Measurement Of Tremor Research Articles

Using a smartwatch and smartphone to assess early Parkinson’s disease in the WATCH-PD study over 12 months

Digital measures may provide objective, sensitive, real-world measures of disease progression in Parkinson’s disease (PD). However, multicenter longitudinal assessments of such measures are few. We recently demonstrated that baseline assessments of gait, tremor, finger tapping, and speech from a commercially available smartwatch, smartphone, and research-grade wearable sensors differed significantly between 82 individuals with early, untreated PD and 50 age-matched controls. Here, we evaluated the longitudinal change in these assessments over 12 months in a multicenter observational study using a generalized additive model, which permitted flexible modeling of at-home data. All measurements were included until participants started medications for PD. Over one year, individuals with early PD experienced significant declines in several measures of gait, an increase in the proportion of day with tremor, modest changes in speech, and few changes in psychomotor function. As measured by the smartwatch, the average (SD) arm swing in-clinic decreased from 25.9 (15.3) degrees at baseline to 19.9 degrees (13.7) at month 12 (P = 0.004). The proportion of awake time an individual with early PD had tremor increased from 19.3% (18.0%) to 25.6% (21.4%; P < 0.001). Activity, as measured by the number of steps taken per day, decreased from 3052 (1306) steps per day to 2331 (2010; P = 0.16), but this analysis was restricted to 10 participants due to the exclusion of those that had started PD medications and lost the data. The change of these digital measures over 12 months was generally larger than the corresponding change in individual items on the Movement Disorder Society—Unified Parkinson’s Disease Rating Scale but not greater than the change in the overall scale. Successful implementation of digital measures in future clinical trials will require improvements in study conduct, especially data capture. Nonetheless, gait and tremor measures derived from a commercially available smartwatch and smartphone hold promise for assessing the efficacy of therapeutics in early PD.

Acoustic Voice Tremor index in the measurement of voice tremor: Development and validation

Acoustic Voice Tremor index in the measurement of voice tremor: Development and validation

Bilateral Deep Brain Stimulation of the Ventral Intermediate Nucleus of the Thalamus Improves Objective Acoustic Measures of Essential Vocal Tremor.

Deep brain stimulation of the ventral intermediate nucleus of the thalamus (VIM-DBS) is an established treatment for medically refractory essential tremor. However, the effect of VIM-DBS on vocal tremor remains poorly understood, with results varying by method of vocal tremor assessment and stimulation laterality. This single-center study measures the effect of bilateral VIM-DBS on essential vocal tremor using blinded objective acoustic voice analysis. Ten patients with consecutive essential tremor with comorbid vocal tremor receiving bilateral VIM-DBS underwent voice testing before and after implantation of DBS in this prospective cohort study. Objective acoustic measures were extracted from the middle one second of steady-state phonation including cepstral peak prominence, signal-to-noise ratio, percentage voicing, tremor rate, extent of fundamental frequency modulation, and extent of intensity modulation. DBS surgery was performed awake with microelectrode recording and intraoperative testing. Postoperative voice testing was performed after stable programming. Patients included 6 female and 4 male, with a mean age of 67 ± 6.7 years. The VIM was targeted with the following coordinates relative to the mid-anterior commissure:posterior commissure point: 13.2 ± 0.6 mm lateral, 6.2 ± 0.7 mm posterior, and 0.0 mm below. Mean programming parameters were amplitude 1.72.0 ± 0.6 mA, pulse width 63.0 ± 12.7 µs, and rate 130.6 ± 0.0 Hz. VIM-DBS significantly improved tremor rate from 4.43 ± 0.8 Hz to 3.2 ± 0.8 Hz ( P = .001) CI (0.546, 1.895), jitter from 1 ± 0.94 to 0.53 ± 0.219 ( P = .02) CI (-0.124, 1.038), cepstral peak prominence from 13.6 ± 3.9 to 18.8 ± 2.9 ( P = .016) CI (-4.100, -0.235), signal-to-noise ratio from 15.7 ± 3.9 to 18.5 ± 3.7 ( P = .02) CI (-5.598, -0.037), and articulation rate from 0.77 ± 0.2 to 0.82 ± .14 ( P = .04) CI (-0.097, 0.008). There were no major complications in this series. Objective acoustic voice analyses suggest that bilateral VIM-DBS effectively reduces vocal tremor rate and improves voicing. Further studies using objective acoustic analyses and laryngeal imaging may help refine surgical and stimulation techniques and evaluate the effect of laterality on vocal tremor.

