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Background: Deep brain stimulation (DBS) has been proposed to treat disabling dystonic tremor (DT), but there is debate about the optimal target. DBS of the globus pallidus interna (GPi) may be insufficient to control tremor, and DBS of the ventral intermediate thalamic nucleus (VIM) may inadequately control dystonic features, raising the question of combining both targets.Objectives: To report the respective effects on DT symptoms of high-frequency stimulation of the VIM, the GPi and both targets simultaneously stimulated.Methods: Three patients with DT treated by bilateral high frequency DBS of 2 targets (VIM and GPi) were assessed 12 months after surgery in 4 conditions (VIM and GPi-DBS; GPi-DBS only; VIM-DBS only; DBS switched Off for both targets) by 3 independent movement disorders specialists blinded to the condition.Results: The Fahn-Tolosa-Marin-tremor-rating-scale (FTM-TRS) and Burke-Fahn-Marsden-dystonia-rating-scale (BFM-DRS) scores were more improved by combined DBS than VIM alone or GPi alone. Compared to Off/Off condition, mean total FTM-TRS score decrease was 34%, 42% and 63% respectively with VIM only, GPi only and combined VIM and GPi stimulation. Mean total BFM-DRS score decrease was 34%, 37% and 60% respectively with VIM only, GPi only and combined VIM and GPi stimulation, compared to Off/Off condition. Improvement concerned both motor, functional and activities of daily living sub-scores. No complications or adverse events were observed.Conclusion: Combined VIM- and GPi-DBS, by modulating the cerebello-thalamo-cortical network and the basal ganglia-thalamo-cortical network, both involved in DT pathophysiology, may be more efficient than single DBS targeting only one of them. [ABSTRACT FROM AUTHOR]

Essential tremor (ET) and dystonic tremor (DT) are the two most common tremor disorders, and misdiagnoses are very common due to similar tremor symptoms. In this study, we explore the structural network mechanisms of ET and DT using brain grey matter (GM) morphological networks and combine those with machine learning models. 3D-T1 structural images of 75 ET patients, 71 DT patients, and 79 healthy controls (HCs) were acquired. We used voxel-based morphometry to obtain GM images and constructed GM morphological networks based on the Kullback-Leibler divergence-based similarity (KLS) method. We used the GM volumes, morphological relations, and global topological properties of GM-KLS morphological networks as input features. We employed three classifiers to perform the classification tasks. Moreover, we conducted correlation analysis between discriminative features and clinical characteristics. 16 morphological relations features and 1 global topological metric were identified as the discriminative features, and mainly involved the cerebello-thalamo-cortical circuits and the basal ganglia area. The Random Forest (RF) classifier achieved the best classification performance in the three-classification task, achieving a mean accuracy (mACC) of 78.7%, and was subsequently used for binary classification tasks. Specifically, the RF classifier demonstrated strong classification performance in distinguishing ET vs. HCs, ET vs. DT, and DT vs. HCs, with mACCs of 83.0 %, 95.2 %, and 89.3 %, respectively. Correlation analysis demonstrated that four discriminative features were significantly associated with the clinical characteristics. This study offers new insights into the structural network mechanisms of ET and DT. It demonstrates the effectiveness of combining GM-KLS morphological networks with machine learning models in distinguishing between ET, DT, and HCs. • The findings showed that the ML algorithms achieved good classification performance in classification tasks, the most powerful 17 discriminative features mainly involved the cerebello-thalamo-cortical circuits and basal ganglia area. • RF classifier to perform the classification tasks had achieved good results, especially in identifying DT from ET and HCs. • A significant proportion of discriminative features (15/17, 88.2 %) consistently showed morphological relations between frontal lobe and other brain regions were deemed as the most vital in distinguishing ET, DT, and HCs. • Using SHAP analysis and bounding by a feature importance greater than 0.05, the involvement of the middle frontal gyrus, anterior cingulate and paracingulate gyri, and lingual gyrus were characteristic alterations of ET; the involvement of the SMA, vermis_4_5, and putamen were characteristic alterations of DT. [ABSTRACT FROM AUTHOR]

Dystonic tremor (DT) is defined as the tremor in body parts affected by dystonia. Although deep brain stimulation (DBS) has been used to manage medically-refractory DT patients, its efficacy has not been well established. The objective of this study is to provide an up-to-date systematic review of DBS outcomes for DT patients. We conducted a literature search using Medline, Embase, and Cochrane Library databases in February 2020 according to the PRISMA guidelines. From 858 publications, we identified 30 articles involving 89 DT patients who received DBS of different targets. Thalamic DBS was the most common (n = 39) and improved tremor by 40-50% potentially in the long-term over five years with variable effects on dystonic symptoms. Globus pallidus internus (GPi), subthalamic, and subthalamic nucleus (STN) DBS improved both tremor and dystonic symptoms; however, data were limited. A few studies have reported better tremor and dystonia outcomes with combinations of different targets. Concerning adverse effects, gait/balance disorders, and ataxia seemed to be more common among patients treated with thalamic or subthalamic DBS, whereas parkinsonian adverse effects were observed only in patients treated with subthalamic or GPi DBS. Comparative benefits and limitations of these targets remain unclear because of the lack of randomized controlled trials. In conclusion, DBS of these targets may improve tremor with a variable effect on dystonia with different adverse effect profiles. The shortcomings in the literature include long-term motor outcomes, quality of life outcomes, optimal DBS targeting, and DBS programming strategy. [ABSTRACT FROM AUTHOR]

