Measurement Of Tremor Research Articles

Vocal Characteristics of Elderly Women Engaged in Aerobics in Private Institutions of Salvador, Bahia

To characterize the voice of elderly people engaged in aerobics. Collection of phonation /a:/ from 58 elderly people engaged in aerobics for perceptual voice analysis (RASATI scale) and computed acoustics (Multi Dimensional Voice Program Advanced, software of Kay Pentax®, that analyzes up to 33 measures, proposing normal ranges according to sex). The Spearman correlation test was used, with significance level of 5%. The association between auditory-perceptual assessment of voice and acoustic parameters was not statistically significant but showed less vocal quality deviations. The association between acoustic measures and age was only statistically significant result for the measurement of fundamental frequency (f0) and maximum f0 (fhi). There was no correlation between time of aerobics and acoustic measures, but there was correlation of those measurements with age. There was a statistically significant positive correlation between f0 and fhi with minimal roughness and standard deviation of f0 with hoarseness, breathiness, and asthenia; jitter and shimmer measures with hoarseness, breathiness, and asthenia; noise measurements with hoarseness, breathiness, and harshness; measures of breaking voice hoarseness and breathiness; measures of voiceless segments with hoarseness and asthenia; measures of subharmonic with hoarseness; and measures of vocal tremor with breathiness, asthenia, and instability. There was a significant negative correlation between minimum f0 with breathiness; jitter measures with tension; and soft phonation index with roughness and instability. Elderly women engaged in aerobics showed mostly normal voice, with most values of acoustic measures within normal and positive correlations between perceptual and auditory vocals and acoustic aspects that suggest instability, noise, and vocal tremor.

A new method for evaluating postural hand tremor based on CMOS camera

The balance and stability of body and limbs are controlled by nervous system. The postural tremor measurement has some supplementary diagnostic value for neuropathy, and has a benefit for stability assessment of limbs. To observe the characteristics of postural hand tremor in different cases, and diagnose those functions of nervous system, a measuring system is required to provide an accurate measuring method and those effective characteristic parameters. This article provides descriptions on the design and performance of a new hand tremor measuring system developed to meet such stringent requirements. The new non-contact measuring system is developed from optical measuring technology using a CMOS camera. Details of measuring process and data processing algorithms are provided. Those parameters are proposed to quantify characteristics of postural hand tremor. To illustrate those parameters, a healthy youth and an elderly patient with hypertension and lacunar cerebral infarction was as control. The repeatability of this measuring system has been investigated as well.

Unobtrusive Tremor Detection While Gesture Controlling a Robotic Arm

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00270001/12.jpg"" width=""300"" />Gesture based validation</div> A light weight robotic arm (Jaco) has been interfaced with a novel gesture detection sensor (Leap Motion Controller), substituting complicated conventional input devices, i.e., joysticks and pads. Due to the enhanced precision and high throughput capabilities of the Leap Motion Controller, the unobtrusive measurement of physiological tremor can be extracted. An algorithm was developed to constantly detect and indicate potential user hand tremor patterns in real-time. Additionally a calibration algorithm was developed to allow an optimum mapping between the user hand movement, tracked by the Leap Motion Controller, and the Jaco arm, by filtering unwanted oscillations, allowing for a more natural human-computer interaction. </span>

Unobtrusive Tremor Detection and Measurement via Human-Machine Interaction

Abstract Elderly people possess enhanced working experience during their living. Therefore it is a big value loss for companies, when such individuals get into retirement. Through the development of a novel workspace, which allows elderly people to maintain work- active in a decentralized manner, e.g. from home, this limitation, caused by the demographic change, can be overcome. Additionally most people in advancing age usually suffer from different diseases. By using recent computer-user interfaces like motion sensors devices or smart glasses, it is possible to measure physiological readings unobtrusively while gesture or intuitively controlling a personal computer or system. The authors propose the implementation of a tremor detection system embedded in this decentralized workspace, using the Leap Motion controller as well as the Vuzix Smart Glasses M100.

Cerebellar continuous theta burst stimulation in essential tremor.

