Tremor Rating Scale Research Articles

Effects of Peripheral Cooling on Upper Limb Tremor Severity and Functional Capacity in Persons with MS.

Upper limb intention tremor in persons with multiple sclerosis (pwMS) affects the ability to perform activities of daily life and is difficult to treat. The study investigated the effect of peripheral upper limb cooling on tremor severity and functional performance in MS patients with intention tremor. In experiment 1, 17 patients underwent two 15 min cooling conditions for the forearm (cold pack and cryomanchet) and one control condition. In experiment 2, 22 patients underwent whole arm cooling for 15 min using multiple cold packs. In both experiments, patients were tested at four time points (pre- and post-0, -25 and -50 min cooling) on unilateral tasks of the Test Evaluant les Membres supérieurs des Personnes Agées (TEMPA), Fahn's tremor rating scale (FTRS), Nine Hole Peg Test (NHPT). In experiment 1, the mean FTRS ranged from 13.2 to 14.1 across conditions. A two-way ANOVA showed mainly time effects, showing that cooling the forearm significantly reduced the FTRS, the performance on the NHPT, and three out of four items of the TEMPA, mostly independent of the cooling modality. In experiment 2, the mean FTRS was 13.1. A repeated measures ANOVA showed that cooling the whole arm reduced the FTRS and time needed to execute two out of four items of the TEMPA. These effects occurred immediately after cooling lasting at least 25 min. Cooling the whole upper limb led to a clinically noticeable effect on tremor severity and improved functional performance, which was pronounced during the first half-hour after cooling.

A Novel Accelerometry Method to Perioperatively Quantify Essential Tremor Based on Fahn–Tolosa–Marin Criteria

The disease status, progression, and treatment effect of essential tremor (ET) patients are currently assessed with clinical scores, such as the Fahn–Tolosa–Marin Clinical Rating Scale for Tremor (FTM). The use of objective and rater-independent monitoring of tremors may improve clinical care for patients with ET. Therefore, the focus of this study is to develop an objective accelerometry-based method to quantify ET, based on FTM criteria. Thirteen patients with ET and thirteen matched healthy participants underwent FTM tests to rate tremor severity, paired with tri-axial accelerometric measurements at the index fingers. Analogue FTM assessments were performed by four independent raters based on video recordings. Quantitative measures were derived from the accelerometric data, e.g., the area under the curve of power in the 4–8 Hz frequency band (AUCP) and maximal tremor amplitude. As such, accelerometric tremor scores were computed, using thresholds based on healthy measurements and FTM criteria. Agreement between accelerometric and clinical FTM scores was analyzed with Cohen’s kappa coefficient. It was assessed whether there was a relationship between mean FTM scores and the natural logarithm (ln) of the accelerometric outcome measures using linear regression. The agreement between accelerometric and FTM scores was substantial for resting and intention tremor tests (≥72.7%). However, the agreement between accelerometric postural tremor data and clinical FTM ratings (κ = 0.459) was low, although their logarithmic (ln) relationship was substantial (R2 ≥ 0.724). Accelerometric test–retest reliability was good to excellent (ICC ≥ 0.753). This pilot study shows that tremors can be quantified with accelerometry, using healthy thresholds and FTM criteria. The test–retest reliability of the accelerometric tremor scoring algorithm indicates that our low-cost accelerometry-based approach is a promising one. The proposed easy-to-use technology could diminish the rater dependency of FTM scores and enable physicians to monitor ET patients more objectively in clinical, intraoperative, and home settings.

Neuropathic Tremor in Guillain-Barré Syndrome.

