Objective Tremor Research Articles

Integrating Wearable Sensor Signal Processing with Unsupervised Learning Methods for Tremor Classification in Parkinson's Disease.

Tremor is one of the most common symptoms of Parkinson's disease (PD), assessed using clinician-assigned clinical scales, which can be subjective and prone to variability. This study evaluates the potential of unsupervised learning for the classification and assessment of tremor severity from wearable sensor data. We analyzed 25 resting tremor signals from 24 participants (13 PD patients and 11 controls), focusing on motion intensities derived from accelerometer recordings. The k-means clustering algorithm was employed, achieving a classification accuracy of 76% for tremor versus non-tremor states. However, performance decreased for multiclass tremor severity classification (57.1%) and binary classification of severe versus mild tremor (71.4%), highlighting challenges in detecting subtle intensity variations. The findings underscore the utility of unsupervised learning in enabling scalable, objective tremor analysis. Integration of such models into wearable systems could improve continuous monitoring, enhance rehabilitation strategies, and support standardized clinical assessments. Future work should explore advanced algorithms, enriched feature sets, and larger datasets to improve robustness and generalizability.

A multimodal fusion network based on a cross-attention mechanism for the classification of Parkinsonian tremor and essential tremor

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.

Event‐Feature‐Based Clustering Reveals Continuous Distribution of Tectonic Tremors of 0.3–100 s: Application to Western Japan

AbstractWe develop a methodology to compile an objective tremor catalog by utilizing distinctive event features that differentiate tectonic tremors from non‐tremor events, and combining the envelope cross‐correlation method with clustering technique and neural network. This approach enables tremor extraction without subjective criteria, allowing for the detection of previously overlooked short‐duration tremors. The event features employed to distinguish tremors and non‐tremor events are depth, the mean amplitudes at high and low frequencies, the ratio of these two amplitudes, and event duration. The duration is defined as the minimum period that contains 50% of the seismic energy. The application of this method to western Japan detects 1.7 times more tremors than the previous studies, with the durations of 0.3–∼100 s. The events with short durations are considered low‐frequency earthquakes. The relationship between seismic moment and duration of the detected tremors is consistent with the scaling law of slow earthquakes.

Sobel edge detection for quantifying the effectiveness of focused ultrasound thalamotomy for tremor relief

Abstract Focused ultrasound on the thalamus is employed to relieve tremor in movement disorders. The treatment efficacy is currently assessed by subjective observation of patient tremor during hand movements. The purpose of this study was to create a simple quantitative method to assess tremor based on traditional pen-and-paper spiral drawing that could be employed during treatment and follow-up visits. Image processing was employed to automatically and rapidly clean scanned spiral and line drawings and to isolate the minimal part of the drawing that could provide sufficient data for tremor detection. Sobel edge detection and easily-interpretable statistics of the distribution of edge-angle orientations in the spirals relative to the spiral centres were used as tremor measures. The method was applied to scanned drawings of 122 tremor patients before treatment and in follow-up visits. Discrimination analysis of the tremor measure between drawings in the session before treatment and the follow-up sessions was carried out. The processing yielded correctly cropped and clean spirals. The tremor measure demonstrated consistent tremor reduction in the treated hand drawings in all five follow-up visits during the first year following treatment date in 76 patients from the study cohort. In this study we developed a computational method that rapidly computed tremor severity estimate in an explainable and clinically useful manner from a traditional pen-and-paper spiral drawing. This rapid quantitative and objective tremor assessment can easily be implemented during focused ultrasound treatment and replace the subjective assessment currently employed.

No exaggerated tremor severity perception in functional tremor

Symptoms of functional neurological disorder tend to be variable, yet patients often report them being present constantly and of permanently severe intensity. Furthermore, they typically worsen when they are mentioned or during clinical examination. Such phenomena are sometimes interpreted as indicating symptom exaggeration or even fabrication. To test the notion of inaccurate symptom perception or reporting, we directly compared subjective to objective tremulousness of reaching movements in people with a functional action tremor, people with an organic action tremor and healthy controls. Identical subjective and objective measures were used, thus eliminating any potential metacognitive confounders. Furthermore, we assessed both immediate perceptual experience with a real-time perceptual task, offering the most direct comparison; and near-time retrospective reports as the latter contribute to peoples' overall judgement of their condition. There was no significant difference in subjective compared to objective tremor severity between the three groups for either the real-time or retrospective conditions. People with functional tremor do not perceive or report their tremor in an exaggerated manner, compared to people with an organic tremor or healthy controls. We propose that symptom exacerbation through attentional mechanisms provides an alternative explanation for findings that are frequently attributed to 'exaggeration'.

