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.     

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.     

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.     

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...     

Beta-blockers in isoproterenolenhanced essential tremor

Non-selective adrenergic beta-blocking drugs prevented isoproterenol enhancement of essential tremor amplitude far more effectively than beta-1-selective blockers.     

原发性震颤的立体定向外科治疗

目的探讨原发性震颤的手术价值和方法。方法对23例原发性震颤病人行微电极导向立体定向Vim、Forel-H区毁损术。结果手术后震颤评分改善均>7分,取得显效;无严重并发症。结论立体定向手术是治疗原发性震颤的有效方法,Vim是首选靶点,Forel-H区是较理想的补充靶点。     

脑多巴胺转运体 99mTc-TRODAT-1 SPECT显像对早期帕金森病与特发性震颤鉴别诊断的价值

目的探讨脑多巴胺转运体(DAT)99mTcTRODAT1单光子发射计算机断层脑显像(SPECT)对早期帕金森病(PD)与特发性震颤(ET)鉴别诊断的价值。方法对28例早期PD、15例ET、8例ET合并PD(ETPD)患者和15名健康志愿者进行99mTcTRODAT1SPECT显像,勾画出各组脑内感兴趣区[双侧纹状体(ST)及枕叶(OC)],计算机自动给出各区的放射性计数,计算左、右侧特异性放射性摄取比值(STOC/OC)及不对称指数,并加以比较。结果DAT特异性放射性摄取比值:正常对照组左侧为0.58±0.16、右侧为0.56±0.32,ET患者左侧为0.55±0.22、右侧为0.56±0.24,两侧及两组间比较差异均无显著性;ETPD组左侧为0.44±0.33、右侧为0.45±0.18,早期PD组症状肢体对侧为0.40±0.33、症状肢体同侧为0.51±0.12,以上两组与正常对照组和ET组比较呈显著性降低(P<0.01,P<0.05);且PD组症状肢体的对侧低于同侧,差异有显著性(P<0.05)。非对称性指数:PD组高于ET组,差异有显著性(P<0.05)。结论99mTcTRODAT1SPECT显像有助于早期PD与ET的鉴别诊断。     

Neuroimaging and neuropathological findings in essential tremor

Essential tremor is a chronic neurological syndrome of heterogenous clinical phenotypes and multiple etiologies. Numerous studies have been done in order to investigate the pathological, neuroimaging, physiological, and clinical features of essential tremor; however, a clear pathophysiological mechanism has not been identified. One of the brain structures has been extensively investigated at the macroscopic and the microscopic level in the cerebellum. In the present study, we aim to discuss the main neuroimaging and neuropathological changes of the cerebellum in essential tremor.     

Orthostatic tremor: essential and symptomatic cases

We studied clinically and electrophysiologically 8 patients affected by orthostatic tremor (OT), which is an unusual movement disorder consisting of shaking movements of the legs and trunk in the standing position. We failed to find any cause in 6 of the 8 cases. In 2 patients OT was clearly secondary to neurologic disease: hydrocephalus due to non-tumoral aqueduct stenosis and chronic relapsing polyradiculoneuropathy. The findings obtained suggest a relationship between OT and essential tremor (ET).     

Parkinsonism and essential tremor in a family with pseudo-dominant inheritance of PARK2: an FP-CIT SPECT study.

We report a family with 5 affected individuals manifesting either essential tremor (ET), Parkinsonism, or both, consistent with pseudo-dominant inheritance of PARK2. Two homozygotes presented postural and kinetic tremor several years before the onset of Parkinsonism. Postural and kinetic tremor mimicking ET was the only feature in 1 homozygous and 2 heterozygous carriers of the mutation. Striatal dopamine transporter density was reduced in accordance with phenotype and number of mutated alleles. In 3 homozygotes and 1 heterozygote, a 2-year follow-up single photon emission computed tomography suggested no progression of nigrostriatal deficit.     

Clinical analysis in familial cortical myoclonic tremor allows differential diagnosis with essential tremor.

Familial cortical myoclonic tremor (FCMT) is a rare disorder often leading to a wrong clinical diagnosis of essential tremor. Electrophysiological data are usually considered to allow a correct diagnosis. We describe a FCMT French family with previously unreported clinical features such as sensitivity to glucose deprivation, vibration, repetitive visual patterns, and intense visual or auditory stimulation and contrasts. Electrophysiological studies of the propositus confirm the cortical reflex myoclonus elicited by photic stimulation and the absence of epileptic electroencephalographic discharges. We emphasize that a precise clinical analysis can lead to a correct diagnosis before electrophysiological confirmation. This is also the first-ever report of efficacy of levetiracetam in FCMT.     

John Adams' essential tremor.

John Adams (1735-1826), one of the signers of the Declaration of Independence, was the second President of the United States. Adams had tremor for many years, about which little has been written. We examined John Adams' penmanship over a 62-year period and studied his correspondence and diaries. It is not clear when Adams' tremor began, although in a diary entry dated 6 December 1760, when Adams was 25 years old, there is evidence of low-amplitude kinetic tremor. The tremor continued in his written correspondence, becoming more persistent over time. Later in life, the clarity of his written correspondence diminished, with greater decomposition of characters and a reduction in the size of individual characters. This finding raises some speculation as to whether Adams could have been developing some parkinsonism, although the evidence in favor of this is not compelling. The most likely diagnosis was essential tremor.     

Clinical features of childhood onset essential tremor

Childhood onset essential tremor (ET) is uncommon. It is not clear as to whether ethnicity-specific differences may influence the phenotypic features. To determine the frequency and clinical characteristics of childhood ET in a tertiary referral center. In a prospective evaluation of 120 consecutive ET patients in a movement disorders clinic, we found a 15.5% (19) frequency of childhood onset ET patients. The mean age of onset and mean age was 10.8 ± 4.1 (6–16) years and 25.7 ± 15.0 (16–73) years consisting of 73.6% (14/19) men and 26.4% (5/19) women. A positive family history of ET was present in 11 of 19 (52.6%). Presence of a head tremor was observed in 2/19 (10.5%). We highlighted a relatively high frequency (15,5%) of childhood ET in our Asian cohort. In addition, we drew attention to the male preponderance and the low frequency of head tremor in childhood ET corroborating study findings in white ET patients. These observations appear to transcend ethnic and cultural differences and lend further support that gender difference may play a role in the pathogenesis and expression of ET.