Patient-reported treatment satisfaction in essential tremor: levels of satisfaction and predictors of satisfaction.

Although managing symptoms is paramount for both essential tremor (ET) patients and their healthcare providers, studies of treatment satisfaction are surprisingly lacking. We evaluated the satisfaction of patients who used a range of treatments and assessed the relation of a wide array of factors to satisfaction. One hundred four ET participants (age = 74.5 ± 10.2 years) completed a battery of self-report items. These included demographic information, measures of tremor and clinical history, psychological state, current ET treatment, and a series of questions about satisfaction with treatment. Analyses of responses to the four current treatment satisfaction questions revealed that the proportion of participants who were satisfied ranged from 35.0% to 57.3% (i.e., approximately 1/3 to 1/2); conversely, the proportion who were dissatisfied ranged from 9.2% to 37.0%. The remainder were neutral. Higher satisfaction levels were observed in participants who were included in treatment selection and who had undergone deep brain stimulation surgery, p's < 0.05. Lower levels of satisfaction were found in participants with a negative psychological state, higher self-rated tremor severity, head/voice/jaw tremors, and more severe physical side effects; and who used botulinum toxin therapy, p's < 0.05. Between 1/3 and 1/2 of patients were satisfied with their treatment, whereas up to 1/3 were dissatisfied. In this initial exploration of correlates of treatment satisfaction in ET patients, we identified a number of associations between satisfaction and clinical, psychological and treatment variables. Additional research is warranted to further explore the nature of these relations over time.

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.

Mapping Relevance of Digital Measures to Meaningful Symptoms and Impacts in Early Parkinson's Disease.

Adoption of new digital measures for clinical trials and practice has been hindered by lack of actionable qualitative data demonstrating relevance of these metrics to people with Parkinson's disease. This study evaluated of relevance of WATCH-PD digital measures to monitoring meaningful symptoms and impacts of early Parkinson's disease from the patient perspective. Participants with early Parkinson's disease (N = 40) completed surveys and 1:1 online-interviews. Interviews combined: 1) symptom mapping to delineate meaningful symptoms/impacts of disease, 2) cognitive interviewing to assess content validity of digital measures, and 3) mapping of digital measures back to personal symptoms to assess relevance from the patient perspective. Content analysis and descriptive techniques were used to analyze data. Participants perceived mapping as deeply engaging, with 39/40 reporting improved ability to communicate important symptoms and relevance of measures. Most measures (9/10) were rated relevant by both cognitive interviewing (70-92.5%) and mapping (80-100%). Two measures related to actively bothersome symptoms for more than 80% of participants (Tremor, Shape rotation). Tasks were generally deemed relevant if they met three participant context criteria: 1) understanding what the task measured, 2) believing it targeted an important symptom of PD (past, present, or future), and 3) believing the task was a good test of that important symptom. Participants did not require that a task relate to active symptoms or "real" life to be relevant. Digital measures of tremor and hand dexterity were rated most relevant in early PD. Use of mapping enabled precise quantification of qualitative data for more rigorous evaluation of new measures.

Effect of Ventral Intermediate Nucleus Deep Brain Stimulation on Vocal Tremor in Essential Tremor.

There is a paucity of literature examining the effect of Ventral Intermediate Nucleus (VIM) deep brain stimulation (DBS) on voice in patients with vocal tremor (VT). Investigate the effect of unilateral and bilateral VIM DBS on voice in patients with Essential Tremor (ET) and VT. All patients receiving VIM DBS surgery underwent voice evaluation pre- and six-months post-operatively. We collected patient-reported quality-of-life outcome measures and acoustic voice measures of sustained phonation and connected speech. Acoustic measures specific to VT included amplitude tremor intensity index (ATRI), frequency tremor intensity index (FTRI), rate and extent of F0 modulation, and rate and extent of intensity modulation. Five patients, age 72.8 ± 2.6 years, 4 female, 1 male with mean disease duration of 29 ± 26.2 years met the inclusion criteria and were included. Two subjects had bilateral procedure and three had unilateral. We observed significant improvements in measures of vocal tremor including ATRI, FTRI, rate of F0 modulation, rate of intensity modulation, and extent of intensity modulation, as well as patient reported voice-related quality of life measured by VHI-10. Bilateral VIM DBS cases showed greater improvement in VT than unilateral cases. Both unilateral and bilateral VIM DBS resulted in significant improvement of VT, with more improvement demonstrated in patients having bilateral as compared to unilateral VIM DBS. In addition, patients also reported significant improvements in voice-related quality of life. If larger studies confirm our results, VIM DBS has the potential to become a treatment specifically for disabling VT.

