Isometric features of orthostatic tremor: an electromyographic analysis

A patient is described with "orthostatic" tremor. Electromyography revealed tremor bursts of 15 Hz in the lower extremities while standing and with isometric activation of the muscles, but the bursts disappeared with isotonic activation of muscles. Similar tremor was recorded in the arms with isometric, but not isotonic activation. Review of previously reported cases confirms these findings. The clinical and electrophysiologic features of this tremor distinguish it from other recognized forms of tremor.     

Orthostatic tremor during modification of standing.

Primary orthostatic tremor (OT) occurs only during standing. We studied whether modification of the condition standing influences OT. In seven patients with OT, surface EMG was recorded from both tibialis anterior and gastrocnemius muscles during two maneuvers: relief, whereby the patient was gradually lifted by a crane, and tilting, whereby the patient was tilted by a tilting table to positions of 90 degrees (upright standing), 45 degrees (diagonal position), and 0 degrees (lying position). We determined the parameters tremor frequency, tremor intensity, coherence, and phase shift between the different muscles. Relief did not influence OT. In contrast, tilting modified significantly tremor intensity and phase shifts; tremor frequencies and coherences were not influenced. We chose both these maneuvers because of their different impact on the standing condition: relief modifies the factors afferent input and muscle forcing but not the factor postural set, whereas tilting modifies all three factors. The fact that tilting modifies OT, whereas relief does not, suggests an important role of postural set in OT generation. Afferent input and muscle forcing seem to play less important role.     

合并静止性震颤的原发性震颤患者临床特点分析

目的了解北京地区社区中老年人原发性震颤(essential tremor,ET)的临床特征及其与预后的关系。方法2000年在北京城区、近郊平原、远郊山区调查了2835名55岁以上中老年人,采用筛查和临床诊断两步法确诊患者。发现ET患者135例,对其中合并静止性震颤的患者进行分析,并于2004年对其进行随访。结果其中合并上肢静止性震颤患者17例,占12.6%,合并静止性震颤组震颤总分、头部震颤的比例、肢体震颤总分均明显高于对照组。两组年龄、性别组成、病史无显著性差异,姿势性震颤和动作性震颤的程度差异不明显。4年后随访到13例(13/17),其中3例死亡,实际调查的10例中有9例仍诊断为ET,另1例诊断为临床很可能ET。结论有相当部分社区ET患者可以合并静止性震颤,合并静止性震颤的患者提示病情较重。     

Intention tremor of the head in patients with essential tremor.

Patients with essential tremor (ET) have kinetic arm tremor; this tremor can also have an intentional component. We are unaware of reports of intention tremor of the head in ET. Our aims were to describe, provide electrophysiological data and video documentation of, and estimate the prevalence of intention tremor of the head in our sample. Ten (9.0%; 95% confidence interval = 4.7%-14.3%) of 111 patients had intention tremor of the head; in 7 it involved the neck and in 3 the chin. These patients trended toward having more severe kinetic arm tremor and they had more severe intention tremor of the arms. These observations provide further support for the evolving view that the cerebellum may be involved in ET.     

特发性震颤的临床和电生理学特点

目的 探讨特发性震颤(EI)的临床和电生理学特点.方法 回顾性分析并比较33例ET患者(ET组)和30例生理性震颤患者(对照组)的震颤类型、程度、幅度和负重对其的影响,以总结ET的临床和电生理学特点.结果 ET组患者动作性震颤(KT)的震颤程度明显高于对照组,震颤幅度明显大于对照组(均P＜0.01);而姿势性震颤(PT...     

Electrophysiologic transition from physiologic tremor to essential tremor.

