Tremor and disability outcomes following deep brain stimulation for multiple sclerosis-associated tremor.

BACKGROUND: Tremor in multiple sclerosis (MS) is often refractory to medications. Deep brain stimulation (DBS) may help, but possible side effects and disease exacerbation limit its use. OBJECTIVES: Evaluate outcomes of DBS for MS-associated tremor. METHODS: Retrospective review of 18 patients with MS-associated tremor who underwent DBS, analyzing Expanded Disability Status Scale (EDSS) and Fahn-Tolosa-Marin (FTM) tremor scores. RESULTS: Median age at surgery was 49.5 years (range, 28-75), with postoperative follow-up 2.5 years (range, 0-22). No relapses (0/18) or new lesions (0/8) occurred postoperatively. All had ventral intermediate nucleus leads; other targets were not used in programming. EDSS remained stable (median 6 to 6.25; p = 0.2). FTM scores improved (median 14.5 to 10, p = 0.008). Patients with EDSS 3.5-6 had variable outcomes (p = 0.02). CONCLUSIONS: DBS is a potential treatment for severe MS tremor and did not provoke relapse. Targeting VIM alone may optimize tremor control and maintain magnetic resonance imaging (MRI) access.