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Parkinsonian tremor (PT) and Essential tremor (ET) exist as upper limb tremors in clinical practice. Notably, their types of trembling share similar presentations and overlapping frequencies. To enhance objectivity and efficiency in the diagnosis of these two diseases, there is a pressing need for more objective tremor classification procedures. This study proposes a novel multimodal fusion network based on a cross-attention mechanism (MFCA-Net) to automate the classification of upper limb tremors between PTs and ETs. To this end, 140 patients with PTs and ETs were recruited, and acceleration and surface electromyography (sEMG) signals were collected from the forearm during tremor episodes. To comprehensively capture the global and local features of input signals, a multiscale convolution in MFCA-Net was designed. Furthermore, the cross-attention mechanism was applied to fuse the features of the two input signals. The results demonstrate that the final classification accuracy exceeded 97.18% when MFCA-Net was used. Compared with the single acceleration signal and single sEMG signal inputs, the recognition accuracies increased by 18.91% and 10.04%, respectively. Therefore, the proposed MFCA-Net in this study serves as an objective and potential tool for assisting clinicians in the diagnosis of PT and ET patients., Competing Interests: Declarations Competing interests The authors declare no competing interests. Ethics statement The study involving human participants was reviewed and approved by the Ruijin Hospital Ethics Committee of Shanghai Jiao Tong University School of Medicine (No. 2023 − 359). Patients/participants provided written informed consent to participate in this study. All the experiments were performed in accordance with the relevant guidelines and regulations., (© 2024. The Author(s).)

Background: Automated sleep detection in movement disorders may allow monitoring sleep, potentially guiding adaptive deep brain stimulation (DBS)., Objectives: The aims were to compare wake-versus-sleep status (WSS) local field potentials (LFP) in a home environment and develop biomarkers of WSS in Parkinson's disease (PD), essential tremor (ET), and Tourette's syndrome (TS) patients., Methods: Five PD, 2 ET, and 1 TS patient were implanted with Medtronic Percept (3 STN [subthalamic nucleus], 3 GPi [globus pallidus interna], and 2 ventral intermediate nucleus). Over five to seven nights, β-band (12.5-30 Hz) and/or α-band (7-12 Hz) LFP power spectral densities were recorded. Wearable actigraphs tracked sleep., Results: From sleep to wake, PD LFP β-power increased in STN and decreased in GPi, and α-power increased in both. Machine learning classifiers were trained. For PD, the highest WSS accuracy was 93% (F1 = 0.93), 86% across all patients (F1 = 0.86). The maximum accuracy was 86% for ET and 89% for TS., Conclusion: Chronic intracranial narrowband recordings can accurately identify sleep in various movement disorders and targets in this proof-of-concept study. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

Competing Interests: The authors have no conflict of interest to declare.

Background: Essential tremor (ET) and Parkinson's disease (PD) are the two most prevalent movement disorders, sharing several overlapping tremor clinical features. Although growing evidence pointed out that changes in similar brain network nodes are associated with these two diseases, the brain network topological properties are still not very clear., Objective: The combination of graph theory analysis with machine learning (ML) algorithms provides a promising way to reveal the topological pathogenesis in ET and tremor-dominant PD (tPD)., Methods: Topological metrics were extracted from Resting-state functional images of 86 ET patients, 86 tPD patients, and 86 age- and sex-matched healthy controls (HCs). Three steps were conducted to feature dimensionality reduction and four frequently used classifiers were adopted to discriminate ET, tPD, and HCs., Results: A support vector machine classifier achieved the best classification performance of four classifiers for discriminating ET, tPD, and HCs with 89.0% mean accuracy (mACC) and was used for binary classification. Particularly, the binary classification performances among ET vs. tPD, ET vs. HCs, and tPD vs. HCs were with 94.2% mACC, 86.0% mACC, and 86.3% mACC, respectively. The most power discriminative features were mainly located in the default, frontal-parietal, cingulo-opercular, sensorimotor, and cerebellum networks. Correlation analysis results showed that 2 topological features negatively and 1 positively correlated with clinical characteristics., Conclusions: These results demonstrated that combining topological metrics with ML algorithms could not only achieve high classification accuracy for discrimination ET, tPD, and HCs but also help to reveal the potential brain topological network pathogenesis in ET and tPD., (© 2024. Fondazione Società Italiana di Neurologia.)

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.

Background: Subtle parkinsonian signs, i.e., rest tremor and bradykinesia, are considered soft signs for defining essential tremor (ET) plus., Objectives: Our study aimed to further characterize subtle parkinsonian signs in a relatively large sample of ET patients from a clinical and neurophysiological perspective., Methods: We employed clinical scales and kinematic techniques to assess a sample of 82 ET patients. Eighty healthy controls matched for gender and age were also included. The primary focus of our study was to conduct a comparative analysis of ET patients (without any soft signs) and ET-plus patients with rest tremor and/or bradykinesia. Additionally, we investigated the asymmetry and side concordance of these soft signs., Results: In ET-plus patients with parkinsonian soft signs (56.10% of the sample), rest tremor was clinically observed in 41.30% of cases, bradykinesia in 30.43%, and rest tremor plus bradykinesia in 28.26%. Patients with rest tremor had more severe and widespread action tremor than other patients. Furthermore, we observed a positive correlation between the amplitude of action and rest tremor. Most ET-plus patients had an asymmetry of rest tremor and bradykinesia. There was no side concordance between these soft signs, as confirmed through both clinical examination and kinematic evaluation., Conclusions: Rest tremor and bradykinesia are frequently observed in ET and are often asymmetric but not concordant. Our findings provide a better insight into the phenomenology of ET and suggest that the parkinsonian soft signs (rest tremor and bradykinesia) in ET-plus may originate from distinct pathophysiological mechanisms., (© 2024. The Author(s).)

Disorders of the gastrointestinal tract in patients suffering from hypokinetic movement disorders, and in particular Parkinson's disease, have increasingly been the subject of more intensive neuromedical research. So far, few data are available for patients with hyperkinetic movement disorders and ataxias. This review article summarizes the currently available and relevant publications on this topic. The particular focus is on essential tremor, restless legs syndrome, Huntington's disease and the group of hereditary ataxias. Further intensive research will be necessary in the future to collect detailed information also for these disease symptoms about specific disturbance patterns, in order to understand the underlying pathological pathways and to derive specific treatment approaches., (© 2024. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Essential tremor (ET) stands as the most prevalent movement disorder, characterized by rhythmic and involuntary shaking of body parts. Achieving an accurate and comprehensive assessment of tremor severity is crucial for effectively diagnosing and managing ET. Traditional methods rely on clinical observation and rating scales, which may introduce subjective biases and hinder continuous evaluation of disease progression. Recent research has explored new approaches to quantifying ET. A promising method involves the use of intelligent devices to facilitate objective and quantitative measurements. These devices include inertial measurement units, electromyography, video equipment, and electronic handwriting boards, and more. Their deployment enables real-time monitoring of human activity data, featuring portability and efficiency. This capability allows for more extensive research in this field and supports the shift from in-lab/clinic to in-home monitoring of ET symptoms. Therefore, this review provides an in-depth analysis of the application, current development, potential characteristics, and roles of intelligent devices in assessing ET., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Essential tremor (ET) and Parkinson's disease (PD) are the most common causes of tremor and the most prevalent movement disorders, with overlapping clinical features that can lead to diagnostic challenges, especially in the early stages., Areas Covered: In the present paper, the authors review the clinical and experimental studies and emphasized the major aspects to differentiate between ET and PD, with particular attention to cardinal phenomenological features of these two conditions. Ancillary and experimental techniques, including neurophysiology, neuroimaging, fluid biomarker evaluation, and innovative methods, are also discussed for their role in differential diagnosis between ET and PD. Special attention is given to investigations and tools applicable in the early stages of the diseases, when the differential diagnosis between the two conditions is more challenging. Furthermore, the authors discuss knowledge gaps and unsolved issues in the field., Expert Opinion: Distinguishing ET and PD is crucial for prognostic purposes and appropriate treatment. Additionally, accurate diagnosis is critical for optimizing clinical and experimental research on pathophysiology and innovative therapies. In a few years, integrated technologies could enable accurate, reliable diagnosis from early disease stages or prodromal stages in at-risk populations, but further research combining different techniques is needed.

