Article

OBJECTIVE: To investigate the effect of spasticity and involuntary synergistic
activation on force perception during voluntary activation of spastic paretic
muscles. METHODS: Eleven stroke subjects with spastic hemiparesis performed
various isometric elbow-flexion force-matching tasks. Subjects were instructed to
generate a target reference force with visual feedback using one arm (impaired or
non-impaired) and then to produce a force with the other arm to match the
magnitude of the reference force without visual feedback.
The reference arm was
at rest in unilateral exertion trials and maintained contraction in bilateral
exertion trials during the matching force-production period. RESULTS: Both force
and effort mismatches occurred in most conditions, and there were asymmetries in
force perception. When the non-impaired arm was the matching arm, effort and
force overestimation occurred, but effort was matched better than force. When the
impaired arm was the matching arm, force underestimation and effort
overestimation occurred, but force was matched better than effort. No difference
in matching performance was found between unilateral and bilateral
exertion-matching tasks. CONCLUSION: Overall, both force and effort
misperceptions occur in stroke survivors with spasticity. Spasticity and spastic
synergistic activation probably contribute to force and effort misperception
during voluntary activation in chronic stroke.

Langue : ANGLAIS