Feasibility of Magnetic Resonance-Compatible Accelerometers to Monitor Tremor Fluctuations During Magnetic Resonance-Guided Focused Ultrasound Thalamotomy: Technical Note.

Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is used to treat essential tremor and tremor-dominant Parkinson disease. Feedback is collected throughout the procedure to verify the location of the target and completeness of response; however, variability in clinical judgments may underestimate or overestimate treatment response. To objectively quantify joint motion after each sonication using accelerometers secured to the contralateral upper extremity in an effort to optimize MRgFUS treatment. Before the procedure, 3 accelerometers were secured to the patient's arm, forearm, and index finger. Throughout the procedure, tremor motion was regularly recorded during postural and kinetic tremor testing and individual joint angle measures were modeled. The joint angle from each accelerometer was compared with baseline measurements to assess changes in angles. Subsequent adjustments to the target location and sonication energy were made at the discretion of the neurosurgeon and neuroradiologist. Intraoperative accelerometer measurements of hand tremor from 18 patients provided quantified data regarding joint angle reduction: 87.3%, 94.2%, and 86.7% for signature writing, spiral drawing, and line drawing tests, respectively. Target adjustment based on accelerometer monitoring of the angle at each joint added substantial value toward achieving optimal tremor reduction. Real-time accelerometer recordings collected during MRgFUS thalamotomy offered objective quantification of changes in joint angle after each sonication, and these findings were consistent with clinical judgments of tremor response. These results suggest that this technique could be used for fine adjustment of the location of sonication energy and number of sonications to consistently achieve optimal tremor reduction.

Automated analysis of pen-on-paper spirals for tremor detection, quantification, and differentiation

Objective: To develop an automated algorithm to detect, quantify, and differentiate between tremor using pen-on-paper spirals. Methods: Patients with essential tremor (n = 25), dystonic tremor (n = 25), Parkinson’s disease (n = 25), and healthy volunteers (HV, n = 25) drew free-hand spirals. The algorithm derived the mean deviation (MD) and tremor variability from scanned images. MD and tremor variability were compared with 1) the Bain and Findley scale, 2) the Fahn–Tolosa–Marin tremor rating scale (FTM–TRS), and 3) the peak power and total power of the accelerometer spectra. Inter and intra loop widths were computed to differentiate between the tremor. Results: MD was higher in the tremor group (48.9 ± 26.3) than in HV (26.4 ± 5.3; p &lt; 0.001). The cut-off value of 30.3 had 80.9% sensitivity and 76.0% specificity for the detection of the tremor [area under the curve: 0.83; 95% confidence index (CI): 0.75, 0.91, p &lt; 0.001]. MD correlated with the Bain and Findley ratings (rho = 0.491, p = 0 &lt; 0.001), FTM–TRS part B (rho = 0.260, p = 0.032) and accelerometric measures of postural tremor (total power, rho = 0.366, p &lt; 0.001; peak power, rho = 0.402, p &lt; 0.001). Minimum Detectable Change was 19.9%. Inter loop width distinguished Parkinson’s disease spirals from dystonic tremor (p &lt; 0.001, 95% CI: 54.6, 211.1), essential tremor (p = 0.003, 95% CI: 28.5, 184.9), or HV (p = 0.036, 95% CI: -160.4, -3.9). Conclusion: The automated analysis of pen-on-paper spirals generated robust variables to quantify the tremor and putative variables to distinguish them from each other. Significance: This technique maybe useful for epidemiological surveys and follow-up studies on tremor.

