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[Stereotactic ventrolateral thalamotomy in the treatment of essential tremor].

BACKGROUND AND PURPOSE: Essential tremor is the most common tremorogenic movement disorder. In the majority of patients the progression of the disease is slow and the pharmacological treatment effectively alleviates tremor. In rare cases of increased essential tremor the surgical treatment (ventrolateral thalamotomy) is indicated. The goal of this study was to assess the effectiveness of unilateral thalamotomy in the treatment of essential tremor. MATERIAL AND METHODS: 10 stereotactic ventrolateral thalamotomies were performed in 9 patients for pharmacologically intractable essential tremor. Right thalamotomy was done in 5 patients and left thalamotomy in 4 patients. The study included five men and four women. Patients were assessed according to the Clinical Rating Scale for Tremor (CRST) before surgery and at 3, 12 and 24 months after thalamotomy. RESULTS: In the postoperative period there was a marked reduction of essential tremor in the contralateral arm and, to a lower extent, in the contralateral leg. The mean presurgery value for contralateral upper extremity postural tremor (scores 5/6 CRST) decreased from 3.5 to mean postsurgery value of 0.6. The tremor reduction contributed to 59% improvement in specific motor tasks of upper extremities (Part B of CRST) at 2 years follow-up. There was also improvement of functional disabilities (Part C of CRST) by 62% when compared to preoperative value 2 years postoperatively. CONCLUSIONS: Ventrolateral thalamotomy is a highly effective method in the treatment of essential tremor. The side effects related to surgery are rare and most of them are transient.

Adult↗
PubMed1989

Tremor disorders of aging: diagnosis and management.

Tremor disorders are commonly encountered in the elderly. Physiological tremor is present in all of us and may be enhanced by drugs or other circumstances to cause symptomatic dysfunction. Essential tremor consists of postural and kinetic tremors which may involve the hands, head, and voice. Approximately 50% of cases are hereditary. Significant disability may occur. Propranolol and primidone provide effective treatment for some patients. The tremor of Parkinson's disease occurs in resting and postural positions. Treatment with levodopa usually reduces the tremor. Anticholinergics may also decrease tremor but often cause mental side effects in the elderly. Disturbances of the cerebellum may cause a kinetic tremor of the extremities or shakiness of the trunk. Tremors may also occur on a psychogenic basis. Proper classification of tremor disorder will lead to appropriate diagnosis and, often, effective treatment.

Aged↗
PubMed1978

Quantification of high pressure nervous syndrome (HPNS) tremor in the guinea pig.

Previous studies have demonstrated two tremorgenic systems that involve separate brain mechanisms and exhibit different peak frequencies. One system (the thalamo-cortical) generates low frequency (4--8 Hz) tremor; the other (the olivo-cerebellar) produces high frequency (10--18 Hz) tremor. Based on this evidence, the present study focused on determining whether one or both of these tremor systems is involved in the high pressure nervous syndrome (HPNS). Specifically, the concern was to identify and to quantify amplitude and frequency characteristics of HPNS tremor in 8 guinea pigs breathing helium-oxygen during compression (40 ft/min) in a chamber dive to 61.6 ATA (2000 fsw) with a bottom time of 1 h. Rectal temperature was recorded and maintained at 39 degrees C +/- 1 degree. Leg tremor was recorded by magnetic inductance and stored on magnetic tape for power spectral analysis. Frequency histograms of the tremor data revealed development of a biphasic response. From surface to about 31.3 ATA (1000 fsw), a low-power, single, 4- to 6-Hz component was evident, which resembled fine or moderate tremor. Between 34.3 ATA (1100 fsw) and 61.6 ATA, a 12- to 18-Hz component emerged abruptly with a dramatic increase in power, which reflected coarse, uncontrollable tremors. In the first 5 to 10 min after the animals arrived at maximum pressure, relative power of the high frequency component dropped to and remained near base-line levels. These results support the hypothesis that HPNS tremor consists of two components and possibly two separate tremor systems.

Animals↗
PubMed1995

[Clinical subtypes of essential tremor and their electrophysiological and pharmacological differences].