Neuropathic Tremor (NT) is a postural/kinetic tremor of the upper extremity, often encountered in patients with chronic neuropathies such as paraprotein-associated and hereditary neuropathies. To describe the clinical and electrophysiological features of NT in a previously underrecognized setting- during recovery from Guillain-Barré Syndrome (GBS). Patients with a documented diagnosis of GBS in the past, presenting with tremor were identified from review of clinical records. Participants underwent structured, videotaped neurological examination, and electrophysiological analysis using tri-axial accelerometry-surface electromyography. Tremor severity was assessed using the Fahn-Tolosa-Marin Tremor Rating Scale. We describe the clinical and electrophysiological features of 5 patients with GBS associated NT. Our cohort had a fine, fast, and slightly jerky postural tremor of frequency ranging from 8 to 10 Hz. Dystonic posturing and overflow movements were noted in 4/5 patients. Tremor appeared 3 months-5 years after the onset of GBS, when patients had regained near normal muscle strength and deep tendon jerks were well elicitable. Electrophysiological analysis of tremor strongly suggested the presence of a central oscillator in all patients. NT is not limited to chronic inflammatory or hereditary neuropathies and may occur in the recovery phase of GBS. The tremor is characterized by a high frequency, jerky postural tremor with dystonic posturing. Electrophysiological evaluation suggests the presence of a central oscillator, hypothetically the cerebellum driven by impaired sensorimotor feedback.

Tremor in Patients with Relapsing-Remitting Multiple Sclerosis: Clinical Characteristics and Impact on Quality of Life.

Little is known about the prevalence and clinical characteristics of tremors in patients with multiple sclerosis (MS), their associated clinical disability, and their impact on quality of life (QoL). This study aimed to investigate the frequency and types of tremors in patients with relapsing remitting MS (RRMS) in remission, and their impact on patients' QoL. A total of 250 patients with RRMS in remission were examined for tremors. All patients were assessed using the Expanded Disability Status Scale (EDSS). Patients with tremors underwent further assessment using the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS), the Beck Depression Inventory (BDI), the Montreal Cognitive Assessment (MoCA) scale, and the Short Form 36 Health Survey Questionnaire (SF-36). Brain MRI was obtained for a subgroup of patients. Tremors were detected in 36 patients (14.4%) and were associated with significantly worse EDSS scores, BDI (P = 0.021), MoCA, most SF-36 domains, higher total and last year relapses (P < 0.001) and longer disease duration (P = 0.027). Patients with tremors showed higher lesion load (P = 0.007), more infratentorial (P ≤ 0.001), cerebellar and diencephalic lesions (P = 0.024), and cortical atrophy (P = 0.012). Total FTMTRS was significantly correlated to age, EDSS, and physical functioning. Dystonia was associated with tremors in 17 patients (6.8% of total RRMS patients and 47.2% of patients with tremors). The current study confirms the common occurrence of tremors and their subtypes among patients with RRMS with mild disability and demonstrates their association with increased disability and impaired QoL.

Acute stimulation with symmetric biphasic pulses induces less ataxia compared to cathodic pulses in DBS for essential tremor

BackgroundSymmetric biphasic pulses have been shown to acutely increase the therapeutic window of ventralis intermedius deep brain stimulation (Vim-DBS) for essential tremor (ET) compared to cathodic pulses. Acute supratherapeutic stimulation can induce ataxic side effects in Vim-DBS. ObjectiveTo investigate the effect on tremor, ataxia and dysarthria of 3 h of biphasic stimulation in patients with DBS for ET. MethodsA randomized, doubled-blind, cross-over design was used to compare standard cathodic pulses with symmetric biphasic pulses (anode-first) during a 3-h period per pulse shape. During each 3-h period, all stimulation parameters were identical, except for the pulse shape. Tremor (Fahn-Tolosa-Marin Tremor Rating Scale), ataxia (International Cooperative Ataxia Rating Scale) and speech (acoustic and perceptual measures) were assessed hourly during the 3-h periods. ResultsTwelve ET patients were included. During the 3-h stimulation period, tremor control was equivalent between the two pulse shapes. Biphasic pulses elicited significantly less ataxia than cathodic pulses (p = 0.006). Diadochokinesis rate of speech was better for the biphasic pulse (p = 0.048), but other measures for dysarthria were not significantly different between the pulses. ConclusionSymmetric biphasic pulses induce less ataxia than conventional pulses after 3 h of stimulation DBS in ET patients.