Method of Еmotional State Assessment Using a Complex of Psychophysiological and Tensotremorometric Methods

The object of research is emotional tension. The subject of the study is assessment of emotional tension in the process of presentation of emotionally significant stimuli in the form of images and sounds according to the parameters of physiological activity and tensotremorometry in the process of maintaining isometric effort. Particular attention is paid to the consideration of methods of determination of tremor and its connection with emotional tension. Key aspects are the consideration of the key frequency range of physiological tremor analysis 8-16 hertz, methods of tremor measurement such as accelerometry, tensotremorometry, electromyography. Studies of the relationship between tensotremorometry on the frequency range of physiological tremor and emotional tension are considered. We propose a new method for analyzing tremor according to tensotremorometry data using the sliding window method and filtering the frequencies characteristic of physiological tremor. Methods of recording physiological activity in the form of photoplethysmography and skin electrical activity were used for reliability of the results obtained. We described and confirmed the connection between emotional tension during the demonstration of meaningful stimuli and finger tremor, while holding a given force in an isometric condition. The new technique has wide possibilities for use in the psychological and clinical fields, in particular, in detection of hidden information, assessment of the stress resistance of personnel, and determination of the functional state of a person, as well as in the study of the psycho-emotional state of students.

A Review of Techniques Used to Suppress Tremor

The most frequent movement disorder is Tremor, which has an increased incidence and prevalence in people over 65 who have Parkinson's disease or essential tremors. Although not life-threatening, it prevents patients from performing their daily activities. An overview of different types of tremors and their treatment in medical and surgical views are discussed in this paper with a review of the stimulation nerves and muscles technique. Then a look at tremor detection and measurement methods are considered with a review of the medical devices' mechanism of action that is placed as a substitute treatment for patients that have a low response to medications and surgical treatment to provide effective and safe tremor suppression.

Study of Local Site Conditions for Seismic Hazard Assessment at the BHU Campus, Varanasi, North India, using Ambient Noise Measurements

Abstract The ambient noise measurement approach has been applied for detailed seismic hazard mapping in the Banaras Hindu University (BHU), campus, Varanasi. Thirty three single stations, two standard penetration tests (SPT), and two array micro tremor measurements were carried out to determine the local site characteristics. In this study, H/V spectral ratio confirms that the sites have an average predominant frequency of around 0.53Hz and an average amplitude of 7.94. These resonant frequencies are related to the thickness of the sediments in the region. Based on the available lithological data and estimated sub-surface structures, shallow and deeper cross-sections through two profiles within the BHU campus are presented. The estimated shallow sub-surface structures are correlated with 150 m boreholes data for a better understanding of sub-soil stratification. These studies show the presence of clay up to a depth of ~40 m, mixed with sand and pebbles at some locations, followed by layers of sand, and clay with pebbles ~200 m. Findings of the present study are also well correlated with inverted shear wave velocity profiles. The Vs observed from the array measurements and N-value from standard penetration test (SPT) are positively correlated to each other and give a better understating of Vs. Thus, the inverted 1-D shear velocity models clearly show low shear wave velocity having sediment thickness of 30 to 40 meters. Finally, fundamental frequency, amplification, vulnerability index, and shear wave velocity maps are presented. Additionally, the borehole data are used to calibrate the results of the present study of the shallow sub-surface structure. Subsequently, computed maps are a very useful tool for engineers to quantify the intensity of earthquake ground motion, which will be helpful to determine the capacity of buildings to resist earthquakes.

Characterization of Parkinson's Disease using spectral features of kinetic tremor: correlation of on-line digitized handwriting and classical motor scales

