Biomarkers demonstrate increased consumption, but not abuse, of ethanol in essential tremor

Ethanol is known to improve tremor in a proportion of patients with essential tremor. Increased incidence of alcoholism has been suspected in essential tremor patients; however, no objective evaluation has been performed using laboratory markers to date. Data on alcohol intake in the last 30 days were acquired in 95 essential tremor patients and 35 healthy controls. Blood and urine markers related to alcohol metabolism and liver function were evaluated. Self-reported alcohol intake and biomarker levels were higher in essential tremor, but the difference was only significant for carbohydrate-deficient transferrin. None of the subjects presented with laboratory parameters reflecting chronic alcohol abuse. Our data do not reflect a higher incidence of alcoholism in patients with essential tremor. Their alcohol intake is well controlled and does not exceed the limits of healthy social drinking.     

Somatosensory temporal discrimination in essential tremor and isolated head and voice tremors

The aim of this study was to investigate the somatosensory temporal discrimination threshold in patients with essential tremor (sporadic and familial) and to evaluate whether somatosensory temporal discrimination threshold values differ depending on the body parts involved by tremor. We also investigated the somatosensory temporal discrimination in patients with isolated voice tremor. We enrolled 61 patients with tremor: 48 patients with essential tremor (31 patients with upper limb tremor alone, nine patients with head tremor alone, and eight patients with upper limb plus head tremor; 22 patients with familial vs. 26 sporadic essential tremor), 13 patients with isolated voice tremor, and 45 healthy subjects. Somatosensory temporal discrimination threshold values were normal in patients with familial essential tremor, whereas they were higher in patients with sporadic essential tremor. When we classified patients according to tremor distribution, somatosensory temporal discrimination threshold values were normal in patients with upper limb tremor and abnormal only in patients with isolated head tremor. Temporal discrimination threshold values were also abnormal in patients with isolated voice tremor. Somatosensory temporal discrimination processing is normal in patients with familial as well as in patients with sporadic essential tremor involving the upper limbs. By contrast, somatosensory temporal discrimination is altered in patients with isolated head tremor and voice tremor. This study with somatosensory temporal discrimination suggests that isolated head and voice tremors might possibly be considered as separate clinical entities from essential tremor. © 2015 International Parkinson and Movement Disorder Society     

Tremor in chronic alcoholism

We examined 100 alcoholics who had had no alcohol for more than 21 days, 100 controls, and 50 patients with essential tremor. Three percent of the controls and 47% of the alcoholics had a postural tremor. Alcoholic tremor was never severe, and functional disability occurred in only 17% of patients. There was no relation to age or duration of drinking, and only 1% of the alcoholics had a family history of tremor compared with 46% in essential tremor. Tremor frequency was significantly greater in the alcoholics than in essential tremor. Propranolol therapy decreased tremor more in the alcoholics than in essential tremor. The tremor of chronic alcoholism differs from essential tremor.     

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.     

Long-term EMG recordings differentiate between parkinsonian and essential tremor

The differential diagnosis of tremor is mainly based on clinical criteria.Nevertheless, these criteria are in some cases not sufficient to differentiate between different tremor forms. Long-term EMG has proven to be a valid and reliable method for the quantification of pathological tremors. The aim of the study was to develop a long-term EMG-based automated analysis procedure that separates parkinsonian tremor from essential tremor. Using longterm EMG tremor was recorded in 45 consecutive patients, 26 with Parkinson's disease (PD) and 19 with essential tremor (ET). Eight tremor parameters were generated automatically. By stepwise backward regression a subset of these criteria was extracted to achieve an automated classification of the tremor by a mathematical model. The obtained model was then tested on a new group of 13 patients in early stages of the disease. Significant differences between groups were found for tremor occurrence, tremor asymmetry, mean tremor frequency and standard deviation of phase of antagonistic muscles. Due to data overlap a classification of the two tremor forms was not possible based on a single tremor parameter. Using logistic regression, a linear formula based on the three parameters tremor occurrence, mean tremor frequency and standard deviation of phase was established and predicted the correct diagnosis in 93% of patients. The validation of the model on the new group of patients in early stages of the tremor disease yielded a correct diagnosis in 100% of cases. We conclude that long-term EMG recording allows a rater-independent classification of parkinsonian versus essential tremor.     

Clozapine in the treatment of tremor

In an open trial 25 tremor patients were treated with clozapine in small doses (18-75 mg per day). The effect was measured with a new movement analyzer. Nine of 12 essential tremor patients were greatly improved. In six of nine patients with Parkinson tremor and in two combined essential tremor/Parkinson tremor patients tremor almost disappeared. Sedation is a major side effect, but decreases in most patients with time. The risk of agranulocytosis makes blood control necessary.     

