Does Reciprocal Inhibition, a Rehabilitation Technique, Convert to Reciprocal Facilitation in Patients With Upper Motor Neuron Lesions?

Reciprocal inhibition is a spinal segmental control mechanism that facilitates motor activities in healthy people and is also used in treating spasticity. Considering the current literature, there are some studies claiming that this is reversed in patients with upper motor neuron lesions and that there is reciprocal facilitation instead of inhibition. However, the proposed evidence is not convincing. Our aim in this study was to investigate the presence of reciprocal facilitation in detail in patients with upper motor neuron lesions. This study was conducted in five patients with spinal cord lesions and five healthy individuals. Both the tibialis anterior and soleus muscles of the cases were recorded using surface and multi-motor unit electromyography (EMG) electrodes. To elicit an H reflex in the soleus muscle, an electric current was delivered through the popliteal fossa using the monopolar technique. The Achilles tendon was tapped with the reflex hammer to elicit a T reflex. Since the H-reflex and T-reflex responses were detected in the tibialis anterior muscle surface and multi-motor unit EMG recordings, the findings were evaluated as direct stimulation, cross-talk, and reciprocal facilitation. Methodologically, This research aimed to be a guiding study for future studies.