The pathophysiological mechanisms of essential tremor (ET) are still not entirely clear. In the present study, we aimed to investigate the cerebello-thalamo-cortical connectivity in ET using the cerebellar continuous theta burst stimulation (cTBS) and possible effects on tremor and reaching movements. Sixteen patients with ET and 11 healthy subjects underwent two experimental sessions: (i) cTBS over the right cerebellar hemisphere (real cerebellar cTBS) and (ii) cTBS over the neck muscles (sham cerebellar cTBS). The two sessions were performed at least 1week apart. The effects of real and sham cerebellar cTBS were quantified as excitability changes on contralateral primary motor cortex, as well as possible changes of postural tremor and reaching movements on the ipsilateral arm. Primary motor cortex excitability was assessed by recording the input/output curve of the motor-evoked potentials from the right first dorsal interosseous muscle. Tremor was rated clinically. Objective assessment of tremor and reaching movements was performed using kinematic techniques. Real cerebellar cTBS reduced the excitability in the contralateral primary motor cortex in healthy subjects though not in patients with ET. There was no significant change in tremor severity and reaching movements, as assessed by clinical examination or kinematic techniques, after real or sham cerebellar cTBS in patients with ET. Finally, there was no correlation between individual changes of M1 excitability and kinematic measures of tremor and reaching movement abnormalities in patients with ET. The results suggest that functional cerebello-thalamo-cortical connectivity tested by cTBS is abnormal in ET and that cerebellar cTBS does not ameliorate tremor in this condition.

Changes in physiological tremor resulting from sleep deprivation under conditions of increasing fatigue during prolonged military training.

The aim of the study was to define the changes of the characteristics of physiological postural tremor under conditions of increasing fatigue and lack of sleep during prolonged military training (survival). The subjects of the study were 15 students of the Polish Air Force Academy in Dęblin. The average age was 19.9±1.3 years. During the 36-hour-long continuous military training (survival) the subjects were deprived of sleep. Four tremor measurements were carried out for each of the subjects: Day 1 – morning, after rest (measurement 0); Day 2 – morning, after overnight physical exercise (measurement 1); afternoon, after continuous sleep deprivation (measurement 2); Day 3 – morning, after a full night sleep (measurement 3). The accelerometric method using an acceleration measuring kit was applied to analyse tremor. A significant difference between mean values of the index evaluating tremor power in low frequencies L2-4 in measurement 0 and measurement 3 was observed (p<0.01). No significant differences were found in mean values of index L10-20. Mean frequencies F2-4 differed significantly from each other (F2,42=4.53; p<0.01). Their values were 2.94±0.11, 2.99±0.9, 2.93±0.07 and 2.91±0.07 for successive measurements. A gradual, significant decrease of F8-14 was observed (F2,42=5.143; p<0.01). Prolonged sleep deprivation combined with performing tasks demanding constant physical effort causes long-lasting (over 24 hours) changes of the amplitude of low-frequency tremor changes. This phenomenon may significantly influence psychomotor performance, deteriorating the ability to perform tasks requiring movement precision.

Smartphone-based evaluation of parkinsonian hand tremor: quantitative measurements vs clinical assessment scores.

With an ever-growing number of technologically advanced methods for the diagnosis and quantification of movement disorders, comes the need to assess their accuracy and see how they match up with widely used standard clinical assessment tools. This work compares quantitative measurements of hand tremor in twenty-three Parkinson's disease patients, with their clinical scores in the hand tremor components of the Unified Parkinson's Disease Rating Scale (UPDRS), which is considered the "gold standard" in the clinical assessment of the disease. Our measurements were obtained using a smartphone-based platform, which processes the phone's accelerometer and gyroscope signals to detect and measure hand tremor. The signal metrics used were mainly based on the magnitude of the acceleration and the rotation rate vectors of the device. Our results suggest relatively strong correlation (r>0.7 and p<;0.01) between the patients' UPDRS hand tremor scores and the signal metrics applied to the measured signals.

