Deep brain stimulation of the ventral intermediate nucleus of the thalamus in medically refractory orthostatic tremor: Preliminary observations

Orthostatic tremor (OT) is a disabling movement disorder associated with postural and gait impairment in the elderly. Medical therapy often yields insufficient benefit. We report the clinical and electrophysiological data on two patients with medication‐refractory OT treated with deep brain stimulation of the ventral intermediate thalamic nucleus (Vim DBS). Patient 1 underwent bilateral deep brain stimulation (DBS) and Patient 2 unilateral Vim DBS following 28 and 30 years of disease duration, respectively. Both patients showed increased latency to symptom onset after rising from a seated position, improved tolerance for prolonged standing, and slower crescendo of tremor severity when remaining upright. Postoperative evaluation demonstrated decreased amplitude of electromyographic activity with persistence of well‐defined oscillatory behavior showing strong coherence at 15 Hz between all muscles tested in the upper and lower limbs. Postural sway was unchanged. Clinical benefits have been sustained for over 18 months in Patient 1, and receded after 3 months in Patient 2. These findings support the consideration of bilateral Vim DBS implantation as a therapeutic option in patients with medically refractory OT. Further efficacy studies on chronic stimulation to disrupt the abnormal oscillatory activity in this disorder are warranted. © 2008 Movement Disorder Society     

Treating post-traumatic tremor with deep brain stimulation: Report of five cases

BackgroundPost-traumatic tremor is one of the most common movement disorders resulting from severe head trauma. However, literature regarding successful deep brain stimulation (DBS) treatment is scarce, resulting in ambiguity regarding the optimal lead location. Most cases support the ventral intermediate nucleus, but there is evidence to defend DBS of the zona incerta, ventral oralis anterior/posterior, and/or a combination of these targets. We report five patients with disabling post-traumatic tremor treated with DBS of the ventral intermediate nucleus and of the globus pallidus internus.MethodsPatients were referred to the Vanderbilt Movement Disorders Division, and surgical intervention was determined by a DBS Multidisciplinary Committee. Standard DBS procedure was followed.ResultsPatients 1–4 sustained severe diffuse axonal injuries. Patients 1–3 underwent unilateral ventral intermediate nucleus DBS for contralateral tremor, while Patient 4 underwent bilateral ventral intermediate nucleus DBS. Patients 1–3 experienced good tremor reduction, while Patient 4 experienced moderate tremor reduction with some dystonic posturing of the hands. Patient 5 had dystonic posturing of the right upper extremity with tremor of the left upper extremity. He was treated with bilateral DBS of the globus pallidus internus and showed good tremor reduction at follow-up.ConclusionUnilateral or bilateral DBS of the ventral intermediate nucleus and bilateral DBS of the globus pallidus internus may be effective and safe treatment modalities for intractable post-traumatic tremor. Further studies are needed to clarify the optimal target for surgical treatment of post-traumatic tremor.     

Effects of ventral intermediate nucleus deep brain stimulation across multiple effectors in essential tremor

ObjectiveEssential tremor (ET) prominently affects the upper-limbs during voluntary movements, but can also affect the lower-limbs, head, and chin. Although deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of thalamus improves both clinical ratings and quantitative measures of tremor, no study has quantified effects of DBS on tremor across multiple body parts. Our objective was to quantify therapeutic effects of DBS across multiple body parts in ET.MethodsWe performed quantitative assessment of tremor in ET patients who had DBS for at least one year. We assessed tremor on and off VIM-stimulation using triaxial accelerometers on the upper-limbs, lower-limbs, head and chin during seated and standing tasks.ResultsVIM-DBS significantly reduced tremor, but there was no statistical difference in degree of tremor reduction across the measured effectors. Compared to healthy controls, ET patients treated with DBS showed significantly greater tremor power (4–8 Hz) across all effectors during seated and standing tasks.ConclusionsVIM-DBS reduced tremor in ET patients. There was no significant difference in the degree of tremor reduction across the measured effectors.SignificanceThis study provides new quantitative evidence that VIM-DBS is effective at reducing tremor across multiple parts of the body.     