Whole-brain network transitions within the framework of ignition and transfer entropy following VIM-MRgFUS in essential tremor patients

Magnetic resonance-guided focused ultrasound (MRgFUS) lesioning of the ventralis intermedius nucleus (VIM) has shown promise in treating drug-refractory essential tremor (ET). It remains unknown whether focal VIM lesions by MRgFUS have broader restorative effects on information flow within the whole-brain network of ET patients. We applied an information-theoretical approach based on intrinsic ignition and the concept of transfer entropy (TE) to assess the spatiotemporal dynamics after VIM-MRgFUS. Eighteen ET patients (mean age 71.44 years) underwent repeated 3T resting-state functional magnetic resonance imaging combined with Clinical Rating Scale for Tremor (CRST) assessments one day before (T0) and one month (T1) and six months (T2) post-MRgFUS, respectively. We observed increased whole brain ignition-driven mean integration (IDMI) at T1 (p < 0.05), along with trend increases at T2. Further, constraining to motor network nodes, we identified significant increases in information-broadcasting (bilateral supplementary motor area (SMA) and left cerebellar lobule III) and information-receiving (right precentral gyrus) at T1. Remarkably, increased information-broadcasting in bilateral SMA was correlated with relative improvement of the CRST in the treated hand. In addition, causal TE-based effective connectivity (EC) at T1 showed an increase from right SMA to left cerebellar lobule crus II and from left cerebellar lobule III to right thalamus. In conclusion, results suggest a change in information transmission capacity in ET after MRgFUS and a shift towards a more integrated functional state with increased levels of global and directional information flow.

Tremor supression following treatment with MRgFUS: skull density ratio consistency and degree of posterior dentatorubrothalamic tract lesioning predicts long-term clinical outcomes in essential tremor.

Magnetic resonance-guided focussed ultrasound (MRgFUS) is an incisionless ablative procedure, widely used for treatment of Parkinsonian and Essential Tremor (ET). Enhanced understanding of the patient- and treatment-specific factors that influence sustained long-term tremor suppression could help clinicians achieve superior outcomes via improved patient screening and treatment strategy. We retrospectively analysed data from 31 subjects with ET, treated with MRgFUS at a single centre. Tremor severity was assessed with parts A, B and C of the Clinical Rating Scale for Tremor (CRST) as well as the combined CRST. Tremor in the dominant and non-dominant hand was assessed with Hand Tremor Scores (HTS), derived from the CRST. Pre- and post-treatment imaging data were analysed to determine ablation volume overlap with automated thalamic segmentations, and the dentatorubrothalamic tract (DRTT) and compared with percentage change in CRST and HTS following treatment. Tremor symptoms were significantly reduced following treatment. Combined pre-treatment CRST (mean: 60.7 ± 17.3) and HTS (mean: 19.2 ± 5.7) improved by an average of 45.5 and 62.6%, respectively. Percentage change in CRST was found to be significantly negatively associated with age (β = -0.375, p = 0.015), and SDR standard deviation (SDRSD; β = -0.324, p = 0.006), and positively associated with ablation overlap with the posterior DRTT (β = 0.535, p < 0.001). Percentage HTS improvement in the dominant hand decreased significantly with older age (β = -0.576, p < 0.01). Our results suggest that increased lesioning of the posterior region of the DRTT could result in greater improvements in combined CRST and non-dominant hand HTS, and that subjects with lower SDR standard deviation tended to experience greater improvement in combined CRST.

The Effects of Thalamic Deep Brain Stimulation on Gait in Essential Tremor: a Kinematic Study. (P7-11.001)

