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

Essential tremor (ET) is a widespread late-life neurological disease. Genetic and environmental factors likely play an etiological role. Harmane (1-methyl-9H-pyrido[3,4-b]indole) is a potent tremor-producing neurotoxin. In 2002, we demonstrated elevated blood harmane concentrations in an initial sample of 100 ET cases compared to 100 controls. Between 2002 and 2007, we assembled a new and larger sample of ET cases and controls. We now attempt to replicate our previous findings. Cases and controls were frequency-matched on age, gender, and race. Blood harmane concentrations were quantified by high-performance liquid chromatography. Subjects comprised 150 ET cases and 135 controls (mean age 65.3+/-15.5 vs. 65.5+/-14.2 years, p=0.94). Mean log blood harmane concentration was approximately 50% higher in cases than controls (0.50+/-0.54g(-10)/ml vs. 0.35+/-0.62g(-10)/ml, p=0.038). In a logistic regression analysis, log blood harmane concentration was associated with ET (OR(adjusted) 1.56, 95% CI 1.01-2.42, p=0.04), and odds of ET was 1.90 (95% CI 1.07-3.39, p=0.029) in the highest versus lowest log blood harmane tertile. Log blood harmane was highest in ET cases with familial ET (0.53+/-0.57g(-10)/ml), intermediate in cases with sporadic ET (0.43+/-0.45g(-10)/ml) and lowest in controls (0.35+/-0.62g(-10)/ml) (test for trend, p=0.026). Blood harmane appears to be elevated in ET. The higher concentrations in familial ET suggests that the mechanism may involve genetic factors.
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PMID:Elevated blood harmane (1-methyl-9H-pyrido[3,4-b]indole) concentrations in essential tremor. 1824 11

The aim of this study was to determine the prevalence of essential tremor (ET) in a Turkish population living in Sile, a rural town located on Black Sea coast of Istanbul. This study was designed as a descriptive cross-sectional field study. People aged 18 years and over were selected for the study. Tremor surveillance questionnaire was applied by door-to-door visits. Subsequently, all subjects who answered the questionnaire had a standard tremor examination. Diagnosis was made based on Washington Heights-Inwood Genetic Study of Essential Tremor (WHIGET) diagnosis and clinical evaluation scale. A total of 2227 people was screened. The prevalence of ET was found to be 3.09% (95% Cl=2.42-3.91%) in Turkish population aged over 18 years. The prevalence of ET increased by age in both genders.
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PMID:Prevalence of essential tremor: a door-to-door survey in Sile, Istanbul, Turkey. 1847 48

Essential tremor (ET), traditionally considered benign, is a serious neurologic condition with life-altering repercussions. Its involuntary, rhythmic oscillations involve alternating, irregular, or simultaneous contractions of agonist and antagonist muscles. It is the most common of the 20 known tremor disorders and often confused with Parkinson's disease. Numerous drugs can aggravate ET, and alcohol consumption may alleviate it. Its etiology is unknown. Proven drug treatments are currently limited to propranolol and primidone. This article reviews ET with examples from history to demonstrate points.
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PMID:Essential tremor: symptoms and treatment. 1854 Jul 90

Essential tremor (ET) is one of the most prevalent neurological disorders, affecting between 0.4 and 3.9% of the population. As there have been few studies of the functional impact of ET, knowledge of this area is limited. One study relied on subjective reports of tremor severity while a second focused on issues relating to treatment. Knowledge about the functional impact of ET is important for the valid assessment of efficacy in therapeutic trials as well as the diagnosis of ET in genetic and epidemiological studies. In order to examine the issue of functional disability in ET in greater detail, we designed the Columbia University Assessment of Disability in Essential Tremor (CADET). The critical elements of the study design have not been consistently applied to ET research to date. We describe this novel study.
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PMID:Columbia University Assessment of Disability in Essential Tremor (CADET): methodological issues in essential tremor research. 1859 Nov 47

We recorded resting-state neuronal activity from the human subthalamic nucleus (STN) during functional stereotactic surgeries. By inserting up to five parallel microelectrodes for single- or multiunit recordings and applying statistical spike-sorting methods, we were able to isolate a total of 351 single units in 65 patients with Parkinson's disease (PD) and 33 single units in 9 patients suffering from essential tremor (ET). Among these were 93 pairs of simultaneously recorded neurons in PD and 17 in ET, which were detected either by the same (n = 30) or neighboring microelectrodes (n = 80). Essential tremor is a movement disorder without any known basal ganglia pathology and with normal dopaminergic brain function. By comparing the neuronal activity of the STN in patients suffering from PD and ET we intended to characterize, for the first time, changes of basal ganglia activity in the human disease state that had previously been described in animal models of Parkinson's disease. We found a significant increase in the mean firing rate of STN neurons in PD and a relatively larger fraction of neurons exhibiting burstlike activity compared with ET. The overall proportion of neurons exhibiting intrinsic oscillations or interneuronal synchronization as defined by significant spectral peaks in the auto- or cross-correlations functions did not differ between PD and ET when considering the entire frequency range of 1-100 Hz. The distribution of significant oscillations across the theta (1-8 Hz), alpha (8-12 Hz), beta (12-35 Hz), and gamma band (>35 Hz), however, was uneven in ET and PD, as indicated by a trend in Fisher's exact test (P = 0.05). Oscillations and pairwise synchronizations within the 12- to 35-Hz band were a unique feature of PD. Our results confirm the predictions of the rate model of Parkinson's disease. In addition, they emphasize abnormalities in the patterning and dynamics of neuronal discharges in the parkinsonian STN, which support current concepts of abnormal motor loop oscillations in Parkinson's disease.
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PMID:Neuronal activity of the human subthalamic nucleus in the parkinsonian and nonparkinsonian state. 1870 54

