title: Long-term efficacy of thalamic deep brain stimulation for tremor: double-blind assessments.
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.
authors.affiliation: The Department of Clinical Neuroscience, Division of Neurosurgery, University in Lund, Sweden. stig.rehncrona@neurokir.lu.se
authors.forename: Stig
authors.initials: S
authors.lastname: Rehncrona
authors.forename: Bo
authors.initials: B
authors.lastname: Johnels
authors.forename: Håkan
authors.initials: H
authors.lastname: Widner
authors.forename: Anna-Lena
authors.initials: AL
authors.lastname: Törnqvist
authors.forename: Marwan
authors.initials: M
authors.lastname: Hariz
authors.forename: Olof
authors.initials: O
authors.lastname: Sydow
mesh_terms: D000368:Aged; D018450:Disease Progression; D004311:Double-Blind Method; D004599:Electric Stimulation Therapy / Q000379:methods*; D020329:Essential Tremor / Q000453:epidemiology / Q000209:etiology / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D015588:Observer Variation; D010300:Parkinson Disease / Q000150:complications; D013788:Thalamus / Q000502:physiology*; D013995:Time