PND112 Real-World Evidence for Symptomatic Relief in Essential Tremor Using Transcutaneous Afferent Patterned Stimulation Therapy

This analysis evaluated real-world efficacy of Transcutaneous Afferent Patterned Stimulation (TAPS) therapy for symptomatic tremor relief in essential tremor (ET) patients. TAPS is a non-invasive neuromodulation therapy delivering peripheral electrical stimulation tuned to each patient’s tremor physiology. TAPS has been shown to be a safe and effective symptomatic therapy in single-session and longitudinal home-use clinical trials. This analysis evaluated de-identified data from patients using a wrist-worn TAPS device (Cala Health, Burlingame, CA, USA) for at least 30 days. An accelerometer on the device captured tremor severity prior to and immediately following the patient’s therapeutic sessions. Therapy efficacy for each patient was quantified using (i) median improvement in tremor power for that patient’s 25% most severe sessions, (ii) median improvement in device-measured tremor power over all available sessions, and (iii) patient-reported improvements in activities of daily living and quality of life as measured by an opt-in post-market survey. 178 patients met the 30-day inclusion criteria and had at least 10 sessions with accelerometer recordings. Objective tremor severity measurements from 8,828 therapy sessions showed that 90% of patients had a ≥2-fold reduction in tremor power during their most severe sessions (i.e., when therapeutic relief was most needed) and 57% of patients had ≥2-fold reduction in tremor power aggregated over all sessions. 48 of 178 patients responded to the survey. Patients overwhelmingly (92%) reported activities of daily living as the area of most important therapeutic need, with 69% reporting improvement in at least one of eating/drinking/writing and 48% reporting improvement in overall quality of life. The observed tremor relief with home-use of TAPS therapy was reproduced across objective and patient-rated metrics and is consistent with previous clinical trial findings on efficacy of TAPS. These findings suggest TAPS therapy may be a valuable option for ET patients seeking non-invasive, non-pharmacological symptomatic treatment.

Transcutaneous Afferent Patterned Stimulation Therapy Reduces Hand Tremor for One Hour in Essential Tremor Patients.

Essential tremor (ET) patients often experience hand tremor that impairs daily activities. Non-invasive electrical stimulation of median and radial nerves in the wrist using a recently developed therapy called transcutaneous afferent patterned stimulation (TAPS) has been shown to provide symptomatic tremor relief in ET patients and improve patients’ ability to perform functional tasks, but the duration of tremor reduction is unknown. In this single-arm, open-label study, fifteen ET patients performed four hand tremor-specific tasks (postural hold, spiral drawing, finger-to-nose reach, and pouring) from the Fahn-Tolosa-Marin Clinical Rating Scale (FTM-CRS) prior to, during, and 0, 30, and 60 min following TAPS. At each time point, tremor severity was visually rated according to the FTM-CRS and simultaneously measured by wrist-worn accelerometers. The duration of tremor reduction was assessed using (1) improvement in the mean FTM-CRS score across all four tasks relative to baseline, and (2) reduction in accelerometer-measured tremor power relative to baseline for each task. Patients were labeled as having at least 60 min of therapeutic benefit from TAPS with respect to each specified metric if all three (i.e., 0, 30, and 60 min) post-therapy measurements were better than that metric’s baseline value. The mean FTM-CRS scores improved for at least 60 min beyond the end of TAPS for 80% (12 of 15, p = 4.6e–9) of patients. Similarly, for each assessed task, tremor power improved for at least 60 min beyond the end of TAPS for over 70% of patients. The postural hold task had the largest reduction in tremor power (median 5.9-fold peak reduction in tremor power) and had at least 60 min of improvement relative to baseline beyond the end of TAPS therapy for 73% (11 of 15, p = 9.8e–8) of patients. Clinical ratings of tremor severity were correlated to simultaneously recorded accelerometer-measured tremor power (r = 0.33–0.76 across the four tasks), suggesting tremor power is a valid, objective tremor assessment metric that can be used to track tremor symptoms outside the clinic. These results suggest TAPS can provide reductions in upper limb tremor symptoms for at least 1 h post-therapy in some patients, which may improve patients’ ability to perform tasks of daily living.

