Search

Background: Head tremor is common in dystonia syndromes and difficult to treat. Deep brain stimulation (DBS) is a therapeutic option in medically-refractory cases. In most DBS-centers, the globus pallidus internus (GPi) is targeted in patients with predominant dystonia and the ventrointermediate nucleus of the thalamus (Vim) in predominant tremor. The aim of the study was to evaluate the effect of GPi- versus Vim-DBS in dystonic or essential head tremor., Methods: All patients with dystonia or essential tremor (ET) (n = 381) who underwent DBS surgery at our institution between 1999 and 2020 were screened for head tremor in our database according to predefined selection criteria. Of the 33 patients meeting inclusion criteria tremor and dystonia severity were assessed at baseline, short- (mean 10 months) and long-term follow-up (41 months) by two blinded video-raters., Results: Twenty-two patients with dystonic head tremor received either GPi- (n = 12) or Vim-stimulation (n = 10), according to the prevailing clinical phenotype. These two groups were compared with 11 patients with ET, treated with Vim-stimulation. The reduction in head tremor from baseline to short- and long-term follow-up was 60-70% and did not differ significantly between the three groups., Conclusions: GPi-DBS effectively and sustainably reduced head tremor in idiopathic dystonia. The effect was comparable to the effect of Vim-DBS on head tremor in dystonia patients with predominant limb tremor and to the effect of Vim-DBS on head tremor in ET., (© 2024 The Authors. Movement Disorders Clinical Practice published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Background: Thalamic deep brain stimulation (DBS) is established for medically refractory tremor syndromes and globus pallidus stimulation (GPi‐DBS) for medically refractory dystonia syndromes. For combined tremor and dystonia syndromes, the best target is unclear. Objectives: We present four patients with two different profiles whose clinical course demonstrates that our current analysis of clinical symptomatology is not a sufficient predictor of surgical success. Methods: Outcome parameters were assessed with observer‐blinded video ratings and included the Fahn‐Tolosa‐Marin‐Tremor Rating Scale (FTM‐TRS) and the Unified Dystonia Rating Scale (UDRS). Results: Two patients with "predominant lateralized action tremor" of the hands and mild cervical dystonia showed no relevant tremor improvement after GPi‐DBS, but UDRS improved (mean, 45%). Rescue ventral intermediate nucleus of the thalamus (Vim)‐DBS electrodes were implanted and both patients benefited significantly with a mean tremor reduction of 51%. Two other patients with "axial‐predominant action tremor of the trunk and head" associated with cervical dystonia underwent bilateral Vim‐DBS implantation with little effect on tremor (24% reduction in mean FTM‐TRS total score) and no effect on dystonic symptoms. GPi rescue DBS was implanted and showed a significant effect on tremor (63% reduction in mean FTM‐TRS) and dystonia (49% reduction in UDRS). Conclusions: The diagnosis of dystonic tremor alone is not a sufficient predictor to establish the differential indication of GPi‐ or Vim‐DBS. Further criteria (eg, proximal‐distal distribution of tremor/dystonia) are needed to avoid rescue surgery in the future. On the other hand, the course of our patients encourages rescue surgery in such severely disabled patients if the first target fails. [ABSTRACT FROM AUTHOR]