We divided 19 patients with essential tremor into two subtypes according to clinical characteristics of the tremor. Ten patients had pure postural tremor distributed in the hand(s), head, and face (group A). Nine patients had tremor extending to the voice or leg(s), associated with resting tremor and/or hyperkinesie volitionnelle of the hand(s) (group B). Their ages, the age of onset, and the duration of illness were not different between the two groups. Electrophysiologically, the tremor of group A patients had higher frequencies than that of group B patients, and had synchronized activities for antagonistic muscles. Four of group B patients had reciprocal antagonistic activities of the tremor. Inactive phase of tremor induced by an electrically-evoked muscle twitch was invariably within the range of the physiological silent period for group A patients, and prolonged beyond the range for four of group B patients. Pharmacologically, 78% of group A patients responded well to beta-blocker, which was effective for 25% of group B patients. Sixty per cent of beta-blocker-resistant group B patients responded well to phenobarbital. In conclusion, a peripheral mechanism, presumably beta-adrenergic drive, is important for the tremor in group A patients, while central pathogenic mechanisms are more important for the tremor of group B patients.

Adrenergic beta-Antagonists↗
PubMed1996

Can tremor be used to measure the effect of chronic mercury exposure in human subjects?

Clinical and quantitative studies in which tremor was used to evaluate the effect of chronic exposure to organic and inorganic mercury in human subjects during the last 20 years were identified in MEDLINE and BIOLOGICAL ABSTRACTS. In the selected studies, methods varied widely by types of transducers used, anatomical locations of tremor testing, tasks executed by the subjects, types of tremor recorded and durations of trials. Measurements of tremor in these studies also varied by frequency, amplitude, waveform and reproducibility. Typically measures of variability were not included. Results obtained depended heavily on the methods and analyses used. We suggest that, although many contradictions and discrepancies have been noted in these studies, tremor can probably be used to measure the effect of chronic mercury exposure. This would involve more rigorous and uniform recording procedures and analyses. Specific suggestions proposed include: realizing the limitations of accelerometric data; considering the effect of weight on the tested limb; controlling recording conditions; selecting samples more carefully; recording other physiological variables besides tremor; using tasks and manoeuvres that unmask subclinical abnormalities in tremor; reporting frequency, amplitude, waveform and variability of tremor; understanding the limitations of power spectra analysis; separating tremor characteristics according to types of mercury exposure; and considering supraspinal influences that both vision and voluntary movements have on tremor.

Environmental Exposure↗
PubMed1998

["Primary" orthostatic tremor. 10 clinical electrophysiologic observations].

Orthostatic tremor is an unusual kind of potentially disabiling tremor appearing immediately when standing. Clinical examination is normal in primary form except for wide base standing and unsteadiness which disappear when walking. Arm tremor resembling essential tremor is found present in one third of cases. Electrophysiological exploration is necessary for diagnosis and shows a regular rapid tremor (frequency around 16 Hz). We present 10 new cases, 3 men and 7 women, 37 to 74 years old. Unsteadiness when standing was the predominant complaint in 9 cases, the other first described pains in the lower limbs. All had visible or palpable tremor predominant in thighs. Four patients had postural arm tremor, one had neurogen syndrome in the lower limbs corresponding to toxic polyneuropathy which developed after tremor. Electromyographic study found high frequency (13-17.3 Hz) rhythmic discharge in weight-bearing muscles. Orthostatic tremor cannot be considered as a clinical variant of postural essential tremor. Its pathophysiology is unknown but the efficacy of clonazepam, primidone or barbiturates suggests the impairment of the gabaergic system.

Adult↗
PubMed2004

Botulinum toxin type A for treating voice tremor.