Tremor, defined as an "involuntary, rhythmic, oscillatory movement of a body part", is a key feature of many neurological conditions including Parkinson's disease and essential tremor. Clinical assessment continues to be performed by visual observation with quantification on clinical scales. Methodologies for objectively quantifying tremor are promising but remain non-standardized across centers. Our center performs full-body behavioral testing with 3D motion capture for clinical and research purposes in patients with Parkinson's disease, essential tremor, and other conditions. The objective of this study was to assess the ability of several candidate processing pipelines to identify the presence or absence of tremor in kinematic data from patients with confirmed movement disorders and compare them to expert ratings from movement disorders specialists. We curated a database of 2272 separate kinematic data recordings from our center, each of which was contemporaneously annotated as tremor present or absent by a movement physician. We compared the ability of six separate processing pipelines to recreate clinician ratings based on F1 score, in addition to accuracy, precision, and recall. The performance across algorithms was generally comparable. The average F1 score was 0.84±0.02 (mean ± SD; range 0.81-0.87). The second highest performing algorithm (cross-validated F1=0.87) was a hybrid that used engineered features adapted from an algorithm in longstanding clinical use with a modern Support Vector Machine classifier. Taken together, our results suggest the potential to update legacy clinical decision support systems to incorporate modern machine learning classifiers to create better-performing tools.

Background: The positive predictive value (PPV) of the International Classification of Diseases, Ninth Revision-Clinical Modification (ICD-9-CM) code for "essential and other specified forms of tremor" in identifying essential tremor (ET) cases was found to be less than 50%. The ability of the ICD-10-CM G25.0 code for "essential tremor" to identify ET has not been determined. The study objective was to determine the PPV of the G25.0 code., Methods: Patients in a tertiary health system with a primary care encounter associated with ICD-10-CM code G25.0 in 2022 underwent medical record review to determine if the consensus criteria from the International Parkinson and Movement Disorder Society for an ET diagnosis were met., Results: 442 patients were included. The PPV of G25.0 in identifying probable ET cases was 74.7% (95% confidence interval (CI) 70.4-78.5%). Among patients prescribed propranolol, the PPV improved to 87.8% (95% CI 78.0-93.6%)., Discussion: Compared to the ICD-9-CM code 333.1, G25.0 is superior for identifying ET cases. A potential limitation of this study is that the consensus criteria applied relies on nonspecific physical exam findings which may lead to an overestimation of the PPV of G25.0., Highlights: The ICD-10-CM diagnosis code for essential tremor has not been previously validated. The objective of this study was to determine the PPV of the G25.0 code. The PPV in identifying essential tremor cases was 74.7%. The PPV improved among patients prescribed propranolol., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Background: Large-language models (LLMs) driven by artificial intelligence allow people to engage in direct conversations about their health. The accuracy and readability of the answers provided by ChatGPT, the most famous LLM, about Essential Tremor (ET), one of the commonest movement disorders, have not yet been evaluated., Methods: Answers given by ChatGPT to 10 questions about ET were evaluated by 5 professionals and 15 laypeople with a score ranging from 1 (poor) to 5 (excellent) in terms of clarity, relevance, accuracy (only for professionals), comprehensiveness, and overall value of the response. We further calculated the readability of the answers., Results: ChatGPT answers received relatively positive evaluations, with median scores ranging between 4 and 5, by both groups and independently from the type of question. However, there was only moderate agreement between raters, especially in the group of professionals. Moreover, readability levels were poor for all examined answers., Discussion: ChatGPT provided relatively accurate and relevant answers, with some variability as judged by the group of professionals suggesting that the degree of literacy about ET has influenced the ratings and, indirectly, that the quality of information provided in clinical practice is also variable. Moreover, the readability of the answer provided by ChatGPT was found to be poor. LLMs will likely play a significant role in the future; therefore, health-related content generated by these tools should be monitored., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Objectives/hypothesis: Essential vocal tremor (EVT) is an uncommon but challenging condition to manage. Several medical and interventional treatment options have been reported but efficacy remains unclear. We performed a scoping review of high-quality clinical trials to identify effective evidence-based treatments for EVT., Study Design: Scoping review., Methods: Relevant studies were identified using the databases MedLine, Cochrane Central Register of Controlled Trials, and Embase. Subjective and objective outcomes for each modality were analyzed and the effect sizes were quantified using Hedges' g measure to allow comparison between studies., Results: We identified 421 studies eligible for screening with 11 included in the final analysis. Evidence supporting effective EVT treatments was found for bilateral versus unilateral deep brain stimulation (DBS) (Hedges' g 0.65, 95% CI = 0.10-1.20) and octanoic acid (Hedges' g 1.15, 95% CI = 0.40-1.90). Evidence to support the use of methazolamide was not sufficient (Hedges' g 0.51, 95% CI = -0.64 to 1.66). Botulinum toxin (BT) injections were equivalent when comparing unilateral versus bilateral (Hedges' g -0.18, 95% CI = -1.06 to 0.70); BT did not display any advantage over propranolol (Hedges' g -0.47, 95% CI = -1.73 to 0.78) or injection augmentation (Hedges' g 0.068, 95% CI = -0.98 to 1.12)., Conclusions: Our review finds very little high-quality evidence supporting any treatment for EVT. Octanoic acid reduced fluctuations in EVT but did not affect the perception of the tremor. In refractory cases, bilateral DBS was superior to unilateral DBS in improving subjective voice outcomes. Unilateral and bilateral BT injections were equivalent, and BT injection was not more effective than injection augmentation. Further direct comparison in well-designed prospective studies may help clarify optimal treatment for EVT patients., (Copyright © 2021 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Background: The tremor characteristics of patients with spinocerebellar ataxia 12 (SCA12) are often likened to those in patients with essential tremor (ET); however, data are sparse, and videotaped tremor examinations are rare., Case Report: A 37-year-old woman with progressive hand and head tremors underwent genetic testing after conventional diagnostics failed to explain her symptoms. A PPP2R2B variation confirmed spinocerebellar ataxia type 12 (SCA12), a condition not previously considered because classical cerebellar signs were absent. The tremor characteristics of this patient differed in numerous respects from those seen in patients with ET., Discussion: Although often likened to ET, under careful scrutiny, the tremor characteristics observed in this patient with SCA12 were inconsistent with those typically seen in ET. Such discrepancies highlight the necessity of careful phenotyping for tremor disorders, particularly in familial cases. Recognizing the specific tremor phenomenology of SCA12 and distinguishing it from ET is crucial to avoid misdiagnosis and to guide appropriate management and familial counseling., Highlights: This report characterizes in detail an early-stage SCA12 patient initially misdiagnosed as essential tremor, underscoring the importance of nuanced clinical assessment and genetic testing in atypical tremor cases. Similar patients should be meticulously phenotyped to prevent misclassification and enhance our understanding of tremor pathophysiology., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Background: Tremor disorders remain as clinical diagnoses and the rate of misdiagnosis between the commonest non-parkinsonian tremors is relatively high., Objectives: To compare the clinical features of Essential Tremor without other features (pure ET), ET plus soft dystonic signs (ET + DS), and tremor combined with dystonia (TwD)., Methods: We compared the clinical features of patients with pure ET, ET + DS, and TwD enrolled in The ITAlian tremor Network (TITAN). Linear regression models were performed to determine factors associated with health status and quality of life., Results: Three-hundred-eighty-three patients were included. Sex distribution was significantly different between the groups with males being more represented in pure ET and females in TwD. The initial site of tremor was different between the groups with about 40% of TwD having head tremor and ET + DS unilateral upper limb tremor at onset. This pattern mirrored the distribution of overt dystonia and soft dystonic signs at examination. Sensory trick, task-specificity, and position-dependence were more common, but not exclusive, to TwD. Pure ET patients showed the lowest degree of alcohol responsiveness and ET + DS the highest. Midline tremor was more commonly encountered and more severe in TwD than in the other groups. Regression analyses demonstrated that tremor severity, sex, age, and to a lesser degree the variable "group", independently predicted health status and quality of life, suggesting the existence of other determinants beyond tremor., Conclusions: Pure ET and TwD manifest with a phenotypic overlap, which calls for the identification of diagnostic biomarkers. ET + DS shared features with both syndromes, suggesting intra-group heterogeneity., (© 2024 International Parkinson and Movement Disorder Society.)

