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Kreiman, Jody, Brian Gabelman y Bruce R. Gerratt. "Perception of Vocal Tremor". Journal of Speech, Language, and Hearing Research 46, n.º 1 (febrero de 2003): 203–14. http://dx.doi.org/10.1044/1092-4388(2003/016).
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Vocal tremors characterize many pathological voices, but acoustic-perceptual aspects of tremor are poorly understood. To investigate this relationship, 2 tremor models were implemented in a custom voice synthesizer. The first modulated fundamental frequency (F0) with a sine wave. The second provided irregular modulation. Control parameters in both models were the frequency and amplitude of the F0 modulating waveform. Thirty-two 1-s samples of /a/, produced by speakers with vocal pathology, were modeled in the synthesizer. Synthetic copies of each vowel were created by using tremor parameters derived from different features of F0 versus time plots of the natural stimuli or by using parameters chosen to match the original stimuli perceptually. Listeners compared synthetic and original stimuli in 3 experiments. Sine wave and irregular tremor models both provided excellent matches to subsets of the voices. The perceptual importance of the shape of the modulating waveform depended on the severity of the tremor, with the choice of tremor model increasing in importance as the tremor increased in severity. The average frequency deviation from the mean F0 proved a good predictor of the perceived amplitude of a tremor. Differences in tremor rates were easiest to hear when the tremor was sinusoidal and of small amplitude. Differences in tremor rate were difficult to judge for tremors of large amplitude or in the context of irregularities in the pattern of frequency modulation. These results suggest that difference limens are larger for modulation rates and amplitudes when the tremor pattern is complex. Further, tremor rate, regularity, and amplitude interact, so that the perceptual importance of any one dimension depends on values of the others.
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Sabah najim, Nawras, Abdulnasir H. Ameer y Azad A. Mohammed. "The Electrophysiological Perspectives of Essential, Enhanced Physiological, and Physiological Tremors". Journal of the Faculty of Medicine Baghdad 64, n.º 2 (24 de julio de 2022): 86–90. http://dx.doi.org/10.32007/jfacmedbagdad.6421921.
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Abstract: Background: The most frequent movement issue seen in clinical practice is tremors. It is known as repetitive, involuntary oscillations. The diagnostic process for tremor patients can be time-consuming and complicated, as the identification of “Essential Tremor” and its distinction from other types of tremor. Objectives: This study aimed to describe the electrophysiological findings of essential, enhanced physiological, and physiological tremors, using surface electromyography and an accelerometer. Patients and Methods: The study included 24 patients with essential tremors, 10 patients with enhanced physiological tremors, and 10 patients with physiological tremors. We assessed the frequency, amplitude, and muscular contraction pattern of tremors during rest, posture, and a 1 kg load. Results: The tremor frequency of essential tremor patients was about 4.2-10.1 Hertz, while enhanced physiological tremor and physiological tremor were increased to 6.1–12.7 Hertz and 5.1-10.2 Hertz, respectively. The essential tremor group muscle contraction pattern was predominantly synchronous, as do all enhanced physiological, and physiological tremor patients, but with more fine low amplitude muscle bursts. By varying the tremor frequency and the weight load effect, tremor analysis could discriminate essential from enhanced physiological, and physiological tremors. Conclusions: The tremor analysis using surface electromyography and an accelerometer is sufficient to differentiate between essential tremors, enhanced physiological tremors, and physiological tremors.
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Samotus, Olivia, Jack Lee y Mandar Jog. "Developing a Consistent, Reproducible Botulinum Toxin Type A Dosing Method for Upper Limb Tremor by Kinematic Analysis". Toxins 13, n.º 4 (8 de abril de 2021): 264. http://dx.doi.org/10.3390/toxins13040264.
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Botulinum toxin type A (BoNT-A) injection patterns customized to each patient’s unique tremor characteristics produce better efficacy and lower adverse effects compared to the fixed-muscle-fixed-dose approach for Essential Tremor (ET) and Parkinson’s disease (PD) tremor therapy. This article outlined how a kinematic-based dosing method to standardize and customize BoNT-A injections for tremors was developed. Seven ET and eight PD participants with significant tremor reduction and minimal perceived weakness using optimized BoNT-A injections determined by clinical and kinematic guidance were retrospectively selected to develop the kinematic-based dosing method. BoNT-A dosages allocated per joint were paired to baseline tremor amplitudes per joint. The final kinematic-based dosing method was prospectively utilized to validate BoNT-A injection pattern selection without clinical/visual assessments in 31 ET and 47 PD participants with debilitating arm tremors (totaling 122 unique tremor patterns). Whole-arm kinematic tremor analysis was performed at baseline and 6-weeks post-injection. Correlation and linear regression analyses between baseline tremor amplitudes and the change in tremor amplitude 6-weeks post-injection, with BoNT-A dosages per joint, were performed. Injection patterns determined using clinical assessment and interpretation of kinematics produced significant associations between baseline tremor amplitudes and optimized BoNT-A dosages in all joints. The change in elbow tremor was only significantly associated with the elbow total dose as the change in the wrist and shoulder tremor amplitudes were not significantly associated with the wrist and shoulder dosages from the selected 15 ET and PD participants. Using the kinematic-based dosing method, significant associations between baseline tremor amplitudes and the change (6-weeks post-first treatment) in tremor at each joint with BoNT-A dosages for all joints was observed in all 78 ET and PD participants. The kinematic-based dosing method provided consistency in dose selection and subsequent tremor reduction and can be used to standardize tremor assessments for whole-arm tremor treatment planning.
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HEO, JAE-HOON, HYEONG-MIN JEON, EUI-BUM CHOI, DO-YOUNG KWON y GWANG-MOON EOM. "EFFECT OF SENSORY ELECTRICAL STIMULATION ON RESTING TREMORS IN PATIENTS WITH PARKINSON’S DISEASE AND SWEDDs". Journal of Mechanics in Medicine and Biology 19, n.º 07 (noviembre de 2019): 1940033. http://dx.doi.org/10.1142/s0219519419400335.
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Patients with scans without evidence of dopaminergic deficits (SWEDDs) show symptoms (e.g., tremors) similar to those of Parkinson’s disease (PD) patients, so they are often misdiagnosed. Sensory electrical stimulation (SES) was reported to suppress essential tremor in patients, but SES was never applied to patients with PD and SWEDDs. As the pathophysiological mechanisms of PD and SWEDDs are likely to be different, we hypothesized that the effect of SES would also be different in the two patient groups. This study aimed to test that hypothesis. Fourteen patients with PD and nine with SWEDDs participated in this study. Three wrist muscles were stimulated for 15[Formula: see text]s using SES with a stimulation intensity lower than the motor threshold. Angular motion of the index finger was measured via a triaxial gyrosensor before, during, and after stimulation. Outcome measures included the amplitude and peak frequency of the angular motion of the index finger. Tremor amplitude decreased during and after SES in patients with PD ([Formula: see text]). However, tremor amplitudes during and after SES were not different from the base level in SWEDDs patients. The peak frequency of tremors temporarily decreased during stimulation in PD patients, but not in SWEDDs patients. SES suppressed tremors in patients with PD, but not with SWEDDs. The results could help understand the pathophysiological differences of tremors between PD and SWEDDs.
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Dirkx, Michiel F., Heidemarie Zach, Bastiaan R. Bloem, Mark Hallett y Rick C. Helmich. "The nature of postural tremor in Parkinson disease". Neurology 90, n.º 13 (23 de febrero de 2018): e1095-e1103. http://dx.doi.org/10.1212/wnl.0000000000005215.