Detecting within- and between-day manifestations of neuromuscular fatigue at work: an exploratory study

Cumulative neuromuscular fatigue may result from exposure to physically demanding work, such as repetitive and/or sustained work with insufficient recovery. The aims of this exploratory study were to develop a battery of field usable fatigue measures and to document hand/arm fatigue in physically demanding work over multiple workdays and after a weekend break. Sixteen plumbers were observed for five days and measures of handgrip force, variability, tremor and discomfort were obtained pre-, mid- and post-shift. This exploratory study demonstrated increasing fatigue of the hand/arm over the day and persistent fatigue from Tuesday to Friday, and that a number of the measures did not return to baseline values following a weekend break. The findings provide preliminary evidence of cumulative fatigue in residential plumbing and insight into neuromuscular fatigue measurement. However, further work is needed to develop and refine a set of fatigue measures to detect neuromuscular fatigue at the workplace.

0187 Alcohol consumption as a confounder in neurobehavioral studies of neurotoxicants

ObjectivesTo study the effects of manganese (Mn) exposure and alcohol consumption on tremor.MethodTremor was measured in 137 shipyard welders (age 39.9) and 137 referents (turner/fitters) (age 40.1) with the Catsys...

Association of Parkinson disease risk loci with mild parkinsonian signs in older persons.

Parkinsonian motor signs are common in the aging population and are associated with adverse health outcomes. Compared with Parkinson disease (PD), potential genetic risk factors for mild parkinsonian signs have been largely unexplored. To determine whether PD susceptibility loci are associated with parkinsonism or substantia nigra pathology in a large community-based cohort of older persons. Eighteen candidate single-nucleotide polymorphisms from PD genome-wide association studies were evaluated in a joint clinicopathologic cohort. Participants included 1698 individuals and a nested autopsy collection of 821 brains from the Religious Orders Study and the Rush Memory and Aging Project, 2 prospective community-based studies. The primary outcomes were a quantitative measure of global parkinsonism or component measures of bradykinesia, rigidity, tremor, and gait impairment that were based on the motor Unified Parkinson's Disease Rating Scale. In secondary analyses, we examined associations with additional quantitative motor traits and postmortem indices, including substantia nigra Lewy bodies and neuronal loss. Parkinson disease risk alleles in the MAPT (rs2942168; P = .0006) and CCDC62 (rs12817488; P = .004) loci were associated with global parkinsonism, and these associations remained after exclusion of patients with a PD diagnosis. Based on motor Unified Parkinson's Disease Rating Scale subscores, MAPT (P = .0002) and CCDC62 (P = .003) were predominantly associated with bradykinesia, and we further discovered associations between SREBF1 (rs11868035; P = .005) and gait impairment, SNCA (rs356220; P = .04) and rigidity, and GAK (rs1564282; P = .03) and tremor. In the autopsy cohort, only NMD3 (rs34016896; P = .03) was related to nigral neuronal loss, and no associations were detected with Lewy bodies. In addition to the established link to PD susceptibility, our results support a broader role for several loci in the development of parkinsonian motor signs and nigral pathology in older persons.

Early phenotypic differences between Parkinson's disease patients with and without freezing of gait

Previous studies have associated freezing of gait in Parkinson's disease with the presence of specific phenotypic features such as mood disturbances, REM sleep behavior disorder and selective cognitive impairments. However, it is not clear whether these features are present in the earlier stages of disease or simply represent a more general pattern of progression. To investigate this issue, the current study evaluated motor, cognitive, affective and autonomic features as well as REM sleep behavior disorder in Parkinson's disease patients in the early stages of the condition. Thirty-eight freezers and fifty-three non-freezers with disease duration of less than five years and a Hoehn and Yahr stage of less than three were included in this study. The groups were matched on a number of key disease features including age, disease duration, motor severity and dopamine dose equivalence. Furthermore, patients were assessed on measures of motor, cognitive, affective and autonomic features, as well as REM sleep behavior disorder. Compared to non-freezers, patients with freezing of gait had significantly more non-tremor symptoms and a selective impairment on executive functions, such as set-shifting ability and working memory. Freezers and non-freezers did not differ on measures of tremor, autonomic function, REM sleep behavior disorder, mood or more general cognition. These results suggest the pathophysiological mechanisms underlying freezing of gait in the early clinical stages of Parkinson's disease are likely to be related to specific changes in the frontostriatal pathways rather than being due to brainstem or more diffuse neuropathology.