Tremor is a commonly encountered condition in the primary care setting and can manifest at rest, with action, or both. Common causes include Parkinson disease, essential tremor, and drug-induced tremor. In this article, the authors discuss how to examine a patient with tremor and which features of the history and examination can help clue the provider in to the appropriate diagnosis. They also review treatments for varying types of tremor and when referral to a neurologist may be necessary., Competing Interests: Disclosure None of the authors have commercial or financial interests to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Essential tremor (ET) is a common neurological disorder, with clinical and pathophysiological links to the cerebellum. Inquiries into the etiology, pathophysiology, and nosology of ET stand to benefit from the identification of disease biomarkers. Serum neurofilament light chain (NfL) has emerged as a novel signature of conditions in which neuronal injury reflects an outcome of the ongoing disease process. We sought to investigate the concentrations of NfL in ET patients and healthy controls. In this case-control study, our powered study population of 41 ET patients and 40 age-matched healthy controls underwent clinical assessments and measurement of serum NfL concentration using Simoa technology. Serum NfL was elevated in ET patients - mean log-transformed serum NfL concentration = 1.23 ± 0.19 (95% confidence interval [CI] = 1.17-1.29) vs. 1.08 ± 0.15 (95% CI = 1.03-1.13), p = 0.0002. This difference persisted after accounting for age, sex and Montreal Cognitive Assessment score in a multiple linear regression model (p = 0.002) and in an age-matched sample subset of 35 ET cases and 35 controls (p = 0.006). There was no association between tremor severity and serum NfL levels (p = 0.73). In this sample of ET patients and controls, serum NfL concentrations were significantly higher in ET. Studies in additional cohorts of ET cases would be of value in attempting to replicate these results and assessing diagnostic utility., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Background: The term dystonic tremor is being increasingly used in neurological publications despite uncertainties about its meaning. We provide here a historical reconstruction from its original introduction in 1984 to help distinguish dystonia from essential tremor., Methods: A comprehensive Pubmed search of MeSH terms "dystonia", "tremor", and "essential tremor" provided the information base for reconstructing historical usage of the term "dystonic tremor"., Results: Over the years, this expression was enriched of additional meanings and sided by companion descriptors, such as tremor associated with dystonia. Dystonic tremor has been considered characteristically coarse, jerky, irregular, directional and asymmetrical. These characteristics, however, are not included in the most recent definitions of tremor. The relationship between tremor and dystonia is not easy to untangle, as the two phenomena are often recognized in association. Tremor and dystonia experts have developed different visions of dystonic tremor that have been variably implemented. There are currently two independent consensus definitions, which are not coincident and imply different pathophysiological interpretations., Conclusions: This historical reappraisal highlights that usage of the expression dystonic tremor has evolved over time to lose its original meaning. Notwithstanding inconsistencies of current definitions, its usage has steadily increased and it is time now to agree on an updated terminology., (© 2024 International Parkinson and Movement Disorder Society.)