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ObjectiveTo disentangle the different forms of postural tremors in Parkinson disease (PD).MethodsIn this combined observational and intervention study, we measured resting and postural tremor characteristics in 73 patients with tremulous PD by using EMG of forearm muscles. Patients were measured both “off” medication (overnight withdrawal) and after dispersible levodopa-benserazide 200/50 mg. We performed an automated 2-step cluster analysis on 3 postural tremor characteristics: the frequency difference with resting tremor, the degree of tremor suppression after posturing, and the dopamine response.ResultsThe cluster analysis revealed 2 distinct postural tremor phenotypes: 81% had re-emergent tremor (amplitude suppression, frequency difference with resting tremor 0.4 Hz, clear dopamine response) and 19% had pure postural tremor (no amplitude suppression, frequency difference with resting tremor 3.5 Hz, no dopamine response). This finding was manually validated (accuracy of 93%). Pure postural tremor was not associated with clinical signs of essential tremor or dystonia, and it was not influenced by weighing.ConclusionThere are 2 distinct postural tremor phenotypes in PD, which have a different pathophysiology and require different treatment. Re-emergent tremor is a continuation of resting tremor during stable posturing, and it has a dopaminergic basis. Pure postural tremor is a less common type of tremor that is inherent to PD, but has a largely nondopaminergic basis.
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Milanov, Ivan. "Clinical and Electromyographic Examinations of Patients with Essential Tremor". Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 27, n.º 1 (febrero de 2000): 65–70. http://dx.doi.org/10.1017/s0317167100052008.
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ABSTRACT:Background:It is believed that no clinical differences exist among essential, familial and senile tremor, or between the tremor with synchronous or alternating electromyographic activity. The aim of this study was to evaluate the clinical and electromyographic findings in a large group of patients with different types of essential tremor.Methods:Two hundred and twenty patients with sporadic, familial or senile variants of essential tremor were examined. According to the electromyographic activity recorded from the antagonistic muscles, the patients were subdivided into a group with synchronous (SYN) and a group with alternating (ALT) activity. The historical aspects of the disease were noted, and a detailed neurological examination was performed.Results:A widespread tremor involving upper and lower limbs and 3-4 different anatomical regions was typical for familial tremor. It also had higher amplitude than the sporadic and senile tremor. ALT tremor had a higher amplitude and longer burst duration than SYN and more often involved lower limbs. Rest tremor was common in the ALT group. Overall, ALT tremor was more common than previously supposed.Conclusion:The familial and ALT tremors are more disabling than other types of essential tremor. Since electromyographic ALT activity is common in essential tremor, its presence does not reliably distinguish essential and Parkinsonian tremor.
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Kim, Jeonghee, Thomas Wichmann, Omer T. Inan y Stephen P. DeWeerth. "Analyzing the Effects of Parameters for Tremor Modulation via Phase-Locked Electrical Stimulation on a Peripheral Nerve". Journal of Personalized Medicine 12, n.º 1 (8 de enero de 2022): 76. http://dx.doi.org/10.3390/jpm12010076.
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(1) Background: Non-invasive neuromodulation is a promising alternative to medication or deep-brain stimulation treatment for Parkinson’s Disease or essential tremor. In previous work, we developed and tested a wearable system that modulates tremor via the non-invasive, electrical stimulation of peripheral nerves. In this article, we examine the proper range and the effects of various stimulation parameters for phase-locked stimulation. (2) Methods: We recruited nine participants with essential tremor. The subjects performed a bean-transfer task that mimics an eating activity to elicit kinetic tremor while using the wearable stimulation system. We examined the effects of stimulation with a fixed duty cycle, at different stimulation amplitudes and frequencies. The epochs of stimulation were locked to one of four phase positions of ongoing tremor, as measured with an accelerometer. We analyzed stimulation-evoked changes of the frequency and amplitude of tremor. (3) Results: We found that the higher tremor amplitude group experienced a higher rate of tremor power reduction (up to 65%) with a higher amplitude of stimulation when the stimulation was applied at the ±peak of tremor phase. (4) Conclusions: The stimulation parameter can be adjusted to optimize tremor reduction, and this study lays the foundation for future large-scale parameter optimization experiments for personalized peripheral nerve stimulation.
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Berbakov, Lazar, Čarna Jovanović, Marina Svetel, Jelena Vasiljević, Goran Dimić y Nenad Radulović. "Quantitative Assessment of Head Tremor in Patients with Essential Tremor and Cervical Dystonia by Using Inertial Sensors". Sensors 19, n.º 19 (30 de septiembre de 2019): 4246. http://dx.doi.org/10.3390/s19194246.
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Tremor is most common among the movement disabilities that affect older people, having a prevalence rate of 4.6% in the population older than 65 years. Despite this, distinguishing different types of tremors is clinically challenging, often leading to misdiagnosis. However, due to advances in microelectronics and wireless communication, it is now possible to easily monitor tremor in hospitals and even in home environments. In this paper, we propose an architecture of a system for remote health-care and one possible implementation of such system focused on head tremor monitoring. In particular, the aim of the study presented here was to test new tools for differentiating essential tremor from dystonic tremor. To that aim, we propose a number of temporal and spectral features that are calculated from measured gyroscope signals, and identify those that provide optimal differentiation between two groups. The mean signal amplitude feature results in sensitivity = 0.8537 and specificity = 0.8039 in distinguishing patients having cervical dystonia with or without tremor. In addition, mean signal amplitude was shown to be significantly higher in patients with essential tremor than in patients with cervical dystonia, whereas the mean peak frequency is not different between two groups.
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Cichaczewski, Ederson, Renato P. Munhoz, Joaquim M. Maia, Percy Nohama, Edison M. Nóvak y Helio A. Teive. "Electrophysiologic characteristics of tremor in Parkinson?s disease and essential tremor". Arquivos de Neuro-Psiquiatria 72, n.º 4 (abril de 2014): 301–6. http://dx.doi.org/10.1590/0004-282x20140006.
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Tremor in essential tremor (ET) and Parkinson’s disease (PD) usually present specific electrophysiologic profiles, however amplitude and frequency may have wide variations. Objective: To present the electrophysiologic findings in PD and ET. Method: Patients were assessed at rest, with posture and action. Seventeen patients with ET and 62 with PD were included. PD cases were clustered into three groups: predominant rest tremor; tremor with similar intensity at rest, posture and during kinetic task; and predominant kinetic tremor. Results: Patients with PD presented tremors with average frequency of 5.29±1.18 Hz at rest, 5.79±1.39 Hz with posture and 6.48±1.34 Hz with the kinetic task. Tremor in ET presented with an average frequency of 5.97±1.1 Hz at rest, 6.18±1 Hz with posture and 6.53±1.2 Hz with kinetic task. Seven (41.2%) also showed rest tremor. Conclusion: The tremor analysis alone using the methodology described here, is not sufficient to differentiate tremor in ET and PD.
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Mostile, Giovanni, Robert Fekete, Joseph P. Giuffrida, Toby Yaltho, Anthony Davidson, Alessandra Nicoletti, Mario Zappia y Joseph Jankovic. "Amplitude fluctuations in essential tremor". Parkinsonism & Related Disorders 18, n.º 7 (agosto de 2012): 859–63. http://dx.doi.org/10.1016/j.parkreldis.2012.04.019.
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Röösli, Claudia, Fabian Walter, Stephan Husen, Lauren C. Andrews, Martin P. Lüthi, Ginny A. Catania y Edi Kissling. "Sustained seismic tremors and icequakes detected in the ablation zone of the Greenland ice sheet". Journal of Glaciology 60, n.º 221 (2014): 563–75. http://dx.doi.org/10.3189/2014jog13j210.
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AbstractDuring summer 2011, seismic activity in the ablation zone of the western Greenland ice sheet (GrIS) was monitored using a network of three-component seismometers. The seismic record includes a large variety of icequakes and seismic tremors that demonstrate a clear correlation with subglacial water flow. We verified the existence of well-known shallow icequakes (related to surface crevasse formation), deep icequakes (located at 100–160 m depth) and narrow-banded short-term seismic tremors (tens of seconds in duration). In addition, we present previously unreported long-term tremors lasting several hours. Using attenuation of the measured tremor amplitude, we locate the epicentre of this long-term tremor to a large moulin within our study area. Between 3 and 11 Hz, our continuous seismic record is dominated by this ‘moulin tremor’ and shows strong correlation with the water level of the generating moulin. We argue that monitoring of icequake and glacial tremor sources bears high potential for investigating glacier hydraulics and dynamics, and is thus an ideal supplement to traditional glaciological measurements.