Tremor is one of the motor impairments of Parkinson’s disease (PD). To date, kinetic tremor in PD is barely examined and there is lack of information on the relation between its severity and scales related to specific motor deficits [1]. In this study, we aimed at investigating the correlation between handwriting-related kinetic tremor and motor score measures by motor part of Unified Parkinson's Disease Rating Scale (UPDRS-III) [2], using a digitizing tablet. In this preliminary study, eight PD patients (7 M/1 F; age 74.5±8 years) draw an accurate Archimedes’ Spiral (AS) and fast, overlapped Circles (C) for a duration of 15 seconds. All patients underwent motor deficit assessment using UPDRS-III. Power Spectral Density of both velocity and acceleration profiles in their horizontal, vertical, and curvilinear components was estimated by using Welch’s method, with a Hamming window on intervals of 5 s and a 50% overlap. To analyze the power distribution related to different movement-associated phenomena, the ratio between two frequency bands (BME/BT) and the BT bandwidth (BW) were calculated for each subject. BME is the band of voluntary Movement Execution required by the task, ranging from 0.2 to 4 Hz, and BT is the band associated with involuntary Tremor, ranging from 4.0 to 12 Hz [3]. Normalized Jerk, a classic kinematic feature representing handwriting fluidity, was also estimated. The correlation between the parameters and UPDRS-III scores were assessed using Spearman’s rank correlation coefficients. All the evaluations were conducted in the pharmacological on state of PD patients. A positive correlation was found between Jerk and UPDRS-III scores (Table 1). On the contrary BME /B T correlates negatively with motor scale scores in horizontal and vertical velocities (Vx, Vy) for both tasks, vertical and curvilinear acceleration (Ay, Ac) for AS task, horizontal and vertical acceleration (Ax, Ay) for C task. Only Ay of C task shows correlation with motor scores. The results highlight that the severity of motor deficits in PD patients, as assessed by a widely employed motor scale, correlates with the outcomes of spectral and kinematic analysis of handwriting that indicate a loss of fluency, an increased power at BT level and a thinning of the spectral peak of B T . This suggests that handwriting assessment of parkinsonian dysgraphia can be used to implement clinical evaluation and represents a non-invasive, low-cost method for the identification of objective and reproducible biomarkers of kinetic tremor.

Real-World Evidence of Transcutaneous Afferent Patterned Stimulation for Essential Tremor.

Background:Transcutaneous afferent patterned stimulation (TAPS) is a prescription, wrist-worn device-delivered, non-invasive neuromodulation therapy for treatment of hand tremor in patients with essential tremor (ET). This retrospective post-market surveillance study evaluated real-world effectiveness of TAPS from patients using therapy on-demand for at least 90 days between August 2019 through June 2021.Methods:Demographics were summarized from TAPS prescriptions received from the patient’s healthcare provider. Therapy usage and effectiveness were analyzed from device logs, which included tremor measurements from onboard motion sensors. Tremor history and patient-reported outcomes were assessed from a voluntary survey.Results:A total of 321 patients (average age 71 years, 32% female) met the criteria for this analysis, 216 of whom had tremor measurements available for analysis and 69 of whom completed the survey. Total usage period ranged from 90 to 663 days, with 28% of patients using the device for over one year. Patients used therapy 5.4 ± 4.5 (mean ± 1 standard deviation) times per week. TAPS reduced tremor power by 71% (geometric mean) across all sessions, with 59% of patients experiencing >50% tremor reduction after their sessions. Eighty-four percent (84%) of patients who returned the voluntary survey reported improvement in at least one of eating, drinking, or writing, and 65% of patients reported improvement in quality of life. Self-reported device-related safety complaints were consistent with adverse events in prior clinical trials.Discussion:Real-world evidence is consistent with prior clinical trials and confirms TAPS provides safe and effective tremor control for many patients with ET. Future work assessing multi-year safety and effectiveness would be valuable to extend these data.

Tremor, finger and hand dexterity and force steadiness, do not change after mental fatigue in healthy humans.

The effects of mental fatigue have been studied in relation to specific percentages of maximal aerobic or anaerobic efforts, maximal voluntary contractions or the performance of sport specific skills. However, its effects on tremor, dexterity and force steadiness have been only marginally explored. The present work aimed at filling this gap. In twenty-nine young individuals, measurement of postural, kinetic and isometric tremor, pinch force steadiness and finger and hand dexterity were performed before and after either 100 min of mental fatigue or control tasks. During the interventions blood pressure, oxygen saturation and heart rate and perceived effort in continuing the task were recorded every 10 minutes. Tremor was analysed in both time (standard deviation) and frequency domain (position, amplitude and area of the dominant peak) of the acceleration signal. Finger dexterity was assessed by Purdue pegboard test and hand dexterity in terms of contact time in a buzz wire exercise. Force steadiness was quantified as coefficient of variation of the force signal. Postural, kinetic and isometric tremors, force steadiness and dexterity were not affected. Higher oxygen saturation values and higher variability of heart rate and blood pressure were found in the intervention group during the mental fatigue protocol (p < .001). The results provide no evidence that mental fatigue affects the neuromuscular parameters that influence postural, kinetic or isometric tremor, force steadiness and dexterity when measured in single-task conditions. Increased variability in heart rate may suggest that the volunteers in the intervention group altered their alert/stress state. Therefore, it is possible that the alterations that are commonly observed during mental fatigue, and that could have affected tremor, steadiness and dexterity only last for the duration of the cognitive task and are not detectable anymore soon after the mental task is terminated.

