Deep brain stimulation of the nucleus ventralis intermedius for Holmes (rubral) tremor and associated dystonia caused by upper brainstem lesions. Report of two cases

Deep brain stimulation in posterior subthalamic area for Holmes tremor: Case reports with review of the literature

Background

Holmes tremor (HT) is a refractory tremor associated with cortico-basal ganglia loops and cerebellothalamic tract abnormalities. Various drug treatments have been attempted; however, no treatment method has yet been established. Historically, thalamic deep brain stimulation (DBS) has been performed in medically refractory cases. Recently, the posterior subthalamic area (PSA) has been used for HT. Here, we report cases of HT and review the effectiveness and safety of PSA-DBS for HT.

Cases

We conducted a retrospective chart review of two patients with HT who underwent PSA-DBS. Improvement in tremors was observed 1 year after surgery without apparent complications.

Literature review

We identified 12 patients who underwent PSA-DBS for HT, including our cases. In six patients, PSA was targeted alone; for the rest, the ventralis intermediate nucleus (Vim) of the thalamus and PSA were simultaneously targeted. The Fahn-Tolosa-Marin Tremor Rating Scale improvement rates were 56.8% (range, 33.9-82.1%; n = 6) and 77.8% (range, 42.6-100%; n = 5) for the PSA-DBS and PSA+Vim-DBS, respectively.

Conclusion

Reasonable improvements in HT were observed after PSA-DBS. PSA might be an appropriate target for improving the symptoms of HT. Long-term observations, accumulation of cases, and randomized studies are required in future.

Tremor and myoclonus

Tremor and myoclonus are two common hyperkinetic movement disorders. Tremor is characterized by rhythmic oscillatory movements while myoclonic jerks are usually arrhythmic. Tremor can be classified into subtypes including the most common types: essential, enhanced physiological, and parkinsonian tremor. Myoclonus classification is based on its anatomic origin: cortical, subcortical, spinal, and peripheral myoclonus. The clinical presentations are unfortunately not always classic and electrophysiologic investigations can be helpful in making a phenotypic diagnosis. Video-polymyography is the main technique to (sub)classify the involuntary movements. In myoclonus, advanced electrophysiologic testing, such as back-averaging, coherence analysis, somatosensory-evoked potentials, and the C-reflex can be of additional value. Recent developments in tremor point toward a role for intermuscular coherence analysis to differentiate between tremor subtypes. Classification of the movement disorder based on clinical and electrophysiologic features is important, as it enables the search for an etiological diagnosis and guides tailored treatment.

Deep brain stimulation of the ventralis intermedius nucleus of the thalamus and posterior subthalamic area for Holmes' tremor secondary to brainstem hemorrhage: A case report

Holmes' tremor is a rare but severely disabling movement disorder characterized by a combination of resting, action, and intention tremor. Because Holmes' tremor is usually resistant to pharmacotherapy, surgical treatment is required for symptom control in most cases. We report the case of a 56-year-old man who was diagnosed with Holmes' tremor and treated with stimulation of the ventralis intermedius nucleus of the thalamus and posterior subthalamic area. Deep brain stimulation alleviated the patient's tremor over a 3-year follow-up period.

Deep brain stimulation in uncommon tremor disorders: indications, targets, and programming

BACKGROUND

In uncommon tremor disorders, clinical efficacy and optimal anatomical targets for deep brain stimulation (DBS) remain inadequately studied and insufficiently quantified.

METHODS

We performed a systematic review of PubMed.gov and ClinicalTrials.gov. Relevant articles were identified using the following keywords: "tremor", "Holmes tremor", "orthostatic tremor", "multiple sclerosis", "multiple sclerosis tremor", "neuropathy", "neuropathic tremor", "fragile X-associated tremor/ataxia syndrome", and "fragile X."