The effects of subthalamic nucleus deep brain stimulation on parkinsonian tremor

Deep brain stimulation (DBS) of the ventral intermediate (Vim) nucleus of the thalamus has been the target of choice for patients with disabling essential tremor or medication refractory parkinsonian tremor. Recently there is evidence that the subthalamic nucleus (STN) should be the targets for patients with tremor associated with Parkinson's disease (PD). To assess the effects of STN DBS on parkinsonian tremor, eight consecutive patients with PD and disabling tremor were videotaped using a standardized tremor protocol. Evaluations were performed at least 12 h after last dose of medication with the DBS turned off followed by optimal DBS on state. A rater blinded to DBS status evaluated randomized video segments with the tremor components of the Unified Parkinson Disease Rating Scale (UPDRS) and Tremor Rating Scale (TRS). Compared with DBS off state there were significant improvements in mean UPDRS tremor score 79.4% (p = 0.008), total TRS score 69.9% (p = 0.008) and upper extremity 92.5% (p = 0.008) TRS subscore. Functional improvement was noted with pouring liquids. Our findings provide support that STN DBS is an effective treatment of tremor associated with PD.     

丘脑底核慢性电刺激与苍白球毁损术治疗帕金森病疗效比较

目的分别应用脑深部电刺激(deepbrainstimulation,DBS)和苍白球毁损术(posteroventralpallidot-omy,PVP)治疗原发性帕金森病(Parkinson'sdisease,PD),对照研究DBS和PVP对PD患者的震颤、肢体僵硬、运动迟缓的疗效。方法应用CT影像学与微电极电生理定位结合的方法进行靶点定位,为11例帕金森病患者进行同期双侧丘脑底核电极植入,26例患者进行分期双侧苍白球腹后部毁损术,经过至少6个月的随访并行UPDRS评分。结果11例同期进行双侧丘脑底核电极植入及26例分期进行双侧苍白球毁腹后部毁损术患者术后的震颤、肢体僵硬、运动迟缓症状均不同程度的改善,但以DBS手术的改善程度更为明显,两组患者手术前后的UPDRS评分下降程度差异显著(P<0.05)。结论双侧同期DBS是目前治疗PD相对较好的方法,双侧电极植入在改善肢体症状的同时可以明显控制、改善中轴症状,在治疗中晚期PD患者方面较PVP有较大的优势。     

Predictors of deep brain stimulation outcome in tremor patients

Background

Deep brain stimulation of the ventro-intermedius nucleus of the thalamus is an established treatment for tremor of differing etiologies but factors that may predict the short- and especially long-term outcome of surgery are still largely unknown.

Surgical targets for dystonic tremor: Considerations between the globus pallidus and ventral intermediate thalamic nucleus

Dystonic tremor (DT) is characterized by coexisting tremor and abnormal dystonic posturing in the same segment. DT is often medically refractory and DBS is an important therapeutic option. However, the optimal surgical target for DT remains uncertain with Vim, GPi and zona incerta previously reported as effective. We retrospectively reviewed the outcome data from all patients with DT involving at least one upper extremity who underwent DBS at Vanderbilt University from July 2006 to July 2010. We evaluated the improvement of tremor and dystonia after their response to DBS was judged to be maximal. Ten patients met the inclusion criteria. Vim was targeted in four patients and three had unilateral procedure and one bilateral Vim DBS. GPi was targeted in four patients with bilateral DBS procedure in every patient from this subgroup. A combined bilateral GPi and unilateral Vim DBS was performed in two patients. The best results for tremor control were observed in patients with Vim DBS but they had persisting mild dystonia. Patients with GPi DBS had average DT improvement by approximately 50% but their dystonia symptoms were markedly improved. We propose that the patients with DT with a mild dystonia should be considered for Vim DBS procedure and the coexistence of severe DT and dystonia may be successfully controlled by combined GPi and Vim DBS surgeries.     

A pilot study: Microlesion effects and tremor outcome in the ventrointermediate deep brain stimulation (VIM-DBS)

Objectives

To perform a pilot study to investigate the relationship between the microlesion effect (MLE) seen in deep brain stimulation (DBS) of the ventralis intermedius nucleus (VIM) and subsequent tremor response and DBS parameter settings.