Objective: Essential tremor is among the most prevalent neurological diseases. Diagnosis is based entirely on neurological evaluation. Historically, there were few postmortem brain studies, hindering attempts to develop pathologically based criteria to distinguish essential tremor from control brains. However, an intensive effort to bank essential tremor brains over recent years has resulted in postmortem studies involving >200 brains, which have identified numerous degenerative changes in the essential tremor cerebellar cortex. Although essential tremor and controls have been compared with respect to individual metrics of pathology, there has been no overarching analysis to derive a combination of metrics to distinguish essential tremor from controls. We asked whether there is a constellation of pathological findings that separates essential tremor from controls, and how well that constellation performs., Methods: Analyses included 100 essential tremor brains from the essential tremor centralized brain repository and 50 control brains. A standard tissue block from the cerebellar cortex was used to quantify 11 metrics of pathological change. Three supervised classification algorithms were investigated, with data divided into training and validation samples., Results: Using three different algorithms, we illustrate the ability to correctly predict a diagnosis of essential tremor, with sensitivity and specificity >87%, and in the majority of situations, >90%. We also provide a web-based application that uses these metric values, and based on specified cutoffs, determines the likely diagnosis., Interpretation: These analyses set the stage for use of pathologically based criteria to distinguish clinically diagnosed essential tremor cases from controls, at the time of postmortem., (© 2024 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background: The Essential Tremor Rating Assessment Scale (TETRAS) is a popular scale for essential tremor (ET), but its activities of daily living (ADL) and performance (P) subscales are based on a structured interview and physical exam. No patient-reported outcome (PRO) scale for ET has been developed according to US regulatory guidelines., Objective: Develop and validate a TETRAS PRO subscale., Methods: Fourteen items, rated 0-4, were derived from TETRAS ADL and structured cognitive interviews of 18 ET patients. Convergent validity analyses of TETRAS PRO versus TETRAS ADL, TETRAS-P, and the Quality of Life in Essential Tremor Questionnaire (QUEST) were computed for 67 adults with ET or ET plus. Test-retest reliability was computed at intervals of 1 and 30 days. The influence of mood (Hospital Anxiety and Depression Scale, HADS) and coping behaviors (Essen Coping Questionnaire, ECQ) was examined with multiple linear regression., Results: TETRAS PRO was strongly correlated (r > 0.7) with TETRAS ADL, TETRAS-P, and QUEST and exhibited good to excellent reliability (Cronbach alpha 95%CI = 0.853-0.926; 30-day test-retest intraclass correlation 95%CI = 0.814-0.921). The 30-day estimate of minimum detectable change (MDC) was 6.6 (95%CI 5.2-8.0). TETRAS-P (r semipartial = 0.607), HADS depression (r semipartial = 0.384), and the coping strategy of information seeking and exchange of experiences (r semipartial = 0.176) contributed statistically to TETRAS PRO in a multiple linear regression (R 2 = 0.67)., Conclusions: TETRAS PRO is a valid and reliable scale that is influenced strongly by tremor severity, moderately by mood (depression), and minimally by coping skills. The MDC for TETRAS PRO is probably sufficient to detect clinically important change., Competing Interests: LCS receives consulting fees from Medtronic, WCG Medavante, and Encora Therapeutics, receives honoraria from Wiley for editorial work, and research grant funding from Praxis Precision Medicines and NIH. MTS is supported by research funds from Praxis, Biogen, and NIH. SB has served as site PI for clinical research trials funded by Sage and AbbVie. AF has stock ownership in Inbrain Pharma and has received payments as consultant and/or speaker from Abbvie, Abbott, Boston Scientific, Ceregate, Dompé Farmaceutici, Inbrain Neuroelectronics, Ipsen, Medtronic, Iota, Syneos Health, Merz. He has received research support from Abbvie, Boston Scientific, Medtronic, Praxis, ES and receives royalties from Springer. SHK receives consulting fees from Praxis, Sage, and Jazz. KEL is president of the International Essential Tremor Foundation. HM received consulting fees from Ipsen Pharma and receives research support from MODUS Outcomes LLC, TEVA Pharmaceuticals, SAGE Therapeutics, Bukwang Pharmaceuticals, Neurocrine Biosciences, CDHI Foundation. HAS received research support from Transposon, NINDS, Parkinson Study Group/UCB, Parkinson’s Foundation, MJFF, Jazz Pharmaceuticals, Intra-cellular Therapeutics and Barrow Neurological Foundation. HAS has also served as a consultant for Abbvie, Sage/Biogen, Praxis, KeifeRx, Fasikl and Jazz Pharmaceuticals. AWS reports grant support from the NIH R01 NS122943 as PI and R01 NS121120-01 as a Co-I. She reports past funding from Benign Essential Blepharospasm Research Foundation, Dystonia Coalition, Dystonia Medical Research Foundation, and National Organization for Rare Disorders. AWS has received consultant fees from Merz, Jazz, Fasikl, Encora and Acadia. She is the current Vice President for the Tremor Research Group and recent advisor for Supernus and Biogen-Sage. CS received grant funding from Teva Pharmaceuticals and the Parkinson Foundation. RJE receives consulting fees from Applied Therapeutics, ES Therapeutics, Neurocrine Biosciences, Encora, Fasikl, Jazz, and Sage; and serves on the International Essential Tremor Foundation Medical Advisory Board., (Copyright: © 2024 The Author(s).)

Essential tremor (ET) is one of the most common tremor disorders and can be disabling in its affect on daily activities. There have been major breakthroughs in the treatment of tremor and ET is the subject of important ongoing research. This review will present recent advancements in the epidemiology, genetics, pathophysiology, diagnosis, comorbidities, and imaging of ET. Current and future treatment options in the management of ET will also be reviewed. The need for continued innovation and scientific inquiry to address the unmet needs of persons of ET will be highlighted., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Okelberry and Dr. Lyons have nothing to disclose. Dr. Pahwa serves as a consultant for Abbott, AbbVie, ACADIA, Acorda, Allevion, Amneal, Appello, Biogen, BioVie, CalaHealth, Convatec, Fasikl, Genetech, Insightec, Jazz, Keiferx, Kyowa, Lundbeck, Merz, Mitsubishi Tanabe, Neurocrine, Ono, PhotoPharmics, PSG, Reagenxbio, Sage, Sun Biopharma, Supernus, and UCB. He receives research support from Abbott, AbbVie, Alexza, Amylyx, Annovis, ASK Bio, Attune, Biogen, Bluerock, Bukwang, Cerevance, Cerevel, EIP, Fasikl, GemVax, Global Kinetics, Inhibikase, Intra-cellular Therapies (ITI), Jazz, Michael J Fox Foundation, Neurocrine, Neuroderm, ONO, Parkinson's Foundation, Praxis, Roche, Sage, Scion, Sun Pharma, Teva, Theravance, and UCB., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Evaluating tremor severity is a critical component of diagnosing and clinically managing patients with essential tremor (ET). We examined the comparability of tremor severity ratings derived from two frequently used tremor rating scales: the Washington Heights-Inwood Genetic Study of Essential Tremor (WHIGET) rating scale and the Tremor Research Group Essential Tremor Rating Scale (TETRAS)., Methods: A trained assistant administered and videotaped a neurological examination, including eight items assessing upper limb action tremor (arms outstretched, arms in the wingbeat position, finger-nose-finger maneuver, and drawing of Archimedes spirals). An experienced movement disorders neurologist reviewed the videos and assigned WHIGET and TETRAS ratings. We calculated associations between TETRAS and WHIGET ratings using Spearman rank order correlations. Subsequently, we collapsed these ratings into four tremor severity categories (absent, mild, moderate, severe) and then two broader tremor severity categories (absent/mild, moderate/severe). We calculated weighted Kappa coefficients to assess agreement between category assignments based on the TETRAS and the WHIGET., Results: Spearman's r ' s were significant for all items ( p's ≤ 0.001, mean r = 0.89). Weighted Kappa's revealed substantial to near perfect agreement for all eight items (mean k = 0.86, range = 0.64 to 1.00)., Conclusion: Analyses revealed substantial strength of association and substantial to near perfect agreement between items rated with the WHIGET and TETRAS scales. These data indicated that ratings provided by each scale are highly comparable., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Essential tremor (ET) is one of the most common neurological diseases. New evidence suggest that ET is associated with cognitive disorders other than motor symptoms. We aimed to investigate executive dysfunctions, which are comorbid cognitive deficiencies that may accompany ET. The study was conducted as an observational, case-control study in the Neurology Department of Ankara City Hospital in a 3-month period. The "Fahn-Tolosa-Marin Tremor Evaluation Scale" was used to rate tremor severity. Both patients and control group were subjected to the Mini Mental Test, followed by the Stroop TBAG test (TBAG is composed of the first letters of "TUBİTAK Temel Bilimler Araştırma Grubu," which means Scientific and Technological Research Council of Turkey Basic Sciences Research Group), word fluency (category fluency), phonemic fluency (K), and abstract thinking (binary similarities, proverb interpretation) tests. Both the patient and the control group consisted of 20 women and 20 men, with age, gender, and educational background compatible. Mean age of the patient group was 34.80 ± 13.23 years, while it was 34.95 ± 10.21 years in control group. In the ET group, statistically significant impairment was detected in the Stroop Test section 5 duration and error + correction number, category fluency, binary similarity, and phonemic fluency tests compared to the control group. There was a correlation between the severity of tremor and especially Stroop, category fluency, and binary similarity tests such that, as the severity of tremor increased, these test scores deteriorated. In ET patients, an impairment, accompanying tremor, may be present in executive functions that are a part of frontal lobe functions even in younger patients. This finding may suggest that impairment in the cerebellum-thalamus-frontal lobe connection may play a role in ET pathology.