Outcomes and Adverse Effects of Deep Brain Stimulation on the Ventral Intermediate Nucleus in Patients with Essential Tremor

Objective This study was aimed at identifying the potential outcome predictors, comparing the efficacy in patients with different tremor characteristics, and summarizing the adverse effect rates (AERs) of deep brain stimulation on the ventral intermediate nucleus (VIM-DBS) for essential tremor (ET). Methods An extensive search of articles published to date in 2019 was conducted, and two main aspects were analyzed. Improvement was calculated as a percentage of change in any objective tremor rating scale (TRS) and analyzed by subgroup analyses of patients' tremor characteristics, laterality, and stimulation parameters. Furthermore, the AERs were analyzed as follows: the adverse effects (AEs) were classified as stimulation-related, surgical-related, or device-related effects. A simple regression analysis was used to identify the potential prognostic factors, and a two-sample mean-comparison test was used to verify the statistical significance of the subgroup analyses. Results Forty-six articles involving 1714 patients were included in the meta-analysis. The pooled improvement in any objective TRS score was 61.3% (95% CI: 0.564-0.660) at the mean follow-up visit (20.0 ± 17.3 months). The midline and extremity symptoms showed consistent improvement (P = 0.440), and the results of the comparison of postural and kinetic tremor were the same (P = 0.219). In addition, the improvement in rest tremor was similar to that in action tremor (OR = 2.759, P = 0.120). In the simple regression analysis, the preoperative Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS) scores and follow-up time were negatively correlated with the percentage change in any objective TRS score (P < 0.05). The most common adverse event was dysarthria (10.5%), which is a stimulation-related AE (23.6%), while the rates of the surgical-related and device-related AEs were 6.4% and 11.5%, respectively. Conclusion VIM-DBS is an efficient and safe surgical method in ET, and the efficacy was not affected by the body distribution of tremor, age at surgery, and disease duration. Lower preoperative FTM-TRS scores likely indicate greater improvement, and the effect of VIM-DBS declines over time.

Similar association between objective and subjective symptoms in functional and organic tremor

BackgroundA previous study reported a dramatic mismatch in objectively detected and self-reported tremor duration in patients with functional tremor. As these findings have an important and widespread impact in both clinical care and research, we conducted a validation study with a longer study duration and a larger sample of patients. MethodsFourteen patients with functional tremor and 19 with organic tremor completed a 30 day study period. Objective tremor duration was recorded using a wrist-worn accelerometer. Simultaneously, participants completed a web-based diary five times a day, each time rating their symptom burden since the previous diary entry. ResultsPatients with functional tremor had shorter objective tremor duration compared to patients with organic tremor (21.6% vs 30.7%, P = 0.034). A post-hoc analysis revealed the difference in objective duration was mainly due to patients with essential tremor (37.2%). Subjective symptom burden was not significantly different between functional and organic tremors (38.7 vs 28.7 on a 0–100 VAS scale, P = 0.138). Finally, a mixed model analysis did not reveal significant differences in the association between subjective and objective tremor symptoms (P = 0.168). Conclusionspatients with functional tremor do have an objectively detectable, persistent tremor during daily life activities. Furthermore, they have a similar symptom burden and a similar association between subjective and objective tremor symptoms as patients with organic tremor.

Towards remote monitoring of Parkinson’s disease tremor using wearable motion capture systems

The management of movement disorders is shifting from a centralized-clinical assessment towards remote monitoring and individualized therapy. While a variety of treatment options are available, ranging from pharmaceutical drugs to invasive neuromodulation, the clinical effects are inconsistent and often poorly measured. For instance, the lack of remote monitoring has been a major limitation to optimize therapeutic interventions for patients with Parkinson’s Disease (PD). In this work, we focus on the assessment of full-body tremor as the most recognized PD symptom. Forty PD and twenty two healthy participants were recruited. The main assessment tool was an inertial measurement unit (IMU)-based motion capture system to quantify full-body tremor and to separate tremor-dominant from non-tremor-dominant PD patients as well as from healthy controls. We developed a new measure and evaluated its clinical utility by correlating the results with the Unified Parkinson’s Disease Rating Scale (UPDRS) scores as the gold standard. Significant correlation was observed between the UPDRS and the tremor severity scores for the selected tasks. The results suggest that it is feasible and clinically meaningful to utilize the suggested objective tremor score for the assessment of PD patients. Furthermore, this portable assessment tool could potentially be used in the home environment to monitor PD tremor and facilitate optimizing therapeutic interventions.