Patients and methods

Nineteen thalami in 12 patients (11 essential tremor and 1 Parkinson's disease), who underwent unilateral (n = 5) and bilateral VIM-DBS (n = 7) were assessed at pre- and 24-h post-operation, at their initial DBS activation, and at 6-month follow-up. The severity of tremor was rated (from 0 to 4) for each activity including hand at rest, outstretched, wing beating, finger–nose–finger, dot approximation and spiral drawing (total score ranging from 0 to 24). The difference of total tremor score before and 24-h after electrode implants (MLE) was segregated into 3 groups based on immediate (24 h) post-operative tremor improvement: (1) minimal (none or mild, 0–2), (2) moderate (>2–4), and (3) marked (>4). At the initial activation (23.4 ± 3.7 days post-operation), the mean OFF tremor scores were still marginally better in marked than the minimal and moderate MLE groups.

Results

At 6 months, 14 of 19 thalami (74%) were eligible for follow-up analysis. The “OFF” stimulation MLE disappeared in all groups. There was no significant difference of mean ON tremor scores among the groups; however, DBS parameter settings, including amplitude and pulse width, trended to be mildly lower in those with a marked MLE.

Conclusion

MLE has minimal long term clinical effect except for possibly allowing for lower DBS settings.     

Long-term effects of bilateral deep brain stimulation of the subthalamic nucleus on depression in patients with Parkinson's disease

ObjectiveTo study the long-term effects of deep brain stimulation (DBS) of the bilateral subthalamic nucleus (STN) on depression in patients with Parkinson's disease (PD) and to discuss the mechanism.MethodsA STN–DBS group (n = 27) and anti-Parkinson's medication control group with paired designing were set up. The evaluation of the depression and motor function was performed a total of six times. Depression was evaluated by the Self-Rating Depression Scale (SDS) and Hamilton Rating Scale for Depression (HAMD). Motor function was evaluated by the third part of the Unified Parkinson's Disease Rating Scale (UPDRS-III).ResultsCompared with the preoperative and the medication control group, the UPDRS-III scores of the STN–DBS group decreased remarkably within 18 months postoperatively (P ≤ 0.001), and the SDS scores decreased notably within 6 months postoperatively (P ≤ 0.05), and the HAMD scores decreased notably within 3 months postoperatively (P ≤ 0.05). The UPDRS-III scores were strongly correlated with their SDS scores within 6 months postoperatively (P ≤ 0.05), especially at 5 weeks postoperation (P ≤ 0.001). UPDRS-III scores were also strongly correlated with HAMD scores at 5 weeks postoperation (P ≤ 0.05). The mean value of the bilateral voltages was obviously correlated with SDS and HAMD scores (P ≤ 0.05) within 18 months postoperatively.ConclusionThe improvement in motor symptoms resulting from STN–DBS can improve depression in PD patients, but its long-term effects were unremarkable. Within the treatment range, the higher the mean value of bilateral voltages then the more severe was the depression in PD patients.     

Deep brain stimulation for Holmes’ tremor related to a thalamic abscess

BACKGROUND: Medical treatment is usually ineffective for Holmes' tremor, and surgery is the treatment of choice for many patients. Here we report the case of a 14-year-old girl who developed Holmes' tremor related to a thalamic abscess and was successfully treated with thalamic deep brain stimulation. CASE REPORT: The patient presented with left hemiparesis and headache and was hospitalized. Investigation revealed a thalamic abscess in the left cerebral hemisphere. The abscess was drained via stereotactic surgery and a course of antibiotic treatment was completed. Four months after treatment, the patient developed Holmes' tremor in her left upper extremity. When attempts at medical treatment with levodopa, clonazepam, and trihexyphenidyl all failed, an implant was placed and deep brain stimulation of the ventral intermediate nucleus of the thalamus was initiated. During 2.5 years of follow-up, her tremor diminished by 90%. CONCLUSION: This case demonstrates that medically resistant Holmes' tremor related to a thalamic lesion can be successfully treated with thalamic deep brain stimulation.     