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Smeja, M., F. Foerster, G. Fuchs, D. Emmans, A. Hornig y J. Fahrenberg. "24-h Assessment of Tremor Activity and Posture in Parkinson's Disease by Multi-Channel Accelerometry". Journal of Psychophysiology 13, n.º 4 (octubre de 1999): 245–56. http://dx.doi.org/10.1027//0269-8803.13.4.245.
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Abstract This study describes a new method, based on accelerometry, which quantifies tremor activity and posture continuously. A total of 25 right-handed patients with Parkinson's disease were recorded in a rest condition and in a postural tremor test, and during 24-h ambulatory monitoring. The tremor parameters, such as amplitude, frequency, and occurrence (percent of time), were derived by joint amplitude-frequency analysis. The DC components of multi-channel accelerometry allowed the detection of posture. A repeated measurement MANOVA was used to test the effects of posture and night-day differences in tremor activity. Further issues included consistencies of amplitude measurements across hands, between tasks, and between segments of recordings. Findings indicated an increase between resting tremor and postural tremor in the three tremor parameters, an increase under distraction, and enhanced activity in sitting compared to standing/walking. The best predictions of daytime monitoring measures, based on resting measures, were made for left hand tremor. This methodology is suitable for the detection of diurnal changes in tremor activity, especially amplitude changes, and for the psychophysiological investigation of enhanced tremor caused by task demands and emotional reactions.
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Mitsui, Yuichi, Thi Thi Zin, Nobuyuki Ishii y Hitoshi Mochizuki. "Imaging Tremor Quantification for Neurological Disease Diagnosis". Sensors 20, n.º 22 (22 de noviembre de 2020): 6684. http://dx.doi.org/10.3390/s20226684.
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In this paper, we introduce a simple method based on image analysis and deep learning that can be used in the objective assessment and measurement of tremors. A tremor is a neurological disorder that causes involuntary and rhythmic movements in a human body part or parts. There are many types of tremors, depending on their amplitude and frequency type. Appropriate treatment is only possible when there is an accurate diagnosis. Thus, a need exists for a technique to analyze tremors. In this paper, we propose a hybrid approach using imaging technology and machine learning techniques for quantification and extraction of the parameters associated with tremors. These extracted parameters are used to classify the tremor for subsequent identification of the disease. In particular, we focus on essential tremor and cerebellar disorders by monitoring the finger–nose–finger test. First of all, test results obtained from both patients and healthy individuals are analyzed using image processing techniques. Next, data were grouped in order to determine classes of typical responses. A machine learning method using a support vector machine is used to perform an unsupervised clustering. Experimental results showed the highest internal evaluation for distribution into three clusters, which could be used to differentiate the responses of healthy subjects, patients with essential tremor and patients with cerebellar disorders.
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Makhoul, Karim, Rechdi Ahdab, Naji Riachi, Moussa A. Chalah y Samar S. Ayache. "Tremor in Multiple Sclerosis—An Overview and Future Perspectives". Brain Sciences 10, n.º 10 (12 de octubre de 2020): 722. http://dx.doi.org/10.3390/brainsci10100722.
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Tremor is an important and common symptom in patients with multiple sclerosis (MS). It constituted one of the three core features of MS triad described by Charcot in the last century. Tremor could have a drastic impact on patients’ quality of life. This paper provides an overview of tremor in MS and future perspectives with a particular emphasis on its epidemiology (prevalence: 25–58%), clinical characteristics (i.e., large amplitude 2.5–7 Hz predominantly postural or intention tremor vs. exaggerated physiological tremor vs. pseudo-rhythmic activity arising from cerebellar dysfunction vs. psychogenic tremor), pathophysiological mechanisms (potential implication of cerebellum, cerebello-thalamo-cortical pathways, basal ganglia, and brainstem), assessment modalities (e.g., tremor rating scales, Stewart–Holmes maneuver, visual tracking, digitized spirography and accelerometric techniques, accelerometry–electromyography coupling), and therapeutic options (i.e., including pharmacological agents, botulinum toxin A injections; deep brain stimulation or thalamotomy reserved for severe, disabling, or pharmaco-resistant tremors). Some suggestions are provided to help overcome the unmet needs and guide future therapeutic and diagnostic studies in this complex disorder.
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Feys, Peter, Werner Helsen, Stephan Ilsbroukx y Tom Meurrens. "Is MS Intention Tremor Amplitude Related to Changed Peripheral Reflexes?" ISRN Neurology 2011 (26 de septiembre de 2011): 1–7. http://dx.doi.org/10.5402/2011/192414.
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Intention tremor is related to lesions in the cerebellum or connected pathways. Intention tremor amplitude decreased after peripheral arm cooling in patients with multiple sclerosis (MS), likely caused by a reduction of muscle spindle afferent inflow, while amplitude increased when muscle spindles were artificially stimulated by tendon vibration. This study investigated the contribution of peripheral reflexes to the generation of MS intention tremor. Tendon reflexes of biceps, triceps, and brachioradialis, muscles were measured, using an electromechanical triggered reflex hammer. MS patients with (n = 17) and without (n = 17) upper limb intention and 18 healthy controls were tested. Latency of brachioradialis, biceps, and triceps tendon reflexes was greater in MS patients with tremor than in healthy controls and MS patients without tremor (except for the triceps reflex). Peak and peak-to-peak amplitude were not different between groups. It is concluded that tendon reflexes were delayed but not enlarged in MS patients with tremor.
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HEO, JAE-HOON, HYEONG-MIN JEON, EUI-BUM CHOI, DO-YOUNG KWON y GWANG-MOON EOM. "CONTINUOUS SENSORY ELECTRICAL STIMULATION FOR THE SUPPRESSION OF PARKINSONIAN REST TREMOR". Journal of Mechanics in Medicine and Biology 18, n.º 07 (noviembre de 2018): 1840006. http://dx.doi.org/10.1142/s0219519418400067.
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This paper aims to investigate the effect of continuous sensory electrical stimulation (SES) on the suppression of a Parkinsonian rest tremor. Fourteen patients with Parkinson’s disease participated in this study. Three wrist muscles were electrically stimulated on sensory level under motor threshold. Intensity of stimulation was determined for each muscle of each patient as the maximum tolerable current amplitude that does not induce muscle contraction. Tri-axial gyro sensors were attached to three upper limb segments. The angular velocity of each segment was measured for each of the three sessions, i.e., PRE-, ON- and POST- stimulations. Outcome measures were the tremor amplitude and main frequency of each axis in the power spectrum. Decrease in tremor amplitude was significant at ON and POST sessions in finger and at POST session in hand and forearm. Decrease in main frequency was significant mainly at ON session. About one-third of patients showed reduction in tremor power at ON-stimulation and at POST-stimulation. Subjects with suppression of tremor showed greater initial tremor amplitude than those without suppression. Continuous SES suppressed the Parkinsonian rest tremor. The results suggest that the properties of tremor-generating loop may be altered by continuous SES and the effect lasts temporarily.
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Amarantini, David, Isabelle Rieu, Giovanni Castelnovo, Frédérique Fluchère, Chloé Laurencin, Bertrand Degos, Aurélia Poujois et al. "Quantification of Head Tremors in Medical Conditions: A Comparison of Analyses Using a 2D Video Camera and a 3D Wireless Inertial Motion Unit". Sensors 22, n.º 6 (19 de marzo de 2022): 2385. http://dx.doi.org/10.3390/s22062385.
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This study compares two methods to quantify the amplitude and frequency of head movements in patients with head tremor: one based on video-based motion analysis, and the other using a miniature wireless inertial magnetic motion unit (IMMU). Concomitant with the clinical assessment of head tremor severity, head linear displacements in the frontal plane and head angular displacements in three dimensions were obtained simultaneously in forty-nine patients using one video camera and an IMMU in three experimental conditions while sitting (at rest, counting backward, and with arms extended). Head tremor amplitude was quantified along/around each axis, and head tremor frequency was analyzed in the frequency and time-frequency domains. Correlation analysis investigated the association between the clinical severity of head tremor and head linear and angular displacements. Our results showed better sensitivity of the IMMU compared to a 2D video camera to detect changes of tremor amplitude according to examination conditions, and better agreement with clinical measures. The frequency of head tremor calculated from video data in the frequency domain was higher than that obtained using time-frequency analysis and those calculated from the IMMU data. This study provides strong experimental evidence in favor of using an IMMU to quantify the amplitude and time-frequency oscillatory features of head tremor, especially in medical conditions.