Does Added Objective Tremor Monitoring Improve Clinical Outcomes in Essential Tremor Treatment?

Essential tremor (ET) with an estimated prevalence of 2-3% of the US population can impair daily function and negatively impact patient quality of life1. Tremor can be rated by summary measures like the Global Clinical Impression scale for overall tremor severity (CGI-s) and change (CGI-c) and by various tremor-specific rating scales (TRS) such as the Essential Tremor Rating Scale (TETRAS). This article is protected by copyright. All rights reserved.

Evaluating machine learning algorithms estimating tremor severity ratings on the Bain–Findley scale

Tremor is a debilitating symptom of some movement disorders. Effective treatment, such as deep brain stimulation (DBS), is contingent upon frequent clinical assessments using instruments such as the Bain–Findley tremor rating scale (BTRS). Many patients, however, do not have access to frequent clinical assessments. Wearable devices have been developed to provide patients with access to frequent objective assessments outside the clinic via telemedicine. Nevertheless, the information they report is not in the form of BTRS ratings. One way to transform this information into BTRS ratings is through linear regression models (LRMs). Another, potentially more accurate method is through machine learning classifiers (MLCs). This study aims to compare MLCs and LRMs, and identify the most accurate model that can transform objective tremor information into tremor severity ratings on the BTRS. Nine participants with upper limb tremor had their DBS stimulation amplitude varied while they performed clinical upper-extremity exercises. Tremor features were acquired using the tremor biomechanics analysis laboratory (TREMBAL). Movement disorder specialists rated tremor severity on the BTRS from video recordings. Seven MLCs and 6 LRMs transformed TREMBAL features into tremor severity ratings on the BTRS using the specialists’ ratings as training data. The weighted Cohen’s kappa () defined the models’ rating accuracy. This study shows that the Random Forest MLC was the most accurate model ( = 0.81) at transforming tremor information into BTRS ratings, thereby improving the clinical interpretation of tremor information obtained from wearable devices.

Clinical validation of a precision electromagnetic tremor measurement system in participants receiving deep brain stimulation for essential tremor

Tremor is characterized commonly through subjective clinical rating scales. Accelerometer-based techniques for objective tremor measurement have been developed in the past, yet these measures are usually presented as an unintuitive dimensionless index without measurement units. Here we have developed a tool (TREMBAL) to provide quantifiable and objective measures of tremor severity using electromagnetic motion tracking. We aimed to compare TREMBAL’s objective measures with clinical tremor ratings and determine the test–retest reliability of our technique. Eight participants with ET receiving deep brain stimulation (DBS) therapy were consented. Tremor was simultaneously recorded using TREMBAL and video during DBS adjustment. After each adjustment, participants performed a hands-outstretched task (for postural tremor) and a finger–nose task (for kinetic tremor). Video recordings were de-identified, randomized, and shown to a panel of movement disorder specialists to obtain their ratings. Regression analysis and Pearson’s correlations were used to determine agreement between datasets. Subsets of the trial were repeated to assess test–retest reliability. Tremor amplitude and velocity measures were in close agreement with mean clinical ratings (r > 0.90) for both postural and kinetic tremors. Test–retest reliability for both translational and rotational components of tremor showed intra-class correlations >0.80. TREMBAL assessments showed that tremor gradually improved with increasing DBS therapy—this was also supported by clinical observation. TREMBAL measurements are a sensitive, objective and reliable assessment of tremor severity. This tool may have application in clinical trials and in aiding automated optimization of deep brain stimulation.