双侧丘脑底核脑深部电刺激治疗帕金森病

目的 应用双侧丘脑底核脑深部电刺激（DBS）治疗难治性帕金森病（PD），并对其疗效作出评价。方法 对7例帕金森病患者采用磁共振导向立体定向及术中电生理验证方法，将刺激电极分别植入丘脑底核，采用同期或分期植入刺激发生器。术后1周用程控计算机在体外调速刺激参数，以达到最佳疗效。结果 6例患者术后均获得了显著的疗效。震颤完全消失，肌强直、步态、姿障碍以及药物所致的并发症明显,面时多巴胺类药物用量明显减少，1例曾接爱双侧丘脑腹中间核及一侧苍白球毁损后的患者只得到了轻度改善。结论 DBS法治疗中晚期PD，具有安全，副作用可逆转的优点，且可根据患者的不同状况及病情发展调节刺激参数达到最佳症状控制，完全控制震颤，明显改善肌张力障碍、步态、资势等运动障碍及药物所致的并发症，另外多巴胺类药物的用量也明显减少。     

Determining an efficient deep brain stimulation target in essential tremor - Cohort study and review of the literature

IntroductionDeep brain stimulation (DBS) is a highly efficacious treatment for essential tremor (ET). Still, the optimal anatomical target in the (sub)thalamic area is a matter of debate. The aim of this study was to determine the optimal target of DBS for ET regarding beneficial clinical outcome and impact on activities of daily living as well as stimulation-induced side effects and compare it with previously published coordinates.MethodsIn 30 ET patients undergoing bilateral DBS, severity of tremor was assessed by blinded video ratings before and at 1-year follow-up with DBS ON and OFF. Tremor scores and reported side effects and volumes of tissue activated were used to create a probabilistic map of DBS efficiency and side effects.ResultsDBS was effective both in tremor suppression as well as in improving patient reported outcomes, which were positively correlated. The “sweet spot” for tremor suppression was located inferior of the VIM in the subthalamic area, close to the superior margin of the zona incerta. The Euclidean distance of active contacts to this spot as well as to 10 of 13 spots from the literature review was predictive of individual outcome. A cluster associated with the occurrence of ataxia was located in direct vicinity of the “sweet spot”.ConclusionOur findings suggest the highest clinical efficacy of DBS in the posterior subthalamic area, lining up with previously published targets likely representing the dentato-rubro-thalamic tract. Side effects may not necessarily indicate lead misplacement, but should encourage clinicians to employ novel DBS programing options.     

丘脑底核脑深部刺激术治疗帕金森病的手术方法和疗效分析

目的 总结帕金森病(PD)脑深部刺激术(DBS)治疗的手术方法和效果。方法 对25例帕金森病患者进行了丘脑底核DBS治疗,其中单侧17例,双侧8例。采用磁共振扫描结合微电极记录技术进行靶点定位。术后用UPDRS运动评分评价刺激效果。结果 25例PD患者术后随访5～34个月,平均8.3个月。脉冲发生器开启时,在“关”状态下,UPDRS运动评分改善率50.2％;在“开”状态下,UPDRS运动评分改善率20.7％,未发现任何并发症。结论 丘脑底核DBS是改善PD患者运动功能较为理想的治疗方法。     

丘脑底核脑深部电刺激治疗原发性帕金森病的不良事件

目的观察原发性帕金森病(Parkinson disease,PD)患者行丘脑底核脑深部电刺激术(deep brain stimulation of subthalamic nucleus,STN DBS)的不良事件。方法纳入行STN DBS的原发性帕金森病45例,收集患者一般临床资料,术后随访至3~9年,观察术后不良事件。结果手术相关不良事件:微毁损效应44例、囊袋积液2例、颅内出血1例、嗜睡1例;未观察到任何装置相关不良事件;刺激或疾病相关不良事件:异动症15例、步态平衡障碍12例,焦虑抑郁状态6例,构音障碍与多巴胺失调综合征各4例,智能减退2例,少数患者出现体重增加、幻觉、睁眼困难等。7例患者因共存疾病死亡。结论 STN DBS大部分不良事件可以控制,术后个体化调整参数及药物,有利于减少STN DBS不良事件。     

Mesial temporal inhibition in a patient with deep brain stimulation of the anterior thalamus for epilepsy

We investigated the electrophysiological effects of high-frequency anterior thalamic deep brain stimulation using intracerebral mesial and lateral temporal depth electrodes in a patient with intractable focal epilepsy. Monopolar and bipolar stimulation delivered to the thalamic anterior nucleus using the programmable ITREL II stimulation device led to a significant decrease of cross power spectral density and a nonsignificant decrease of coherence in ipsilateral hippocampal structures. No such effect was found in lateral temporal or contralateral sites. The hippocampal inhibition was clearly related to the voltage (> or =7 V) and frequency (> or =70 Hz) of the thalamic stimulus and occurred with a delay of approximately 60 s after stimulus onset.