Background: Essential tremor (ET) represents a heterogeneous condition which may overlap with Parkinson disease (PD) even at early stages, by sharing some subtle clinical aspects. Longstanding ET demonstrated also higher risk of developing PD, especially with a Tremor-dominant (TD-PD) phenotype. Therefore, differential diagnosis between ET and early PD could be quite challenging. Optical coherence tomography (OCT) has been recognized as a reliable tool to assess the retina as a proxy of neurodegeneration. We aimed to explore the possible role of retinal assessment in differential diagnosis between ET and early PD., Methods: Macular layers and peripapillary retinal nerve fiber layer (RNFL) thickness among ET, early PD, and healthy controls (HCs) were assessed using OCT., Results: Forty-two eyes from 23 ET, 41 eyes from 21 early PD, and 33 eyes from 17 HCs were analyzed. Macular RNFL, ganglion cell layer, inner plexiform layer, and inner nuclear layer were thinner in PD as compared with ET and even more in HCs. Differences between ET and PD were more evident when considering the TD-PD subgroup, especially for RNFL. Among ET patients, thickness of the inner macular layers showed negative linear relationship with both age at onset and disease duration. Peripapillary temporal quadrant thinning was found in ET compared with HCs., Conclusions: Macular inner retina was thinner in patients with ET and early PD compared with HCs. These findings suggest that the retinal assessment may have a utility in the differential diagnosis between ET and PD., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the North American Neuro-Opthalmology Society.)

Background: Jaw clonus refers to involuntary, rhythmic jaw contractions induced by a hyperactive trigeminal nerve stretch reflex; however, the movements, when triggered without a stretch, can be confused with a tremor., Phenomenology Shown: This video demonstrates a patient with amyotrophic lateral sclerosis presenting with rapid rhythmic jaw movements seen at rest, alongside a power spectrum analysis revealing a narrow high-frequency peak of 10 Hz., Educational Value: Rhythmic jaw movements are seen in many disorders such as Parkinson's disease, essential tremor, tardive syndromes, and cranial myorhythmias; however, a high-frequency movement, regardless of clonus or tremor, can indicate amyotrophic lateral sclerosis when accompanied by typical upper and lower motor neuron signs., Highlights: The presented video abstract shows a patient with amyotrophic lateral sclerosis with rhythmic jaw movements seen at rest. A power spectrum analysis of the rhythmic movements revealed a 10 Hz peak, a frequency higher than those seen in patients with Parkinson's disease, essential tremor, myorhythmia, and tardive syndromes., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2024 The Author(s).)

Deep brain stimulation (DBS) using Medtronic's Percept™ PC implantable pulse generator is FDA-approved for treating Parkinson's disease (PD), essential tremor, dystonia, obsessive compulsive disorder, and epilepsy. Percept™ PC enables simultaneous recording of neural signals from the same lead used for stimulation. Many Percept™ PC sensing features were built with PD patients in mind, but these features are potentially useful to refine therapies for many different disease processes. When starting our ongoing epilepsy research study, we found it difficult to find detailed descriptions about these features and have compiled information from multiple sources to understand it as a tool, particularly for use in patients other than those with PD. Here we provide a tutorial for scientists and physicians interested in using Percept™ PC's features and provide examples of how neural time series data is often represented and saved. We address characteristics of the recorded signals and discuss Percept™ PC hardware and software capabilities in data pre-processing, signal filtering, and DBS lead performance. We explain the power spectrum of the data and how it is shaped by the filter response of Percept™ PC as well as the aliasing of the stimulation due to digitally sampling the data. We present Percept™ PC's ability to extract biomarkers that may be used to optimize stimulation therapy. We show how differences in lead type affects noise characteristics of the implanted leads from seven epilepsy patients enrolled in our clinical trial. Percept™ PC has sufficient signal-to-noise ratio, sampling capabilities, and stimulus artifact rejection for neural activity recording. Limitations in sampling rate, potential artifacts during stimulation, and shortening of battery life when monitoring neural activity at home were observed. Despite these limitations, Percept™ PC demonstrates potential as a useful tool for recording neural activity in order to optimize stimulation therapies to personalize treatment., (Creative Commons Attribution license.)

Background: The merits of classifying the heterogeneous group of essential tremors into essential tremor (ET) and essential tremor plus (ETP) are debated., Objectives: We studied the electrophysiological and spiral characteristics of tremor in ET and ETP., Methods: We reviewed standardized videos from a tremor database and clinically classified patients into ET, ETP, or dystonic tremor (DT). The following variables were derived from combined tri-axial accelerometry-surface electromyography (EMG)-peak frequency, total power, peak power, full width half maximum, tremor stability index and EMG-coherence. We analyzed hand-drawn spirals to derive mean deviation, tremor variability, inter-, and intra-loop widths. We compared these variables among the groups., Results: We recruited 72 participants (81.9% male) with mean age 47.7 ± 16.1 years and Fahn-Tolosa-Marin Tremor Rating Scale total score 31.1 ± 14.1. Patients with ET were younger (P = 0.014) and had less severe tremor (P = 0.020) compared to ETP and DT. In ETP group, 48.6% had subtle dystonia. Peak frequency was greater in ETP (7.3 ± 0.3 Hz) compared to DT (6.1 ± 0.4 Hz; P = 0.024). Peak power was greater in ETP and DT for postural tremor. Rest tremor was recordable on accelerometry in 26.7% of ET. Other variables were similar among the groups., Conclusion: Electrophysiological evaluation revealed postural tremor of frequency 6 to 7 Hz in ET, ETP, and DT with subtle differences more severe tremor in ETP and DT, and higher frequency in ETP compared to DT. Our findings suggest a similar tremor oscillator in these conditions, supporting the view that these entities are part of a spectrum of tremor disorders, rather than distinct etiological entities., (© 2023 International Parkinson and Movement Disorder Society.)

Background: Tremors are involuntary rhythmic movements commonly present in neurological diseases such as Parkinson's disease, essential tremor, and multiple sclerosis. Intention tremor is a subtype associated with lesions in the cerebellum and its connected pathways, and it is a common symptom in diseases associated with cerebellar pathology. While clinicians traditionally use tests to identify tremor type and severity, recent advancements in wearable technology have provided quantifiable ways to measure movement and tremor using motion capture systems, app-based tasks and tools, and physiology-based measurements. However, quantifying intention tremor remains challenging due to its changing nature., Methodology & Results: This review examines the current state of upper limb tremor assessment technology and discusses potential directions to further develop new and existing algorithms and sensors to better quantify tremor, specifically intention tremor. A comprehensive search using PubMed and Scopus was performed using keywords related to technologies for tremor assessment. Afterward, screened results were filtered for relevance and eligibility and further classified into technology type. A total of 243 publications were selected for this review and classified according to their type: body function level: movement-based, activity level: task and tool-based, and physiology-based. Furthermore, each publication's methods, purpose, and technology are summarized in the appendix table., Conclusions: Our survey suggests a need for more targeted tasks to evaluate intention tremors, including digitized tasks related to intentional movements, neurological and physiological measurements targeting the cerebellum and its pathways, and signal processing techniques that differentiate voluntary from involuntary movement in motion capture systems., (© 2024. The Author(s).)