A STUDY OF EFFICACY OF TREATMENT FOR ESSENTIAL TREMOR USING TREMOROGRAPHY

Background: Essential tremor is one of the most prevalent extrapyramidal disorders, while treatment efficacy in such patients remains low. Clinical polymorphism of essential tremor requires a differentiated treatment approach, that should be implemented with consideration of objective tremor parameters. Aim: To study efficacy of treatment of essential tremor based on tremorography. Materials and methods: We followed up 85 patients with essential tremor (mean age, 69.05±1.2 years) who were treated with anticonvulsants as monotherapy (primidone or topiramate), or with combination treatment with non-selective beta-blockers (propranolol), anxiolytics (hydroxizine, etifoxine) and aminophenylbutyric acid. During the treatment, we assessed changes in functional status by Fahn-Tolosa-Marin Tremor Severity Scale and by tremorography. Results: Under treatment with primidone, there was a decrease in global tremor assessment of postural tremor (p=0.036) and of action tremor (p=0.001). During treatment with topiramate, there was a decrease in global tremor assessment in all tests performed (p<0.0002). Non-specific treatment (anxiolytics) exerted a positive effect on the functional state of patients with essential tremor. Conclusion: Tremor amplitude and duration are the objective parameters that define its severity. The treatment guidelines for essential tremor in the elderly patients have been developed.

Clinicians' Tendencies to Under-Rate Parkinsonian Tremors in the Less Affected Hand.

The standard assessment method for tremor severity in Parkinson’s disease is visual observation by neurologists using clinical rating scales. This is, therefore, a subjective rating that is dependent on clinical expertise. The objective of this study was to report clinicians’ tendencies to under-rate Parkinsonian tremors in the less affected hand. This was observed through objective tremor measurement with accelerometers. Tremor amplitudes were measured objectively using tri-axis-accelerometers for both hands simultaneously in 53 patients with Parkinson’s disease during resting and postural tremors. The videotaped tremor was rated by neurologists using clinical rating scales. The tremor measured by accelerometer was compared with clinical ratings. Neurologists tended to under-rate the less affected hand in resting tremor when the contralateral hand had severe tremor in Session I. The participating neurologists corrected this tendency in Session II after being informed of it. The under-rating tendency was then repeated by other uninformed neurologists in Session III. Kappa statistics showed high inter-rater agreements and high agreements between estimated scores derived from the accelerometer signals and the mean Clinical Tremor Rating Scale evaluated in every session. Therefore, clinicians need to be aware of this under-rating tendency in visual inspection of the less affected hand in order to make accurate tremor severity assessments.

Lithium tremor revisited: pathophysiology and treatment

Tremor occurs frequently as a side-effect of lithium, and it is, however, easily overlooked in the clinical setting. In this article, we attempt to review the pathophysiology and the clinical approach of lithium tremor. We searched the Pubmed and Cochrane Library for relevant articles up to the year 2012. Sixty-four articles including 10 review papers, 3 clinical trials, and 12 case reports were reviewed. Lithium tremor is classified as a postural tremor and subcategorized as an exaggerated physiologic tremor. Differential diagnosis includes metabolic abnormalities, benign essential tremor, Parkinson's disease, and lithium toxicity. Various methods of evaluating lithium tremor and treatment options are discussed. When lithium tremor has developed, thorough history taking, physical examination, and blood examination including serum lithium level are needed. Pharmacotherapy is indicated only in patients with disabling tremor.

An accelerometry-based study of lower and upper limb tremor in Parkinson’s disease

Over the past two decades, several studies have aimed to quantify the kinetic properties of tremor with primary focus on the upper limbs. However, there is a lack of investigation into the properties of tremor in the lower limbs. The objective of this preliminary study was to investigate the properties of oscillatory movement, at rest and in posture, in both the upper and lower limbs of Parkinson’s disease (PD) patients with clinically undetectable to modest rest/postural tremor and healthy controls. PD patients (N=16) and controls (N=8) were examined clinically by a movement disorders specialist and oscillatory movements in all four extremities were evaluated using a portable biaxial accelerometer. While tremor intensity and frequency did not differ between groups, the intraindividual variability of rest and postural tremor frequency in the dexterity-dominant lower limb was lower in people living with PD than in healthy adults. Additionally, rest tremor frequency was discrepant between upper and lower limbs in PD. Our work introduces the possibility that minute variations in lower limb movements, which are imperceptible upon expert clinical exam, can be used to differentiate a diseased sample from a healthy one. These preliminary findings suggest that additional work using objective tremor measurement may improve our understanding of lower limb motor dysfunction in PD and lead to the refinement of current, and the development of new, metrics to enhance early diagnosis, differential diagnosis, and symptom quantification.

