Ulrika Sandvik

Thalamic and subthalamic deep brain stimulation for essential tremor: where is the optimal target?

BACKGROUND Brain damage markers released in cerebrospinal fluid (CSF) and blood may provide valuable information about diagnosis and outcome prediction after traumatic brain injury (TBI). OBJECTIVE To examine the concentrations of ubiquitin C-terminal hydrolase-L1 (UCH-L1), a novel brain injury biomarker, in CSF and serum of severe TBI patients and their association with clinical characteristics and outcome. METHODS This case-control study enrolled 95 severe TBI subjects (Glasgow Coma Scale [GCS] score, 8). Using sensitive UCH-L1 sandwich ELISA, we studied the temporal profile of CSF and serum UCH-L1 levels over 7 days for severe TBI patients. RESULTS Comparison of serum and CSF levels of UCH-L1 in TBI patients and control subjects shows a robust and significant elevation of UCH-L1 in the acute phase and over the 7-day study period. Serum and CSF UCH-L1 receiver-operating characteristic curves further confirm strong specificity and selectivity for diagnosing severe TBI vs controls, with area under the curve values in serum and CSF statistically significant at all time points up to 24 hours (P < .001). The first 12-hour levels of both serum and CSF UCH-L1 in patients with GCS score of 3 to 5 were also significantly higher than those with GCS score of 6 to 8. Furthermore, UCH-L1 levels in CSF and serum appear to distinguish severe TBI survivors from nonsurvivors within the study, with nonsurvivors having significantly higher and more persistent levels of serum and CSF UCH-L1. Cumulative serum UCH-L1 levels > 5.22 ng/mL predicted death (odds ratio, 4.8). CONCLUSION Serum levels of UCH-L1 appear to have potential clinical utility in diagnosing TBI, including correlating to injury severity and survival outcome.BACKGROUND: The ventrolateral thalamus (ventral intermediate nucleus [Vim]) is the traditional target for neurosurgical treatment of essential tremor. The target, however, has varied substantially among different neurosurgeons. OBJECTIVE: To evaluate the effect of deep brain stimulation in the thalamus and posterior subthalamic area (PSA) in relation to electrode location. METHODS: Thirty-six (17 Vim/19 PSA) patients with 44 deep brain stimulation electrodes were included in this retrospective study. The effect of stimulation was evaluated with standardized settings for each contact using items from the Essential Tremor Rating Scale. RESULTS: When each contact was evaluated in terms of the treated hand with standardized stimulation, the electrode contact providing the best effect in the individual patient was located in the zona incerta or radiation prelemniscalis in 54% and the Vim in 12%. Forty contacts provided a tremor reduction of > 90%. Of these, 43% were located in the PSA and 18% in the Vim according to the Schaltenbrand atlas. Of these 40 contacts, 37 were found in the PSA group. CONCLUSION: More contacts yielding an optimal effect were found in the PSA group than in the Vim. Many patients operated on in the Vim got the best effect from a contact located in the PSA. This might suggest that the PSA is a more efficient target than the Vim.

Deep brain stimulation in the posterior subthalamic area in the treatment of essential tremor

To evaluate the posterior subthalamic area (PSA) as a target for deep brain stimulation (DBS) in the treatment of essential tremor (ET). The ventral intermediate nucleus of the thalamus is the traditional target for DBS in the treatment of ET. Recent studies have presented beneficial effects of DBS in the PSA in the treatment of tremor. Twenty‐one patients with ET were included in this study. All patients were evaluated before and 1 year after surgery, on and off stimulation, using the essential tremor rating scale (ETRS). A marked microlesional effect was noticed in 83%, in some cases obviating the need for electrical stimulation for many months. The total ETRS was reduced from 46.2 at baseline to 18.7 (60%). Item 5/6 (tremor of the upper extremity) was improved from 6.2 to 0.3 (95%), and items 11 to 14 (hand function) from 9.7 to 1.3 (87%) concerning the contralateral hand. Activities of daily living were improved by 66%. No severe complication occurred. Eight patients presented a postoperative mild dysphasia that regressed within days to weeks. DBS in the PSA resulted in a marked reduction of tremor.

