Examination of the segmental pathophysiological mechanisms of spasticity.

The purpose of this investigation was to ascertain a complex of electromyographic methods suitable for evaluation of the basic segmental pathophysiological mechanisms of spasticity. Clinical and electromyographic examinations were performed on 120 patients with spastic hemiparesis after stroke. Patients muscle tone, muscle force and tendon reflexes were assessed by the well known clinical five point scales. A battery of electromyographic methods was used to analyze different segmental mechanisms of spasticity: for alpha motoneurone activity--the F-wave parameters; for gamma motoneurone activity--the TA/H amplitude ratio; for common interneurone activity--the flexor reflex parameters; for presynaptic inhibition--the Hvibrated/Hmaximal amplitude ratio. Our results revealed that nearly all of the patients have increased alpha motoneurone activity on the spastic side. In most of the patients at least two of the segmental mechanisms are altered. Different mechanisms participate with different frequency in development of spasticity. We suppose that alpha-motoneurone hyperactivity usually develops secondary after alteration of some other segmental mechanism. In conclusion the applied complex of electromyographic methods gives the possibility for evaluation of the individual pathophysiological profile of patients with spasticity. This is a background for appropriate treatment.