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Sandström, Linda, Patric Blomstedt, Fredrik Karlsson y Lena Hartelius. "The Effects of Deep Brain Stimulation on Speech Intelligibility in Persons With Essential Tremor". Journal of Speech, Language, and Hearing Research 63, n.º 2 (26 de febrero de 2020): 456–71. http://dx.doi.org/10.1044/2019_jslhr-19-00014.
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Purpose The aim of this study was to investigate how deep brain stimulation (DBS) of the caudal zona incerta (cZi) affects speech intelligibility in persons with essential tremor. Method Thirty-five participants were evaluated: off stimulation, on chronic stimulation optimized to alleviate tremor, and during unilateral stimulation at increasing amplitude levels. At each stimulation condition, the participants read 10 unique nonsense sentences from the Swedish Test of Intelligibility. Two listeners, blinded to stimulation condition, transcribed all recorded sentences orthographically in a randomized procedure. A mean speech intelligibility score for each patient and stimulation condition was computed, and comparisons were made between scores off and on stimulation. Results Chronic cZi-DBS had no significant effect on speech intelligibility, and there was no difference in outcome between bilateral and unilateral treatments. During unilateral stimulation at increasing amplitudes, nine participants demonstrated deteriorating speech intelligibility. These nine participants were on average older and had more superior contacts activated during the evaluation compared with the participants without deterioration. Conclusions Chronic cZi-DBS, optimized for tremor suppression, does not generally affect speech intelligibility in persons with essential tremor. Furthermore, speech intelligibility may be preserved in many individuals, even when stimulated at high amplitudes. Adverse effects of high-amplitude unilateral stimulation observed in this study were associated with stimulation originating from a more superior location, as well as with the participants' age. These results, highlighting age and stimulation location as contributing to speech intelligibility outcomes, were, however, based on a limited number of individuals experiencing adverse effects with high-amplitude stimulation and should, therefore, be interpreted with caution.
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Paschal, O’Gorman, Williams Stefan, Fang Hui, Qahwaji Rami, Patel Parisa, Graham Christopher D y Alty Jane. "WED 112 Seeing invisible parkinsonian tremor with a smartphone camera". Journal of Neurology, Neurosurgery & Psychiatry 89, n.º 10 (13 de septiembre de 2018): A12.1—A12. http://dx.doi.org/10.1136/jnnp-2018-abn.43.
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Arthur C Clarke’s ‘third law’ states that any sufficiently advanced technology is indistinguishable from magic. Computer vision is the processing of images or video by computer to extract useful information. A technique termed ‘Eulerian magnification’ involves amplification of tiny movements from video recordings, so that very small motions can become visible to the human eye. This has the potential to detect tremor that is of such small amplitude it cannot otherwise be seen. Crucially, the only hardware required is a camera and computer processor, items that are ubiquitous. There is only one previous report of Eulerian magnification applied to a simple video of a Parkinson’s patient, but Parkinsonian signs could clearly be seen in the pre-processing video, and no control video was shown. We present remarkable video in which no tremor is seen in either patient or control before processing, and yet a Parkinsonian tremor is revealed in patient but not control after amplification. Blinded clinician ratings detect a greater number of Parkinsonian tremors after computer processing. Furthermore, we report a method using an ‘optical flow’ computing technique that records pixel motion vectors, and enables the computer to measure the direction and relative amplitude of this amplified movement.
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McCarroll, R. S. y J. H. De Vries. "The Influence of Tonic Muscle Activation on Human Jaw Displacement Tremor". Journal of Dental Research 67, n.º 8 (agosto de 1988): 1081–85. http://dx.doi.org/10.1177/00220345880670080401.
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Jaw displacement tremor was investigated. Both tremor amplitude and tremor frequency were found to increase with increasing muscle activation. Co-contraction of jaw elevator and jaw depressor muscles was employed in order to vary muscle activation levels without the teeth being in occlusion. Reproducibility of tremor changes was statistically significant for each individual investigated. The relationship between tremor frequency and tremor amplitude, over the range of muscle activation investigated, varied per individual. It is hypothesized that the physiological basis for this inter-individual variation is differences in the development of jaw stiffness with increasing muscle activation between subjects. This explanation may be the basis, at least in part, for the clinical presence of objective jaw stiffness in one subject and its absence in another.
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Iizuka, T., A. Takeuchi, M. Shirataka, N. Ikeda y N. Mamorita. "Development of a System for Measurement and Analysis of Tremor Using a Three-axis Accelerometer". Methods of Information in Medicine 48, n.º 06 (2009): 589–94. http://dx.doi.org/10.3414/me9243.
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Summary Objectives: The aim of the study was to develop a low-cost and compact system for analysis of tremor using a three-axis accelerometer (the Wii Remote (Nintendo)). To analyze tremor, we hypothesized that the influence of gravitational acceleration should be separated from that of movement. This hypothesis was tested experimentally and we also attempted to record and analyze tremor using our system in a clinical ward. Methods: A system for tremor measurement and analysis was developed using the three-axis accelerometer built into the Wii Remote. The frequency and amplitude of mechanical oscillation were calculated using methods for frequency analysis of the axis of largest variance and an estimation of tremor amplitude. Results: The system consists of a program for measurement and analysis of Wii Remote acceleration (Tremor Analyzer), a Wii Remote, a Bluetooth USB adapter and a Web camera. The Tremor Analyzer has a GUI (graphical user interface) that is divided into five segments. The sampling period of the analyzer is 30 msec. To confirm the hypothesis, mechanical oscillations were fed to the Wii Remote. The peak frequency of the power spectrum and the frequency of the oscillation generator were in good agreement, except at 1 Hz (0.01 G) and 2 Hz (0.02 G). With a change in the sum of squares of the three axes from 1.0 to 1.8 (G), the estimated and generated amplitude (0.3 cm) were in close agreement. Conclusions: This system using a Wii Remote is capable of analyzing frequency and estimated amplitude of tremor between 3 Hz and 15 Hz.
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Winholtz, William S. y Lorraine Olson Ramig. "Vocal Tremor Analysis With the Vocal Demodulator". Journal of Speech, Language, and Hearing Research 35, n.º 3 (junio de 1992): 562–73. http://dx.doi.org/10.1044/jshr.3503.562.
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Acoustic analysis of vocal tremor has the potential to make significant quantitative and diagnostic contributions to the study of vocal disorders. This paper presents a new device for analysis of vocal tremor. The Vocal Demodulator produces amplitude- and frequency-demodulated outputs and measures the frequency and level (percent) of low-frequency tremor components in sustained phonation. A standard microphone is used to transduce the voice signal for input to the demodulator. The input fundamental frequency (F o ) range is 70–1200 Hz, and frequency response of the amplitude and frequency demodulation is 2.5–25 Hz. Five parameters are displayed in real time: F o , amplitude-modulation frequency, amplitude-modulation level, frequency-modulation frequency, and frequency-modulation level. Validation, calibration, and reliability data from synthesized test signals with modulation, as well as phonation from subjects with vocal tremor, subjects producing vibrato, and subjects with normal voice are presented. Research and clinical applications of this device are suggested.
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de Faria, Stephanie Martins, Daiene de Morais Fabrício, Vitor Tumas, Paula Costa Castro, Moacir Antonelli Ponti, Jaime EC Hallak, Antonio W. Zuardi, José Alexandre S. Crippa y Marcos Hortes Nisihara Chagas. "Effects of acute cannabidiol administration on anxiety and tremors induced by a Simulated Public Speaking Test in patients with Parkinson’s disease". Journal of Psychopharmacology 34, n.º 2 (7 de enero de 2020): 189–96. http://dx.doi.org/10.1177/0269881119895536.