<h3>Objective:</h3> To determine the effect of ventral intermediate thalamic nucleus (VIM) deep brain stimulation (DBS) on gait parameters in patients with essential tremor (ET). <h3>Background:</h3> DBS is an established treatment for medication-refractory ET. ET can be associated with primary gait impairment; additionally, the effect of VIM-DBS on gait is currently debated, with reports ranging from a more frequently observed worsening to an improvement with therapeutic stimulation. Determining VIM-DBS effects on gait is pivotal to determine patient candidacy for this treatment. <h3>Design/Methods:</h3> Database review from our kinematics laboratory identified 27 patients (women, 15; men, 12) with ET who underwent VIM-DBS (bilateral, 5; unilateral, 22) and pre- and post-DBS quantitative gait kinematics analysis with a 3D commercial motion analysis (MA) system. Post-DBS assessments were performed on stimulation. Changes in gait outcomes from pre- to post- were expressed as effect sizes (Cohen’s d) and categorized as “small,” “medium,” or “large” using established cutoff values. Post-DBS Tremor Research Group Essential Tremor Rating Scale motor scores on and off stimulation were retrospectively reviewed and available for 22 patients; percent change of on versus off stimulation was calculated and scores were compared with paired samples t-tests. <h3>Results:</h3> Patients underwent DBS at a mean age of 69.4±8.5 years. The average percent reduction of the contralateral upper limb tremor scores on versus off stimulation was 80.4±13.4 (p&lt;0.001), 10.3±3.7 months after surgery. Postoperative MA was performed 9.6±5.9 months after surgery. Small worsening effects were observed in gait speed (d=−0.32), cadence (d=−0.39), and step length (d=−0.24), which were not statistically significant. No changes were observed in step width. <h3>Conclusions:</h3> Thalamic DBS improved tremor scores, but we observed a small, non-statistically significant, worsening trend of some gait parameters. Further study is required to clarify the observed effect of VIM-DBS on gait and identify pre-DBS gait features predictive of poor gait outcomes. <b>Disclosure:</b> Dr. Testini has nothing to disclose. Dr. McKay has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Biocircuit Technologies. The institution of Dr. McKay has received research support from NIH. The institution of Dr. McKay has received research support from the McCamish Foundation. Dr. Tripathi has nothing to disclose. Miss Genias has nothing to disclose. Mr. Skelton has received personal compensation for serving as an employee of AthenaHealth. Douglas Bernhard has nothing to disclose. Dr. Miocinovic has nothing to disclose. Dr. Aia has nothing to disclose. The institution of Dr. Buetefisch has received research support from NIH. The institution of Dr. Higginbotham has received research support from NIH/NINDS . The institution of Dr. Higginbotham has received research support from Bright Focus Foundation. The institution of Dr. Higginbotham has received research support from American Academy of Neurology. Dr. Scorr has received research support from Dystonia Medical Research Foundation. Shirley Triche has nothing to disclose. Dr. Factor has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Acorda. Dr. Factor has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Sunovion. Dr. Factor has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Alterity. Dr. Factor has received personal compensation in the range of $10,000-$49,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Lundbeck. Dr. Factor has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. The institution of Dr. Factor has received research support from Impax. The institution of Dr. Factor has received research support from Biohaven. The institution of Dr. Factor has received research support from Sunovion. The institution of Dr. Factor has received research support from Vaccinex. The institution of Dr. Factor has received research support from Voyager. The institution of Dr. Factor has received research support from Neurocrine. The institution of Dr. Factor has received research support from US World Meds. The institution of Dr. Factor has received research support from Addex. The institution of Dr. Factor has received research support from Prelinia. The institution of Dr. Factor has received research support from Medtronics. The institution of Dr. Factor has received research support from Boston Scientific. Dr. Factor has received publishing royalties from a publication relating to health care. Dr. Factor has received publishing royalties from a publication relating to health care. Dr. Factor has received publishing royalties from a publication relating to health care. Dr. Factor has received publishing royalties from a publication relating to health care. Dr. Esper has received research support from Centers for Disease Control and Prevention. Dr. Esper has received publishing royalties from a publication relating to health care.

