[Changes in multi-locally recorded muscle responses following cortex stimulation in patients with multiple sclerosis]

The application of transcranial brain stimulation widens the range of neurophysiological tools available for the diagnostic evaluation of impaired function in central conduction pathways. A standardized examination of 25 patients with multiple sclerosis (diagnoses of different certainties using the classification by Bauer) was performed with electrical brain stimulation and EMG recordings from 3 muscles in each of the upper and lower extremities (Fig. 2). The occurrence and the change (amplitude, latency) of abnormal cortically evoked muscle responses correlated with the distribution and the severity of the clinical motor deficits respectively (Fig. 1 to 4 and Tab. 1). Furthermore, in some cases, abnormal responses were found in clinically unaffected limbs. Non-invasive stimulation of the motor cortex may reveal lesions affecting the function of the fast conducting component of the corticospinal tract even when there is no pathological clinical finding. In patients suspected of having multiple sclerosis the use of this technique may allow greater diagnostic certainty or even an early diagnosis.