BACKGROUND: Voice tremor, like spasmodic dysphonia and other tremor disorders, may respond to botulinum toxin type A injections. OBJECTIVE: To evaluate the safety and efficacy of botulinum toxin type A injections as treatment for voice tremor. DESIGN: A randomized study of 3 doses of botulinum toxin type A with 6 weeks of follow-up. SETTING: A single-site tertiary care center. PARTICIPANTS AND METHODS: Thirteen subjects (11 women, 2 men; mean age, 73 years) with voice tremor and no spasmodic dysphonia or head, mouth, jaw, or facial tremor were entered into this study. Patients received 1.25 U (n = 5), 2.5 U (n = 5), or 3.75 U (n = 3) of botulinum toxin type A in each vocal cord. All patients were evaluated at baseline and postinjection at weeks 2, 4, and 6. MAIN OUTCOME MEASURES: The primary outcome measure was the patient tremor rating scale, with secondary measures including patient-rated functional disability, response rating scale, independent randomized tremor ratings, and acoustical measures. RESULTS: All patients at all dose levels noted an effect from the injection. The mean time to onset of effect was 2.3 days (range, 1-7 days). For all patients combined, mean tremor severity scale scores (rated by patients on a 5-point scale) improved 1.4 points at week 2, 1.6 points at week 4, and 1.7 points at week 6. Measures of functional disability, measures of the effect of injection, independent ratings of videotaped speech, and acoustic measures of tremor also showed improvement. The main adverse effects at all doses were breathiness and dysphagia. CONCLUSION: Voice tremor improves following injections of botulinum toxin type A.

Aged↗
PubMed1999

123I-IPT brain SPECT study in essential tremor and Parkinson's disease.

OBJECTIVE: To investigate nigral neuronal damage in patients with isolated postural tremor and those with postural and rest tremor without parkinsonism. METHODS: Using [123I]-N-(3-iodopropen-2-yl)-2 -carbomethoxy-3beta-(4-chlorophenyl) tropane SPECT, we measured the basal ganglia-occipital cortex/occipital cortex ([BG-OCC]/OCC) uptake ratios in 21 control subjects and patients with isolated postural tremor (n = 9), postural and rest tremor (n = 6), and PD (n = 11). RESULTS: In the patients with PD, the means (+/-SD) of the (BG-OCC)/OCC ratios of the ipsilateral (2.35+/-0.37) and the contralateral (1.97+/-0.33) sides to the more severely affected limbs were significantly lower than the mean of the bilateral (BG-OCC)/OCC ratios of the age-matched control subjects (3.83+/-0.66). The mean (+/-SD) of the bilateral (BG-OCC)/OCC ratios of the patients with isolated postural tremor (3.60+/-0.83) was comparable with that of the age-matched control subjects. However, the mean (+/-SD) of the bilateral (BG-OCC)/OCC ratios of the patients with postural and rest tremor (2.61+/-0.18) was lower than that of the control subjects (p < 0.05). The mean of the bilateral (BG-OCC)/OCC ratios of the patients with postural and rest tremor was comparable with that of the side ipsilateral to the severely affected limbs of the patients with PD. However, it was higher than that of the side contralateral to the limbs more severely affected by PD. Four of the six patients with postural and rest tremor had (BG-OCC)/OCC ratios lower than 2 standard deviations from the mean of the age-matched control subjects. CONCLUSIONS: Later in their clinical courses, some patients with postural tremor may acquire rest tremor in association with mild substantia nigra neuronal loss.

Adult↗
PubMed2001

Analysis of pathological tremors using the autoregression model.

The usefulness of analysis of acceleration data using an autoregression model (AR) for differential diagnosis of Parkinson's disease and other diseases with tremors was investigated. The order of the AR model used in this study was 7, in accordance with Akaike's final prediction error criterion. The subjects included 19 patients with Parkinson's disease; 21 patients with essential tremor, which mainly appears in old people, as well as Parkinson's disease; and 13 healthy old people as a control group. The results of analysis of acceleration data showed that the first prediction coefficient, just as the main tremor frequency, was a useful parameter for differentiating patients in the Parkinson's disease patient group and essential tremor patient group. The seventh prediction coefficient was found to be a useful parameter for distinguishing pathological tremors observed in Parkinson's disease and essential tremor disease from physiological tremors observed in healthy people. Although the usefulness of other prediction coefficients for differential diagnosis of Parkinson's disease and other diseases with tremors has not yet been clarified, the results of this study showed that information obtained from AR model parameters in addition to information on main tremor frequency is useful for the diagnosis of Parkinson's disease.

Acceleration↗
PubMed2004

A clinical study of non-parkinsonian and non-cerebellar tremor at a specialty movement disorders clinic.