RESULTS

We identified a total of 263 cases treated with DBS for uncommon tremor disorders. Of these, 44 had Holmes tremor (HT), 18 orthostatic tremor (OT), 177 multiple sclerosis (MS)-associated tremor, 14 neuropathy-associated tremor, and 10 fragile X-associated tremor/ataxia syndrome (FXTAS). DBS resulted in favorable, albeit partial, clinical improvements in HT cases receiving Vim-DBS alone or in combination with additional targets. A sustained improvement was reported in OT cases treated with bilateral Vim-DBS, while the two cases treated with unilateral Vim-DBS demonstrated only a transient effect. MS-associated tremor responded to dual-target Vim-/VO-DBS, but the inability to account for the progression of MS-associated disability impeded the assessment of its long-term clinical efficacy. Neuropathy-associated tremor substantially improved with Vim-DBS. In FXTAS patients, while Vim-DBS was effective in improving tremor, equivocal results were observed in those with ataxia.

CONCLUSIONS

DBS of select targets may represent an effective therapeutic strategy for uncommon tremor disorders, although the level of evidence is currently in its incipient form and based on single cases or limited case series. An international registry is, therefore, warranted to clarify selection criteria, long-term results, and optimal surgical targets.

[Rare tremor syndromes]

BACKGROUND

There is a group of uncommon sporadic tremor syndromes, which are only partially taken into account in the current classification of tremor. Their knowledge is of diagnostic and therapeutic relevance and they should be considered in the differential diagnosis of frequent tremor syndromes.

OBJECTIVE

Differential diagnostics and treatment of uncommon tremor syndromes.

METHOD

Literature search (PubMed, Google Scholar).

RESULTS

Holmes tremor, myorhythmia, palatal tremor, limb-shaking transient ischemic attack (TIA), tardive tremor, neuropathic tremor, tremor induced by peripheral trauma and orthostatic tremor syndrome are described.

CONCLUSION

Uncommon sporadic tremor syndromes are mainly symptomatic with various underlying neurological or systemic pathologies. Their recognition accelerates the diagnostic process and has therapeutic relevance.

Holmes' Tremor with Shoulder Pain Treated by Deep Brain Stimulation of Unilateral Ventral Intermediate Thalamic Nucleus and Globus Pallidus Internus

A 21-year-old male was admitted with severe right arm and hand tremors after a thalamic hemorrhage caused by a traffic accident. He was also suffering from agonizing pain in his right shoulder that manifested after the tremor. Neurologic examination revealed a disabling, severe, and irregular kinetic and postural tremor in the right arm during target-directed movements. There was also an irregular ipsilateral rest tremor and dystonic movements in the distal part of the right arm. The amplitude was moderate at rest and extremely high during kinetic and intentional movements. The patient underwent left globus pallidum internus and ventral intermediate thalamic nucleus deep brain stimulation. The patient improved by more than 80% as rated by the Fahn-Tolosa-Marin Tremor Rating Scale and Visual Analog Scale six months after surgery.

Deep Brain Stimulation in Neurological and Psychiatric Disorders

BACKGROUND

Deep brain stimulation (DBS) is the chronic electrical stimulation of selected target sites in the brain through stereotactically implanted electrodes. More than 150 000 patients around the world have been treated to date with DBS for medically intractable conditions. The indications for DBS include movement disorders, epilepsy, and some types of mental illness.

METHODS

This review is based on relevant publications retrieved by a selective search in PubMed and the Cochrane Library, and on the current guidelines of the German Neurological Society (Deutsche Gesellschaft für Neurologie, DGN).

RESULTS

DBS is usually performed to treat neurological diseases, most often movement disorders and, in particular, Parkinson's disease. Multiple randomized controlled trials (RCTs) have shown that DBS improves tremor, dyskinesia, and quality of life in patients with Parkinson's disease by 25% to 50%, depending on the rating scales used. DBS for tremor usually involves stimulation in the cerebello-thalamo-cortical regulatory loop. In an RCT of DBS for the treatment of primary generalized dystonia, the patients who underwent DBS experienced a 39.3% improvement of dystonia, compared to only 4.9% in the control group. Two multicenter trials of DBS for depression were terminated early because of a lack of efficacy.

CONCLUSION

DBS is an established treatment for various neurological and psychiatric diseases. It has been incorporated in the DGN guidelines and is now considered a standard treatment for advanced Parkinson's disease. The safety and efficacy of DBS can be expected to improve with the application of new technical developments in electrode geometry and new imaging techniques. Controlled trials would be helpful so that DBS could be extended to further indications, particularly psychiatric ones.

