Deep brain stimulation (DBS) is an established treatment for essential tremor (ET). The nucleus ventralis intermedius thalami (Vim) is the target of choice, but promising results have been presented regarding DBS in the posterior subthalamic area (PSA). The aim of this study was to evaluate the possible influence of gender, age and severity of disease on the outcome of these procedures. Sixty eight patients (34 Vim, 34 PSA) with ET were included in this non-randomised study. Evaluation using the Essential Tremor Rating Scale (ETRS) was performed before, and one year after surgery concerning PSA DBS, and at a mean of 28 ± 24 months concerning Vim DBS. Items 5/6 and 11-14 (hand tremor and hand function) were selected for analysis of tremor outcome. The efficacy of DBS on essential tremor was not related to age or gender. Nor was it associated with the severity of tremor when the percentual reduction of tremor on stimulation was taken into account. However, patients with a more severe tremor at baseline had a higher degree of residual tremor on stimulation. Tremor in the treated hand and hand function were improved with 70% in the Vim group and 89% in the PSA group.
"There are few studies comparing VIM and PSA targets for DBS treatment of ET. One retrospective study57 including 36 ET patients (17 VIM/19 PSA) with 44 DBS electrodes reported that the electrode contact providing the best effect in individual tremor control, measured by the ETRS, was located predominantly in the Zi or Raprl (54%) compared to VIM (12%). Another prospective study including 68 ET patients (34 VIM/34 PSA) reported improvement in hand tremor and hand function (measured by ETRS) by 70% in the VIM group compared to 89% in the PSA group,58 though the duration of follow-up varied between the two groups, with mean follow-up of 1 year for PSA DBS compared to 28 ± 24 months’ follow-up for VIM DBS, and this may have potentially affected the outcomes. "
[Show abstract][Hide abstract] ABSTRACT: Deep-brain stimulation (DBS) is an established treatment for medically refractory essential tremor (ET). This article reviews the current evidence supporting the efficacy and safety of DBS targets, including the ventral intermediate (VIM) nucleus and posterior subthalamic area (PSA) in treatment of ET.
A structured PubMed search was performed through December 2012 with keywords "deep brain stimulation (DBS)," "essential tremor (ET)," "ventral intermediate (VIM) nucleus," "posterior subthalamic area (PSA)," "safety," and "efficacy."
Based on level IV evidence, both VIM and PSA DBS targets appear to be safe and efficacious in ET patients in tremor reduction and improving activities of daily living, though the literature on PSA DBS is limited in terms of bilateral stimulation and long-term follow-up. DBS-related adverse effects are typically mild and stimulation-related. Hardware-related complications after DBS may not be uncommon, and often require additional surgical procedures. Few studies assessed quality-of-life and cognition outcomes in ET patients undergoing DBS stimulation.
DBS appears to be a safe and effective treatment for medically refractory ET. More systematic studies comparing VIM and PSA targets are needed to ascertain the most safe and effective DBS treatment for medically refractory ET. More research is warranted to assess quality-of-life and cognition outcomes in ET patients undergoing DBS.
[Show abstract][Hide abstract] ABSTRACT: Essential tremor (ET) is the most common movement disorder and often affects the quality of life. There are only a few studies evaluating the quality of life after deep brain stimulation (DBS).
This is a prospective study of 16 patients undergoing deep brain stimulation in the caudal Zona incerta (cZi). The quality of life was assessed with Quality of Life in Essential Tremor Questionnaire (QUEST) and SF-36 scores, and the tremor was evaluated using the essential tremor rating scale (ETRS).
In the tremor rating, hand tremor on the treated side improved by 95%, hand function by 78% and activities of daily living by 71%. The QUEST score showed statistically significant improvements in the psychosocial and activities of daily living subscores. The SF-36 score did not show any significant improvement.
Although very good tremor reduction was achieved, the improvement in the quality of life scores was more modest. This could partly be explained by the quality of life being affected by other factors than the tremor itself.
[Show abstract][Hide abstract] ABSTRACT: OBJECTIVE: To evaluate the effects of reoperation with deep brain stimulation (DBS) in the caudal zona incerta (cZi) in patients with failed DBS in the ventral intermediate (Vim) nucleus of the thalamus for essential tremor. METHODS: The results of reoperation with cZi DBS in five patients with failed Vim DBS were retrospectively analyzed. RESULTS: Two patients had early failure of Vim DBS, and three after several years of good effect. The mean deviation from the atlas Vim target point was 1.4 mm. Before the reoperation Vim DBS improved hand function and tremor in the treated hand at 25 %, whereas cZi DBS achieved an improvement of 57%. Although cZi was more efficient than Vim DBS, also in the patients with late failure of Vim DBS, they still exhibited a considerable residual tremor on cZi DBS. CONCLUSIONS: The effect on tremor was, in this small sample population, improved by implanting an electrode in the cZi. The effect was modest in those patients suffering a deterioration years after the initial operation.
World Neurosurgery 12/2011; 78(5). DOI:10.1016/j.wneu.2011.12.013 · 2.88 Impact Factor
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