A method to quantitate the input-output properties of the stretch reflex during walking

In the clinical, neurological examination, the presence of spasticity is evaluated when the patient is asked to relax. Often the clinical examination does not relate to the subjective description of spasticity that the patient experiences during his/her daily motor activities. Several investigations have shown that the input-output properties of spinal neural reflex circuits are a function of the motor task. One reason for the discrepancies between the clinical and subjective description of spasticity could be that the level of spasticity depends on the motor task. In developing methods to quantitate changes in reflex control in persons with spasticity, it might therefore be of importance that such methods are capable of investigating the motor system during different and relevant motor tasks. Here we present a method by which it is possible to quantitate the input-output properties of the stretch reflex during walking in healthy as well as motor impaired subjects.