Tremor is a key clinical feature of several common neurological disorders. Adequate management of tremor has been an unmet need in clinical practice. Most of the anti-tremor medications have limited efficacy and are associated with undesirable adverse effects, especially in elderly patients. Several studies have reported good outcomes with the use of botulinum neurotoxin (BoNT) for the treatment of tremor. This article aims to systematically review these studies and to highlight the role of BoNT in the management of tremor. A PubMed search was performed in August 2018 to identify articles pertinent to this review. Majority of the studies that have assessed the efficacy of BoNT in tremor, enrolled patients with essential tremor (ET), Parkinson's disease (PD), and dystonic tremor. Results of these studies suggest clinically meaningful improvement in hand tremor in both ET and PD and vocal tremor in ET after BoNT therapy. Additionally, BoNT has been reported to be efficacious in alleviating head and palatal tremor, tremor in multiple sclerosis, and proximal positional tremor. It is apparent that BoNT injections tailored to the needs of individual patients yield better efficacy and lower adverse effects compared to fixed-muscle-fixed-dose approach. BoNT individualized approach adds to the armamentarium for patients who have medically refractory tremors or those who are unable to tolerate the anti-tremor medications. The studies are limited and mostly open-label; thus, randomized placebo-controlled studies are needed to prove the efficacy of BoNT in various tremor conditions. [ABSTRACT FROM AUTHOR]

Pediatric Movement Disorders encompass a very large and complex group of diseases, among which Tremor is one of the least studied. Evaluation of tremors in kids carries significant challenges, in particular the fact that many tremor etiologies have other associated movement disorders that make tremor identification more difficult. Also, it is sometimes difficult to differentiate tremors from other shaking disorders. Yet, the correct identification of tremor leads to appropriate treatments and sometimes practical cures. Thus, in this paper we have strived to provide a succinct, clinically useful and practical review of pediatric tremors. The most useful classification of tremors in based on their predominance during rest or activity. By far, the most common tremor in children is during action. We provide a clinical algorithm on how to assess pediatric tremors at the bedside, as well as multiple useful tables. We also review common tremor etiologies. [ABSTRACT FROM AUTHOR]

Questionable signs of dystonia are a common finding in patients with essential tremor (ET). Brain structural alterations in ET patients plus dystonic soft signs (ET + ds) in comparison to ET patients without dystonic soft signs (ET-ds) or patients with tremor associated with manifest dystonia (TAWD) have not been examined yet. Therefore, our study aims to explore alterations of brain grey matter in patients with ET + ds. A total of 68 elderly patients with ET-ds (n = 32), ET + ds (n = 20) or idiopathic cervical dystonia with dystonia associated action tremor of the upper limbs (TAWD, n = 16) and 42 age-matched healthy controls underwent a clinical and electrophysiological assessment and 3T MRI. For grey matter alterations T1 MRI images were analysed by voxel-based morphometry. Additionally, regression analyses with clinical parameters (tremor frequency, severity and disease duration) were performed. VBM showed a significant increase of grey matter in the right lentiform nucleus in ET + ds and TAWD compared to HC and ET-ds. Further, an increase of cortical grey matter in the middle frontal gyrus in ET + ds was shown. The hypertrophy of the lentiform nucleus in ET + ds was correlated with disease severity and duration. Patients with ET + ds showed grey matter brain structural alterations similar to TAWD. Our findings suggest an involvement of the basal ganglia-cortical loop in ET + ds which may indicate a pathophysiological similarity with TAWD rather than ET. • Questionable signs of dystonia are a common finding in patients with ET plus. • VBM shows an increase of grey matter in the right lentiform nucleus in ET plus. • Lentiform nucleus hypertrophy is correlated with disease severity and duration. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: This study is aimed at investigating the neuroanatomical patterns characterizing dystonic tremor in comparison with essential tremor. Methods: Voxel-based morphometry and cortical thickness data of 12 patients with dystonic tremor, 14 patients with essential tremor and 23 age- and sex-matched healthy control subjects were analyzed. Results: Patients with dystonic tremor showed a thickening and increased gray matter volume (surviving whole-brain correction for multiple comparisons) of the left sensorimotor cortex when compared to other groups. Otherwise, patients with essential tremor were characterized by a subtle atrophy of the anterior cerebellar cortex. Discussion: Our multimodal structural neuroimaging study demonstrated that patients with dystonic tremor and essential tremor are characterized by different neuroanatomical abnormalities. The involvement of the sensorimotor cortex in patients with dystonic tremor suggests that this disorder may share some pathophysiological mechanisms with focal dystonia. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Background Tremor of the upper/middle part of the face, including the perinasal region and the forehead has been very rarely described in some patients with Parkinson's disease or Essential Tremor. It has not yet been reported in patients with idiopathic dystonia. Methods We describe here a series of 8 patients with common forms of idiopathic focal/segmental dystonia with tremor involving the upper/middle part of the face, along with demonstrative videos and electrophysiological recordings. Results The distribution of the tremor was confined to the face in two patients, whereas in six patients tremor was also evident either in the head/lower part of the face or in their upper limbs. Electrophysiological recordings disclosed a slightly irregular tremor with a frequency at about 3-5 Hz. Conclusions A number of patients with classical forms of dystonia can show a tremor involving the upper/middle part of the face. [ABSTRACT FROM AUTHOR]