• Journal of Biomedical Engineering Research
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• v.37 no.1
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• pp.15-20
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• 2016

Essential tremor is a neurological disorder with a tremor of the arms and hands. It is well known that essential tremor is characterized by the postural tremor and the action tremor. There has been no report on the quantitative difference in the characteristics of two tremor types. The purpose of this study was to investigate the possible difference in tremor characteristics of postural and action tremors. Seventeen patients with essential tremor ($68.9{\pm}7.9years$, 7 men, 10 women) participated in this study. Patients performed the tasks of postural maintenance (arms outstretched) and daily actions (spiral drawing). Three-axes (pitch, roll and yaw) gyro sensors were attached on index finger, back of hand and forearm, from which the segment and the joint angular velocities were calculated. Outcome measure was the tremor amplitude defined as the root-mean-square mean of the vector-sum angular velocity at segments and joints. Two-way ANOVA showed that task and joint had main factor on the tremor amplitude (p < 0.05). Post-hoc analysis revealed that tremor amplitude at the metacarpo-phalangeal joint was not affected by task (p > 0.05). However, tremor amplitude at the wrist joint differed among the tasks (p < 0.05), and it was greater in the action tasks than in postural task. Tremor was greater at finger segments than at hand and forearm and it increased in action tasks. The results of this study would be helpful for the understanding and task-specific treatments of the essential tremor.

• Annals of Clinical Neurophysiology
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• v.4 no.1
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• pp.44-50
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• 2002

Introduction : Orthostatic tremor develops in the legs while standing up with no weakness, pain or imbalance in the leg and the tremor is characteristically not observed when walking. However there have been some confusions about orthostatic tremor in several aspects. For the past ten years, we have observed 4 patients with orthostatic tremor. In each case tests were performed to investigate the following three important areas of inquiry about orthostatic tremor. Firstly, whether this disorder is an independent diagnostic entity or a variant of essential tremor. Secondly, whether the progress of this disorder is specifically related with standing posture. Lastly, the nature of the pathophysiologic mechanism behind the appearance of the tremor when standing after the lapse of a certain latent period and its disappearance upon the commencement of walking. Methods : Our 4 cases of orthostatic tremor were studied clinically, electrophysiologically, and pharmacologically. Electrophysiological tests included tremor spectrum test and electromyography. Results : We observed the presence of this tremor in several other tonic postures, as well as its absence, in a vertically lifted position from all our cases. Our cases registered a variable tremor frequency between 5 and 12 Hz according to the tremor spectrum test and EMG. Furthermore all our 4 cases demonstrated patterns of both synchronous EMG activity and alternating EMG activity at various times in homologous muscles of both legs. Orthostatic tremor was improved significantly with propranolol as well as clonazepam. Conclusions : From the results of our study we drew the following conclusions. It is probable that orthostatic tremor is simply a variant of essential tremor rather than being an independent diagnostic entity and that in most cases its development is specifically related with muscle contraction rather than merely with the act of standing. Furthermore we discovered a clue in the previously described neural control mechanism that the nuclear bag fibers in the muscle spindle have lag time of several seconds in their response to muscle strength and that their baseline does not reset fully in rapidly moving muscle. This neural control mechanism could offer sufficient explanation for the phenomena of tremor appearance when standing and disappearance when walking in orthostatic tremor.

• Annals of Clinical Neurophysiology
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• v.3 no.2
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• pp.128-135
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• 2001

