[Early Experience with the VerciseTM DBS System in the Treatment of Dystonic Tremor].

Six cases of dystonic tremor were treated with the VerciseTM deep brain stimulation(DBS)system, which has the multiple independent current control(MICC)technology. The mean preoperative score of Burke-Fahn-Marsden dystonia rating scale was 16.2±9.4, which was reduced to 6.1±4.6 at 5 months postoperatively. A 65-year-old male presented an intractable dystonic tremor of the jaw, neck, and shoulders due to tardive syndrome. He experienced the successful tremor relief after unipolar DBS in the globus pallidus internus(GPi)with VerciseTM but complained of dysarthria. Steering the current ventrally induced nausea without alleviating dysarthria, while steering the current dorsally alleviated dysarthria but a further dorsal current induced mandibular dyskinesia. The current steering with MICC enabled the simulation field in GPi with successful balance, maximizing tremor suppression, and minimizing the adverse effects. In a second case, 61-year-old male in whom cervical dystonia with rotatory tremor had been successfully treated with interleaving stimulation of GPi-DBS had needed to repeat the replacement of a non-rechargeable pulse generator in only 15-month interval. After the substitution of VerciseTM, the interleaving stimulation of 9.5mA in total was replaced by 8.5mA with the current steering of MICC, while the patient's symptomatic control was unchanged. The microlesion effects after lead implantation are unclear and therapeutic effects are often delayed in cases of dystonia;therefore, the submaximal stimulation intensities must be frequently applied in the early phase following the implantation of DBS. A fine current steering of VerciseTM DBS is very useful in both, the early and late phases of GPi-DBS for dystonic syndrome.

Deep brain stimulation of the subthalamic nucleus reverses oral tremor in pharmacological models of parkinsonism: interaction with the effects of adenosine A2A antagonism.

Deep brain stimulation (DBS) of the subthalamic nucleus is increasingly being employed as a treatment for parkinsonian symptoms, including tremor. The present studies used tremulous jaw movements, a pharmacological model of tremor in rodents, to investigate the tremorolytic effects of subthalamic DBS in rats. Subthalamic DBS reduced the tremulous jaw movements induced by the dopamine D2 family antagonist pimozide and the D1 family antagonist ecopipam, as well as the cholinomimetics pilocarpine and galantamine. The ability of DBS to suppress tremulous jaw movements was dependent on the neuroanatomical locus being stimulated (subthalamic nucleus vs. a striatal control site), as well as the frequency and intensity of stimulation used. Importantly, administration of the adenosine A2A receptor antagonist MSX-3 reduced the frequency and intensity parameters needed to attenuate tremulous jaw movements. These results have implications for the clinical use of DBS, and future studies should determine whether adenosine A2A antagonism could be used to enhance the tremorolytic efficacy of subthalamic DBS at low frequencies and intensities in human patients.

Task-specific writing tremor: clinical phenotypes, progression, treatment outcomes, and proposed nomenclature.

Task-specific tremor diagnoses remain controversial. We evaluated 56 subjects seen with writing tremor. The diagnosis was made if there was a clear history of exclusive tremor while writing for at least 3 years before noticing tremor in any other scenario and the continued presence of writing tremor as the most prominent aspect of their tremor disorder on examination. The age of tremor onset was 47.2 ± 18.0 years (73.2% male). Ethnic backgrounds were Caucasian (68.4%), African (23.2%), Hispanic (5.2%), and Asian/Indian (3.3%), and 44% reported any tremor in a first degree relative. Writing tremor often progressed to other task-specific tremors or rest tremor but not to immediate postural tremor, as usually seen in essential tremor. The other tremor provoking scenarios were eating/drinking (14), brushing teeth/shaving/make-up (5), typing (2), suture removal (1), and drafting (1) and occurred a mean of 7.5 years after the onset of writing tremor. Fourteen developed a "rest" (true rest or crescendo) tremor but only 2 of these met clinical criteria for Parkinson's disease. Pharmacologic treatments of writing tremor, including with ethanol, were generally poor, whereas deep brain stimulation of the ventral intermediate (VIM) thalamus was successful. Compared with patients with "classic" essential tremor in our clinic, writing tremor patients were more likely African, more likely male, had an older age of onset, a lower likelihood of familial tremor, and were more refractory to tremor medications and ethanol. This supports segregation between task-specific tremor and essential tremor but does not support the specific diagnosis of "writing tremor" because many patients progress to tremor with other tasks.

Clinical features, pathophysiology, treatment, and controversies of tremor in dystonia.

Dystonia and tremor frequently co-occur. In some cases, they have shared biological mechanisms, while in others dystonia and tremor are two comorbid conditions. The term "dystonic tremor" is used to describe tremor in those who have dystonia. Two mutually exclusive definitions of "dystonic tremor" were proposed. According to one definition, dystonic tremor is the tremor in the dystonic body part. An alternate definition of dystonic tremor entails irregular and jerky oscillations that have saw tooth appearance with or without overt dystonia. This paper outlines the differences in two definitions of dystonic tremor and identifies their limitations. Given the diverse views defining "dystonic tremor", this paper will use the term "tremor in dystonia". In addition, we will outline different ways to separate the subtypes of tremor in dystonia. Then we will discuss pathophysiological mechanisms derived from the objective measures and single neuron physiology analyses of tremor in dystonia. This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh.

[Tremor].

