Describe outcomes of deep brain stimulation (DBS) for MS-associated tremor in a single center and identify baseline features associated with optimal outcomes.

We identified 18 patients who underwent DBS for MS-associated tremor including: relapsing MS, 2; secondary progressive, 8; primary progressive, 8. Median age of MS onset was 32 years (range, 21 – 65). DBS surgery was performed at median age of 49.5 years (range, 28 – 75) with a median follow-up of 2.5 years (range, 0 – 22) after. Seven patients were on MS disease modifying therapy. After surgery, no clinical relapses (0/18) or new MRI lesions (0/8) occurred. One patient had an early surgical complication (1/18). There was no change in EDSS following DBS surgery (median preoperative 6 [3 – 6.5]; postoperative 6.25 [1 – 8]; p=0.2). There was a reduction in FTM score with stimulation (preoperative median 13 [4 – 22], postoperative last follow-up 11 [2 – 16], p=0.03). There was an interaction (p<0.001) between preoperative EDSS score and tremor outcome, such that all patients with preoperative EDSS ≤3 or ≥6.5 had sustained improvement in FTM, while those with preoperative EDSS 3.5 to 6 had variability in tremor outcomes (5/8 sustained improvement).

DBS represents a potential avenue for treatment of severe tremor in MS and did not provoke inflammatory MS activity in our cohort. Baseline EDSS may be a helpful tool to identify ideal DBS candidates.