Long‐term efficacy of thalamic deep brain stimulation for tremor: Double‐blind assessments

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Abstract
Thalamic deep brain stimulation (DBS) is proven to suppress tremor in Parkinson's disease (PD) and essential tremor (ET). However, there are few reports on its long‐term efficacy. We studied the efficacy of DBS at 2 years and 6–7 years after electrode implantations in the ventrointermediate nucleus of the thalamus in 39 patients (20 PD, 19 ET) with severe tremor. Twenty‐five of the patients completed the study. Evaluations were done in a double‐blind manner with the Unified Parkinson's Disease Rating Scale (UPDRS) and Essential Tremor Rating Scale (ETRS). DBS decreased tremor sum scores in PD (P < 0.025) compared to the preoperative baseline (median, 7; Q25–75, 6–9) both at 2 years (median, 2; Q25–75, 2–3.5; n = 16) and at 6 to 7 years (median, 2.5; Q25–75, 0.5–3; n = 12). Stimulation on improved tremor sum as well as sub scores (P < 0.025) compared to stimulation off conditions. In ET, thalamic stimulation improved (P < 0.025) kinetic and positional tremor at both follow‐up periods (n = 18 and n = 13, respectively) with significant improvements (P < 0.025) in hand‐function tests. PD but not ET patients showed a general disease progression. Stimulation parameters were remarkably stable over time. We conclude that high‐frequency electric thalamic stimulation can efficiently suppress severe tremor in PD and ET more than 6 years after permanent implantation of brain electrodes. © 2002 Movement Disorder Society
Funding Information
  • Faculty of Medicine, University in Lund, Sweden
  • Medtronic Inc., Minneapolis, Minnesota, USA