ABSTRACT
BACKGROUND: Spasticity is a common sequela of upper motor neuron pathology, such as cerebrovascular diseases and cerebral palsy. Intervention for spasticity of the ankle plantarflexors in physical therapy may include tone-inhibiting casting and/or orthoses for the ankle and foot. However, the physiological mechanism of tone reduction by such orthoses remains unclarified. OBJECTIVE: To investigate the electrophysiologic effects of tone-inhibiting insoles in stroke subjects with hemiparesis by measuring changes in reciprocal Ia inhibition (RI) in the ankle plantarflexor. DESIGN: An interventional before-after study. SETTING: Acute stroke unit or ambulatory rehabilitation clinic of a university hospital in Japan. PARTICIPANTS: Ten subjects (47-84 years) with hemiparesis and 10 healthy male control subjects (31-59 years) were recruited. METHODS: RI of the spastic soleus in response to the electrical stimulation of the deep peroneal nerve was evaluated by stimulus-locked averaging of rectified electromyography (EMG) of the soleus while subjects were standing. MAIN OUTCOME MEASUREMENTS: The magnitude of RI, defined as the ratio of the lowest to the baseline amplitude of the rectified EMG at approximately 40 milliseconds after stimulation, was measured while subjects were standing with and without the tone-inhibiting insole on the hemiparesis side. RESULTS: Enhancement of EMG reduction with the tone-inhibiting insole was significant (P < .05) in the subjects with hemiparesis, whereas no significant changes were found in controls. CONCLUSION: Tone-inhibiting insoles enhanced RI of the soleus in subjects after stroke, which might enhance standing stability by reducing unfavorable ankle plantarflexion tone. LEVEL OF EVIDENCE: III.
Subject(s)
Electric Stimulation Therapy/methods , Electromyography/methods , Gait/physiology , Muscle, Skeletal/physiopathology , Paresis/rehabilitation , Shoes , Stroke/complications , Adult , Aged , Aged, 80 and over , Equipment Design , Female , Follow-Up Studies , Humans , Male , Middle Aged , Paresis/etiology , Paresis/physiopathology , Stroke/physiopathology , Stroke Rehabilitation/methodsABSTRACT
Electroneurography is one of the most useful tests for evaluating facial nerve function. Because many patients with peripheral facial palsy complain of difficulty with eye closure, recording compound muscle action potentials (CMAPs) of the orbicularis oculi (OC) is important. However, electromyographers often encounter OC CMAPs that have an initial positivity. In the present study, facial motor potentials of a healthy subject were recorded using an electrode on the acromion and electrical activities over the facial muscles were evaluated.The contralateral OC electrode was the most inactive. A CMAP recorded using two electrodes on the ipsilateral OC showed an initial positivity. It is assumed that the onset discrepancy between electrical activities of the two electrodes on the OC results in an initial positivity. Thus, the authors recommend that electromyographers avoid using a reference electrode on the ipsilateral OC for recording its CMAP. The bilateral OC montage could be useful for recording OC CMAPs.
