Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “TREMOR”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,063 records · Page 59Linked to original sources
PubMed2000

Irregular jerky tremor, myoclonus, and thalamus: a study using low-frequency stimulation.

High-frequency thalamic stimulation alleviates tremor in Parkinson's disease (PD) and essential tremor (ET). The origin of thalamic myoclonus is unexplained and the effects of low-frequency thalamic stimulation on movement control are still unknown. We studied the effects of stimulation at a low frequency of 15 Hz in five drug-free patients (3 PD, 2 ET) 6 months after thalamic implantation of quadripolar electrodes (unilateral in four patients, bilateral in one patient). Clinical, electrophysiological, and videotaped assessment, using a monopolar 15 Hz frequency (3 V, 90 micros) stimulation current applied simultaneously through two adjacent contacts of the electrode, was performed. We observed myoclonus and irregular jerky tremor in the upper limb contralateral to the site of stimulation. The jerks lasted less than 200 ms, were irregular and not synchronous with stimulation, were superimposed on rest or postural tremor, and increased in response to tactile, proprioceptive, or vibratory stimuli. The fact that this complex movement disorder can be induced by low-frequency stimulation in the ventral intermediate nucleus (Vim) of the thalamus suggests that it results, at least partly, from dysfunction of the Vim and possibly adjacent nuclei of the thalamus.

Aged↗
PubMed2001

The relation between EMG activity and kinematic parameters strongly supports a role of the action tremor in parkinsonian bradykinesia.

The kinematics characteristics of an upper arm extension of large amplitude (90 degrees) performed in the horizontal plane and the simultaneous activity of the shoulder muscles were recorded in 12 parkinsonian patients and in six normal control subjects. The movement, triggered by an acoustic "go" signal, was preceded by an isometric adduction. Within the whole population of individuals (n = 18) a strong, positive correlation was observed between the root mean square value of agonist EMG activity, evaluated during the acceleration phase of the movement, and both peak velocity and acceleration. In six patients tremor bursts at the frequency of 8-14 Hz (action tremor) were observed during the movement phase in the anterior, middle, and posterior deltoid: all these patients showed low root mean square values and were bradykinetic with respect to the control subjects. The remaining six patients did not show this action tremor during the movement phase. All but one had an agonist activation of normal duration and amplitude, showed high root mean square values, and performed well in the range of control subjects. We conclude that the inability to suppress the activity of pathological oscillator(s) responsible for the action tremor plays a fundamental role in the bradykinesia associated with Parkinson's disease.

Aged↗
PubMed1980

An autosomal dominant syndrome of hemiplegic migraine, nystagmus, and tremor.

A mother and son suffer from hemiplegic migraine with onset in childhood. Both have nystagmus which has not changed for many years, but the date of onset is uncertain. They have an asymmetrical tremor, clinically indistinguishable from essential tremor. Neuroophthalmological examination revealed inability to produce smooth pursuit, gaze-paretic nystagmus, rebound nystagmus, failure of fixation suppression of the vestibuloocular reflex both horizontally and vertically, and low gain of the optokinetic system. These abnormalities, confirmed by electrooculography, are commonly seen in disease of the cerebellum and brainstem. Treatment with propranolol and pizotyline lessened the number of episodes of hemiplegia and improved the tremor. Hemiplegic migraine has been reported in association with nystagmus, retinal degeneration, deafness, and ataxia in varying combinations in three other families with autosomal dominant inheritance. These associated neurological manifestations likely represent system degenerations rather than the effect of repeated ischemia imputable to the migraine itself. The syndrome of hemiplegic migraine, tremor, and ocular smooth pursuit system disorder seen in this family appears to be inherited as a single autosomal dominant trait, although more than one autosomal dominant gene may be involved.

Adolescent↗
PubMedDate not supplied

Neuropathology, tremor and electromyogram in rats exposed to manganese phosphate/sulfate mixture.

In Canada, Methylcyclopentadienyl manganese tricarbonyl (MMT) replaced tetraethyl lead in gasoline as an antiknock agent from 1976 until 2003. The combustion of MMT leads to increased manganese (Mn) concentrations in the atmosphere, and represents one of the main sources of human exposure to Mn. The nervous system is the major target of the toxicity of Mn and Mn compounds. The purpose of this study was to investigate exposure-response relationships for neuropathology and tremor, and the associated electromyogram (EMG), following subchronic inhalation exposure of rats to a mixture of Mn phosphate/sulfate particles. Rats were exposed 6 h per day, 5 days per week for 13 consecutive weeks at 30, 300 or 3000 microg m(-3) Mn phosphate/sulfate mixture and compared with controls. Half of the rats had EMG electrodes implanted in the gastrocnemius muscle of the hind limb to assess tremor at the end of Mn exposure. Two days after the end of Mn exposure, rats were killed by exsanguination and Mn concentrations in the brain (caudate putamen, globus pallidus and frontal cortex) were determined by neutron activation analysis while neuropathology was assessed by counting neuronal cells in 2.5 mm x 2.5 mm grid areas. Increased Mn concentrations were observed in all brain sections at the highest level of exposure. The neuronal cell loss was significantly different in the globus pallidus and the caudate putamen at the highest level of exposure (3000 microg m(-3)). No sign of tremor was observed among the rats. In conclusion, exposure to a high level of Mn phosphate/sulfate mixture brought on neuropathological changes in a specific area of the brain; however, no sign of tremor was observed.