The relationship of tremor severity with proximal and distal muscle strength and upper extremity functional skills in older adults with essential tremor

Although it is known that muscle strength training is effective in Essential Tremor (ET), it is not known which muscle groups are more affected. The study was conducted to examine the relationship between tremor severity and proximal and distal muscle strength and upper extremity functional skills in older adults with ET. A total of 40 older adults who were diagnosed with ET (mean age of 74.07 ± 4.83years) and 40 older adults without tremor (mean age of 70.10 ± 4.05years) were included in the study. Tremor severity was evaluated with the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS), the proximal muscular strength with digital muscle dynamometer, handgrip strength with hand dynamometer, and pinch grip strength with pinchmeter. The Arm and Shoulder Problems Questionnaire (DASH) was used to determine the functional status of the upper extremities. Fine Manual Dexterity was measured with the Nine-Hole Peg Test (NHPT). All proximal and distal muscle strengths were significantly lower, DASH and NHPT were significantly higher in the group with ET (p < 0.05). A significant negative correlation was detected between tremor severity and all proximal and distal muscular strength and a significant positive correlation between tremor severity and DASH in group with ET (p < 0.05). However, no significant correlations were found between tremor severity and NHPT in the group with ET. It was found that older adults who had tremors had low proximal and distal muscular strength, upper extremity functionality was affected and hand skills was impaired. Furthermore tremor severity is affected by both proximal and distal muscle strength.

Gamma Knife Thalamotomy for Essential Tremor: A Retrospective Analysis

Gamma knife (GK) thalamotomy has been used as a treatment option for essential tremor (ET). Numerous studies on GK use in ET treatment have reported more varied responses and complication rates. Data from 27 patients with ET who underwent GK thalamotomy were retrospectively analyzed. The Fahn-Tolosa-Marin Clinical Rating Scale for Tremor, handwriting, and spiral drawing were evaluated. Postoperative adverse events and magnetic resonance imaging findings were also evaluated. The mean age at GK thalamotomy was 78.1±4.2years. The mean follow-up period was 32.5±19.4months. The preoperative postural tremor, handwriting, and spiral drawing scores were 3.4±0.6, 3.3±1.0, and 3.2±0.8, respectively, all of which showed significant improvements to 1.5±1.2 (55.9% improvement, P < 0.001), 1.4±1.1 (57.6% improvement, P < 0.001), and 1.6±1.3 (50% improvement, P < 0.001), respectively, at the available final follow-up evaluations. Three patients presented with no improvement in tremor. Six patients presented with adverse effects, including complete hemiparesis, foot weakness, dysarthria, dysphagia, lip numbness, and finger numbness, at the final follow-up period. Two patients presented with serious complications, including complete hemiparesis due to massive widespread edema and chronic encapsulated expanding hematoma. One patient died of aspiration pneumonia following severe dysphagia secondary to chronic encapsulated expanding hematoma. GK thalamotomy is an efficient procedure for treating ET. Careful treatment planning is necessary to reduce complication rates. The prediction of radiation complications will increase the safety and effectiveness of GK treatment.

Bilateral transcranial direct current stimulation may be a feasible treatment of Parkinsonian tremor.

Parkinsonian tremor is a common pathological tremor that affects over 6 million people worldwide. It lowers patients' quality of life and threatens their career development, especially when patients' occupation requires dexterous manipulation. In spite of current available treatments in clinics, there is a lack of low-cost, low side-effect, effective solutions for Parkinsonian tremor. Transcranial direct current stimulation (tDCS) may be an alternative treatment. In this research, we explored the immediate effect of tDCS with a novel bilateral electrode setup over Parkinsonian tremor. In such a bilateral setup, the cathode was placed over the primary cortex contralateral to the more affected side of Parkinsonian tremor while the anode symmetrically over the other hemisphere. It was designed as a modification to the traditional cathodal setup. The performance of this bilateral setup was compared with three other setups including anodal setup, cathodal setup, and sham (control). A randomized, sham-controlled, double-blind, crossover experiment was carried out over 13 qualified patients diagnosed with idiopathic Parkinson's disease (PD). Before and after the stimulus of each tDCS setup, subjects were tested before and after tDCS with four measures, including the Unified Parkinson's Disease Rating Scale (UPDRS), Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS), Purdue Pegboard Test (PPT) and a self-design Continuous Tremor Signal Assessment (CTSA). Tremor intensity calculated from CTSA data were regarded as the primary outcome of the experiment. Statistical results of CTSA, FTMTRS and PPT showed both bilateral tDCS and cathodal tDCS effectively suppressed Parkinsonian tremor. A quantitative comparison of the effect in tremor suppression indicated the optimal suppressive effect was obtained with bilateral tDCS. Based on the results of UPDRS, anodal tDCS was found to benefit subjects' overall performance the most, however, it had little effect in improving Parkinsonian tremor, as revealed by the results of other evaluations. Our study suggests a beneficial immediate effect of bilateral tDCS in Parkinsonian tremor suppression. In addition, we assume there may be an underlying interhemispheric unbalance of cortical excitability which contributes to Parkinsonian tremor genesis. Identifier: ChiCTR2100054804.