Clinical Outcome and Characterization of Local Field Potentials in Holmes Tremor Treated with Pallidal Deep Brain Stimulation

BACKGROUND

Holmes tremor (HT) is an irregular, low-frequency rest tremor associated with prominent action and postural tremors. Currently, the most effective stereotactic target and neurophysiologic characterization of HT, specifically local field potentials (LFPs) are uncertain. We present the outcome, intraoperative neurophysiologic analysis with characterization of LFPs in a patient managed with left globus pallidus interna deep brain stimulation (Gpi DBS).

CASE REPORT

A 24-year-old male underwent left Gpi DBS for medically refractory HT. LFPs demonstrated highest powers in the delta range in Gpi. At the 6-month follow-up, a 90% reduction in tremor was observed.

DISCUSSION

Pallidal DBS should be considered as an alternative target for management of refractory HT. LFP demonstrated neuronal activity associated with higher power in the delta region, similarly seen in patients with generalized dystonia.

Deep brain stimulation for the treatment of uncommon tremor syndromes

Introduction: Deep brain stimulation (DBS) has become a standard therapy for the treatment of select cases of medication refractory essential tremor and Parkinson’s disease however the effectiveness and long-term outcomes of DBS in other uncommon and complex tremor syndromes has not been well established. Traditionally, the ventralis intermedius nucleus (VIM) of the thalamus has been considered the main target for medically intractable tremors; however alternative brain regions and improvements in stereotactic techniques and hardware may soon change the horizon for treatment of complex tremors.

Areas covered: In this article, we conducted a PubMed search using different combinations between the terms ‘Uncommon tremors’, ‘Dystonic tremor’, ‘Holmes tremor’ ‘Midbrain tremor’, ‘Rubral tremor’, ‘Cerebellar tremor’, ‘outflow tremor’, ‘Multiple Sclerosis tremor’, ‘Post-traumatic tremor’, ‘Neuropathic tremor’, and ‘Deep Brain Stimulation/DBS’. Additionally, we examined and summarized the current state of evolving interventions for treatment of complex tremor syndromes.

Expertcommentary: Recently reported interventions for rare tremors include stimulation of the posterior subthalamic area, globus pallidus internus, ventralis oralis anterior/posterior thalamic subnuclei, and the use of dual lead stimulation in one or more of these targets. Treatment should be individualized and dictated by tremor phenomenology and associated clinical features.

Pallidal stimulation for Holmes tremor: clinical outcomes and single-unit recordings in 4 cases

OBJECT

Holmes tremor (HT) is characterized by irregular, low-frequency (< 4.5 Hz) tremor occurring at rest, with posture, and with certain actions, often affecting proximal muscles. Previous reports have tended to highlight the use of thalamic deep brain stimulation (DBS) in cases of medication-refractory HT. In this study, the authors report the clinical outcome and analysis of single-unit recordings in patients with medication-refractory HT treated with globus pallidus internus (GPi) DBS.

METHODS

The authors retrospectively reviewed the medical charts of 4 patients treated with pallidal DBS for medication-refractory HT at the University of California, San Francisco, and San Francisco Veterans Affairs Medical Center. Clinical outcomes were measured at baseline and after surgery using an abbreviated motor-severity Fahn-Tolosa-Marin (FTM) tremor rating scale. Intraoperative microelectrode recordings were performed with patients in the awake state. The neurophysiological characteristics identified in HT were then also compared with characteristics previously described in Parkinson's disease (PD) studied at the authors' institution.

RESULTS

The mean percentage improvement in tremor motor severity was 78.87% (range 59.9%–94.4%) as measured using the FTM tremor rating scale, with an average length of follow-up of 33.75 months (range 18–52 months). Twenty-eight GPi neurons were recorded intraoperatively in the resting state and 13 of these were also recorded during contralateral voluntary arm movement. The mean firing rate at rest in HT was 56.2 ± 28.5 Hz, and 63.5 ± 19.4 Hz with action, much lower than the GPi recordings in PD. GPi unit oscillations of 2–8 Hz were prominent in both patients with HT and those with PD, but in HT, unlike PD, these oscillations were not suppressed by voluntary movement.

CONCLUSIONS

The efficacy of GPi DBS exceeded that reported in prior studies of ventrolateral thalamus DBS and suggest GPi may be a better target for treating HT. These clinical and neurophysiological findings help illuminate evolving models of HT and highlight the importance of cerebellar–basal ganglia interactions.