We electrophysiologically examined the transition from physiologic tremor to essential tremor in people at risk for familial essential tremor. Two healthy people from different families with hereditary essential tremor were studied on multiple occasions. A 23-year-old man was studied in 1995, 1997, and 2004, and a 44-year-old woman was studied in 1993, 1995, 1997, and 2003. Hand acceleration and forearm electromyographic readings were measured with and without 300-g loading to determine the characteristic frequency-invariant motor unit entrainment of essential tremor. Clinically and electrophysiologically, the man and woman had normal tremor until the last examination, when both exhibited a fine tremulousness in the outstretched hands and frequency-invariant motor unit entrainment at 7.5 and 6.5 Hz, respectively. At no time did either patient exhibit a prominent 8-12 Hz component of physiologic tremor. Essential tremor in young adults may begin at frequencies less than 8-12 Hz, and this electrophysiologic abnormality is detectable when clinical examinations reveal only questionably abnormal tremor. More young adults at risk for essential tremor must be studied to determine whether initial frequencies less than 8 Hz are the rule or the exception. Nevertheless, the data from our 2 patients demonstrate that a prominent 8-12 Hz component of physiologic tremor does not always precede the development of essential tremor; therefore, the origins of essential tremor and the 8-12 Hz component of physiologic tremor may be different.     

Prevalence and clinical classification of tremor in elderly—A community‐based survey in Brazil

Prevalence data on different types of tremor among the elderly population are very scarce. The objective of this study was to study the prevalence of tremor in a community‐dwelling elderly population in the town of Bambuí, Brazil. The authors studied 1186 inhabitants aged≥64 years. This was a 2‐phase study in which all participants who screened positive in a questionnaire for tremor and parkinsonism or who used drugs capable of causing/suppressing tremor were examined. In this population, the prevalence rate was 17.4% for tremor, 7.4% for essential tremor, 5.6% for parkinsonian tremor, 2.8% for enhanced physiological tremor, and 1.6% for other causes. There were no gender differences in prevalence rates for all types. Patients who had Parkinson's disease with tremor were older than those who had essential tremor, whereas patients who had enhanced physiological tremor were significantly younger. The age‐specific prevalence of tremor increased with advancing age for both men and women. The prevalence of tremor in the studied population was high and increased with advancing age. Essential tremor, parkinsonian tremor, and enhanced physiological tremor were the most commonly identified causes. © 2013 Movement Disorder Society     

Tremor on smiling

Facial tremor occurring on smiling is a rare phenomenon and has been described (to the best of our knowledge) in the literature only once. We describe two patients who presented with a bilateral facial tremor that occurred only on smiling and other activation of therisorii muscles and had a high frequency of 9 Hz. One patient additionally suffered from young‐onset Parkinson's disease, whereas the other had no further neurological symptoms or signs apart from this tremor. Anti‐parkinsonian medication was unhelpful for the facial tremor in the patient with Parkinson's disease. Tremor on smiling may be a discrete entity or may be associated in some cases of Parkinson's disease. © 2009 Movement Disorder Society     

Alcohol consumption of patients with essential tremor

Most patients with essential tremor experience a transient improvement after ingesting a small amount of alcohol. It has been accordingly suggested that essential tremor patients may have an increased risk of developing alcoholism. In this study, the frequency and amount of alcohol intake of essential tremor patients were found to be largely similar to the drinking habits of a control sample from the general population. This indicates that essential tremor does not generally augment alcohol consumption, nor is it a common cause of alcoholism.     

Postural tremor in X‐linked spinal and bulbar muscular atrophy

Postural tremor is a common initial symptom in spinal and bulbar muscular atrophy (SBMA), but its pathophysiological mechanisms remain to be studied. This study was undertaken to examine the physiological mechanisms underlying postural tremor in SBMA. For eight patients (36–63 years old) with genetically confirmed SBMA, we recorded surface electromyograms (EMGs) from the forearm muscles and hand movements with an accelerometer (ACC) while maintaining a posture with and without a weight load. We then analyzed their power spectra and coherence. The peak tremor frequency was 6–9 Hz in seven patients and 2–3 Hz in one patient. Oscillatory movements were associated with EMG activity in five patients, but not in three patients. Weight loads and postural changes affected the tremor frequency in all patients. Tremor was classified as “reflex tremor” in five patients and “mechanical tremor” in three patients. These results suggest that peripheral factors play important roles in tremor genesis in SBMA, although its clinical features resemble essential tremor. Subclinical sensory disturbance or a decrease of motor unit numbers might be candidates for such peripheral factors contributing to tremor genesis in SBMA. © 2009 Movement Disorder Society     