Objective: Essential tremor (ET), while defined by progressive motor symptoms, is increasingly associated with cognitive impairments (e.g. attention, memory, and executive functions). This study characterizes the cognitive profile of individuals with ET on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), a commonly-used neuropsychological screening measure. Method: Seventy-seven individuals (mean age: 70.6, 34% female) diagnosed with ET and being considered for surgical/procedural intervention were recruited from a Movement Disorders Clinic. All participants completed the RBANS, Grooved Pegboard Test (GPB), and Fahn, Tolosa, Marin Tremor Scale (FTMTS) in the clinical evaluation of their tremor. Results: One-sample t -tests found Immediate Memory, Language, Attention, and Total Scale Index scores to be significantly lower than the expected population mean ( p < .05). List Learning, Semantic Fluency, Coding, and List Recall subtests were significantly lower and Picture Naming was significantly higher than the expected population mean ( p < .05). GPB scores were correlated with the Attention Index as well as List Learning and Coding subtests. FTMTS Severity was correlated with the Coding subtest and FTMTS Disability was correlated with the Figure Recall subtest. Conclusions: Results support prior literature indicating cognitive weaknesses in those with ET. Individuals with ET had poorer global cognitive abilities, with specific decrements in Immediate Memory, Attention, and Language. Notably, the Attention Index and Coding subtest were most affected by motor functioning. Cognitive screening measures, like the RBANS, can efficiently identify strengths and weaknesses in individuals with ET seeking surgical/procedural interventions.

Introduction: Essential tremor (ET) patients may exhibit a variety of non-motor features, including cognitive decline and depressive symptoms. Studies of several neurodegenerative diseases link depression to cognitive decline, suggesting depression is an early marker of dementia. We examined whether baseline depressive symptoms predict incident dementia in elders with ET., Methods: Hundred and forty-one ET cases aged 70 years or older at baseline, enrolled in a prospective study of cognitive performance, took part in evaluations at baseline and at 18, 36, 54, and 72 months. Participants completed the Geriatric Depression Scale (GDS), a 30-item self-report measure of depressive symptoms, and a battery of neuropsychological tests and functional assessments, from which we derived cognitive diagnoses at each evaluation. Cox proportional hazards regression equations determined incident dementia risk based on participants' baseline depression scores., Results: Mean baseline age was 81.5 ± 6.7 years. Higher baseline GDS scores were associated with increased risk of dementia in an unadjusted model (hazards ratio [HR] = 1.11, 95% confidence interval [CI] = 1.02-1.20, p = 0.01) and after controlling for baseline age, education, number of medications, and tremor onset age (HR = 1.13, 95% CI = 1.02-1.25, p = 0.02)., Conclusion: Baseline depression scores predicted incident dementia in elders with ET. With each one-point increase in baseline depression score, there was a 13% increase in incident dementia risk. Given the published data that reported depression may be twice as high in elders with ET compared to controls, this association is particularly worrisome in the ET population., (© 2024 S. Karger AG, Basel.)

Background and Purpose: Essential tremor (ET) is one of the most common neurological disorders, but information on treatment pattern is still scant. The aim of this study was to describe the demographic and clinical characteristics, treatment patterns, and determinants of drug use in patients with newly diagnosed ET in France and the United Kingdom., Methods: Incident cases of ET diagnosed between January 1, 2015 and December 31, 2018 with 2 years of follow-up were identified by using The Health Improvement Network (THIN®) general practice database. During the follow-up, we assessed the daily prevalence of use and potential switches from first-line to second-line treatment or other lines of treatment. Logistic regression models were conducted to assess the effect of demographic and clinical characteristics on the likelihood of receiving ET treatment., Results: A total of 2957 and 3249 patients were selected in the United Kingdom and France, respectively. Among ET patients, drug use increased from 12 months to 1 month prior the date of index diagnosis (ID). After ID, nearly 40% of patients received at least one ET treatment, but during follow-up drug use decreased and at the end of the follow-up approximately 20% of patients were still on treatment. Among treated patients, ≤10% maintained the same treatment throughout the entire follow-up, nearly 20% switched, and 40%-75% interrupted any treatment. Results from the multivariate analysis revealed that, both in France and the United Kingdom, patients receiving multiple concomitant therapies and affected by psychiatric conditions were more likely to receive an ET medication., Conclusion: This study shows that ET is an undertreated disease with a lower-than-expected number of patients receiving and maintaining pharmacological treatment. Misclassification of ET diagnosis should be acknowledged; thus, results require cautious interpretation., (© 2023 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Background: Tremors other than those associated with Parkinson's disease (non-parkinsonian tremor) are commonly observed in clinical settings. However, their frequency and clinical characteristics have rarely been reported., Objectives: To classify non-parkinsonian tremors based on the consensus statement on the classification of tremors, from the task force of the International Parkinson and Movement Disorder Society published in 2018., Methods: A prospective registry at a tertiary care teaching institute., Results: A total of 475 patients with non-parkinsonian tremors were recruited for the study. 67.57% (n = 321) of our patients were male and a family history of tremor was present in 20.84% (n = 99) of patients. Dystonic tremor (DT) was the most common non-parkinsonian tremor (33.26%). 27.78% of patients fulfilled the new classification criteria for essential tremor, with 13.47% classified as pure ET (ET) and 14.31% exhibiting neurological soft signs, leading to the classification of ET plus (ETP). Patients with ETP had more family history (57.35%) [vs DT (26.48%, p = 0.00004) and ET (10.93%, p = 0.00003], longer duration of disease [mean ± standard deviation (SD) = 9.53 ± 8.64 years] [vs DT (5.60 ± 5.93, p = 0.0003) and ET (6.38 ± 5.97, p = 0.01) years], and more severe tremor as measured by the essential tremor rating assessment scale total score [mean ± SD = 27.42 ± 11.70] [vs DT (23.50 ± 8.62, p = 0.007) and ET (22.12 ± 8.19, p = 0.007)] compared with patients with DT and ET., Conclusions: DT was the most common cause of non-parkinsonian tremor in our registry followed by essential tremor syndrome. ETP was more common than ET., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2023 The Author(s).)

Two scales have been developed and validated in English to evaluate the impact of tremor on daily life, namely Quality of life in Essential Tremor Questionnaire (QUEST) and Essential Tremor Embarrassment Assessment (ETEA). The psychometric properties of the French version of these two scales were assessed for 117 patients with head tremor. Both scales showed excellent acceptability, very good internal consistency (Cronbach's alpha coefficient>0.8) and reproducibility (Lin concordance coefficient>0.8), satisfactory external validity and satisfactory sensitivity to change. In conclusion, the French versions of QUEST and ETEA are comprehensive, valid and reliable instruments for assessing patients with head tremor., (Copyright © 2023 Elsevier Masson SAS. All rights reserved.)