Current perspectives on deep brain stimulation for severe neurological and psychiatric disorders

Deep brain stimulation (DBS) has become a well-accepted therapy to treat movement disorders, including Parkinson's disease, essential tremor, and dystonia. Long-term follow-up studies have demonstrated sustained improvement in motor symptoms and quality of life. DBS offers the opportunity to selectively modulate the targeted brain regions and related networks. Moreover, stimulation can be adjusted according to individual patients' demands, and stimulation is reversible. This has led to the introduction of DBS as a treatment for further neurological and psychiatric disorders and many clinical studies investigating the efficacy of stimulating various brain regions in order to alleviate severe neurological or psychiatric disorders including epilepsy, major depression, and obsessive-compulsive disorder. In this review, we provide an overview of accepted and experimental indications for DBS therapy and the corresponding anatomical targets.

Hypertrophic olivary degeneration and holmes' tremor secondary to bleeding of cavernous malformation in the midbrain

Background

Hypertrophic olivary degeneration (HOD) is a rare phenomenon, probably related to transsynaptic degeneration of the inferior olivary nucleus. It usually occurs as a response to primary injury of dento-rubro-olivary pathways.

Case report

A young man developed Holmes' tremor 7 months after a cavernous malformation bleed in the midbrain. Typical findings of HOD were observed in the magnetic resonance images: bilateral and asymmetric hypertrophy of the olivary nucleus with slight hypersignal in T2-weighted images. Because of the striking disability related to drug-resistant tremor, the patient underwent stereotactic thalamotomy (nucleus ventralis intermedius of the thalamus/zona incerta) with pronounced functional improvement over time.

Discussion

Disruption of circuits in the Guillain–Mollaret triangle classically results in palatal myoclonus, however midbrain (Holmes') tremor can also occur, as we now describe.

Multitarget, dual-electrode deep brain stimulation of the thalamus and subthalamic area for treatment of Holmes' tremor

Object

Holmes' tremor (HT) is generally considered to be a symptomatic tremor associated with lesions of the cerebellum, midbrain, or thalamus. Deep brain stimulation (DBS) therapy for essential tremor and parkinsonian tremor has proved quite successful. In contrast, surgical treatment outcomes for HT have often been disappointing. The use of 2 ipsilateral DBS electrodes implanted in parallel within the thalamus for severe essential tremor has been reported. Since dual-lead stimulation within a single target can cover a wider area than single-lead stimulation, it produces greater effects. On the other hand, DBS of the subthalamic area (SA) was recently reported to be effective for refractory tremor.

Methods

The authors implanted 2 DBS electrodes (one at the nucleus ventralis oralis/nucleus ventralis intermedius and the other at the SA) in 4 patients with HT. For more than 2 years after implantation, each patient's tremor was evaluated using a tremor rating scale under the following 4 conditions of stimulation: “on” for both thalamus and SA DBS; “off” for both thalamus and SA DBS; “on” for thalamus and “off” for SA DBS; and “on” for SA and “off” for thalamus DBS.

Results

The tremor in all patients was improved for more than 2 years (mean 25.8 ± 3.5 months). Stimulation with 2 electrodes exerted greater effect on the tremor than did 1-electrode stimulation. Interestingly, in all patients progressive effects were observed, and in one patient treated with DBS for 1 year, tremor did not appear even while stimulation was temporarily switched off, suggesting irreversible improvement effects.

The presence of both resting and intentional/action tremor implies combined destruction of the pallidothalamic and cerebellothalamic pathways in HT. A larger stimulation area may thus be required for HT patients. Multitarget, dual-lead stimulation permits coverage of the wide area needed to suppress the tremor without adverse effects of stimulation. Some reorganization of the neural network may be involved in the development of HT because the tremor appears several months after the primary insult. The mechanism underlying the absence of tremor while stimulation was temporarily off remains unclear, but the DBS may have normalized the abnormal neural network.

Conclusions

The authors successfully treated patients with severe HT by using dual-electrode DBS over a long period. Such DBS may offer an effective and safe treatment modality for intractable HT.

