Objective: The aim of this study was to develop objective evaluation method of spasticity which reflects the characteristics of lengthening velocity-dependent stretch reflex of spasticity.

Method: Kinematic analysis for knee angle and rectus femoris muscle lengthening parameters, and dynamic EMG were performed simultaneously during pendular movement of spastic lower leg for thirty two patients with spasticity and ten normal control subjects. Angular parameters consist of angular relaxation index (ARI), maximal angular velocity (MAV), angular threshold (AT) and angular velocity threshold (AVT). And lengthening parameters consist of lengthening relaxation index (LRI), maximal lengthening velocity (MLV), lengthening threshold (LT) and lengthening velocity threshold (LVT).

Results: 1) ARI, MAV, AT, and AVT according to Modified Ashworth scale (MAS) were 1.32⁑0.11, 303.84⁑45.11 deg/sec, 44.19⁑13.81 deg, 262.15⁑33.54 deg/sec in MAS I, 1.16⁑0.16, 279.92⁑42.94 deg/sec, 30.33⁑6.02 deg, 247.65⁑35.92 deg/sec in MAS II, and 0.95⁑0.14, 241.31⁑19.98 deg/sec, 20.55⁑2.68 deg, 209.11⁑48.11 deg/sec in MAS III (P＜0.05). 2) LRI, MLV, LT, and LVT according to MAS were 1.27⁑0.11, 0.58⁑0.07, 1.164⁑0.14, 0.53⁑0.05 in MAS I, 1.12⁑0.09, 0.53⁑0.05, 1.150⁑0.08, 0.42⁑0.04 in MAS II, and 0.99⁑0.10, 0.44⁑0.01, 1.137⁑0.15, 0.36⁑0.02 in MAS III (P＜0.05). 3) There were significant correlation between various pendulum test parameters and MAS.

Conclusion: Muscle lengthening parameters as well as knee angular parameters were sensitive parameters reflecting the degree of spasticity. LVT is the most sensitive parameter among all parameters (p＜0.01).

Objective: To investigate waveform changes of compound muscle action potentials (CMAPs) related to voluntary muscle contraction and alteration of muscle length and to evaluate the effect of peripheral neuropathy on temporal and spatial summations of CMAPs.

Method: The influence of voluntary muscle contraction and alteration of muscle length on CMAP was studied in 37 median nerves of 21 patients with median neuropathy.

Results: In patients with no apparent axonopathy, temporal summation was partially disturbed without significant change of spatial summation. Shortening of muscle length or voluntary contraction produced a physiologic improvement of spatial and temporal summations. There was a decrease in temporal and spatial summations, more prominent in temporal summation, with lengthening of the muscle. In axonopathy, spatial summation was markedly deteriorated with partial reduction of temporal summation. Spatial summation was not affected by the change of muscle length or voluntary contraction. Temporal summation was improved by muscle shortening or voluntary contraction and was decreased by muscle lengthening.

Conclusion: Peripheral neuropathy has an effects on physiological spatial and temporal summations of CMAPs. Temporal summation is preferentially decreased in cases without axonopathy. When axonopathy is apparent, spatial summation is profoundly disturbed with partial reduction of temporal summation.