A new method for quantitative tremor assessment in sports

BackgroundThe physiological tremor consists in an involuntary oscillation of the limbs, in the range of 10 Hz, which is generated in part from supraspinal brain structures. Its quantitative assessment in the sport science is relevant for sports requiring ability and for the assessment of fatigue. However, the measurement of tremor is not yet entered in standard sports medicine practice because expensive and complex instrumentations are needed. We present a simple, compact and cost-effective device for tremor measurement, based on the remote of the Wii console, the Wiimote, a wirless triaxial accelerometer which can communicate via bluetooth with a personal computer. Materials and MethodsEight male healthy volunteers were asked to maintain with the dominant hand the Wiimote pointing a fixed target for for a minimum of 90 seconds. The conversion of bluetooth data sent by the Wiimote in a final file containing the accelerometer informations has been obtained using a custom script in GlovePie environment. The analysis of the predominant frequency band was done in R environment. We then demonstrated the sensibility of the Wiimote to the modification of tremor induced by a muscular exercise, analyzing tremor after 20 repetitions, at the maximum velocity of full range elbow extension/flexion exercises. Moreover, we compared the analysis of tremor using the Wiimote with two other widely used approaches, spiralometry and laser pointing. ResultsUsing the Wiimote it is possible to get a real time feedback on hand tremor. The sampling rate was sufficient to observe the frequency peak at 8-10 Hz, which characterizes postural tremor and the increase of tremor intensity after the exercise. Moreover the Wiimote largely outperformed the spiralometry and laser pointing system. ConclusionsThe Wii remote application represents an accessible and simple way for clinicians to quantify tremor which might easily become part of the standard toolkit for scientists and sports medicine professionals.

Understanding Tremor in Rapid Upper Limb Movements Using 3D Accelerometers Data

Tremor is a manifestation of a variety of human neurodegenerative diseases, notably Parkinson’s disease (PD) and Essential Tremor (ET), both affecting millions worldwide. PD is primarily caused by a progressive loss of dopamine neurons in the nigrostriatal system that leads to widespread motor symptoms such as bradykinesia, rigidity, tremor and postural instability. ET typically involves a tremor of the arms, hands or fingers. No definitive test or biomarker is yet available for PD or ET, so the rate of misdiagnosis is relatively high. As tremor is a very common feature at the onset of both diseases, it is crucial to be able to characterize it. This is made possible using acce?lerometers to quantify the tremor amplitude and frequency. In this work we aim to find tasks involving upper limb movements that are suitable to modulate both types of tremor. Four tasks were tested, differing on whether the arms moved together or alternatingly and whether loads were added. Significant differences in tremor measures were found when patients were asked to perform simultaneous rapid arms movements with loads placed on their wrists. These results may allow the design of an efficient fMRI protocol for identifying the cortical circuits responsible for the modulation of tremor.

System pomiarowy do rejestracji drżeń parkinsonowskich

In this paper, the authors present the hand tremor measurement system. The correct diagnosis of Parkinson's disease is crucial for the selection of proper treatment and future prognosis. Unfortunately most of clinical diagnostic criteria require a detailed patient history and long observation time. There are also available specialist survey methods, but they are quite expensive and not suitable for general diagnosis. The proposed solution is to use acceleration sensor can provide possibly fast and accurate diagnosis. (Parkinson hand tremors measurement system).

Quantitative methods for evaluating the efficacy of thalamic deep brain stimulation in patients with essential tremor.

Deep brain stimulation (DBS) of the thalamus is a safe and efficient method for treatment of disabling tremor in patient with essential tremor (ET). However, successful tremor suppression after surgery requires careful selection of stimulus parameters. Our aim was to examine the possible use of certain quantitative methods for evaluating the efficacy of thalamic DBS in ET patients in clinical practice, and to compare these methods with traditional clinical tests. We examined 22 patients using the Essential Tremor Rating Scale (ETRS) and quantitative assessment of tremor with the stimulator both activated and deactivated. We used an accelerometer (CATSYS tremor Pen) for quantitative measurement of postural tremor, and a eurythmokinesimeter (EKM) to evaluate kinetic tremor in a rapid pointing task. The efficacy of DBS on tremor suppression was prominent irrespective of the method used. The agreement between clinical rating of postural tremor and tremor intensity as measured by the CATSYS tremor pen was relatively high (rs = 0.74). The agreement between kinetic tremor as assessed by the ETRS and the main outcome variable from the EKM test was low (rs = 0.34). The lack of agreement indicates that the EKM test is not comparable with the clinical test. Quantitative methods, such as the CATSYS tremor pen, could be a useful complement to clinical tremor assessment in evaluating the efficacy of DBS in clinical practice. Future studies should evaluate the precision of these methods and long-term impact on tremor suppression, activities of daily living (ADL) function and quality of life.