The posterior subthalamic area in the treatment of movement disorders : past, present, and future

THE INTRODUCTION OF thalamotomy in 1954 led naturally to exploration of the underlying subthalamic area, with the development of such procedures as campotomy and subthalamotomy in the posterior subthalamic area. The most popular of these procedures was the subthalamotomy, which was performed in thousands of patients for various movement disorders. Today, in the deep brain stimulation (DBS) era, subthalamic nucleus DBS is the treatment of choice for Parkinsons disease, whereas thalamic and pallidal DBS are mainly used for nonparkinsonian tremor and dystonia, respectively. The interest in DBS in the posterior subthalamic area has been quite limited, however, with a total of 95 patients presented in 14 articles. During recent years, interest has increased, and promising results have been published concerning both Parkinsons disease and nonparkinsonian tremor. We reviewed the literature to investigate the development of surgery in the posterior subthalamic area from the lesional era to the present.

Long term follow-up of deep brain stimulation of the caudal zona incerta for essential tremor

Purpose The ventral intermediate nucleus of thalamus is the standard target for deep brain stimulation (DBS) in essential tremor (ET). However, favourable data have recently highlighted the caudal zona incerta (cZi) as an alternative target. Reports concerning the long-term results are however lacking, and we have therefore evaluated the long-term effects in our patients with ET and cZi DBS. Methods 18 patients were evaluated using the Essential Tremor Rating Scale (ETRS) before and on-/off-stimulation at 1 and 3–5 years after surgery (mean 48.5±10.6 months). Two patients were operated on bilaterally but all electrodes were evaluated separately. The stimulation parameters were recorded and the stimulation strength calculated. Results A baseline total ETRS mean score of 46.0 decreased to 21.9 (52.4%) at the final evaluation. On the treated side, tremor of the upper extremity (item 5 or 6) improved from 6.1 to 0.5 (91.8%) and hand function (items 11–14) improved from 9.3 to 2.0 (78.0%). Activities of daily living improved by 65.8%. There was no increase in stimulation strength over time. Conclusion cZi DBS is a safe and effective treatment for the long term suppression of ET.

Deep brain stimulation of the subthalamic nucleus versus the zona incerta in the treatment of essential tremor

BackgroundDeep brain stimulation (DBS) is an effective treatment for essential tremor (ET). Currently the ventrolateral thalamus is the target of choice, but the posterior subthalamic area (PSA), including the caudal zona incerta (cZi), has demonstrated promising results, and the subthalamic nucleus (STN) has been suggested as a third alternative. The objective of the current study was to evaluate the effect of STN DBS in ET and to compare this to cZi DBS.MethodsFour patients with ET were implanted with two ipsilateral electrodes, one in the STN and one in the cZi. All contacts were evaluated concerning the acute effect on tremor, and the effect of chronic DBS in either target was analyzed.ResultsSTN and cZi both proved to be potent targets for DBS in ET. DBS in the cZi was more efficient, since the same degree of tremor reduction could here be achieved at lower energy consumption. Three patients became tremor-free in the treated hand with either STN or cZi DBS, while the fourth had a minor residual tremor after stimulation in either target.ConclusionIn this limited material, STN DBS was demonstrated to be an efficient treatment for ET, even though cZi DBS was more efficient. The STN may be an alternative target in the treatment of ET, pending further investigations to decide on the relative merits of the different targets.

Quality of life following DBS in the caudal zona incerta in patients with essential tremor.

BackgroundEssential 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).FindingsThis 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).ResultsIn 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.ConclusionsAlthough 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.

Thalamotomy for Essential Tremor: A Very Long-Term Follow-Up

The movement disorder essential tremor (ET) has been treated in the past with thalamotomy, a surgical treatment known to cause dysarthria as a side effect. The aim of the current study was to evalu ...