Abstract
It is well-known that the knee joint reflex of the spastic patient is facilitated by increasing of γ-motoneuron excitability and decreasing of presynaptic inhibition capability. There had been however few reports about quantification of these factors. We tried therefore to represent the knee joint reflex two-dimensionally with them. Ten waveforms of the knee-joint motion for the quantification were reconstructed from the pendulum-test data measured from stroke patients of 1 or 1+ MAS grade at supine position by Kim et al [JBSE, Vol. 6, No. 3]. Indexes of the quantification were firing-rate to γ-motoneuron Hγd and reciprocal of firing-rate to presynaptic inhibition neuron Hie. Their normalized values were estimated by an inverse pendulum-test simulator in which both spinal-cord model and spindle model were improved so that the value of each parameter might be determined to only one. According to results of the inverse simulation, plots of (Hγd, Hie) in the subjects showed a two dimensional extent and there existed some subjects having pretty different values even if with the same MAS and near equal R-I index.