Biospeckle in the human sclera and impact on laser speckle correlation measurement of eye tremor

Ocular microtremor (OMT) is an involuntary fixational eye movement. We identify the implications of biospeckle for a noninvasive, laser speckle correlation technique to measure OMT. Biospeckle from the in-vivo eye is characterized and, using the resulting characteristics, a mathematical model to describe the biospeckle from the eye is designed and tested. Through in-vivo measurements, biospeckle is shown to disrupt the temporal stability of the speckle images over time. However, provided each speckle image is cross correlated with the previous image within a sufficiently short time, the stability of speckle images captured from the eye is shown to be adequate to measure OMT-like displacements.

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.

Monitoring methane emission of mud volcanoes by seismic tremor measurements: a pilot study

Abstract. A new approach for estimating methane emission at mud volcanoes is here proposed based on measurements of the seismic tremor on their surface. Data obtained at the Dashgil mud volcano in Azerbaijan reveal the presence of energy bursts characterized by well-determined features (i.e. waveforms, spectra and polarization properties) that can be associated with bubbling at depth. Counting such events provides a possible tool for monitoring gas production in the reservoir, thus minimizing logistic troubles and representing a cheap and effective alternative to more complex approaches. Specifically, we model the energy bursts as the effect of resonant gas bubbles at depth. This modelling allows to estimate the dimension of the bubbles and, consequently, the gas outflow from the main conduit in the assumption that all emissions from depth occur by bubble uprising. The application of this model to seismic events detected at the Dashgil mud volcano during three sessions of measurements carried out in 2006 and 2007 provides gas flux estimates that are in line with those provided by independent measurements at the same structure. This encouraging result suggests that the one here proposed could be considered a new promising, cheap and easy to apply tool for gas flux measurements in bubbling gas seepage areas.

Robotic Tremor Suppression: A Tool for Stapes Surgery?

Objective: 1) Create a custom micropick for Micron, a fully handheld robotic micromanipulator. 2) Demonstrate phenomenon of physiologic tremor and evaluate bracing technique in simulated otologic surgery. 3) Evaluate feasibility and efficacy of Micron, to decrease surgeon tremor, positioning error, and force applied in tasks simulating otologic surgery. Method: Two positioning conditions tested: hovering mid-air and lightly contacting surface. 3D axes error, tremor, and force measurements. Experimental conditions: 1) unaided, 2) unaided with bracing, 3) Micron alone, 4) Micron with bracing. Tremor and position error were analyzed with a high-pass filter. Significance ( P &lt; .05)(*) via 2-tailed t test. Results: Positioning Error: Root mean square (RMS) and maximum error (ME) are reported. Reduction in ME was seen in the surface task, with bracing alone and Micron alone. However, the hover task showed significant benefits with only Micron + bracing. Force Error: RMS and maximum force error showed no difference between conditions. Tremor Error: Positioning error contains tremor and overall drift from the goal position. Statistically significant reduction in tremor both in RMS and ME is seen with Micron, bracing, and the combination. Micron + bracing produced the largest reduction in tremor. Conclusion: Our initial results demonstrate Micron significantly reduced maximum positioning error (tremor) in simulated otologic surgery. Additionally, we confirmed bracing significantly dampens tremor. Interestingly, the use of Micron and bracing yielded the largest reduction in tremor, suggesting an additive effect. No difference in force applied was found.

Experimental Study on Dynamic Characteristics and Seismic Response Analysis of Yingxian Wooden Pagoda

In order to have a better understanding of the vibration characteristics, micro tremor measurements are carried out on Yingxian Wooden pagoda. Horizontal vibration modes of the tower and the torsional vibration modes on each floor are attained by analysis of the test results. Based on transfer function method, elastic displacements of the tower under the different seismic waves are derived. Trough theoretical analysis, the significative conclusions are received as a basis for researching and protecting the ancient building.