[Deep brain stimulation for hyperkinetic movement disorders]

The term hyperkinetic movement disorder encompasses dystonia, tremor, chorea, myoclon and tics. These symptoms are all caused by dysfunctional neural networks including the basal ganglia loop and can be accompanied by other neurological or psychiatric symptoms. Deep brain stimulation (DBS) is an important extension of therapeutic options for this group of patients in whom drug therapy is limited. Permanent electrodes are implanted in various subcortical brain areas in order to achieve an improvement in motor symptoms by high frequency stimulation. Already established indications include primary generalized or segmental dystonia and essential tremor but an increasingly better understanding of systemic pathophysiology has allowed DBS to be explored as a treatment for other disorders of the hyperkinetic spectrum. This article provides an overview of common hyperkinetic movement disorders from the viewpoint of recent advances in neurostimulation therapy.

The treatment of tremor

Tremor is a hyperkinetic movement disorder characterized by rhythmic oscillations of one or more body parts. It can be disabling and may impair quality of life. Various etiological subtypes of tremor are recognized, with essential tremor (ET) and Parkinsonian tremor being the most common. Here we review the current literature on tremor treatment regarding ET and head and voice tremor, as well as dystonic tremor, orthostatic tremor, tremor due to multiple sclerosis (MS) or lesions in the brainstem or thalamus, neuropathic tremor, and functional (psychogenic) tremor, and summarize main findings. Most studies are available for ET and only few studies specifically focused on other tremor forms. Controlled trials outside ET are rare and hence most of the recommendations are based on a low level of evidence. For ET, propranolol and primidone are considered drugs of first choice with a mean effect size of approximately 50 % tremor reduction. The efficacy of topiramate is also supported by a large double-blind placebo-controlled trial, while other drugs have less supporting evidence. With a mean effect size of about 90 % deep brain stimulation in the nucleus ventralis intermedius or the subthalamic nucleus may be the most potent treatment; however, there are no controlled trials and it is reserved for severely affected patients. Dystonic limb tremor may respond to anticholinergics. Botulinum toxin improves head and voice tremor. Gabapentin and clonazepam are often recommended for orthostatic tremor. MS tremor responds only poorly to drug treatment. For patients with severe MS tremor, thalamic deep brain stimulation has been recommended. Patients with functional tremor may benefit from antidepressants and are best be treated in a multidisciplinary setting. Several tremor syndromes can already be treated with success. But new drugs specifically designed for tremor treatment are needed. ET is most likely covering different entities and their delineation may also improve treatment. Modern study designs and long-term studies are needed.

Holmes tremor after brainstem hemorrhage, treated with levodopa

Holmes tremor is a rare movement phenomenon, with atypical low-frequency tremor at rest and when changing postures, often related to brainstem pathology. We report a 70-year-old female patient who was presented with dystonic head and upper limb tremor after brainstem hemorrhage. The patient had experienced a sudden onset of left hemiparesis and right facial paralysis. Brain magnetic resonance imaging showed an acute hemorrhage from the brachium pontis through the dorsal midbrain on the right side. Several months later, the patient developed resting tremor of the head and left arm, which was exacerbated by a sitting posture and intentional movement. The tremor showed a regular low-frequency (1-2 Hz) for the bilateral sternocleidomastoid and cervical paraspinal muscles at rest. The patient's symptoms did not respond to propranolol or clonazepam, but gradually improved with levodopa administration. Although various remedies were attempted, overall, the results were poor. We suggest that levodopa might be a useful remedy for Holmes tremor. The curative or relieving effect of the dopaminergic agent in Holmes tremor needs more research.

Midbrain tremor: a tremor resistant to treatment

Midbrain tremor is a resting, postural, action and intentional tremor of the upper extremity. Partial response to pharmacological agents makes the treatment of this tremor difficult. We report, herein, three cases of patients with midbrain tremors involving their midbrain and thalamic area in ischemic and hemorrhagic strokes. In the first case, the patient presented with a midbrain tremor of the right upper extremity involving left midbrain and thalamic area. After MRI examination, he was placed on benztropine, amantadine, pramipexole and eventually levodopa for treatment, all of which were unsuccessful in improving his tremor. In the second case, the patient presented with a midbrain tremor of the right upper extremity after an hemorrhagic stroke. After viewing CT and MRI scans, the patient was placed on amantadine, pramipexole and eventually levodopa, all of which made no contributions to his tremor. The patient in the third case presented with a blunt trauma to the head which led to the development of a midbrain tremor of his left arm. CT and MRI scans showed abnormalities in the right side of the midbrain and pons. He was initially started on amantadine, with no improvement of his tremor. However, he was eventually placed on trihexyphenidyl which contributed to a 70% improvement in his tremor. In the event of midbrain tremor, treatment should be assessed on a case by case basis, and all options should be considered after a risk-benefit assessment.