Tremor assessment scales before, during and after MRgFUS for essential tremor – results, recommendations and implications

Background neurosurgical interventions such as MR-guided focused ultrasound (MRgFUS) are increasingly deployed for treatment of essential tremor. Objective to make recommendations for monitoring treatment effects during and after MRgFUS based on our investigation of correlations between different scales of tremor severity. Methods twenty-five clinical assessments were collected from thirteen patients before and after unilateral MRgFUS sequential lesioning of the thalamus and posterior subthalamic area for alleviating essential tremor. Scales included Bain Findley Spirography (BFS), Clinical Rating Scale for Tremor (CRST), Upper Extremity Total Tremor Score (UETTS) and Quality of Life of Essential Tremor (QUEST), and were documented at baseline, while lying in the scanner with stereotactic frame attached (BFS), and at 24-month follow-up. Results the four different scales of tremor severity all correlated significantly. BFS and CRST showed a strong correlation of 0.833 (p < 0.001). BFS, UETTS and CRST correlated moderately with QUEST (ρ = 0.575–0.721, p < 0.001). BFS and UETTS correlated significantly with all CRST subparts, with the strongest correlation between UETTS and CRST part C (ρ = 0.831, p < 0.001). Moreover, BFS drawn sitting upright in an outpatient setting correlated with spirals drawn in a supine position on the scanner bed with the stereotactic frame attached. Conclusion we recommend a combination of BFS & UETTS for intraoperative assessment of awake essential tremor patients and BFS & QUEST for pre-operative and follow-up assessments, as these scale sets are quick and simple to collect and provide meaningful information whilst meeting the practical constraints of intraoperative assessment.

Essential tremor and the scales: Quality of life in essential tremor, the Fahn-Tolosa-Marin Tremor Rating Scale; and, the Bain and Findley Clinical Tremor Rating Scale

Essential tremor and the scales: Quality of life in essential tremor, the Fahn-Tolosa-Marin Tremor Rating Scale; and, the Bain and Findley Clinical Tremor Rating Scale

Risk factors of social anxiety in patients with essential tremor.

To study the risk factors of social anxiety (SA) in essential tremor (ET) patients. Motor, cognition, and SA were evaluated using the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS), Mini-Mental State Examination (MMSE), and Liebowitz Social Anxiety Scale (LSAS) for each subject. The potential risk factors of SA in ET were analyzed using univariate analysis. A total of 80 ET patients and 85 healthy controls completed the evaluation. The LSAS evaluation showed that the prevalence of SA in the ET group was 48.8%, higher than that in controls (12.9%, P < 0.001). Female (OR = 4.959, P = 0.014), younger age (OR = 4.172, P = 0.037), and head tremor (OR = 4.707, P = 0.025) were risk factors of SA among ET patients. SA is prevalent in patients with ET. Risk factors, such as female sex, age, and head tremor, should be considered for the prevention and intervention of SA in ET patients.

Magnetic resonance-guided focused ultrasound thalamotomy restored distinctive resting-state networks in patients with essential tremor.

Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy ameliorates symptoms in patients with essential tremor (ET). How this treatment affects canonical brain networks has not been elucidated. The purpose of this study was to clarify changes of brain networks after MRgFUS thalamotomy in ET patients by analyzing resting-state networks (RSNs). Fifteen patients with ET were included in this study. Left MRgFUS thalamotomy was performed in all cases, and MR images, including resting-state functional MRI (rsfMRI), were taken before and after surgery. MR images of 15 age- and sex-matched healthy controls (HCs) were also used for analysis. Using rsfMRI data, canonical RSNs were extracted by performing dual regression analysis, and the functional connectivity (FC) within respective networks was compared among pre-MRgFUS patients, post-MRgFUS patients, and HCs. The severity of tremor was evaluated using the Clinical Rating Scale for Tremor (CRST) score pre- and postoperatively, and its correlation with RSNs was examined. Preoperatively, ET patients showed a significant decrease in FC in the sensorimotor network (SMN), primary visual network (VN), and visuospatial network (VSN) compared with HCs. The decrease in FC in the SMN correlated with the severity of tremor. After MRgFUS thalamotomy, ET patients still exhibited a significant decrease in FC in a small area of the SMN, but they exhibited an increase in the cerebellar network (CN). In comparison between pre- and post-MRgFUS patients, the FC in the SMN and the VSN significantly increased after treatment. Quantitative evaluation of the FCs in these three groups showed that the SMN and VSN increased postoperatively and demonstrated a trend toward those of HCs. The SMN and CN, which are considered to be associated with the cerebello-thalamo-cortical loop, exhibited increased connectivity after MRgFUS thalamotomy. In addition, the FC of the visual network, which declined in ET patients compared with HCs, tended to normalize postoperatively. This could be related to the hypothesis that visual feedback is involved in tremor severity in ET patients. Overall, the analysis of the RSNs by rsfMRI reflected the pathophysiology with the intervention of MRgFUS thalamotomy in ET patients and demonstrated a possibility of a biomarker for successful treatment.

Bilateral Radiofrequency Ventral Intermediate Thalamotomy for Essential Tremor

Introduction: With the advent of MR-guided focused ultrasound, the importance of the efficacy and safety of bilateral ventral intermediate (Vim) thalamotomy for essential tremor (ET) has increased. However, reports on bilateral Vim thalamotomy for ET remain scarce. Methods: To review the results and complications of bilateral Vim thalamotomy for the treatment of ET in the upper extremities, we retrospectively analyzed the patients with ET who underwent bilateral Vim thalamotomy with radiofrequency (RF) thermal coagulation. As bilateral simultaneous thalamotomy can cause surgical complications, thalamotomy was performed in stages. The interval between the first and second thalamotomies was 21.3 ± 14.7 months. We evaluated the efficacy using the Clinical Rating Scale for Tremor (CRST) before and after the first and second treatments, respectively. We also evaluated the complications before and after the first and second treatments, respectively. Moreover, we assessed the adverse events. Results: Seventeen patients were included in the study. The mean follow-up period following the second thalamotomy was 29.3 ± 15.0 months. The CRST part A + B scores were 34.9 ± 9.7, 20.8 ± 7.0, and 7.4 ± 6.8 before, following the first (40.4% improvement, p < 0.0001) and second thalamotomies (78.6% improvement, p < 0.0001), respectively. Nine patients presented with prolonged adverse events, including dysarthria, dysgeusia, dysphagia, tongue numbness, unsteady gait, and postural instability at the last available evaluation. All adverse events were mild and did not interfere with the patient’s daily activities. Discussion/Conclusions: Bilateral Vim thalamotomy with RF thermal coagulation was an effective treatment for ET in both upper extremities. Despite most possible complications being mild, additional studies with a larger sample size are required to ensure patient safety.

Connectomic Basis for Tremor Control in Stereotactic Radiosurgical Thalamotomy.