Background : Tremor is uncommon manifestation of stroke. Therefore a few cases have been reported until now. There is still uncertainty about the characteristics of post-stroke tremor. Furthermore the pathogenesis and responsible structures of post-stroke tremor are not precisely known. We have recently experienced 34 cases of post-stroke tremor for the past 6 years. We analysed the clinical features and electrophysiologic findings of post-stroke tremor to evaluate the general characteristics and to analogize the possible pathogenetic mechanisms of post-stroke tremor. Methods : The clinical characteristics of post-stroke tremor were summarized in according to the onset time, involved body parts, types, tremor frequencies, neuroradiologic findings, and associated symptoms. The tremor frequencies were recorded by using a gyroscope. The spectral analysis of tremor frequencies were done automatically with Motus I soft ware. Results : Tremor onset were remarkably varied. Some patients showed a tremor appearing at the onset of a stroke and other patients showed delayed-onset tremor 10 years after a stroke. Tremor frequencies were also much varied. The range of hand tremor frequencies were from 1.5 to 12 Hz. Lesions were found in 31 cases(infarction 27, hemorrhage 4) on neuroimaging. In the cases of cerebral infarctions, 7 cases showed multiple small vessel diseases and 20 cases showed cerebral vessel lesions. The most commonly involved cerebral vessel lesion was the middle cerebral artery territory Several different clinical patterns of post-stroke tremor were identified. Conclusions : There are some evidences from the data summarized here to suggest that several pathogenetic mechanisms including central oscillators could be involved for the development of tremors and that tremor generating neural circuits could be more complex than previously suggested neural circuits.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.6
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• pp.1044-1049
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• 2011

The purpose of this study was to study clinical characteristics of patients complained of tremor and to evaluate availability of oriental medical treatment. This observation was made on 36 cases that were hospitalized in the Semyung University Oriental Medicine Hospital and evaluated tremor using clinical rating tremor scale(CRTS). The ratio of patients were essential tremor(50%), parkinson's disease(13.9%), psychogenic tremor(13.9%), physiologic tremor(11.1%), cerebellar tremor(11.1%). CRTS score of essential tremor patients decreased significantly. Physiologic tremor patients's CRTS score were under 15 points. Every patient's scores decreased. Two patients's score decreased to 0 point. Every patient were treated with Bojungikki-tang-gamibang. CRTS scores of psychogenic tremor patients were various.(4~24 points) Two patients's scores decreased to 0 point. The CRTS scores of three cases among four patients with cerebellar tremor were not changed. Changes of CRTS score between oriental medication group and western-oriental combined medication group were statistically significant. Changes of CRTS score between over 15 points group and under 15 points group were statistically significant. Kejigayongolmoryo-tang was one of the most widely used herbal medication, which was diagnosed as ascendant hyperactivity of liver yang.

• Current Optics and Photonics
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• v.1 no.6
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• pp.642-648
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• 2017

Involuntary hand tremor has been a serious challenge in micromanipulation tasks and thus draws a significant amount of attention from related fields. To minimize the effect of the hand tremor, a variety of mechanically assistive solutions have been proposed. However, approaches increasing human awareness of their own hand tremor have not been extensively studied. In this paper, a head mount display based virtual reality (VR) system to increase human self-awareness of hand tremor is proposed. It shows a user a virtual image of a handheld device with emphasized hand tremor information. Provided with this emphasized tremor information, we hypothesize that subjects will control their hand tremor more effectively. Two methods of emphasizing hand tremor information are demonstrated: (1) direct amplification of tremor and (2) magnification of virtual object, in comparison to the controlled condition without emphasized tremor information. A human-subject study with twelve trials was conducted, with four healthy participants who performed a task of holding a handheld gripper device in a specific direction. The results showed that the proposed methods achieved a reduced level of hand tremor compared with the control condition.

• The Journal of Internal Korean Medicine
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• v.25 no.4
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• pp.391-400
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• 2004

Tremor is a rhythmic and involuntary muscular contraction characterized by oscillations of a part of the body. Tremor is a symptom of many disorders, including Parkinson's disease, essential tremor, orthostatic tremor, cerebellar disease, peripheral neuropathy and alcohol withdrawal. The appropriate treatment of tremor depends on accurate diagnosis of it's cause. Some tremors respond to treatment of underlying conditions. Senile tremor and Parkinson's tremor are more common in aged people. Yanghyulgupung-tang is effective herbal medication in blood deficiency-type senile tremor. Four cases of senile tremor and Parkinson's tremor are reported. All four patient were treated with Yanghyulgupungtang-gamibang and improvement was seen in all four.