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Background: Cannabidiol (CBD) is one of the main components of Cannabis sativa and has anxiolytic properties, but no study has been conducted to evaluate the effects of CBD on anxiety signs and symptoms in patients with Parkinson’s disease (PD). This study aimed to evaluate the impacts of acute CBD administration at a dose of 300 mg on anxiety measures and tremors induced by a Simulated Public Speaking Test (SPST) in individuals with PD. Methods: A randomised, double-blinded, placebo-controlled, crossover clinical trial was conducted. A total of 24 individuals with PD were included and underwent two experimental sessions within a 15-day interval. After taking CBD or a placebo, participants underwent the SPST. During the test, the following data were collected: heart rate, systemic blood pressure and tremor frequency and amplitude. In addition, the Visual Analog Mood Scales (VAMS) and Self-Statements during Public Speaking Scale were applied. Statistical analysis was performed by repeated-measures analysis of variance (ANOVA) while considering the drug, SPST phase and interactions between these variables. Results: There were statistically significant differences in the VAMS anxiety factor for the drug; CBD attenuated the anxiety experimentally induced by the SPST. Repeated-measures ANOVA showed significant differences in the drug for the variable related to tremor amplitude as recorded by the accelerometer. Conclusion: Acute CBD administration at a dose of 300 mg decreased anxiety in patients with PD, and there was also decreased tremor amplitude in an anxiogenic situation.
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Jensen, Lauren, Michael Dancisak y James Korndorffer. "Muscle-Cooling Intervention to Reduce Fatigue and Fatigue-Induced Tremor in Novice and Experienced Surgeons: A Preliminary Investigation". Surgery Journal 02, n.º 04 (octubre de 2016): e126-e130. http://dx.doi.org/10.1055/s-0036-1594246.
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AbstractA localized, intermittent muscle-cooling protocol was implemented to determine cooling garment efficacy in reducing upper extremity muscular fatigue and tremor in novice (n = 10) and experienced surgeons (n = 9). Subjects wore a muscle-cooling garment while performing multiple trials of a forearm exercise and paired suturing task to induce muscular fatigue and exercise-induced tremor. A reduction in tremor amplitude and an extension in time to fatigue were expected with muscle cooling as compared with control trials. Each subject completed an intervention session (5°C cooling condition) and a control session (32°C or thermal neutral condition). A paired samples t test indicated that tremor amplitude was significantly reduced (t [8] = 1.89458; p < 0.05) in experienced surgeons in two dimensions (up and down, and back and forth). Tremor amplitude was reduced in novice surgeons but the effect was not significant. Time to fatigue and suture time improved in both cohorts with muscle cooling, but the effect did not reach significance. Results from the pilot work suggest muscle cooling as an intervention for reduction of fatigue and tremor is very promising, warranting further investigation. Surgical specialties that require prolonged procedures might benefit more from this intervention.
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Aronson, Arnold E., William S. Winholtz, Lorraine Olson Ramig y Sandra R. Silber. "Rapid Voice Tremor, or “Flutter,” in Amyotrophic Lateral Sclerosis". Annals of Otology, Rhinology & Laryngology 101, n.º 6 (junio de 1992): 511–18. http://dx.doi.org/10.1177/000348949210100612.
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In an attempt to clarify the origin and frequency characteristics of a rapid voice tremor, or “flutter,” in patients with amyotrophic lateral sclerosis (ALS), eight patients (four men and four women; ages 42 to 70 years) who had ALS and rapid voice tremor and an age-and sex-matched control group of eight subjects were asked to sustain the vowel /a/ and their voices were recorded for later analysis. Each segment of phonation was demodulated into amplitude and frequency components. From each subject's 8-second amplitude and frequency signals, a fast Fourier transform analysis was done on a 1-second segment previously identified perceptually as having the most apparent tremor or flutter. The results showed that patients with ALS had multiple combinations of levels and frequencies for amplitude and frequency modulations in comparison with control subjects, who had consistently low levels of modulations. In an attempt to quantify the tremor or flutter in ALS, amplitude and frequency modulations were not clearly or predominantly represented at one point along the spectrum. Nevertheless, these frequency and amplitude modulations are more prominent in patients with ALS than in normal subjects. The origins of these aberrant frequency and amplitude modulations in ALS patients remain obscure, although speculation is that they are of peripheral rather than central nervous system origin.
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Cagnan, Hayriye, John-Stuart Brittain, Simon Little, Thomas Foltynie, Patricia Limousin, Ludvic Zrinzo, Marwan Hariz et al. "Phase dependent modulation of tremor amplitude in essential tremor through thalamic stimulation". Brain 136, n.º 10 (octubre de 2013): 3062–75. http://dx.doi.org/10.1093/brain/awt239.
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Moyer, Paula. "TREMOR RATING SCALE CAN ASSESS AMPLITUDE OF ESSENTIAL TREMOR, RESPONSE TO TREATMENT". Neurology Today 4, n.º 10 (octubre de 2004): 63. http://dx.doi.org/10.1097/00132985-200410000-00015.
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Moyer, Paula. "TREMOR RATING SCALE CAN ASSESS AMPLITUDE OF ESSENTIAL TREMOR, RESPONSE TO TREATMENT". Neurology Today 4, n.º 10 (octubre de 2004): 63,64. http://dx.doi.org/10.1097/00132985-200410000-00019.
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Cleeves, L. y L. J. Findley. "Variability in amplitude of untreated essential tremor." Journal of Neurology, Neurosurgery & Psychiatry 50, n.º 6 (1 de junio de 1987): 704–8. http://dx.doi.org/10.1136/jnnp.50.6.704.
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Dirkx, Michiel F., Heidemarie Zach, Annelies J. van Nuland, Bastiaan R. Bloem, Ivan Toni y Rick C. Helmich. "Cognitive load amplifies Parkinson’s tremor through excitatory network influences onto the thalamus". Brain 143, n.º 5 (1 de mayo de 2020): 1498–511. http://dx.doi.org/10.1093/brain/awaa083.
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Abstract Parkinson’s tremor is related to cerebral activity in both the basal ganglia and a cerebello-thalamo-cortical circuit. It is a common clinical observation that tremor markedly increases during cognitive load (such as mental arithmetic), leading to serious disability. Previous research has shown that this tremor amplification is associated with reduced efficacy of dopaminergic treatment. Understanding the mechanisms of tremor amplification and its relation to catecholamines might help to better control this symptom with a targeted therapy. We reasoned that, during cognitive load, tremor amplification might result from modulatory influences onto the cerebello-thalamo-cortical circuit controlling tremor amplitude, from the ascending arousal system (bottom-up), a cognitive control network (top-down), or their combination. We have tested these hypotheses by measuring concurrent EMG and functional MRI in 33 patients with tremulous Parkinson’s disease, OFF medication, during alternating periods of rest and cognitive load (mental arithmetic). Simultaneous heart rate and pupil diameter recordings indexed activity of the arousal system (which includes noradrenergic afferences). As expected, tremor amplitude correlated with activity in a cerebello-thalamo-cortical circuit; and cognitive load increased tremor amplitude, pupil diameter, heart rate, and cerebral activity in a cognitive control network distributed over fronto-parietal cortex, insula, thalamus and anterior cingulate cortex. The novel finding, obtained through network analyses, indicates that cognitive load influences tremor by increasing activity in the cerebello-thalamo-cortical circuit in two different ways: by stimulating thalamic activity, likely through the ascending arousal system (given that this modulation correlated with changes in pupil diameter), and by strengthening connectivity between the cognitive control network and the cerebello-thalamo-cortical circuit. We conclude that both the bottom-up arousal system and a top-down cognitive control network amplify tremor when a Parkinson’s patient experiences cognitive load. Interventions aimed at attenuating noradrenergic activity or cognitive demands may help to reduce Parkinson’s tremor.
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Sturman, Molly M., David E. Vaillancourt y Daniel M. Corcos. "Effects of Aging on the Regularity of Physiological Tremor". Journal of Neurophysiology 93, n.º 6 (junio de 2005): 3064–74. http://dx.doi.org/10.1152/jn.01218.2004.
