nonparetic limbs and controls. © 2001 John Wiley & Sons, Inc., Muscle Nerve 24:273–283.

Abstract

This study presents the results of a novel paradigm for characterizing abnormal coordination in subjects with hemiparesis. Subjects generated maximum voluntary torques (MVTs) isometrically in four randomly ordered blocks consisting of elbow flexion/extension, shoulder flexion/extension, shoulder abduction/adduction, and shoulder external/internal rotation. A 6–degree-of-freedom (DOF) load cell was used to measure torques in secondary DOFs at the elbow and shoulder, as well as in the torque direction the subject was attempting to maximize. This allowed characterization of the multijoint torque patterns associated with the generation of MVTs in the eight directions examined. Significant differences were found between the torque patterns exhibited by the paretic limb of the hemiparetic group (n = 8) and those observed for the nonparetic limb and control group (n = 4). Potential neural and biomechanical mechanisms underlying these abnormal torque patterns are discussed along with implications for the functional use of the paretic limb. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 273–283, 2001