BACKGROUND: No Indian studies have focused on the clinical aspects of tremor. AIMS: To study the distribution of various etiological types of tremor disorders at a Movement Disorders clinic of a large, tertiary care hospital in India and to study the clinical characteristics of essential tremor [ET]. SETTING AND DESIGN: Prospective cross-sectional study at a tertiary care specialty clinic. MATERIAL AND METHODS: Patients presenting with tremor as the chief complaint, with no features suggestive of parkinsonism, cerebellar disorder or acute central nervous system disorder, were included. Patients were classified into different etiological categories from detailed history. All patients diagnosed as ET, were further interrogated for a detailed family history and examined for characteristics of tremor. These patients were then classified into 'definite', 'probable' and 'possible' ET. RESULTS: One hundred and six patients (mean age 44.4 + 15.1 years) were examined during the study period. ET (59.4%) and dystonic tremor (21.7%) were the commonest types. Only 43% patients of ET reported progression; response to alcohol was seen in only a single patient, a positive family history was present in 52.4% and in 36.4% the inheritance was of an autosomal dominant pattern. CONCLUSION: ET and dystonic tremor are the commonest causes of tremor presenting to a specialty Movement Disorders clinic. Most patients with ET have high-frequency tremor, with mild asymmetry in 40% cases. Alcohol responsiveness may not be a useful tool in the diagnosis of ET.

Adult↗
PubMed1986

Attenuation of response to mental stress in patients with essential tremor treated with metoprolol.

The response to mental stress in patients with benign essential tremor is an exaggeration of the resting tremor. We have studied the ability of metoprolol tartrate to attenuate specifically the tremorgenic response to mental stress in five patients with essential tremor who were each studied on four occasions. Treatment regimens consisted of 0-, 25-, 50-, and 75-mg doses of metoprolol tartrate, given twice daily for seven- to ten-day periods. Tremor was measured while patients were resting comfortably and then again following mental stress over eight-hour study periods. During the baseline study period, the investigational mental stress consistently exaggerated tremor in each patient. Metoprolol treatment reduced both the resting tremor and tremor following mental activity, but the drug-induced change in the response to mental stress was more pronounced than the drug-induced reduction in resting tremor. The ability of metoprolol to blunt the response to mental stress was associated with serum concentrations of the drug. The time courses of metoprolol serum concentrations were similar to the time course of metoprolol's ability to blunt the response to mental stress. Metoprolol possesses the ability to blunt the tremorgenic response to mental stress in patients with essential tremor, but the duration of this effect lasts less than seven hours after administration of a dose.

Adolescent↗
PubMed2003

Beta-blocker therapy for tremor in Parkinson's disease.

BACKGROUND: The tremor of Parkinson's disease can cause considerable disability for the individual concerned. Traditional antiparkinsonian therapies such as levodopa have only a minor effect on tremor. Beta-blockers are used to attenuate other forms of tremor such as Essential Tremor or the tremor associated with anxiety. It is thought that beta-blockers may be of use in controlling the tremor of Parkinson's disease. OBJECTIVES: To compare the efficacy and safety of adjuvant beta-blocker therapy against placebo for the treatment of tremor in patients with Parkinson's disease. SEARCH STRATEGY: Electronic searches of MEDLINE, EMBASE, SCISEARCH, BIOSIS, GEROLIT, OLDMEDLINE, LILACS, MedCarib, PASCAL, JICST-EPLUS, RUSSMED, DISSERTATION ABSTRACTS, SIGLE, ISI-ISTP, Aslib Index to Theses, The Cochrane Controlled Trials Register, Clinicaltrials.gov, metaRegister of Controlled Trials, NIDRR, NRR and CENTRAL were conducted. Grey literature was hand searched and the reference lists of identified studies and reviews examined. The manufacturers of beta-blockers were contacted. SELECTION CRITERIA: Randomised controlled trials of adjuvant beta-blocker therapy versus placebo in patients with a clinical diagnosis of idiopathic Parkinson's disease. DATA COLLECTION AND ANALYSIS: Data was abstracted independently by two of the authors onto standardised forms and disagreements were resolved by discussion. MAIN RESULTS: Four randomised controlled trials were found comparing beta-blocker therapy with placebo in patients with idiopathic Parkinson's disease. These were double-blind cross-over studies involving a total of 72 patients. Three studies did not present data from the first arm, instead presenting results as combined data from both treatment arms and both placebo arms. The risk of a carry-over effect into the second arm meant that these results were not analysed. The fourth study presented data from each arm. This was in the form of a mean total score for tremor for each group. Details of the baseline scores, the numbers of patients in each group and standard deviations were not provided, meaning that the magnitude and significance of any changes due to therapy could not be calculated. One study reported a substantial fall in heart rate in 14 of the 22 patients, with one patient withdrawing after his heart rate dropped to 56 beats per minute (baseline heart rate was not reported). REVIEWER'S CONCLUSIONS: In view of this lack of evidence, it is impossible to determine whether beta-blocker therapy is effective and safe for the treatment of tremor in Parkinson's disease. The high frequency of bradycardia in one trial raises some concerns about the prescription of beta-blockers to normotensive elderly patients but the study was too small for the true degree of risk to be calculated.

