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).