Movement disorders after stroke in adults: a review

Background

Movement disorders occur in association with stroke and may have important clinical implications.

Methods

We reviewed the medical literature regarding the clinical phenomenology, prevalence, localization and etiologic implications, and treatments for movement disorders occurring after stroke in adult patients.

Results

Movement disorders occur uncommonly after stroke and include both hyperkinetic and parkinsonian conditions. They can occur at the time of stroke or appear as a later manifestation. Stroke lesions are typically due to small vessel cerebrovascular disease in the middle or posterior cerebral artery territory, vessels supplying the basal ganglia. Hemorrhagic lesions are more likely to induce hyperkinetic movements. Movement disorders in the setting of stroke tend to resolve spontaneously over time. Medical and surgical therapies are available to treat the movement problems.

Discussion

Movement disorders after stroke can be helpful in localizing lesions after stroke, determining the etiology of stroke, may need to be a target for therapy and may importantly influence long term outcome.

Targeting the brain: considerations in 332 consecutive patients treated by deep brain stimulation (DBS) for severe neurological diseases

Deep brain stimulation (DBS) extends the treatment of some severe neurological diseases beyond pharmacological and conservative therapy. Our experience extends the field of DBS beyond the treatment of Parkinson disease and dystonia, including several other diseases such as cluster headache and disruptive behavior. Since 1993, at the Istituto Nazionale Neurologico "Carlo Besta" in Milan, 580 deep brain electrodes were implanted in 332 patients. The DBS targets include Stn, GPi, Voa, Vop, Vim, CM-pf, pHyp, cZi, Nacc, IC, PPN, and Brodmann areas 24 and 25. Three hundred patients are still available for follow-up and therapeutic considerations. DBS gave a new therapeutic chance to these patients affected by severe neurological diseases and in some cases controlled life-threatening pathological conditions, which would otherwise result in the death of the patient such as in status dystonicus, status epilepticus and post-stroke hemiballismus. The balance of DBS in severe neurological disease is strongly positive even if further investigations and studies are needed to search for new applications and refine the selection criteria for the actual indications.

Post-ischemic Holmes' tremor of the lower extremities

Holmes' tremor, which is known to occur as a result of different lesions centered in the brain stem, cerebellum and thalamus, is a tremor of low frequency, mostly below 4.5 Hz (Deuschl and Bergman in Mov Disord 17(suppl 3):S41–S48, 2002). We present a patient who developed a tremor, mostly involving her lower extremities, secondary to an ischemic infarct affecting the cerebellum, thalamus and midbrain. Attempts at medical treatment with levodopa, quetiapine and levetirecetam all failed. However, pribedil, a dopaminergic receptor-stimulating agent, successfully improved the tremor. Our case is interesting as published reports generally focus on tremors limited to the upper extremities except for one reported case of Holmes' tremor involving the lower extremities more severely (Walker et al. in Mov Disord 22(2):272–274, 2007). It also demonstrates that dopaminergic receptor stimulating agents should be tested before considering invasive therapies.

The clinical and neuroimaging studies in Holmes tremor

AIM

Holmes tremor (HT) is a combination of rest, postural and action tremor. A parallel dysfunction of cerebello-thalamic and nigrostriatal pathways seems necessary to produce this kind of tremor. We present the clinical and neuroimaging study verifying that hypothesis.

MATERIAL AND METHODS

A total of 10 patients: five male, five female, fulfilling consensus criteria were included. Demographic, clinical and neuroimaging data (MRI = 9; CT = 1, SPECT with the use of 123-I-FP CIT: DaTSCAN in six patients to assess the presynaptic dopaminergic nigrostriatal system involvement, indices of asymmetry for ligand uptake for each striatum were calculated) were analyzed.