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The purpose of this investigation was to determine the effects of healthy aging on the regularity of physiological tremor under rest and postural conditions. Additionally, we examined the contribution of mechanical reflex factors to age-related changes in postural physiological tremor. Tremor regularity, tremor–electromyographic (EMG) coherence, tremor amplitude, and tremor modal frequency were calculated for 4 age groups (young: 20–30 yr, young-old: 60–69 yr, old: 70–79 yr, and old-old: 80–94 yr) under resting and loaded postural conditions. There were 6 important findings from this study: 1) there were no differences between the young and elderly subjects for any of the dependent variables measured under the rest condition; 2) postural physiological tremor regularity was increased in the elderly; 3) postural physiological tremor-EMG coherence was also increased in the elderly, and there was a strong linear relation between peak tremor-EMG coherence in the 1- to 8-Hz frequency band and regularity of tremor. This relation was primarily driven by the increased magnitude of tremor-EMG coherence at 5.85 and 6.83 Hz; 4) enhanced mechanical reflex properties were not responsible for the increased magnitude of tremor-EMG coherence in the elderly subjects; 5) tremor amplitude was not different between the 4 age groups, but there was a slight decline in tremor modal frequency in the oldest age group in the unloaded condition; and 6) despite the increases in postural physiological tremor regularity and the magnitude of low frequency tremor-EMG coherence with age, there was a clear demarcation between healthy aging and previously published findings related to tremor pathology.
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Krauss, Joachim K., Mohsen Mohadjer, Fritz Nobbe y Fritz Mundinger. "The treatment of posttraumatic tremor by stereotactic surgery". Journal of Neurosurgery 80, n.º 5 (mayo de 1994): 810–19. http://dx.doi.org/10.3171/jns.1994.80.5.0810.
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✓ The authors report the long-term results of stereotactic surgery for severe posttraumatic appendicular tremor in 35 patients. The tremors developed after severe head trauma in 33 patients (94%) and after mild to moderate head trauma in two (6%). In all but one, the tremor was most evident during activity. The amplitude of the kinetic tremor was greater than 5 cm in 33 patients (94%) and greater than 12 cm in 19 patients (54%). All were severely incapacitated in their daily living activities due to the tremors. The 35 patients underwent 42 stereotactic operations; five patients were reoperated on the same side and two were treated with a bilateral staged procedure. The contralateral zona incerta was the stereotactic target in 12 patients and was targeted in combination with the base of the ventrolateral (oroventral) thalamus in 23 patients. Long-term postoperative follow-up review was obtained in 32 patients (mean follow-up period 10.5 years). Persistent improvement of tremor was noted in 88%. The tremor was absent or markedly reduced in 65%. Functional disability was assessed and quantified with a modified form of an established rating scale for patients with tremor; it was reduced from a mean value of 57% of maximum disability to 37% over the long term (p < 0.001). Follow-up lesion assessment was obtained in 18 patients by multiplanar magnetic resonance imaging and at autopsy in one patient whose death was unrelated to surgery. As in previous studies, the frequency of persistent side effects was relatively high (38%). These consisted mainly of aggravation of preoperative symptoms. The results are compared to those of a total of 55 patients reported from 1960 to 1992. The occurrence of dystonia and dystonic postures is discussed. Stereotactic surgery is a powerful tool to alleviate posttraumatic tremor and to improve functional disability. However, as there is considerable risk of persistent morbidity in patients after severe head trauma, the operation should be restricted to selected cases with disabling tremor.
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Shah, A., J. Coste, JJ Lemaire, E. Schkommodau y S. Hemm-Ode. "Use of quantitative tremor evaluation to enhance target selection during deep brain stimulation surgery for essential tremor". Current Directions in Biomedical Engineering 1, n.º 1 (1 de septiembre de 2015): 488–92. http://dx.doi.org/10.1515/cdbme-2015-0117.
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AbstractDeep brain stimulation (DBS), an effective surgical treatment for Essential Tremor (ET), requires test stimulations in the thalamus to find the optimum site for permanent electrode implantation. During these test stimulations, the changes in tremor are only visually evaluated. This, along with other parameters, increases the subjectivity when comparing the efficacy of different thalamic nuclei. We developed a method to quantitatively evaluate tremor during the test stimulations of DBS surgery and applied to 6 ET patients undergoing this treatment. From the quantitative data collected, we identified effective stimulation amplitudes for every test stimulation position and compared it with the ones identified visually during the surgery. We also classified the data based on the thalamic nuclei in which the center of the stimulating contact was present during test stimulations. Results indicate that, to achieve the same reduction in tremor, on average, the stimulation amplitude identified by our method was 0.6 mA lower than those identified by visual evaluation. The comparison of the different thalamic nuclei showed that stimulations in the Ventro-oral and the Intermediolateral nuclei of the thalamus result in higher reduction in tremor for similar stimulation amplitudes as the frequently targeted Ventrointermediate nucleus. We conclude that our quantitative tremor evaluation method is more sensitive than the widely used visual evaluation. Using such quantitative methods will aid in identifying the optimum target structure for patients undergoing DBS.
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Elble, R. J. "Tremor amplitude is logarithmically related to 4- and 5-point tremor rating scales". Brain 129, n.º 10 (15 de julio de 2006): 2660–66. http://dx.doi.org/10.1093/brain/awl190.
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Habib, Md Ahsan, ASM Alamgir, Subash Kanti Dey, Afroja Alam, Ahmed Asafuddoula y Abu Nasir Rizvi. "Effect of Trihexiphenidyl and Procyclidine for the management of resting tremor". Bangladesh Medical Journal 44, n.º 2 (5 de abril de 2016): 72–75. http://dx.doi.org/10.3329/bmj.v44i2.27241.
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Parkinsons disease is the main etiology of resting tremor but may also rarely occur in Essential Tremor, Multiple System Atrophy & Progressive Suprneuclear Palsy. Levodopa improves bradykinesia, rigidity and other commonly associated symptoms. When resting tremor is the predominant presenting symptom of Parkinson's disease or when tremor persists despite adequate control of other parkinsonian symptoms with low dosages of levodopa, an anticholinergic agent such as trihexyphenidyl or Procyclidine may be the treatment of choice. This prospective interventional study was carried out in the department of Neurology, Bangabandhu Sheikh Mujib Medical University, Dhaka from March, 2014 to June, 2014 with the intention to outline effectiveness, similarities and differences between Trihexyphenidyl and Procyclidine in alleviating resting tremor. For Parkinsons disease, patients presenting with predominant tremor but minimal bradykinesia and rigidity were purposively selected for the study. Resting tremor was assessed by united parkinsons disease rating scale (UPDRS). A total of 30 consecutive patients, both male and female, having resting tremor due to different etiology & attending both indoor and outpatient department of Neurology, BSMMU were randomized to receive either Trihexyphenidyl or Procyclidine for two weeks. For most of the patients (93%) resting tremor were due to Parkinsons disease and only 7% were due to Essential tremor. In case of Trihexiphenidyl, constancy and amplitude of resting tremor were improved in 60% and 80% respectively. In case of Procyclidine, constancy and amplitude of resting tremor were imoroved 87% and 67% respectively. The difference of improvement between Trihexiphenidyl group and Procyclidine group was not statistically significant.Bangladesh Med J. 2015 May; 44 (2): 72-75
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Essing, David, Vera Schlindwein, Mechita C. Schmidt-Aursch, Celine Hadziioannou y Simon C. Stähler. "Characteristics of Current-Induced Harmonic Tremor Signals in Ocean-Bottom Seismometer Records". Seismological Research Letters 92, n.º 5 (28 de abril de 2021): 3100–3112. http://dx.doi.org/10.1785/0220200397.