Adrenergic beta-Antagonists↗
PubMed1981

Essential tremor treated with propranolol: lack of correlation between clinical effect and plasma propranolol levels.

Five patients with essential tremor were treated with increasing daily doses of propranolol. Tremor intensity was assessed after each propranolol dose had been given daily for a period of at least seven days. The evaluation was made 12 to 15 hours after the last propranolol ingestion. It included a semiquantitative clinical tremor evaluation and quantitative registration with an accelerometer. Electronic integration of the accelerometer curves gave an arbitrary measure of tremor intensity. Plasma propranolol concentration was determined at each tremor measurement. The reduction in tremor correlated with increasing propranolol doses, whereas plasma propranolol concentrations varied widely among individuals and could not be correlated with tremor reduction. Most of the patients had considerable diminution in tremor at low propranolol doses, often with an unmeasurable plasma propranolol concentration. Determination of plasma concentrations has little value in long-term treatment of essential tremor with propranolol. The dosage can be sufficiently guided by clinical evaluation of effect.

Adult↗
PubMed1996

The effect of ethanol on alcohol-responsive essential tremor: a positron emission tomography study.

We used H2 15O positron emission tomography (PET) to investigate the effect of ethyl alcohol on regional cerebral blood flow in 6 patients with alcohol-responsive essential tremor and 6 age-matched control subjects. The patients were scanned while at rest and during involuntary postural tremor of the extended right arm. Normal control subjects were scanned at rest and during passive wrist oscillation of the right arm at tremor frequency. Regional cerebral blood flow associated with these conditions was measured before and after oral administration of 2 to 3 units of alcohol. The mean blood alcohol level was 35.3 +/- 20.0 mg/dl in the patient group and caused marked suppression of tremor; it was 33.9 +/- 12.9 mg/dl in the control group. Similar to previous PET studies on essential tremor patients, tremor compared with rest was associated with bilateral cerebellar activation including the cerebellar vermis. This pattern of activation differed from passive wrist oscillation where ipsilateral cerebellar activation was observed. Ethanol ingestion led to bilateral decreases of cerebellar blood flow in both tremor patients and normal subjects, and this was associated with suppression of tremor in the patients. Alcohol-associated increases of regional cerebral blood flow were observed in the inferior olivary nuclei in the patients but not in the control subjects. We conclude that alcohol-induced suppression of essential tremor is mediated via a reduction of cerebellar synaptic overactivity resulting in increased afferent input to the inferior olivary nuclei.

Adult↗
PubMed1997

High-frequency unilateral thalamic stimulation in the treatment of essential and parkinsonian tremor.

