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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fifty-eight patients, 36 with essential tremor (ET) and 22 with Parkinson's disease (PD), received deep brain stimulation (DBS) in the thalamic ventral intermediate (Vim) nucleus. The mean follow-up was 17 months for ET and 21 months for PD patients. Stimulation parameters were adjusted as needed, at various intervals after surgery. Results were assessed using routine clinical evaluation and established outcome scales. All patients needed incremental increase in stimulation parameters at various intervals during the first 6-12 months after surgery. The mean voltage 1 week postoperatively was 1. 45 V in PD patients, and 1.37 V in ET patients. Twelve months later, the figures were 2.14 V in PD and 2.25 V in ET patients. At 1 year, the Essential Tremor Rating Scale (ETRS) improved from 54 to 28 (p < 0.0001). The motor part of the Unified Parkinson's Disease Rating Scale (UPDRS) improved from 37 to 26 (p < 0.01). Tremor items of the UPDRS improved more markedly (p < 0.0001). One week postoperatively 90% of PD, and 89% of ET patients were tremor free. One year later, 70% of PD and 60% of ET patients remained mostly tremor free. Upon switching off stimulation, there was a clear tendency for tremor rebound (p = 0.07) in the PD group, requiring continuous 24-hour stimulation in some patients. Permanent non-adjustable ataxia was induced by stimulation in 2 PD patients.
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PMID:Tolerance and tremor rebound following long-term chronic thalamic stimulation for Parkinsonian and essential tremor. 1085 80

Essential tremor (ET) can be measured objectively by physiological techniques, simple tests of the tremor's impact on function, or subjective use of clinical rating scales. The methods of measuring ET and its influence on patients are reviewed. Multidimensional evaluations are recommended for the assessment of the severity of ET in clinical trials. The term "detractor" describes the relationships between ET and the disability and handicap that it produces.
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PMID:Tremor assessment and quality of life measurements. 1085 49

Essential tremor can be suppressed with chronic, bilateral deep brain stimulation (DBS) of the ventralis intermedius nucleus (Vim), the cerebellar receiving area of the motor thalamus. The goal in this study was to correlate the location of the electrodes with the clinical efficacy of DBS in a patient with essential tremor. The authors report on a woman with essential tremor in whom chronic bilateral DBS directed to the ventral thalamus produced adequate tremor suppression until her death from unrelated causes 16 months after placement of the electrodes. Neuropathological postmortem studies of the brain in this patient demonstrated that both stimulators terminated in the Vim region of the thalamus, and that chronic DBS elicited minor reactive changes confined to the immediate vicinity of the electrode tracks. Although the authors could not identify neuropathological abnormalities specific to essential tremor, they believe that suppression of essential tremor by chronic DBS correlates with bilateral termination of the stimulators in the Vim region of the thalamus.
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PMID:Long-term deep brain stimulation in a patient with essential tremor: clinical response and postmortem correlation with stimulator termination sites in ventral thalamus. Case report. 1088 19

Essential tremor (ET) is a common movement disorder that often becomes refractory to conventional pharmacologic management. Open-label studies suggest that gabapentin is efficacious for ET, but the results of controlled trials have been mixed. To determine the efficacy and tolerability of gabapentin in ET, we conducted a double-blind, placebo-controlled, cross-over trial evaluating two doses (1800 mg per day and 3600 mg per day; N = 25). Patients on other ET medications were maintained on their concurrent medications for 3 months prior to study initiation and throughout the study. Twenty patients (mean age, 69.9 +/- 6.1 yrs) completed the study. Overall, patient global assessments (p <0.05), observed tremor scores (p <0.005), water pouring scores (p <0.05), and activities of daily living scores (p <0.005) significantly improved. Accelerometry scores, spirographs, and investigator global impression scores did not improve. The results were similar for high and low doses. Statistical regression models did not demonstrate any significant predictors for response. Gabapentin may be effective in some cases of ET.
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PMID:Gabapentin for essential tremor: a multiple-dose, double-blind, placebo-controlled trial. 1092 78

Essential tremor (ET) is a common condition that is present in as many as 23% of elderly individuals. Our objective was to determine the risk of ET and to study the impairment resulting from ET among relatives of ET cases compared to relatives of controls. ET cases and matched controls from the Washington Heights-Inwood community, New York, and their first- and second-degree relatives underwent a standardized tremor examination. The risk of having ET in relatives of cases vs relatives of controls was compared using Cox proportional hazards models. Five hundred ninety-one subjects were examined (59 ET cases, 72 controls, 234 case relatives, and 226 control relatives). ET was present in 25 (22.5%) of the 111 first-degree relatives of cases compared to 6 (5.6%) of 107 first-degree relatives of controls [relative risk (RR) = 4.67, 95% confidence interval (CI) = 1.90-11.49, p = 0.0008]. RRs were higher in relatives of cases with onset < or =50 years than in those with later onset (RR = 10.38 vs 4.82). Sixteen (64%) of twenty-five affected first-degree case relatives exhibited moderate tremor while performing tasks such as writing, drinking, or pouring. Relatives of ET patients are five times more likely to develop the disease than are members of the population and ten times more likely if the proband's tremor began at an early age. The majority of the affected relatives can expect to experience impairment resulting from tremor.
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PMID:Risk of tremor and impairment from tremor in relatives of patients with essential tremor: a community-based family study. 1140 28