Administration, Inhalation↗
PubMed2003

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.

Aged↗
PubMed2003

Prevalence of essential tremor in three elderly populations of central Spain.

Although essential tremor (ET) is considered the most prevalent adult movement disorder, the available information on its prevalence and distribution worldwide is not completely understood. We investigated the prevalence and distribution of ET in three elderly Spanish populations using a door-to-door, two-phase approach. A brief screening instrument was administered on May 1, 1994 to subjects over 64 years old taken from the census of one urban municipality of Greater Madrid (quarter of Margaritas, Getafe), one urban district of Madrid (Lista), and one rural site (Arévalo county, Avila) (N = 5278). Study subjects were limited to those who screened positively (N = 472). To increase reliability, each patient was examined by 3 experienced neurologists, and was classified as having ET only when all 3 neurologists agreed (183 of 472). The present study was part of a large-scale epidemiological survey of neurological diseases, and served as a baseline investigation in a 3-year incidence study. Accordingly, 41 ET patients were identified when evaluating subjects who had screened positively for dementia, stroke, or parkinsonism, despite the fact that they had screened negatively for tremor; furthermore, 32 additional ET prevalent cases were detected when evaluating subjects who had screened positively for tremor in the second cross-sectional study (May 1, 1997), although they had screened negatively for tremor in the first cross-sectional study. We identified 256 persons (152 women, 104 men) with ET; of these, 87 patients (34.0%) reported having an affected relative. Two hundred and four (79.7%) of the subjects with ET were detected through this screening and had not been diagnosed previously. The prevalence of ET was 4.8% (95% CI = 4.2-5.4) for the total population; 4.6% (95% CI = 3.7-5.4) in men and 5.0% (95% CI = 4.2-5.8) in women. Age-specific prevalence increased with advancing age for both men and women. Despite the variability in worldwide data, ET is a frequently encountered disorder in elderly people. Furthermore, as ET may be seen as a relatively benign condition, a large proportion of patients may never seek neurological attention.

Aged↗
PubMed2003

Role of dopamine transporter imaging in the diagnosis of atypical tremor disorders.

Dopamine transporter (DAT) imaging detects presynaptic dopamine neuronal dysfunction and thereby assists differentiation of conditions with and without dopamine deficit. In atypical tremor disorders, DAT imaging can differentiate between Parkinson's disease (PD), where dopamine deficit is demonstrated on DAT imaging, and essential tremor, where no dopamine deficit is found. DAT imaging may be particularly informative in monosymptomatic rest tremors, benign tremulous Parkinson's syndrome, and in the elderly in whom essential tremor may be accompanied by pseudoparkinsonism.

Aged↗
PubMed2001

Essential tremor in childhood: a series of nineteen cases.

One in 20 essential tremor (ET) cases arises during childhood. We report 19 pediatric ET cases (mean age = 12.7 years). The majority (68.4%) were male, and only one had head tremor. Childhood and adult forms of ET may differ in several important respects, providing information about the underlying biology of ET. A possible male preponderance in childhood ET cases could reflect a modification of disease expression by gender, such that males manifest the disease at an earlier age than females. A paucity of childhood cases with head tremor suggests that the neuropathological changes in ET may evolve somatotopically. Head tremor may require midline or more extensive bilateral pathology which may only occur later in the disease.

Adolescent↗
PubMed2004

Prevalence of tremor in multiple sclerosis and associated disability in the Olmsted County population.

We applied a clinical tremor rating scale and measures of disability to 200 of 201 multiple sclerosis patients from a prevalence cohort in Olmsted County, Minnesota. In a community-based sample, tremor was found clinically in 51 (25%) patients, although only 6 (3%) patients had severe tremor. Within the population as a whole, tremor was strongly associated with impairment disability and handicap.

Adolescent↗
PubMed2005

Interaction between eye and hand movements in multiple sclerosis patients with intention tremor.

Deficient eye and hand movements are present in patients with multiple sclerosis. In the present study, eye and hand movements were simultaneously measured during visually guided wrist step-tracking tasks in 16 patients with intention tremor and 15 healthy controls. The coupling between eye and hand movements was analyzed during simultaneous eye-hand tracking, and interactions were studied by comparing the coordinated eye-hand condition with isolated eye- or hand-tracking conditions. Despite movement abnormalities, the onset of eye and hand movements was highly correlated and an invariant coupling between the saccadic completion time and hand peak velocity was found, suggesting that the temporal coupling was very much preserved. The differences between the experimental tracking conditions suggest that, in MS patients with intention tremor, the ocular system influenced the hand movements. Intention tremor amplitude was reduced when there was no preceding saccadic eye movement, whereas conversely, eye movements were not affected by different hand tremor severity.