This study utilized cervical vestibular-evoked myogenic potentials tests (cVEMP) and ocular vestibular-evoked myogenic potentials tests (oVEMP) to investigate the vestibulocollic and vestibuloocular reflex arcs and to evaluate cerebellar and brainstem involvement) in essential tremor (ET). Eighteen cases with ET and 16 age- and gender-matched healthy control subjects (HCS) were included in the present study. Otoscopic and neurologic examinations were performed on all participants, and both cervical and ocular VEMP tests were performed. Pathological cVEMP results were increased in the ET group (64.7%) compared to the HCS (41,2%; p > 0.05). The latencies of P1 and N1 waves were shorter in the ET group than in HCS (p = 0.01 and p = 0.001). Pathological oVEMP responses were significantly higher in the ET group (72.2%) compared to the HCS (37.5%; p = 0.01). There was no statistically significant difference in oVEMP N1-P1 latencies between groups (p > 0.05). Because the ET group had high pathological responses to the oVEMP, but not the cVEMP, the upper brainstem pathways may be more affected by ET., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

Background: Although essential tremor (ET) is often divided into familial and sporadic cases, few data compare the evolution of clinical features in these groups over time. Leveraging data from a prospective, longitudinal study, we present analyses of the evolution of a broad range of cognitive, motor (i.e., tremor, tandem gait) and other features (e.g., disability) of ET., Methods: Sixty-six familial and 23 sporadic ET cases completed in-home evaluations at baseline and 18, 36, and 54-month follow-ups. Assessments included detailed neuropsychological testing and videotaped neurological examinations. Analyses compared the longitudinal course of 16 clinical features in familial and sporadic cases., Results: Baseline mean age was 75.2 ± 8.8 years and mean observation period was 4.7 ± 0.3 years. Tremor onset age was lower and childhood onset more common in familial than sporadic cases (p's = 0.02). Longitudinal analyses revealed no significant differences between clinical features displayed by familial and sporadic cases, or differences between the patterns of change in clinical features observed in these groups across time. Sporadic cases' daily activity skills declined significantly, whereas familial cases' did not, p's = 0.04 and 0.34, respectively; however, this finding was non-significant when controlling for false discovery rate. Several additional non-significant trends were noted., Conclusion: Familial and sporadic ET cases differed in onset age, and in the prevalence of childhood tremor onset. Although a number of interesting trends were observed, no significant differences in the evolution of clinical features over time in patients with and without a family history of ET were revealed., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Background: Several validated clinical scales measure the severity of essential tremor (ET). Their assessments are subjective and can depend on familiarity and training with scoring systems., Method: We propose a multi-modal sensing using a wearable inertial measurement unit for estimating scores on the Fahn-Tolosa-Marin tremor rating scale (FTM) and determine the classification accuracy within the tremor type. 17 ET participants and 18 healthy controls were recruited for the study. Two movement disorder neurologists who were blinded to prior clinical information viewed video recordings and scored the FTM. Participants drew a guided Archimedes spiral while wearing an inertial measurement unit placed at the mid-point between the lateral epicondyle of the humerus and the anatomical snuff box. Acceleration and gyroscope recordings were analyzed. The ratio of the power spectral density between frequency bands 0.5-4 Hz and 4-12 Hz, and the sum of power spectrum density over the entire spectrum of 2-74 Hz, for both accelerometer and gyroscope data, were computed. FTM was estimated using regression model and classification using SVM was validated using the leave-one-out method., Results: Regression analysis showed a moderate to good correlation when individual features were used, while correlation was high ([Formula: see text] = 0.818) when suitable features of the gyro and accelerometer were combined. The accuracy for two-class classification of the combined features using SVM was 91.42% while for four-class it was 68.57%., Conclusion: Potential applications of this novel wearable sensing method using a wearable Inertial Measurement Unit (IMU) include monitoring of ET and clinical trials of new treatments for the disorder., (© 2023 The Authors.)

Clinical rating scales for tremors have significant limitations due to low resolution, high rater dependency, and lack of applicability in outpatient settings. Reliable, quantitative approaches for assessing tremor severity are warranted, especially evaluating treatment effects, e.g., of deep brain stimulation (DBS). We aimed to investigate how different accelerometry metrics can objectively classify tremor amplitude of Essential Tremor (ET) and tremor in Parkinson's Disease (PD). We assessed 860 resting and postural tremor trials in 16 patients with ET and 25 patients with PD under different DBS settings. Clinical ratings were compared to different metrics, based on either spectral components in the tremorband or pure acceleration, derived from simultaneous triaxial accelerometry captured at the index finger and wrist. Nonlinear regression was applied to a training dataset to determine the relationship between accelerometry and clinical ratings, which was then evaluated in a holdout dataset. All of the investigated accelerometry metrics could predict clinical tremor ratings with a high concordance (>70%) and substantial interrater reliability (Cohen's weighted Kappa > 0.7) in out-of-sample data. Finger-worn accelerometry performed slightly better than wrist-worn accelerometry. We conclude that triaxial accelerometry reliably quantifies resting and postural tremor amplitude in ET and PD patients. A full release of our dataset and software allows for implementation, development, training, and validation of novel methods.

The Archimedes spiral is a clinical tool that aids in the diagnosis and monitoring of essential tremor. However, spiral ratings may vary based on experience and training of the rating physician. This study sought to generate an objective standard model for tremor evaluation using convolutional neural networks. One senior movement disorders neurologist (Neurologist 1) with over 30 years of clinical experience used the Bain and Findley Spirography Rating Scale to rate 1653 Archimedes spiral images from 46 essential tremor patients (mild to severe tremor) and 75 control subjects (no to mild tremor). Neurologist 1's labels were used as the reference standard to train the model. After training the model, a randomly selected subset of spiral testing data was re-evaluated by Neurologist 1, by a second senior movement disorders neurologist (Neurologist 2) with over 27 years of clinical experience, and by our model. Cohen's Weighted Kappa 95% confidence intervals were calculated from all rater comparisons to determine if our model performs with the same proficiency as two senior movement disorders neurologists. The Cohen's Weighted Kappa 95% confidence intervals for the agreement between the reference standard scores and Neurologist 1's rerated scores, for the agreement between the reference standard scores and Neurologist 2's scores, and for the agreement between the reference standard scores and our model's scores were 0.93-0.98, 0.86-0.94, and 0.89-0.96, respectively. With overlapping Cohen's Weighted Kappa 95% confidence intervals for all agreement comparisons, we demonstrate that our model evaluates spirals with the same proficiency as two senior movement disorders neurologists., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Introduction: Parkinson's disease (PD) and essential tremor (ET) are two disorders known to lead to executive dysfunction, presumably through distinct pathways to the frontal lobes via the striatum or cerebellum, respectively. Memory functioning in PD and ET patients has been previously suggested to be adversely impacted by executive dysfunction. The aims of this exploratory study were to compare memory performance between and within groups on the California Verbal Learning Test - 3 (CVLT-3) through the analysis of core and process scores and to understand the relationship of these scores with measures of executive functioning., Method: Seventy PD and 54 ET patients completed comprehensive neuropsychological testing. Independent sample t-tests or Mann-Whitney tests were used to compare between group core and process scores on the CVLT-3. Within-subjects analyses were conducted via Wilcoxon Signed Rank Test due to nonparametric data. Spearman's correlations were conducted to explore the relationship between memory process scores and measures of executive functioning., Results: The ET and PD samples were similar with regard to age, education, gender, and general cognitive functioning. PD patients made more repetition errors ( U = 2391.50, p = .01) than ET patients and Normal Memory PD patients made more repetition errors than Low Memory PD patients ( U = 711.00, p = .00). Correlational analyses revealed repetition errors were negatively associated with tests of inhibition, set shifting, and working memory ( r s   = -.293, -.232). ET patients demonstrated a preference for a serial cluster learning strategy ( T = 861.00, p = .005), similar to PD patients ( T = 1633.00, p = <.001)., Conclusions: The study revealed presence of higher repetition errors in the PD sample that was demonstrated to have a negative relationship with measures of executive functioning. Implications for investigating process ("qualitative") scores in memory performance to determine extent of executive involvement are discussed.