Essential tremor (ET) may be differentiated from normal or enhanced physiological tremor based on a clinical examination or electrophysiological tests such as quantitative computerized tremor analysis. There have been few head to head comparisons of the two methods. Our objective was to estimate diagnostic agreement between these two methods. Cases and controls underwent a clinical evaluation (interview and videotaped examination) and an electrophysiological evaluation (quantitative computerized tremor analysis using accelerometry and electromyography) on the same day, and diagnoses were independently assigned using clinical vs. electrophysiological criteria. Agreement between diagnoses was assessed with a concordance rate and kappa statistic (kappa).Thirty-two (59.3%) of 54 subjects were diagnosed clinically as ET (possible, probable, or definite), compared with 35 (64.8%) of 54 based on tremor analysis. The concordance rate between the two methods of diagnosis was 94.4% (51 of 54). Kappa was 0.88, indicating a level of agreement between diagnoses that was in the "near perfect" range. All of the subjects who received electrophysiological diagnoses of definite ET also received clinical diagnoses of ET. Conversely, all of the subjects who received clinical diagnoses of definite ET also received electrophysiological diagnoses of ET. The agreement between the clinical and electrophysiological diagnosis of ET was substantial, suggesting that study protocols that were to utilize either technique would arrive at similar diagnostic conclusions. In addition, physiological testing can quantify potentially valuable subclinical measurements as well as detect possible additional cases of ET not diagnosed as such during clinical assessments.
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PMID:Comparison of clinical vs. electrophysiological methods of diagnosing of essential tremor. 1148 90

Essential tremor (ET) is one of the most common movement disorders. The pathogenesis is as yet unknown, although a genetic cause has long been recognised. Clinical and molecular evidence suggested that the ET gene contains a CAG expanded region. We examined a cohort of 240 Italian ET patients, classified as familial (193 cases) and sporadic (47 cases). The clinical manifestations of ET patients confirmed that the disorder is characterised by a large phenotypic variability. Repeat expansion detection (RED) approach did not demonstrate large CAG expansions. Six families were genotyped with 12 microsatellites markers of 2p and 3q regions and analysed according to parametrical methods. Lod scores values obtained in these families excluded the association of ET with 2p and 3q loci. Our findings confirm the presence of genetic heterogeneity and suggest that at least a third locus is involved in the pathogenesis of familial essential tremor.
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PMID:Clinical and genetic study of essential tremor in the Italian population. 1148 91

Patients with nonparkinsonian tremors are the second largest group treated with functional neurosurgery. We summarize the present pathophysiological knowledge of these conditions. Essential tremor (ET) may be due to oscillations within the olivocerebellar circuit. There is experimental evidence from animal models for such a mechanism, and clinical data indicate an abnormal function of the cerebellum in ET. Cerebellar tremor may be closely related to the tremor seen in advanced ET. The malfunction of the cerebellum causes a pathological feed-forward control. Additionally an oscillator within the cerebellum or its input/output pathways may cause cerebellar tremor. Almost nothing is known about the pathophysiology of dystonic tremor. Holmes tremor is based on a nigral and a cerebellar malfunction and presents clinically as the combination of tremor in Parkinson's disease and cerebellar tremor. Neuropathic tremor can be extremely disabling and is thought to be due to an abnormal interaction of the disturbances within the periphery and abnormal cerebellar feedback. Unlike the case of Parkinson's disease, functional neurosurgery of nonparkinsonian tremors is not yet based on a solid pathophysiological background.
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PMID:Pathophysiology of nonparkinsonian tremors. 1194 54

Based on the hypothesis that rhythmical, tremor-like movements produced by normal subjects might be influenced by similar central oscillatory neuronal networks believed to determine the features of the pathologic tremors of Parkinson's disease (PD) or Essential Tremor (ET) patients, we examined the neurophysiological characteristics of a tremor mimicked by normal volunteers and compare this data with those from PD or ET tremors. Voluntarily simulated tremor (VST) was studied in 47 neurologically intact subjects, resting tremor in 10 patients with PD and postural tremor in 10 patients with ET. Using a tremor analysis system based on a solid state gyroscopic sensor sensitive to angular rate, the following parameters were determined: frequency, amplitude (angular displacement) and regularity (Q coefficient of constancy). We also performed an inertial loading test and a test-retest analysis. Nearly all normal subjects were able to simulate a tremor that was indistinguishable, in frequency and regularity, from that of PD or ET, although the amplitude was significantly higher in normal subjects. As in pathological tremors, the VST frequency was significantly influenced by age, but not by gender, handedness or previous knowledge of tremor. Inertial load did not modify the tremor frequency, suggesting that mechanical factors were minor. We also found a logarithmic inverse relationship between frequency and amplitude of the VST. We concluded that VST shares many similarities with pathological tremors. It is therefore possible that all tremors are somehow influenced by the same central oscillators which may become disinhibited and clinically apparent in pathological conditions such as PD or ET.
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PMID:Voluntarily simulated tremor in normal subjects. 1203 89

Essential tremor (ET) is the most prevalent tremor syndrome. It commonly affects the hands, head, voice, and other body parts. Appropriate management begins with correct diagnosis. Primidone and propranolol are the first-line medications for the treatment for ET, but several other medications may also provide benefit. In patients with medically refractory tremor, alternative therapies, including surgery or injections of botulinum toxin, may be considered.
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PMID:Management of essential tremor. 1204 52


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