Cerebello-Thalamo-Cortical Network Dynamics in the Harmaline Rodent Model of Essential Tremor.

Essential Tremor (ET) is a common movement disorder, characterised by a posture or movement-related tremor of the upper limbs. Abnormalities within cerebellar circuits are thought to underlie the pathogenesis of ET, resulting in aberrant synchronous oscillatory activity within the thalamo-cortical network leading to tremors. Harmaline produces pathological oscillations within the cerebellum, and a tremor that phenotypically resembles ET. However, the neural network dynamics in cerebellar-thalamo-cortical circuits in harmaline-induced tremor remains unclear, including the way circuit interactions may be influenced by behavioural state. Here, we examined the effect of harmaline on cerebello-thalamo-cortical oscillations during rest and movement. EEG recordings from the sensorimotor cortex and local field potentials (LFP) from thalamic and medial cerebellar nuclei were simultaneously recorded in awake behaving rats, alongside measures of tremor using EMG and accelerometery. Analyses compared neural oscillations before and after systemic administration of harmaline (10 mg/kg, I.P), and coherence across periods when rats were resting vs. moving. During movement, harmaline increased the 9–15 Hz behavioural tremor amplitude and increased thalamic LFP coherence with tremor. Medial cerebellar nuclei and cerebellar vermis LFP coherence with tremor however remained unchanged from rest. These findings suggest harmaline-induced cerebellar oscillations are independent of behavioural state and associated changes in tremor amplitude. By contrast, thalamic oscillations are dependent on behavioural state and related changes in tremor amplitude. This study provides new insights into the role of cerebello-thalamo-cortical network interactions in tremor, whereby neural oscillations in thalamocortical, but not cerebellar circuits can be influenced by movement and/or behavioural tremor amplitude in the harmaline model.

Are smartphones and machine learning enough to diagnose tremor?

Patients with essential tremor (ET), Parkinson's disease (PD) and dystonic tremor (DT) can be difficult to classify and often share similar characteristics. To use ubiquitous smartphone accelerometers with and without clinical features to automate tremor classification using supervised machine learning, and to use unsupervised learning to evaluate if natural clusterings of patients correspond to assigned clinical diagnoses. A supervised machine learning classifier was trained to classify 78 tremor patients using leave-one-out cross-validation to estimate performance on unseen accelerometer data. An independent cohort of 27 patients were also studied. Next, we focused on a subset of 48 patients with both smartphone-based tremor measurements and detailed clinical assessment metrics and compared two separate machine learning classifiers trained on these data. The classifier yielded a total accuracy of 74.4% and F1-score of 0.74 for a trinary classification with an area under the curve of 0.904, average F1-score of 0.94, specificity of 97% and sensitivity of 84% in classifying PD from ET or DT. The algorithm classified ET from non-ET with 88% accuracy, but only classified DT from non-DT with 29% accuracy. A poorer performance was found in the independent cohort. Classifiers trained on accelerometer and clinical data respectively obtained similar results. Machine learning classifiers achieved a high accuracy of PD, however moderate accuracy of ET, and poor accuracy of DT classification. This underscores the difficulty of using AI to classify some tremors due to lack of specificity in clinical and neuropathological features, reinforcing that they may represent overlapping syndromes.