Adult↗
PubMed2006

Betel quid: Its tremor-producing effects in residents of Araihazar, Bangladesh.

Betel quid consists of a betel nut (Areca catechu) and other additives. It is chewed throughout Asia and is the fourth most commonly used addictive substance in the world. Its stimulant properties are mediated by arecoline and other toxins. The neurological effects of betel quid use have not been studied extensively. To assess tremor, 100 residents of Araihazar, Bangladesh, were asked to draw spirals, which were rated by a blinded neurologist. The average tremor rating was 50% higher in exposed versus unexposed individuals. Betel quid use can produce clinically evident tremor. Population-based epidemiological studies of tremor in Asia should begin to take the effect of this stimulant into account.

Adolescent↗
PubMed2006

Postural tremor suppression is dependent on thalamic stimulation frequency.

Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) reduces tremor in people with essential tremor (ET), yet the dependence of tremor suppression on stimulation frequency remains unclear. To address this issue, we tested tremor suppression for three 15-second measurements during a variety of stimulation frequencies in 11 ET patients treated with VIM DBS. Stimulation frequencies at or above 100 Hz produced maximal benefit; higher frequencies provided no additional benefit. If this short-term measure predicts long-term response in routine activities at home, then this stimulation frequency setting will prolong battery half-life compared to higher frequency settings. These findings suggest that ET patients treated with VIM DBS may receive adequate benefit from stimulation frequencies about 100 Hz and this setting compared to commonly used higher settings will prolong battery life of surgically implanted pulse generators.

Aged↗
PubMed2007

Pregabalin (Lyrica) in the treatment of essential tremor.

We report on 2 essential tremor patients who experienced marked improvement in upper extremity tremor with the use of pregabalin (Lyrica, PGB). On PGB 200 mg/day, tremor amplitude was reduced by at least 40% in the worst affected hand in both patients as measured by accelerometry. Both patients also reported moderate reduction in tremor on the Clinical Global Impression Scale, and Fahn-Tolosa-Marin Part I scores were markedly improved.

Aged↗
PubMed1986

Clonidine in the treatment of essential tremor.

The effect of clonidine treatment (average dose 0.4 mg/day) was investigated in 10 patients with essential tremor in a double-blind placebo-controlled design. Tremor amplitude and frequency were recorded with an accelerometer. Tremor was not significantly altered by clonidine therapy. Side effects were common. It is concluded that clonidine is not effective treatment for essential tremor.

Clinical Trials as Topic↗
PubMed1990

Trunk and head tremor as isolated manifestations of dystonia.

Five patients presenting with isolated tremors of the trunk or neck are described. Their clinical features were similar to seven other patients who presented with head tremor, or arm and head tremor, but then eventually developed obvious torticollis, sometimes with arm dystonia. We conclude that isolated tremor of the trunk or head, especially of slow frequency (2-5 Hz), and in the case of the head in a "no-no" direction, may be the initial manifestation of focal dystonia.

Adult↗
PubMed1991

Quantitative comparison of barbiturates in essential hand and head tremor.

The tremorolytic effects of primidone and phenobarbital in essential tremor of hands and head were compared in a double-blind, placebo-controlled trial. Quantitative measurements of tremor were obtained in 15 patients by means of an accelerometric method. Only primidone proved to be superior to placebo in reducing hand tremor, suggesting that its tremorolytic effectiveness is largely dependent on the parent drug rather than its metabolite phenobarbital. Head tremor tended to improve only in three out of six patients with both primidone and phenobarbital, but, likely due to the small number of affected patients, the effect failed to reach statistical significance.

Aged↗
PubMed1991

Combined resting-postural tremor of the head with a changing axis.

When essential tremor involves the head, it produces a rhythmic, periodic movement with a certain fixed frequency and a variable amplitude. The axis of the tremor has been described as either horizontal (no-no) or vertical (yes-yes) and is present when the head is in an action or postural position. Seven patients who differ in symptoms are described; one subgroup exhibited a combined resting-postural tremor of the head, sometimes with a changing axis; three patients had only postural head tremor with a changing axis.

Aged↗
PubMed1992

Effect of ethosuximide on rest tremor in the MPTP monkey model.

Based on the hypothesis that low-threshold calcium conductance in the thalamus might be involved in the pathophysiology of parkinsonian tremor, ethosuximide was given chronically to a monkey previously treated with MPTP and displaying exceptionally a typical rest tremor. After 5 days of daily treatment, the tremor was reduced by 60%. Diltiazem and verapamil which act on different calcium channels had no such effect. Ethosuximide also potentiated the anti-tremor effect of the dopamine D2 agonist LY-171555.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