Assessment of Spasticity from Emg to Patients’ Perception

The aim of this study was to investigate the infl uence of diff erent positions on stretch refl ex activity of knee fl exors and extensors measured by surface electromyography in poststroke patients with spasticity and its expression in the Ashworth scale. Nineteen poststroke patients with lower-limb spasticity participated in this crossover trial, during which stretch refl ex activity was assessed in both sitting and supine position, in randomized order. Main outcome measures were root mean square (RMS) values of muscle activity and goniometric parameters, obtained during the pendulum test and passive knee fl exion and extension, and Ashworth scores. Results showed that RMS values of bursts of rectus femoris activity were signifi cantly higher in the supine compared with the sitting position (p = 0.006). The fi rst burst of vastus lateralis activity during the pendulum test (p = 0.049) and semitendinosus activity during passive stretch (p = 0.017) were both signifi cantly higher in the supine versus the sitting position. For both the pendulum test and passive movement test, the duration and amplitude of the cyclic movement of the lower leg changed signifi cantly as well. In the supine position, we found signifi cantly higher Ashworth scores for the extensors (p = 0.001) and lower scores for the fl exors (p = 0.002). It was concluded that the outcomes of both clinical and neurophysiological assessment of spasticity are infl uenced considerably by the positioning of the subject. Infl uence of posture and muscle length on stretch refl ex activity | 27