• Journal of Korean Neurosurgical Society
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• v.37 no.5
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• pp.325-328
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• 2005

Objective: Stereotactic thalamic procedure is well known to be a effective treatment for disabling upper limb tremor of essential tremor. However, the effect of this procedure for head tremor, which is midline symptom of that disease entity, has not been sufficiently established. The authors discuss the result of stereotactic thalamic operations for head tremor of their patients who suffered from essential tremor. Methods: We evaluated 4 patients of essential tremor who had head tremor combined with both upper limb tremor. One patient underwent unilateral ventralis intermedius thalamotomy, two patients had unilateral Vim deep brain stimulation(DBS) and one patient had unilateral Vim thalamotomy and contralateral DBS. Postoperative results of tremor were evaluated using our proposed scale. Results: Contralateral upper limb tremors to surgical side were markedly resolved in all patients but there was no meaningful effect for head tremor in 3 patients who underwent unilateral thalamic surgery. In a patient having simultaneously unilateral thalamotomy and contralateral DBS, remarkable improvement of head tremor was observed. Conclusion: Although it is difficult to evaluate the efficacy of thalamic surgery for axial symptom of essential tremor with a few cases, simultaneous unilateral thalamotomy and contralateral DBS would be expected to induce favorable outcomes for head tremor with significant economical advantages.

• The Journal of Internal Korean Medicine
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• v.27 no.3
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• pp.776-783
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• 2006

Tremor is a rhythmic and involuntary muscular contraction characterized by oscillations of a part of the body. The most common of all involuntary movements, tremor can affect various body parts such as hands, head, facial structures, vocal cords, trunk, and legs; most tremors, however, occur in the hands. Clinically, tremor is classified into postural tremor, resting tremor, action tremor, and other kinds of tremor, and treated according to the causes. The author reports the improvement of the patient, hospitalized at Dong Seo Medical Center, whose tremor was not classified specifically in western medicine but was diagnosed as Ganhyeolbujok (肝血不足) by Korean medicine.

• Journal of Biomedical Engineering Research
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• v.36 no.4
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• pp.103-108
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• 2015

Discrimination of Parkinson's disease (PD) from Essential tremor (ET) is often misdiagnosed in clinical practice. Since tremor is time-varying signal, and dominant and harmonic frequencies are shown in tremor only with moderate or severe symptom, there are some limitations to use frequency related features. Moreover, patients with PD or ET can suffer from both resting tremor and postural tremor. In this study, 28 patients with PD and 17 patients with ET were enrolled. Tremor was measured with accelerations on the more affected hand during resting and postural conditions. The ratio of root mean square (RMS) of resting tremor to RMS of postural tremor, the mean coefficients of autocorrelation function (ACF), and the mean of differences of two adjacent coefficients of ACF at resting and postural were calculated and compared between PD and ET. The performance showed 98% accuracy with support vector machine and leave-one-out cross validation. In addition, the method accurately differentiated the patients with tremor-dominant PD from patients with ET, with 100% accuracy. Therefore, the developed algorithm can assist clinicians in diagnosing and categorizing patients with tremor, especially, patients with mild symptom or the early stage of a disease, for proper treatment.

• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.177-184
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• 1996

In light-weight hand tools, static posture may result in postural fatigue. Psotural tremor of the upper extremity in a static posture was measured to provide guidelines for hand tool weight. Postural tremor was measured on five levels of tool weitht : no weight, 400g, 800g, 1200g, and 1600g. Three types of camcorder recording postures were selected. For each condition, postural tremor was measured together with ENG of biceps, deltoid and pectoralis major, and Borg's CR-20 ratings of perceved exertion. Results of the experiment are as follows : frequency analysis of tremor revealed increased amplitude of frequency bands of 2-4Hz and 10-14Hz. Postural tremor of the upper extremeity maintained the initial level until fatigue developed. After the development of fatigue, the rate of change of postural tremor significantly increased. Different tool weights and hand postures showed different rates of tremor increase. Time tp fatigue and corresaponding endurance time were positively correlated with Borg's RPE scores.