Intraoperative optical flow based tremor evaluation - a feasibility study

Deep brain stimulation as treatment for movement related disorders is a common neurosurgical procedure. Nevertheless the targeting procedure can still be optimized as the clinical outcome resulting from intraoperative test stimulation is in general subjectively evaluated. The aim of the present study was to analyse the feasibility of objective tremor evaluation based on optical flow analysis in videos and to compare the results with in parallel performed acceleration measurements. The results demonstrate the feasibility but as well limitations of the applied setup. Solutions to increase the quality in the future are proposed.

Objective tremor registration during DBS surgery for Essential Tremor

Essential Tremor (ET) is characterized by a 4–12-Hz postural and kinetic tremor, most commonly affecting the upper limbs. Deep brain stimulation (DBS) of the thalamus (Vim) has been found to be highly effective in severe/refractory forms of ET. Intra-operative assessment of tremor is performed using clinical methods based on patient and physician perception of tremor intensity. We present for the first time the case of a patient whose tremor was objectively monitored/quantified pre- and intra-operatively using device-based tremor registration to supplement clinical measures. We present the case of a 76-year-old right-handed woman that received unilateral (left-sided) DBS of the ventrointermediate (Vim) nucleus of thalamus (Vim) for medically refractory ET. Tremor was monitored with an accelerometer-based Tremor Pen ®, which is part of a simple portable device (CATSYS 2000 System ®, Danish Product Development Ltd., DK, www.catsys.dk). The patient was asked to perform tasks for tremor evaluation before and during thalamic DBS. Tremor quantification revealed a significant improvement (34.7-fold) in the contralateral (right) limb following macro-stimulation. No significant improvement was registered in the ipsilateral (non-operated) side. Simple electronic tremor registration methods during DBS of the Vim nucleus of the thalamus may supplement the existing methodology that is solely based on subjective measures derived from clinical observations.

Poster Abstract #4: Development of Long-Duration Accelerometry for Use in Clinical Trials of Essential Tremor

Background Essential tremor (ET) is a common movement disorder affecting 0.4% of the general population and 14% of people 65 years and older. Current therapies provide modest tremor suppression and are often accompanied by intolerable side effects. Key to the success of future studies is the development of objective biomarkers to assess tremor in a sensitive and unbiased manner. Numerous subjective and objective tremor measures are available, including laboratory-based accelerometry, electromyography, spirography, and surveys assessing quality of life or impact on activities of daily living. The utility of objective measures are limited by time and expense, and subjective measures lack sensitivity and rely heavily on standardization of ratings or patient responses. Furthermore, all these methods are temporally biased, in that they reflect only brief time intervals. We hypothesized that portable uniaxial monitoring devices could be used to reliably measure tremor over long durations in patients with ET. Methods The study population consisted of adults with ET who underwent an ethanol challenge to assess tremor response, prior to enrollment in a clinical trial at NIH. Wrist-based accelerometers were used (Cambridge Neurotechnology, Cambridge, UK) to record the intensity and duration of tremor and nontremor movements. We developed an algorithm to calculate a Tremor Severity Score (TSS) characterizing tremor patterns over extended time periods. To assess individual subject changes, we normalized the TSS at each timepoint by each subject's own baseline TSS. The primary outcome measures were TSS at baseline, 0–30, 30–60, and 60–90 minutes after ethanol challenge. Results Thirteen patients were included in the analysis. Mean percent reduction in tremors from baseline TSS was 165%, 408%, and 423% at 0–30, 30–60, and 60–90 minutes after ethanol challenge, respectively. A post hoc linear regression of the TSS total score and baseline TSS revealed high correlation ( R 2 = 0.77). Conclusions Our results show that the TSS, based on long-duration accelerometry data, provides a sensitive and reliable method for objectively measuring ET outcomes. This method could serve as a model for the development of low-cost, high-throughput clinical trials. Further work is needed to validate this method with tremor measures in current use.