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Abstract Long-lasting harmonic tremor signals are frequently observed in spectrograms of seismological data. Natural sources, such as volcanoes and icebergs, or artificial sources, such as ships and helicopters, produce very similar harmonic tremor episodes. Ocean-bottom seismometer (OBS) records may additionally be contaminated by tremor induced by ocean-bottom currents acting on the OBS structure. This harmonic tremor noise may severely hinder earthquake detection and can be misinterpreted as volcanic tremor. In a 160-km-long network of 27 OBSs deployed for 1 yr along the Knipovich ridge in the Greenland Sea, harmonic tremor was widely observed away from natural sources such as volcanoes. Based on this network, we present a systematic analysis of the characteristics of hydrodynamically induced harmonic tremor in OBS records to make it distinguishable from natural tremor sources and reveal its generation processes. We apply an algorithm that detects harmonic tremor and extracts time series of its fundamental frequency and spectral amplitude. Tremor episodes typically occur twice per day, starting with fundamental frequencies of 0.5–1.0 Hz, and show three distinct stages that are characterized by frequency-gliding, mode-locking, and large spectral amplitudes, respectively. We propose that ocean-bottom currents larger than ∼5 cm/s cause rhythmical Karman vortex shedding around protruding structures of the OBS and excite eigenvibrations. Head-buoy strumming is the most likely source of the dominant tremor signal, whereas a distinctly different tremor signal with a fundamental frequency ∼6 Hz may be related to eigenvibrations of the radio antenna. Ocean-bottom current velocities reconstructed from the fundamental tremor frequency and from cross correlation of tremor time series between stations match observed average current velocities of 14–20 cm/s in this region. The tremor signal periodicity shows the same tidal constituents as the forcing ocean-bottom currents, which is a further evidence of the hydrodynamic nature of the tremor.
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Muruzheva, Zamira M., Aleksey A. Ezhov, Marina N. Karpenko, Marina A. Fominceva, Victor M. Klimenko y Igor D. Stolyarov. "Clinical and electrophysiological heterogeneity of essential tremor". Medical academic journal 18, n.º 4 (15 de diciembre de 2018): 64–72. http://dx.doi.org/10.17816/maj18464-72.
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This study aimed to identify clinical and electrophysiological signs that determine the phenotypic heterogeneity of essential tremor using a cluster analysis. Seventy-five patients with essential tremor were examined. To identify the heterogeneity of the disease, a cluster analysis was applied (k-means method). Clustering was performed according to clinical and electromyographic parameters. The heterogeneity of essential tremor is justified by amplitude characteristics, topography of tremor, duration disease, and severity of impaired of daily activity. Detecting heterogeneity in essential tremor can broaden understanding of pathogenesis disease and justify heterogeneity of the pharmacological response in patients with essential tremor.
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Carbonell, Kathy M., Brad Story, Rosemary Lester y Andrew J. Lotto. "Discriminating vocal tremor source from amplitude envelope modulations". Journal of the Acoustical Society of America 132, n.º 3 (septiembre de 2012): 2090. http://dx.doi.org/10.1121/1.4755723.
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Aleksandrov, A. Yu, K. O. Uplisova y V. Yu Ivanova. "Biofeedback Specialization Effect on Physiological Tremor Amplitude Dynamics". Human Physiology 46, n.º 2 (marzo de 2020): 127–33. http://dx.doi.org/10.1134/s036211972001003x.
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Slack, Paul S. y Xianghong Ma. "Tremor amplitude determination for use in clinical applications". Measurement Science and Technology 18, n.º 11 (4 de octubre de 2007): 3471–78. http://dx.doi.org/10.1088/0957-0233/18/11/030.
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Akyürekli, Onder, Çağla Kaya, Fisun Ersan y Acarer Ahmet. "WO23 Does tremor amplitude depend on receptor subtype?" Clinical Neurophysiology 119 (mayo de 2008): S26. http://dx.doi.org/10.1016/s1388-2457(08)60103-0.
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Rahimi, Fariborz, Derek Debicki, Angela Roberts-South, Carina Bee, Priya Bapat y Mandar Jog. "Dynamic Decomposition of Motion in Essential and Parkinsonian Tremor". Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 42, n.º 2 (23 de febrero de 2015): 116–24. http://dx.doi.org/10.1017/cjn.2015.12.
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AbstractBackground: Treatment options for essential (ET) and Parkinson disease (PD) tremor are suboptimal, with significant side effects. Botulinum toxin type A (BoNT A) is successfully used in management of various focal movement disorders but is not widely used for tremor. Method: This study examines complexity of wrist tremor in terms of involvement of its three anatomical degrees of freedom (DOF) in two common situations of rest and posture. The study examines tremor in 11 ET and 17 PD participants by kinematic decomposition of motion in 3-DOF. Results: Tremor decomposition showed the motion involved more than one DOF (<70% contribution in one DOF) in most ET (rest: 100%, posture: 64%) and PD (rest: 77%, posture: 77%) patients. Task variation resulted in change in both amplitude and composition in ET, but not in PD. Amplitude significantly increased from rest to posture in ET. Directional bias was observed at the wrist for ET (pronation), and PD (extension, ulnar deviation, pronation). Average agreement between clinical visual and kinematic selection of muscles was 55% across all subjects. Conclusion: This study shows the complexity of tremor and the difficulty in visual judgment of tremor, which may be key to the success of targeted focal treatments such as BoNT A.
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Fekete, Robert. "Paroxysmal Nonkinesigenic Dyskinesia with Tremor". Case Reports in Neurological Medicine 2013 (2013): 1–2. http://dx.doi.org/10.1155/2013/927587.
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Introduction. Paroxysmal nonkinesigenic dyskinesia (PNKD) consists of episodes of chorea, athetosis, or dystonia which are not triggered by movement, with complete remission between episodes. A case of genetically confirmed PNKD with simultaneous tremor has not been previously reported.Case Report. The patient is an 86-year-old right-handed female who presented with episodic stiffness, with onset at age 9. Attacks have a prodrome of difficulty in speaking, followed by abnormal sensation in extremities. Episodes consist of dystonia of trunk associated with upper and lower extremity chorea. There is complete resolution between attacks except for persistent mild head tremor and action tremor of both extremities. Attack frequency and duration as well as tremor amplitude escalated two and a half years ago, in correlation with development of breast carcinoma. Episodes improved after successful cancer treatment, but higher amplitude tremor persisted. There is an autosomal dominant family history of similar episodes but not tremor. Genetic diagnosis was confirmed via A7V mutation of the myofibrillogenesis regulator (MR-1) gene.Conclusion. Exacerbation due to another medical or psychiatric condition should be considered if there is unexpected deterioration in episode frequency or length. PNKD due to MR-1 mutation may exist even in the presence of action tremor.
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Rajput, Ali H. y Alex Rajput. "Medical Treatment of Essential Tremor". Journal of Central Nervous System Disease 6 (enero de 2014): JCNSD.S13570. http://dx.doi.org/10.4137/jcnsd.s13570.
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Essential tremor (ET) is the most common pathological tremor characterized by upper limb action—postural tremor (PT)/kinetic tremor (KT). There are no specific neuropathological or biochemical abnormalities in ET. The disability is consequent to amplitude of KT, which may remain mild without handicap or may become disabling. The most effective drugs for sustained tremor control are propranolol and primidone. Symptomatic drug treatment must be individualized depending on the circumstances that provoke the tremor-related disability. Broad guidelines for treatment are discussed in this review. Patients may be treated intermittently only on stressful occasions with propranolol, clonazepam, or primidone monotherapy, or an alcoholic drink. Those with persistently disabling tremor need continued treatment.
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Samotus, Olivia, Jack Lee y Mandar Jog. "Standardized algorithm for muscle selection and dosing of botulinum toxin for Parkinson tremor using kinematic analysis". Therapeutic Advances in Neurological Disorders 13 (enero de 2020): 175628642095408. http://dx.doi.org/10.1177/1756286420954083.
