A new method for reflex threshold estimation in spastic muscles

Many clinical measures of spasticity, such as Ashworth tests and tendon tap responses, are linked to stretch reflex thresholds but these methods are relatively imprecise and unreliable. To address this deficit, we examined the utility of a system that relies on a small position controlled actuator to better estimate this threshold. We compared the reflex threshold estimates in the passive spastic and contralateral elbow flexor muscles of 4 hemiparetic spastic stroke survivors. We propose that the use of controlled indentation of the tendon may be a practical and accurate method of estimating stretch reflex threshold as well as passive muscle properties.