Neuroanatomical correlates of dystonic tremor: A cross-sectional study

PurposeThis study is aimed at investigating the neuroanatomical patterns characterizing dystonic tremor in comparison with essential tremor.MethodsVoxel-based morphometry and cortical thickness data of 12 patients with dystonic tremor, 14 patients with essential tremor and 23 age- and sex-matched healthy control subjects were analyzed.ResultsPatients with dystonic tremor showed a thickening and increased gray matter volume (surviving whole-brain correction for multiple comparisons) of the left sensorimotor cortex when compared to other groups. Otherwise, patients with essential tremor were characterized by a subtle atrophy of the anterior cerebellar cortex.DiscussionOur multimodal structural neuroimaging study demonstrated that patients with dystonic tremor and essential tremor are characterized by different neuroanatomical abnormalities. The involvement of the sensorimotor cortex in patients with dystonic tremor suggests that this disorder may share some pathophysiological mechanisms with focal dystonia.     

Effects of chronic alcohol consumption on long-term outcomes of thalamic deep brain stimulation for essential tremor

The prevalence of essential tremor (ET) is about 4% above 40 years of age. Chronic alcohol consumption is present in around 20% of patients with ET. Our objective was to identify whether chronic alcohol consumption was associated with a negative effect on tremor outcome after thalamic deep brain stimulation (DBS) in ET patients. We conducted a retrospective chart review, from January 2005 to December 2012, from which 23 patients who had ventral intermediate nucleus (Vim)-DBS surgery for ET were identified. Seven patients had a positive history of chronic alcohol consumption. We defined as chronic alcohol users those patients with a habit of drinking alcohol every day in order to suppress tremor. In the overall group of 23 patients, there was a reduction in the median tremor score from 8 pre-operatively, to 1 post-operatively (p < 0.0001). The alcohol consumers group experienced a reduction in the median tremor score from 6 pre-operatively to 0 post-operatively (p = 0.03). The non-alcohol consumers group had a reduction in the median tremor score from 8 pre-operatively to 1.7 post-operatively (p < 0.0001). Both groups of patients experienced significant benefit from thalamic DBS. A larger study may reveal statistically significant differences between subgroups.     

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...     

Peripheral mechanical loading and the mechanism of the tremor of chronic alcoholism.

The tremor of chronic alcoholism, although clinically similar to essential tremor, has been considered a distinct syndrome. Its underlying mechanism was analyzed in five patients (none in the acute stages of alcohol withdrawal) hospitalized in an alcohol detoxification program. All five patients performed tracking tasks in which they pursued a linearly moving "target" light with a response light that they controlled by flexion-extension activity of the wrist. Stationary and dynamic targets were used with both isometric and unconstrained wrist mechanical interfaces. Frequency, torque, and displacement tremor characteristics were examined under varying inertial loading or isometric voluntary torque conditions. Two simultaneous tremor components were present in all patients: a prominent 4- to 7-Hz low-frequency peak and a smaller-amplitude 9.4- to 9.6-Hz high-frequency peak. As the inertia of the hand was augmented during unconstrained tasks, the low-frequency peak decreased, while the high-frequency peak was unaffected. As required voluntary effort was increased during isometric testing, the amplitude of the low-frequency peak increased. These findings suggest that the low-frequency peak represents the significant pathologic component of the tremor of chronic alcoholism and that it has a biomechanical reflex mechanism similar to that of the lower-amplitude normal physiologic tremor.     

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.     

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.     

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     

Essential tremor: an overdiagnosed condition?

The diagnosis of essential tremor (ET) and its differentiation from other types of tremor is often difficult. In 1994 Bain et al. defined a classical phenotype by studying 20 patients with pure essential tremor and similarly affected family members in at least three generations. We assessed how many of the patients diagnosed by different neurologists at our institution as having ET conformed to this defined phenotype. We randomly selected 50 patients who were diagnosed with ET by any neurologist at the National Hospital for Neurology and Neurosurgery since the publication of the Bain et al. report, and determined the number of patients who had clinical features compatible with the phenotype that it had defined. Only 25 (50%) of these patients had ET so defined. Ten patients clearly had alternative diagnoses: four had clear additional dystonia, two neuropathic tremor, two had unilateral leg tremor, one drud-induced tremor, and one sudden onset after head trauma. The remaining 15 patients also had atypical features including myoclonus (one), onset in a body part other than the arms (six), sudden onset (two), rest tremor (seven), onset after the age of 65 years (four), a family member with an isolated head tremor (one), or reduced armswing (two). The diagnosis of ET is overused even among experienced neurologists, and other types of tremor should be considered in atypical patients before making this diagnosis. Received: 30 November 1999 / Received in revised form: 12 May 2000 / Accepted: 21 June 2000     