Tremor is the most common involuntary movement disorder. It can be an isolated symptom or a symptom of another neurological disorder, such as dystonia, Parkinson disease, spinocerebellar ataxia et al. It is an unintentional, somewhat rhythmic, muscle movement involving to-and-fro movements of one or more parts of the body. It can affect the hands, arms, head, vocal cord, jaw, chin, and legs. Most tremors occur in the hands. Clinically, the most useful way to categorized tremor is whether it occurs mainly at rest, on postural, or during movement (kinetic tremor). Tremor is most common classified by different clinical features and cause or origin; include essential tremor, Parkinsonian tremor, cerebellar tremor, dystonic tremor, orthostatic tremor, physiologic tremor, and psychogenic tremor. Diagnosis need a detail history (include familial inheritance, drugs exposure, alcohol consumption or withdraw); complete physical examination and laboratory tests. Electromyography is also a simple and quick method with which to calculate tremor frequency and amplitude for assisting diagnosis. Treatment for majority of tremor syndrome is purely symptomatic, and is similar regardless of the underlying cause of the tremor. There are different medicines to try in order propranolol, clonazepam, primidome and gabapentin for limb tremors, or trihexyphenidyl for dystonic tremor. Focal botulinum toxin injection may be help in focal tremor. Neurosurgery is only indicated in severe tremor, such as deep brain stimulation (DBS) of subthalamic nucleus for primary or secondary parkinsonian tremor.

Modulation of symptomatic palatal tremor by magnetic stimulation of the motor cortex.

OBJECTIVES: Magnetic stimulation of the motor cortex can be used to determine the involvement of the cortex in rhythmic movement disorders. Symptomatic palatal tremor (SPT) is thought to come from a pacemaker that is relatively resistant to internal and external stimulation. In this study, we investigated the effect of magnetic stimulation of motor cortex on SPT. METHODS: Five male patients, aged 67-79 years, with SPT after brain stem infarction or hemorrhage, all had a synchronous mouth angle twitch with the palatal movement. Electromyographic activity was recorded with a monopolar needle electrode from orbicularis oris. In experiment 1, transcranial magnetic stimulation (TMS) was delivered at 200% motor threshold (MT) to reset SPT. In experiment 2, the effect of TMS intensities was studied at 80-240% MT in two SPT patients. To determine the influence of the TMS, we used the resetting index (RI). RESULTS: TMS reset the tremor in all 5 SPT patients at 200% MT with RIs of 0.86-0.96. The latency of the tremor reappearance after TMS was longer than the pre-stimulus tremor interval, and the intervals between the subsequent tremor bursts were also prolonged. The degree of tremor resetting was closely correlated with the magnetic stimulus intensity and the latency of the tremor reappearance after TMS. CONCLUSIONS: Stimulation of the motor cortex may modulate the generator of SPT.

[Tremors]. / Les tremblements.

Tremor (Tr) is an involuntary rhythmic movement disorder. Its causes are multifold. The physiopathogenesis is complex and only partially understood. The classification, based on clinical grounds distinguishes: 1) Physiological Tr at 8-12 Hz, postural, involving the limbs; 2) Essential Tr at 8 Hz, often familial, postural, involving the limbs; 3) Parkinsonian Tr at 4-6 Hz, present at rest, rarely isolated, often asymmetrical, involving the limbs, sometimes the jaw; 4) Cerebellar Tr at 3-4 Hz, maximal at the end of limb movements. Therapy is based on this classification. The main points for the diagnosis are age of onset, associated signs, toxic factors and heredity.

[Head tremor]. / Temblor de la cabeza.

INTRODUCTION: Head tremor, either as an isolated symptom or as part of a symptomatic complex, occurs in patients with different neurological diseases. Little research has been carried out to analyse the clinical features of this neurological symptom. AIM: To review the symptomatology, aetiology and therapeutics of brain tremors. DEVELOPMENT: Two main types of brain tremor can be distinguished: tremor of the whole brain (holocephalic tremor) and segmented brain tremor (tremor of the jaw, tongue, chin, soft palate, task-specific, orthostatic orolingual and undetermined). Essential tremor, the main cause of brain tremor, and dystonic tremor give rise to holocephalic-type tremor in the vast majority of cases. Brain tremor in Parkinsonism is characteristically of the segmented type. The effectiveness of the pharmacological treatment of brain tremor is very limited. Botulinum toxin is a promising therapy for brain tremors of any causation. In severe cases of brain tremor, functional surgery by means of deep brain stimulation of the intermediate ventral thalamic nucleus is useful, but must be performed bilaterally. CONCLUSIONS: The semiological characteristics of brain tremor are a valuable aid in the aetiological diagnosis. Pharmacological therapy is very limited. Botulinum toxin and functional surgery of the intermediate ventral thalamic nucleus are useful in selected patients.

Long-term suppression of tremor by deep brain stimulation of the ventral intermediate nucleus of the thalamus combined with pallidotomy in hemiparkinsonian patients.

Deep brain stimulation (DBS) of the ventral intermediate nucleus of the thalamus (VIM) is a powerful surgical option in the treatment of tremor-predominant Parkinson's disease. However, its therapeutic efficacy depends on the tremor distribution. DBS is highly efficient in relief of distal appendicular tremor but not other types of tremor. Also, it is generally thought that DBS of the VIM has no significant beneficial effects on other motor symptoms of Parkinson's disease. We report two hemiparkinsonian patients, in whom unilateral VIM DBS combined with posteroventral pallidotomy produced long-lasting suppression of not only hand tremor, but also leg or jaw tremor and other motor symptoms.