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Background: Inadequate efficacy and significant side effect profile makes pharmacological treatment of Parkinson’s disease (PD) tremor challenging. Personalized dosing of botulinum toxin type A (BoNT-A) using tremor analysis has shown efficacy and safety for treating upper limb tremor. This study incorporated a novel, standardized treatment algorithm for determining injection pattern and BoNT-A dosing, customizable by the physician, in PD patients with disabling tremor in one or both arms. Methods: This open-label study included 47 PD participants (25 “De-novo” and 22 “L-dopa”) who received 4 serial BoNT-A treatments with follow-ups at 6 weeks post-treatment over 42 weeks. The treatment algorithm utilized kinematic tremor analysis of each participant’s whole arm tremor and determined the physician’s injection pattern of BoNT-A. Endpoints included changes in angular tremor amplitude, Fahn-Tolosa-Marin (FTM C) tremor scale, Movement Disorder Society-Unified Parkinson’s disease rating scale (MDS-UPDRS) tremor-related score, tremor-related quality of life questionnaire, Likert ratings of perceived weakness, and maximal grip strength. Results: BoNT-A significantly ( p < 0.05) improved tremor amplitude (41.6%), quality of life (23.0%), UPDRS tremor score (29.6%), and arm function (FTM C; 24.6%) for both treatment cohorts from weeks 6 to 42. Maximum grip strength was reduced between 7.4% and 23.0% at follow-up visits and did not impact activities of daily living. Efficacy was obtained with first injection and remained without adjustment over two serial injection in 45% of participants. Conclusions: This is the first study to use a fully standardized treatment algorithm for personalization of BoNT-A injection patterns for disabling PD tremor over serial treatments. A sustained alleviation of tremor severity and improved arm function and quality of life fulfills an important unmet need for the treatment of PD tremor. This study demonstrated that BoNT-A can be administered as a monotherapy in tremor-dominant PD or as an add-on therapy for refractory PD tremor.
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Walsh, Bridget y Anne Smith. "Oral Electromyography Activation Patterns for Speech Are Similar in Preschoolers Who Do and Do Not Stutter". Journal of Speech, Language, and Hearing Research 56, n.º 5 (octubre de 2013): 1441–54. http://dx.doi.org/10.1044/1092-4388(2013/12-0177).
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Purpose In this study, the authors determined whether basic patterns of muscle activation for speech were similar in preschool children who stutter and in their fluent peers. Method Right and left lower lip muscle activity were recorded during conversational speech and sentence repetition in 64 preschool children diagnosed as stuttering (CWS) and in 40 children who do not stutter (CWNS). Measures of electromyography (EMG) amplitude, right–left asymmetry, and bilateral coordination were computed for fluent speech. The potential presence of tremor-like oscillations during disfluencies of CWS was assessed, and EMG amplitudes of fluent and disfluent speech were compared in CWS. Results Across both speaking tasks, lip muscle activation was similar in CWS and CWNS in overall amplitude, bilateral synchrony, and degree of right–left asymmetry. EMG amplitude was reduced during disfluent compared with fluent conversational speech of CWS, and there was no evidence of tremor in the disfluencies of CWS. Conclusion These results support the assertion that stuttering in young children arises not from basic features of muscle contraction but rather from the command signals that control the timing and amplitude of muscle activity. The results indicate that no frank abnormality is present in muscle activation patterns in preschoolers who stutter.
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Keogh, Justin W. L., Steve Morrison y Rod Barrett. "Strength and Coordination Training Are Both Effective in Reducing the Postural Tremor Amplitude of Older Adults". Journal of Aging and Physical Activity 18, n.º 1 (enero de 2010): 43–60. http://dx.doi.org/10.1123/japa.18.1.43.
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The current study investigated the effect of 2 different types of unilateral resistance training on the postural tremor output of 19 neurologically healthy men age 70–80 yr. The strength- (n= 7) and coordination-training (n= 7) groups trained twice a week for 6 wk, performing dumbbell biceps curls, wrist flexions, and wrist extensions, while the control group (n= 5) maintained their normal activities. Changes in index-finger tremor (RMS amplitude, peak, and proportional power) and upper limb muscle coactivation were assessed during 4 postural conditions that were performed separately with the trained and untrained limbs. The 2 training groups experienced significantly greater reductions in mean RMS tremor amplitude, peak, and proportional tremor power 8–12 Hz and upper limb muscle coactivation, as well as greater increases in strength, than the control group. These results further demonstrate the benefits of resistance training for improving function in older adults.
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Hopfner, Franziska, Tatjana Erhart, Karina Knudsen, Delia Lorenz, Susanne A. Schneider, Kirsten E. Zeuner, Günther Deuschl y Gregor Kuhlenbäumer. "Testing for alcohol sensitivity of tremor amplitude in a large cohort with essential tremor". Parkinsonism & Related Disorders 21, n.º 8 (agosto de 2015): 848–51. http://dx.doi.org/10.1016/j.parkreldis.2015.05.005.
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Park, Kye Won, Eun-Jae Lee, Jun Seong Lee, Jinhoon Jeong, Nari Choi, Sungyang Jo, Mina Jung et al. "Machine Learning–Based Automatic Rating for Cardinal Symptoms of Parkinson Disease". Neurology 96, n.º 13 (10 de febrero de 2021): e1761-e1769. http://dx.doi.org/10.1212/wnl.0000000000011654.
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ObjectiveWe developed and investigated the feasibility of a machine learning–based automated rating for the 2 cardinal symptoms of Parkinson disease (PD): resting tremor and bradykinesia.MethodsUsing OpenPose, a deep learning–based human pose estimation program, we analyzed video clips for resting tremor and finger tapping of the bilateral upper limbs of 55 patients with PD (110 arms). Key motion parameters, including resting tremor amplitude and finger tapping speed, amplitude, and fatigue, were extracted to develop a machine learning–based automatic Unified Parkinson's Disease Rating Scale (UPDRS) rating using support vector machine (SVM) method. To evaluate the performance of this model, we calculated weighted κ and intraclass correlation coefficients (ICCs) between the model and the gold standard rating by a movement disorder specialist who is trained and certified by the Movement Disorder Society for UPDRS rating. These values were compared to weighted κ and ICC between a nontrained human rater and the gold standard rating.ResultsFor resting tremors, the SVM model showed a very good to excellent reliability range with the gold standard rating (κ 0.791; ICC 0.927), with both values higher than that of nontrained human rater (κ 0.662; ICC 0.861). For finger tapping, the SVM model showed a very good reliability range with the gold standard rating (κ 0.700 and ICC 0.793), which was comparable to that for nontrained human raters (κ 0.627; ICC 0.797).ConclusionMachine learning–based algorithms that automatically rate PD cardinal symptoms are feasible, with more accurate results than nontrained human ratings.Classification of EvidenceThis study provides Class II evidence that machine learning–based automated rating of resting tremor and bradykinesia in people with PD has very good reliability compared to a rating by a movement disorder specialist.
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Güney, Gökhan, Talisa S. Jansen, Sebastian Dill, Jörg B. Schulz, Manuel Dafotakis, Christoph Hoog Antink y Anne K. Braczynski. "Video-Based Hand Movement Analysis of Parkinson Patients before and after Medication Using High-Frame-Rate Videos and MediaPipe". Sensors 22, n.º 20 (20 de octubre de 2022): 7992. http://dx.doi.org/10.3390/s22207992.
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Tremor is one of the common symptoms of Parkinson’s disease (PD). Thanks to the recent evolution of digital technologies, monitoring of PD patients’ hand movements employing contactless methods gained momentum. Objective: We aimed to quantitatively assess hand movements in patients suffering from PD using the artificial intelligence (AI)-based hand-tracking technologies of MediaPipe. Method: High-frame-rate videos and accelerometer data were recorded from 11 PD patients, two of whom showed classical Parkinsonian-type tremor. In the OFF-state and 30 Minutes after taking their standard oral medication (ON-state), video recordings were obtained. First, we investigated the frequency and amplitude relationship between the video and accelerometer data. Then, we focused on quantifying the effect of taking standard oral treatments. Results: The data extracted from the video correlated well with the accelerometer-based measurement system. Our video-based approach identified the tremor frequency with a small error rate (mean absolute error 0.229 (±0.174) Hz) and an amplitude with a high correlation. The frequency and amplitude of the hand movement before and after medication in PD patients undergoing medication differ. PD Patients experienced a decrease in the mean value for frequency from 2.012 (±1.385) Hz to 1.526 (±1.007) Hz and in the mean value for amplitude from 8.167 (±15.687) a.u. to 4.033 (±5.671) a.u. Conclusions: Our work achieved an automatic estimation of the movement frequency, including the tremor frequency with a low error rate, and to the best of our knowledge, this is the first paper that presents automated tremor analysis before/after medication in PD, in particular using high-frame-rate video data.