Pharmacologic treatment for essential tremor and the tremor of Parkinson's disease is often inadequate. Stereotaxic surgery, such as thalamotomy, can effectively reduce tremors. We performed a multicenter trial of unilateral high-frequency stimulation of the ventral intermedius nucleus of the thalamus in 29 patients with essential tremor and 24 patients with Parkinson's disease, using a blinded assessment at 3 months after surgery to compare clinical rating of tremor with stimulation ON with stimulation OFF and baseline and a 1-year follow-up. Six patients were not implanted because of lack of intraoperative tremor suppression (2 patients), hemorrhage (2 patients), withdrawal of consent (1 patient), and persistent microthalamotomy effect (1 patient). A significant reduction in both essential and parkinsonian tremor occurred contralaterally with stimulation. Patients reported a significant reduction in disability. Measures of function were significantly improved in patients with essential tremor. Complications related to surgery in implanted patients were few. Stimulation was commonly associated with transient paresthesias. Other adverse effects were mild and well tolerated. Efficacy was not reduced at 1 year. Chronic high-frequency stimulation is safe and highly effective in ameliorating essential and parkinsonian tremor.

Aged↗
PubMed2006

Isolated high-frequency jaw tremor relieved by botulinum toxin injections.

Jaw tremor can be seen as a component of various neurological disorders such as essential tremor, Parkinson's disease, dystonia, branchial myoclonus, hereditary geniospasm, task-specific tremor, and Whipple's disease, as well as in normal situations such as shivering, and subclinical physiological jaw tremor. In most of these conditions, the jaw tremor is usually associated with tremor or other abnormal involuntary movements affecting additional body parts, and its frequency is lower than 12 Hz. Schrag and colleagues reported a patient with a high-frequency idiopathic jaw tremor, and they speculated it could be related to orthostatic tremor affecting the masseter muscles. We encountered a similar patient with intermittent rapid focal jaw tremor that was successfully treated with botulinum toxin injections to the masseters.

Adult↗
PubMed2006

Study of possible factors associated with age of onset in essential tremor.

Factors associated with the age of onset of essential tremor (ET) have not been studied in detail. Identification of modifiable factors could lead to strategies to delay disease onset and identification of nonmodifiable factors would be useful while counseling at risk individuals. The objective of this study was to identify factors associated with age of onset of tremor in ET. One hundred ninety-five ET cases were enrolled in an environmental epidemiological study. Clinical questionnaires included questions on age of onset, demographics (age, sex, race, education), early-life exposures (birth order, childhood household size), exposures prior to tremor onset (head trauma, well water, rural living, estrogen replacement therapy), and family history. In unadjusted analyses, age of onset was associated with family history of tremor (40.9 +/- 22.0 years for cases with a family history of tremor vs. 57.3 +/- 18.4 years for cases without a history; P < 0.001), history of head trauma, younger current age, greater tremor severity, and white race. Ninety-one percent of cases with onset before age 20 years had a family history of tremor. Age ofonset was not associated with other variables of interest (e.g., sex, well water, rural living). In an adjusted linear regression model, age of tremor onset was strongly associated with family history of tremor (P < 0.001). The familial form of ET is characterized by an earlier age of onset than the sporadic form. This study did not detect any other exposures that modified the age of onset of ET. Follow-up studies are needed to examine additional factors of potential interest.

Adolescent↗
PubMed1996

Internal tremor in patients with Parkinson's disease.

Although sensory symptoms were not originally described in Parkinson's disease (PD), in recent years it has been increasingly recognized that painful sensations and paresthesias occur in approximately 40% of patients. It has been our observation that PD patients often describe a sensation of internal tremor, a feeling of tremor inside the chest, abdomen, arms, or legs that cannot be seen. We investigated the prevalence and characteristics of internal tremor by administering a questionnaire to 100 consecutive patients with PD and 50 age-matched controls seen in our movement disorders center. A sensation of internal tremor was present in 44% of this sample of PD patients and in 6% of the control population (p < 0.0001). The presence of internal tremor was unrelated to Unified Parkinson's Disease Rating Scale score, Hoehn and Yahr stage, duration of disease, or the presence of observable tremor. The frequency of other sensory symptoms (aching, tingling, burning) was higher in the PD patients with internal tremor (73%) than in those without (45%; p = 0.005). Internal tremor is associated with anxiety in 64% of patients (p < 0.0001). It was described as uncomfortable and was unrelieved by antiparkinsonian medication in three quarters of patients. A sensation of internal tremor is commonly reported by PD patients and should be recognized as a useful diagnostic factor in PD.

Aged↗