[Applied neurophysiology in the deep brain stimulation treatment of multiple sclerosis tremor]

Many patients with multiple sclerosis (MS) develop tremors that may involve one or both lower and/or upper extremities, head and/or voice. In the last few years, chronic high frequency deep brain stimulation of the ventral intermedious (Vim) thalamic nucleus (Vim-DBS, deep brain stimulation) seems to be gradually replacing Vim-thalamotomy in surgical treatment of tremor. The thalamotomy is a destructive procedure of the whole neural components, whereas Vim-DBS has shown to be a selective neurophysiological procedure to block a specific group of neural components, in particular large, fast and low threshold ones. MS is a disease of uncertain etiology characterized by demyelinating plaques in central nervous system. The neurophysiological intraoperative targeting applied to this pathology identifies demyelinated plaques and the functional state of Vim, reduces pitfalls and increases accuracy. Methods included spontaneous and induced multiunit activity recording, semimicroelectrode and tetraelectrode thalamic evoked potentials recording and micro/macro stimulation techniques.