Therapeutic Advances in the Treatment of Holmes Tremor: Systematic Review

ObjectiveWe aimed to formulate a practical clinical treatment algorithm for Holmes tremor (HT) by reviewing currently published clinical data.Materials and MethodsWe performed a systematic review of articles discussing the management of HT published between January 1990 and December 2018. We examined data from 89 patients published across 58 studies detailing the effects of pharmacological or surgical interventions on HT severity. Clinical outcomes were measured by a continuous 1-10 ranked scale. The majority of studies addressing treatment response were case series or case reports. No randomized control studies were identified.ResultsOur review included 24 studies focusing on pharmacologic treatments of 25 HT patients and 34 studies focusing on the effect of deep brain stimulation (DBS) in 64 patients. In the medical intervention group, the most commonly used drugs were levetiracetam, trihexyphenidyl, and levodopa. In the surgically treated group, the thalamic ventralis intermedius nucleus (VIM) and globus pallidus internus (GPi) were the most common brain targets for neuromodulation. The two targets accounted for 57.8% and 32.8% of total cases, respectively. Overall, compared to the medically treated group, DBS provided greater tremor suppression (p = 0.025) and was more effective for the management of postural tremor in HT. Moreover, GPi DBS displayed greater benefit in the resting tremor component (p = 0.042) and overall tremor reduction (p = 0.022).ConclusionsThere is a highly variable response to different medical treatments in HT without randomized clinical trials available to dictate treatment decisions. A variety of medical and surgical treatment options can be considered for the management of HT. Collaborative research between different institutions and researchers are warranted and needed to improve our understanding of the pathophysiology and management of this condition. In this review, we propose a practical treatment algorithm for HT based on currently available evidence.     

Unusual position-sensitive jaw tremor responsive to botulinum toxin.

We report on a woman with a focal position-sensitive jaw tremor present with the jaw held slightly open or while drinking from a cup. Electromyography demonstrated a rhythmic 5 Hz alternating tremor involving masseter and digastric muscles with normal reciprocal inhibition. The tremor was markedly reduced with botulinum toxin injections.     

Topography of essential tremor

IntroductionTopography of tremor manifestations is poorly investigated in essential tremor. The present study explores the prevalence and clinical correlates of head and/or voice tremor in essential tremor.MethodsOut of a prospectively designed registry of 972 patients, 884 patients with definite and probable essential tremor had complete information on tremor localization. Demographic and clinical characteristics were compared among four subgroups: group A (without head or voice tremor, n = 619), B (with head but without voice tremor, n = 155), C (with voice but without head tremor, n = 47), and D (with both head and voice tremor, n = 63).ResultsIn our patients, total prevalence of tremor was 24.7% for head, 12.4% for voice and 7.1% for the combination of head and voice. Logistic regression analyses showed that female gender is strongly associated with head tremor, which was confirmed by an additional meta-analysis. Severe hand tremor was the only factor associated with voice tremor. Both female gender and severe hand tremor increase the odds for having the combination of head and voice tremor. For males, hand tremor severity is significantly increased among those with head and voice tremor alone and in combination, but for females only for the combination. Patients with both head and voice tremor have more frequent involvement of legs and other localizations and are less responsive to β-blockers.ConclusionsFemale gender and severe hand tremor may increase the odds of head and/or voice tremor in essential tremor. The association of hand tremor severity with midline tremor is stronger for males than females.