RESULTS

Hemorrhage was the most frequent etiology and thalamus - the most commonly involved structure. Contrary to the previous reports, the visual assessment did not reveal remarkable interhemispheric differences of DaTSCAN uptake. Quantitative measurements showed only minimal differences.

CONCLUSIONS

It is open to debate whether nigrostriatal pathway damage is crucial for the phenomenology of HT. Alternative hypothesis is presented that HT represents the heterogeneous spectrum of tremors with similar phenomenology, but different pathophysiology.

(99m)Tc-TRODAT-1 SPECT study in evaluation of Holmes tremor after thalamic hemorrhage

Holmes tremor is also known as rubral or midbrain tremor. The tremor usually involves lesions near the red nucleus and the nerve fiber tracts originating in the cerebellum and the substantia nigra. We report a case of a 62-year-old woman who presented with Holmes tremor 5 months after a left thalamic hemorrhage, with a partial recovery 3 years later. Sequential technetium-(99m)TRODAT-1 single-photon emission computed tomography (SPECT) of the patient's brain revealed partially improved tracer uptake reduction in the striatums, particularly on the left side. We propose that involvement of both the nigrostriatal and the dentate-rubro-thalamic pathways are essential in the pathogenesis of Holmes tremor after a thalamic lesion, and regeneration of the nigrostriatal system is possible in this type of tremor after the initial degeneration. The (99m)Tc-TRODAT-1 SPECT study is a useful and convenient tool for evaluating the nigrostriatal dopamine function in patients with Holmes tremor.

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.

Treatment of dystonia with deep brain stimulation

Pallidal deep brain stimulation (DBS) is an established treatment option for medically refractive dystonia. The mechanism by which globus pallidus pars interna (GPi) DBS improves dystonia is still unclear. Primary generalized dystonia usually responds well to this therapy, as recently confirmed in two well-designed, double-blind, controlled trials; however, predictors of outcome within this population are not well known. The role of GPi DBS in idiopathic cervical dystonia resistant to treatment with botulinum toxin, in tardive dystonia, and in some types of secondary dystonia are emerging as populations of patients who may also benefit, but outcomes are not well documented. Serious complications from this therapy are rare. Future research will likely continue to address the most appropriate programming settings for various populations of dystonia, the mechanism by which DBS affects dystonia, and the possibility of alternative brain targets that might have less associated side effects or greater efficacy than the GPi.

Ventral intermediate thalamic stimulation in complex tremor syndromes

BACKGROUND/AIMS

We report on deep brain stimulation (DBS) in the ventral intermediate part of the thalamus in 4 patients with complex tremor syndromes, 2 classified as Holmes tremor (HT) and 2 as thalamic tremor (TT).

RESULTS

Three out of 4 patients showed intraoperative improvement and underwent DBS implantation. One patient with TT without intraoperative improvement was not provided with an implant. A sustained beneficial effect was present after a follow-up ranging from 20 months to 7 years, although there was partial persistence of the intentional tremor and of proximal myoclonic-dystonic movements. The mean global clinical impression score was 2. In 1 HT patient the benefit persisted after battery failure.

CONCLUSION

The study confirms that ventral intermediate thalamic DBS can provide long-term efficacy for HT and TT. While the patients experienced considerable and lasting functional improvement, the effect was incomplete and not all elements of their complex movement disorders were equally suppressed.

[Hypothalamic deep brain stimulation in patients with chronic cluster headaches. Suggestions for patient selection]

Cluster headaches involve a stereotypic symptomatic and belong to the most severe primary pain syndromes. Imaging studies have demonstrated functional and structural changes in the inferior-posterior hypothalamus ipsilateral to the pain. These changes are highly specific to the syndrome, strongly suggesting that this anatomical region is the trigger or generator of the acute attacks and/or determine the duration of the acute pain. These findings have led to the successful therapy of 19 not or difficult to treat patients with hypothalamic deep brain stimulation, resulting in long-term periods without pain and without significant side effects. Recently, however, a patient was reported who died after the operation due to increased blood pressure leading to the rupture of a previously non-diagnosed aneurysm. This article offers a translated summary of the recently published criteria of an international consensus group, which, in addition to a positive ethics vote, should be fulfilled before such deep brain stimulation of the hypothalamus is carried out in such patients.