A Preliminary Study on the Effect of Bhramari Pranayama on Voice of Prospective Singers

Bhramari Pranayama (BP) is a yogic breathing technique that involves producing a vibrating constant pitch sound emulating the buzzing of bumblebee. Since BP deals with breathing and humming in the sustained pitch, it is hypothesized that it can have implications for improving voice quality in individuals. However, there is a dearth of research available to support this assumption. Further, there are no published reports on the effect of BP on voice quality in prospective singers group. Current study was taken up to explore the effect induced by BP in the voice characteristics/quality of prospective singers. The participants included 30 healthy prospective singers in the age range of 18-35 years who were attending music schools within the state of Karnataka, India. BP regimen was demonstrated to all individuals. The voice recordings of the participants were obtained on day 0 and day 30 of BP practice. Acoustic analysis was performed to obtain AVQI and its constituent parameters and voice parameters from the MDVP program. Among the AVQI and its constituent parameters, Cepstral peak prominence-smoothed, Slope LTAS, and Tilt LTAS showed significant differences before and after BP. MDVP showed a significant difference in tremor measures before and after the practice of BP. Results of the present study indicated positive effects of BP on the voice characteristics of the prospective singers and it is reflected in objective acoustic outcome parameters of AVQI and MDVP. This supports the assumption that BP which involves yogic breathing will have beneficial effects on vocal physiology in turn leading to improved voice quality in these individuals. However, it is of future interest to validate these findings on larger samples and populations with different outcome measures. Also, future studies are warranted to verify the efficacy of BP in improving vocal quality and vocal efficiency of individuals with dysphonia.

248 Tremor frequency can be measured using smartphone video

Textbook descriptions of tremulous disorders typically mention the tremor frequencies characteristic of particular conditions, and determination of frequency can aid diagnosis. However, current clinical practice does not involve routine accelerometry or EMG for most tremulous patients, or use of smartphone accel- erometer, and the human eye cannot accurately measure tremor frequency.37 hand videos were recorded with smartphone camera from 5 essential tremor participants, 10 Parkin- son’s participants and 1 functional tremor participant, either showing a hand resting or held in posture. Tremor was simiultaneously measured using a commercially available accelerometer for clinical use (‘Natus Neurology’). The computing technique of ‘optical flow’ was applied to the smartphone video to measure pixel movement over time in two directions perpendicular to the long axis of the hand. Dominant frequencies were extracted from smartphone video optical flow and from clinic accelerometer data using fast Fourier transform.Bland-Altman analysis showed a mean of the difference in measurements between smartphone video (pixel optical flow) and accelerometer of 0.05 Hz (SD 0.16 Hz) with 95% confidence intervals for this mean difference of -0.26 Hz to +0.36 Hz.We demonstrate excellent agreement between our computing method for smartphone video tremor measurement and the gold standard of accelerometry. Our computing technique suggests that neu- rologists already have ‘point and press’ contactless equipment in their pocket that has the potential to augment routine clinical assessment by measuring tremor frequency.stefanwilliams@doctors.org.uk

Intraoperative Quantification of MDS-UPDRS Tremor Measurements Using 3D Accelerometry: A Pilot Study.

The most frequently used method for evaluating tremor in Parkinson’s disease (PD) is currently the internationally standardized Movement Disorder Society—Unified PD Rating Scale (MDS-UPDRS). However, the MDS-UPDRS is associated with limitations, such as its inherent subjectivity and reliance on experienced raters. Objective motor measurements using accelerometry may overcome the shortcomings of visually scored scales. Therefore, the current study focuses on translating the MDS-UPDRS tremor tests into an objective scoring method using 3D accelerometry. An algorithm to measure and classify tremor according to MDS-UPDRS criteria is proposed. For this study, 28 PD patients undergoing neurosurgical treatment and 26 healthy control subjects were included. Both groups underwent MDS-UPDRS tests to rate tremor severity, while accelerometric measurements were performed at the index fingers. All measurements were performed in an off-medication state. Quantitative measures were calculated from the 3D acceleration data, such as tremor amplitude and area-under-the-curve of power in the 4–6 Hz range. Agreement between MDS-UPDRS tremor scores and objective accelerometric scores was investigated. The trends were consistent with the logarithmic relationship between tremor amplitude and MDS-UPDRS score reported in previous studies. The accelerometric scores showed a substantial concordance (>69.6%) with the MDS-UPDRS ratings. However, accelerometric kinetic tremor measures poorly associated with the given MDS-UPDRS scores (R2 < 0.3), mainly due to the noise between 4 and 6 Hz found in the healthy controls. This study shows that MDS-UDPRS tremor tests can be translated to objective accelerometric measurements. However, discrepancies were found between accelerometric kinetic tremor measures and MDS-UDPRS ratings. This technology has the potential to reduce rater dependency of MDS-UPDRS measurements and allow more objective intraoperative monitoring of tremor.