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 associated with Klinefelter syndrome – A case series and review of the literature

BackgroundPrevious case series suggested a link between Klinefelter syndrome (KS) and essential tremor (ET) or an ET-like syndrome.MethodsWe investigated three KS-patients with tremor including tremor-analyzes and discuss our data in context to findings from a literature review. The clinical outcome after deep brain stimulation (DBS) is also reviewed.ResultsTremor in KS is predominantly a postural and kinetic tremor that resembles ET. Our patients were further characterized by absent family history for tremor in first degree relatives, lack of subjective alcohol responsiveness inquired by history, and tremor onset in childhood. One of our patients and two cases from literature improved after DBS of the ventral intermediate nucleus (VIM) of the thalamus.ConclusionsTremor in KS shares several features with ET. If other characteristics such as family history, alcohol responsiveness, and age at tremor onset may serve as discriminating factors from ET, needs to be further investigated. First observations suggest that VIM-DBS may be efficacious.     

A clinical study of non-parkinsonian tremor in Moroccan patients

Objective

To report the characteristics of the most frequent tremors in a population of Moroccan patients.

Background

Tremor is the most common movement disorder. It implies a wide variety of disorders with Parkinson's disease and essential tremor being the most frequent.

Methods

A retrospective study of 148 patients with tremor referred to our movement disorders outpatient clinic was performed. Clinical features and treatment regimens were analyzed. Patients with parkinsonian tremor were excluded.

Results

We included 62 patients with non-parkinsonian tremor. The etiologies were as follows: essential tremor (54.8%), dystonic tremor (19.4%), tremor associated with dystonia (14.5%), enhanced physiological tremor (3.2%), cerebellar tremor (3.2%), psychogenic tremor (3.2%) and Holmes’ tremor (1.6%). The characteristics of essential tremor patients were analyzed. Female patients accounted for 67.6% of patients. Mean age at the onset of tremor was 52.2 ± 16.4 years. Family history of tremor was reported in 17.6% of cases. Tremor affected the arms (94.1%), head (52.9%), voice (35.3%) and legs (8.8%). Tremor was bilateral in 87.5% but was asymmetrical in 50% of patients. Patients had postural tremor (76.5%), kinetic tremor (79.4%) and rest tremor (associated in 11.8%). Treatment relied on propranolol (88.3%), primidone (14.7%), gabapentin (14.7%), clonazepam (14.7%), alprazolam (11.8%), topiramate (5.9%) and, in one patient, radiosurgery.

Conclusions

Essential tremor was the predominant diagnosis, confirming its high prevalence. There was a predominance of female patients and a peak of age at onset in the fifth and sixth decades. Asymmetry of the disease was noted in half of patients.     

Orthostatic tremor: Clinical and electrophysiologic characteristics

Orthostatic tremor, sometimes known as ?shaky legs syndrome,”? is a disorder of middle-aged or elderly people characterized by feelings of unsteadiness in the legs and a fear of falling when standing. Patients stand on a wide base but walk normally. These symptoms are due to high-frequency (13–18 Hz) burst firing in weight-bearing muscles. They are attenuated by walking and are abolished immediately by sitting. Some authors believe that the disorder is a variant of essential tremor. This study reports the clinical and electrophysiologic features of orthostatic tremor in 30 patients. The findings indicate that orthostatic tremor is distinct from essential tremor, both clinically and electrophysiologically. The major differences are the frequency of electromyographic burst firing, the invariable involvement of lower limb and paraspinal muscles, and the task-specific nature of the tremor in orthostatic tremor. The study shows that the diagnosis can be established rapidly with surface electromyographic recordings. © 1993 John Wiley & Sons, Inc.     

Acute effect of transcutaneous electrical nerve stimulation on tremor.

Based on the claims that transcutaneous electrical nerve stimulation is effective in myoclonic dystonia and essential tremor, we evaluated its acute effects in 5 patients with essential tremor and 2 patients with tremor attributed to peripheral neuropathy using as parameters the Washington Heights-Inwood Genetic Study of Essential Tremor rating scale, self-reported impression, and recording of electromyographic activity. We found no significant improvement in any of the parameters tested.