Objective Given the association between essential tremor (ET) and higher rates of cognitive decline, assessing this decline is an important element of research and clinical care. The Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) are two broad, brief measures that are widely used to monitor cognitive impairment in various neurological disorders. We sought to determine the relative ability of the MoCA and the MMSE to detect cognitive decline in elderly patients with ET. Methods We administered a neuropsychological battery to an ET cohort every 18 months over 4.5 years. We defined the gold standard for change in cognition as the change in neuropsychological test scores over consecutive evaluations and applied the Reliable Change Method to detect meaningful increases/decreases in test scores. We performed receiver operating characteristics (ROC) analysis to quantify the area under the curve (AUC) and compare the ability of the MoCA and the MMSE to detect cognitive decline. Results The AUCs for the MoCA and the MMSE did not differ significantly at any interval or when all intervals were pooled for analysis. Across all intervals, the ability of the MoCA and the MMSE to detect cognitive decline was consistently fair or poor. Conclusions We found that the ability of the MoCA and the MMSE to detect cognitive decline in ET patients over 18-month intervals is inadequate. Unchanged scores on the MoCA and the MMSE in ET over time should be approached with caution. We propose that these screening tools should be supplemented with additional neuropsychological tests.

Background: 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., Methods: 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., Results: 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., Conclusion: 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., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Introduction: The existence of non-motor symptoms in essential tremor (ET) and the appearance of a new condition, ET-plus, are two controversial issues., Aims: To offer a review of the current status of these two topics., Development: We performed an analysis of the studies conducted on non-motor symptoms in ET and of the articles for and against the use of the term ET-plus., Conclusions: Non-motor symptoms have gained increased recognition as a feature accompanying ET. Several studies have documented its presence compared to matched controls. It is not clear, however, whether these non-motor symptoms would be part of the spectrum of ET symptoms (a primary phenomenon) or whether they would be symptoms that appear as a consequence of the physical or psychological disability produced by the clinical signs and symptoms of ET itself (a secondary phenomenon). For the time being, their evaluation and treatment are not included within the standard assessment of patients with ET. In view of the heterogeneous phenotype, the term ET-plus aims to improve phenotypic homogeneity for genetic or therapeutic studies. Yet, there is no pathological basis, and epidemiological, genetic and therapeutic research studies have numerous drawbacks. In the absence of clear objective biomarkers, distinguishing between ET and ET-plus by clinical distinction alone is very complex. We should be cautious about using new terms that are not yet backed by sound scientific evidence.

Background: Differentiating early-stage Parkinson's disease (PD) from essential tremor (ET) is challenging since they have some overlapping clinical features. Since early-stage PD may present with slight gait impairment and ET generally does not, gait analysis could be used to differentiate PD from ET using machine learning., Objective: To differentiate early-stage PD from ET via machine learning using gait and postural transition parameters calculated using the raw kinematic signal captured from inertial measurement unit (IMU) sensors., Methods: Gait and postural transition parameters were collected from 84 early-stage PD and 80 ET subjects during the Time Up and Go (TUG) test. We randomly split our data into training and test data. Within the training data, we separated the TUG test into four components: standing, straight walk, turning, and sitting to build weighted average ensemble classification models. The four components' weight indices were trained using logistic regression. Several ensemble models' leave-one-out cross-validation (LOOCV) performances were compared. Independent test data were used to evaluate the model with the best LOOCV performance., Results: The best weighted average ensemble classification model LOOCV results included an accuracy of 84%, Kappa of 0.68, sensitivity of 85.9%, specificity of 82.1%, and AUC of 0.912. Thirty-three gait and postural transition parameters, such as Arm-Symbolic Symmetry Index and 180° Turn-Max Angular Velocity, were included in Feature Group III. The independent test data achieved a 75.8% accuracy., Conclusions: Our findings suggest that gait and postural transition parameters obtained from wearable sensors combined with machine learning had the potential to distinguish between early-stage PD and ET., (© 2023. The Author(s).)

Background: Although it is known that muscle strength training is effective in Essential Tremor (ET), it is not known which muscle groups are more affected., Aim: 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., Methods: A total of 40 older adults who were diagnosed with ET (mean age of 74.07 ± 4.83 years) and 40 older adults without tremor (mean age of 70.10 ± 4.05 years) 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)., Results: 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., Conclusions: 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., (© 2023. The Author(s), under exclusive licence to European Geriatric Medicine Society.)

Background and Purpose: Essential tremor (ET) is a common and heterogeneous disorder characterized by postural/kinetic tremor of the upper limbs and other body segments and by non-motor symptoms, including cognitive and psychiatric abnormalities. Only a limited number of longitudinal studies have comprehensively and simultaneously investigated motor and non-motor symptom progression in ET. Possible soft signs that configure the ET-plus diagnosis are also under-investigated in follow-up studies. We aimed to longitudinally investigate the progression of ET manifestations by means of clinical and neurophysiological evaluation., Methods: Thirty-seven ET patients underwent evaluation at baseline (T0) and at follow-up (T1; mean interval ± SD = 39.89 ± 9.83 months). The assessment included the clinical and kinematic evaluation of tremor and voluntary movement execution, as well as the investigation of cognitive and psychiatric disorders., Results: A higher percentage of patients showed tremor in multiple body segments and rest tremor at T1 as compared to T0 (all p-values < 0.01). At T1, the kinematic analysis revealed reduced finger-tapping movement amplitude and velocity as compared to T0 (both p-values < 0.001). The prevalence of cognitive and psychiatric disorders did not change between T0 and T1. Female sex, absence of family history, and rest tremor at baseline were identified as predictive factors of worse disease progression., Conclusions: ET progression is characterized by the spread of tremor in multiple body segments and by the emergence of soft signs. We also identified possible predictors of disease worsening. The results contribute to a better understanding of ET classification and pathophysiology., (© 2022 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.)

Essential tremor (ET) is one of the most common neurological disorders, and its mainly clinical symptoms, including patient hand's kinetic tremor, dystonia, ataxia, etc., would influence the daily life of patients inordinately. Current ET diagnosis highly replies on the clinical evaluation and neurological examination, so the objective measurement indicators are particularly important in the auxiliary diagnosis of ET. In this research, the Archimedes spiral line freehand sketching samples without template assistance is collected and the Convolutional Neural Network (CNN) model of optimized structure is adopted to fully analyze the tremor, spacing of turns, shape, etc. shown in the handwriting samples of patients with ET, including the following main process: characteristics extraction, model visualization and subregional relevance evaluation. Dropout is used as a regularization technique in the network structure. The test group consisted of 50 patients with confirmed ET and the control group consisted of 40 healthy individuals. The main research objectives of this paper comprise two points: on the one hand, to achieve effective automatic classification of patients with ET and healthy controls using a scheme combining deep learning and simple hand mapping for the purpose of primary disease screening; on the other hand, to design sub-regional automatic classification experiments to demonstrate that Archimedean spiral hand drawings of patients with ET do have distinct local features, and to lay the experimental foundation for future hand drawing-based automatic aid for the identification of a variety of neurodegenerative diseases. Our model's average accuracy rate in test set reaches 89.3%, and average AUC is 0.972, with favorable stability and generalization performance. Besides, subregional characteristics recognition proofs that the spiral line samples of most of the patients with ET show more category-related characteristics in the local area of upper right, which provides evidences and theory update for predecessors' medical research., Competing Interests: Declaration of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 IPEM. Published by Elsevier Ltd. All rights reserved.)