Given the increased use of stereotactic radiosurgical thalamotomy and other ablative therapies for tremor, new biomarkers are needed to improve outcomes. Using resting-state fMRI and MR tractography, we hypothesized that a "connectome fingerprint" can predict tremor outcomes and potentially serve as a targeting biomarker for stereotactic radiosurgical thalamotomy. We evaluated 27 patients who underwent unilateral stereotactic radiosurgical thalamotomy for essential tremor or tremor-predominant Parkinson disease. Percentage postoperative improvement in the contralateral limb Fahn-Tolosa-Marin Clinical Tremor Rating Scale (TRS) was the primary end point. Connectome-style resting-state fMRI and MR tractography were performed before stereotactic radiosurgery. Using the final lesion volume as a seed, "connectivity fingerprints" representing ideal connectivity maps were generated as whole-brain R-maps using a voxelwise nonparametric Spearman correlation. A leave-one-out cross-validation was performed using the generated R-maps. The mean improvement in the contralateral tremor score was 55.1% (SD, 38.9%) at a mean follow-up of 10.0 (SD, 5.0) months. Structural connectivity correlated with contralateral TRS improvement (r = 0.52; P = .006) and explained 27.0% of the variance in outcome. Functional connectivity correlated with contralateral TRS improvement (r = 0.50; P = .008) and explained 25.0% of the variance in outcome. Nodes most correlated with tremor improvement corresponded to areas of known network dysfunction in tremor, including the cerebello-thalamo-cortical pathway and the primary and extrastriate visual cortices. Stereotactic radiosurgical targets with a distinct connectivity profile predict improvement in tremor after treatment. Such connectomic fingerprints show promise for developing patient-specific biomarkers to guide therapy with stereotactic radiosurgical thalamotomy.

Gait Function after High-Intensity Focused Ultrasound Thalamotomy for Essential Tremor: Searching for Technique Optimization

Introduction: Essential tremor (ET) is one of the most prevalent movement disorders in adults and may be highly disabling for some. Magnetic resonance image-guided high-intensity focused ultrasound (MRIgFUS) has been shown to control tremor efficaciously and with acceptable risk. To date, paresthesia and ataxia are the most common adverse effects (AE). Nevertheless, the impact of MRIgFUS thalamotomy on balance is not well established. Methods: Thirty-two patients underwent MRIgFUS for ET and completed 6 months of follow-up. Tremor severity and functional disability were assessed using the Essential Tremor Rating Scale and the Quality of Life in Essential Tremor Questionnaire. The Berg Balance Scale (BBS) was applied to objectively measure balance status. Results: All treatments were successful. The sonication target was 1–2 mm above the depth of the intercommissural line. Procedures lasted less the 2 h, with an average of 8 sonications per patient. Twenty-four patients were included in the tremor analysis. The hand tremor score was improved by 76% after 6 months of follow-up and 87% of patients self-reported marked improvement (≥75%). Disability scores showed marked improvement (78%), leading to a significant improvement in quality of life. At the final follow-up, 48% of the patients reported no side effects. When present, AE were generally transient and were considered mild in 96% of affected patients. Paresthesia and subjective feeling of unsteadiness were the most common persistent complaints (23% and 20%, respectively). Regarding objective ataxia, BBS scores remained stable throughout follow-up for most patients. Only 2 patients suffered a mild worsening of balance although no patients experienced moderate or severe ataxia. Conclusions: Subjective feeling of unsteadiness is one of the most frequent AE after MRIgFUS, although objective ataxia is infrequent and mild. Selecting the most appropriate lesion location and procedural parameters should increase treatment benefits while reducing side effects.

Experience of staged and simultaneous bilateral thalamotomy using MR-guided focused ultrasound in the treatment of essential tremor

To show that effective and safe bilateral MR-guided focused ultrasound (MRgFUS) treatment of essential tremor (ET) is achievable. Four male patients underwent bilateral thalamotomy. Two patients underwent staged thalamotomy, with the ≥12 month interval between operations. Two patients underwent simultaneous bilateral thalamotomy. After six months, all patients noted a significant reduction in symptoms on both sides: when assessing tremors with the Clinical Rating Scale for Tremor, the severity of hyperkinesis decreased by 57.5-69.7%. We did not observe any complications in any of the cases. Our experience indicates that simultaneous bilateral MRI-guided focused ultrasound treatment of ET can be performed safely and effectively. Further research is necessary to estimate the effectiveness and adverse effect rates.

Deep Brain Stimulation for Holmes Tremors and Literature Review.

Deep Brain Stimulation for Holmes Tremors and Literature Review.