The various causes of tremor are considered by order of prevalence in the elderly. 1) Essential tremor occurs in 5% of the population beyond 65 years of age. It is characterized by a tremor accompanying muscle activity, and interesting, when complete, the two upper limbs, the head and the voice, with variable degree of severity. Its progression is very slow. The diagnostic criteria are only clinical, but require ruling out iatrogenic and metabolic causes. 2) Tremor in Parkinson's disease is opposed point by point to essential tremor. However, confusion may occur due to some intermediate clinical situations. In these cases, pharmacology or DaTSCAN data can help to distinguish between the two conditions. 3) Other causes are considered, giving the priority to practical and therapeutic aspects. The psychological consequences of tremor should be taken into account to improve the quality of life of patients with tremor. Terms which stigmatize, such as senile tremor, or terms which minimize the relational and social consequences of tremor, such as benign tremor, should be discarded.
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PMID:[Tremor in the elderly]. 1878 79

Essential tremor (ET) is much more prevalent than Parkinson's disease (PD) in Western countries. We estimated ET and PD prevalence in Wadi Ara Arabic villages in Northern Israel. In this door-to-door survey, all consenting residents aged >or=65 years were systematically examined by an Arabic speaking team. No prescreening questionnaires were used. A random sample of 900 subjects [437 males, mean age (SD) = 72.6 years (6.6)] of the 2,163 eligible residents were evaluated. Sixteen subjects had an action, intentional tremor. Tremor prevalence was estimated as 1.78% (95% CI 1.1-2.87). Nine of these had another likely cause of tremor. Only 7 patients were diagnosed as ET [prevalence 0.78% (95% CI 0.38-1.6)]. PD was diagnosed in 13 subjects. PD prevalence was 1.44% (95% CI 0.84-2.45). ET is unusually uncommon in this population and possibly even less frequent than PD. The PD prevalence in Wadi Ara is similar to that reported in Western countries.
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PMID:Essential tremor might be less frequent than Parkinson's disease in North Israel Arab villages. 1882 47

Essential tremor is one of the most common movement disorders, yet the pharmacological treatments currently available have limited efficacy, being effective in only approximately 50% of patients with this disorder. The most commonly used, and generally most effective, medications for essential tremor are propranolol and primidone, administered either as monotherapy or in combination. If these medications do not provide satisfactory control of tremor, other beta-adrenoceptor antagonists, such as metoprolol or atenolol, and other antiepileptic drugs, such as topiramate or gabapentin, are often tried. In addition, benzodiazepines can be effective in some patients, particularly those with associated anxiety. There is a need for additional medications that result in greater tremor control in a larger number of patients with essential tremor. Several new drugs, including 1-octanol, sodium oxybate, dimethoxymethyl-diphenyl-barbituric acid (T-2000) and carisbamate, are currently under investigation for the treatment of essential tremor.
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PMID:Pharmacotherapy of essential tremor : an overview of existing and upcoming agents. 1899 41

Essential tremor (ET) is a multi-faceted condition best known for postural and action tremor but also may include disordered gait and postural instability. Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of the thalamus provides substantial tremor reduction yet some patients with bilateral VIM DBS have gait and balance impairment. This study examines gait and balance performance in 13 participants with ET who have bilateral VIM DBS compared with a matched control group. Participants with ET were tested with their stimulators off (DBS OFF) and on (DBS ON). For both standard and tandem walking, participants with ET walked significantly more slowly than controls, with significantly lower cadence, spending a lower percentage of the gait cycle in single limb support and a higher percentage in double support compared with controls. Participants with ET also had significantly lower tandem and one leg stance times, Berg balance scores, balance confidence, and required significantly greater time to perform the Timed Up-and-Go relative to controls. There were no significant differences in any gait or balance measures in the DBS OFF versus DBS ON conditions, but the effects of DBS on gait and balance were highly variable among individuals. Future studies are needed to determine why some individuals experience gait and balance difficulties after bilateral thalamic DBS and others do not. A better understanding of the mechanisms underlying gait and balance impairments in those with bilateral DBS is critical to reduce falls and fractures in this group.
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PMID:Gait and balance in essential tremor: variable effects of bilateral thalamic stimulation. 1900 89

Essential Tremor (ET) is characterized by a 4-12-Hz postural and kinetic tremor, most commonly affecting the upper limbs. Deep brain stimulation (DBS) of the thalamus (Vim) has been found to be highly effective in severe/refractory forms of ET. Intra-operative assessment of tremor is performed using clinical methods based on patient and physician perception of tremor intensity. We present for the first time the case of a patient whose tremor was objectively monitored/quantified pre- and intra-operatively using device-based tremor registration to supplement clinical measures. We present the case of a 76-year-old right-handed woman that received unilateral (left-sided) DBS of the ventrointermediate (Vim) nucleus of thalamus (Vim) for medically refractory ET. Tremor was monitored with an accelerometer-based Tremor Pen, which is part of a simple portable device (CATSYS 2000 System, Danish Product Development Ltd., DK, www.catsys.dk). The patient was asked to perform tasks for tremor evaluation before and during thalamic DBS. Tremor quantification revealed a significant improvement (34.7-fold) in the contralateral (right) limb following macro-stimulation. No significant improvement was registered in the ipsilateral (non-operated) side. Simple electronic tremor registration methods during DBS of the Vim nucleus of the thalamus may supplement the existing methodology that is solely based on subjective measures derived from clinical observations.
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PMID:Objective tremor registration during DBS surgery for essential tremor. 1912 90


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