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PubMed1981

Pharmacological characteristics of abnormal behavior induced by harmine with special reference to tremor in mice.

Harmine, a hallucinogen with potent monoamine oxidase inhibitory properties, induced abnormal behavior, including tremor, scratching, head twitch and cage biting, in the mouse. A dose-dependent tremor was produced by all routes of administration of harmine. Although oxotremorine tremor was markedly suppressed by atropine, harmine tremor was unaffected by cholinergic drugs, remarkably inhibited by dopaminergic drugs, antidepressants and diazepam, mildly diminished by p-chlorophenylalanine, markedly augmented by 5-hydroxytryptophan and mildly increased by alpha-methyl-p-tyrosine. These findings suggest that a catecholaminergic (particularly dopaminergic) and serotonergic system imbalance plays an important role in the manifestation of harmine tremor. In view of these characteristics, harmine tremor may be useful as an effective experimental model for the evaluation of antiparkinsonism drugs, along with oxotremorine tremor because of the different mechanism of occurrence. In addition, harmine tremor appears to be useful in characterizing the properties of antidepressant drugs.

5-Hydroxytryptophan↗
PubMed1994

[Essential tremor: clinical characterization in a sample of 176 patients].

We reviewed the clinical records of 176 patients with essential tremor (ET) according to sex, age of onset, family history, tremor characteristics and body distribution. The patients were divided into two groups: familial (F) and non familial (NF). A positive family history for tremor was observed in 47.2% of the patients. Action and postural tremor were the most frequent characteristic (49.4%), postural alone in 26.7% and action alone in 9.1%. Rest tremor was recorded in 10.2%, always associated with other characteristics. There were no clinical differences between the F and NF groups. Hands were involved in 94.9% and the head in 26.5%. Isolated tremor of the hands was the most frequent form of presentation with some greater frequency in males. Sixty per cent of the patients who presented head tremor either isolated or not, were females. The presence or absence of family history did not show difference in this proportion. The age of onset ranged between 4 and 85 years. In the F group a lower mean of onset (36.5 years) was seen in males with statistical significance. In male patients with combined action and postural tremor a lower age of onset was found. The fact of a patient having either parent affected by ET produced no difference in the age of onset. Familial or non familial ET bearing some differences, may not be considered as distinct entities.

Adolescent↗
PubMed1994

[Postural tremor and dystonia. Clinical aspects and physiopathological considerations].

The coexistence of tremor and dystonia is usually seen but there is not a satisfactory explanation for it. Some consider that essential tremor (ET) and idiopathic dystonia (ID) may be genetically linked. To clarify this relationship we evaluated the frequency of postural hand tremor in ID and symptomatic dystonia (SD) patients. We studied the records of patients with dystonia seen in our Movement Disorders Unit. ID was considered when there was no other neurological abnormality in the examination aside from dystonia, normal laboratorial tests and neuroimaging related to dystonia, and a negative past history for any known cause for it, except for genetic predisposition. We analyzed the clinical characteristics of dystonia and the occurrence of postural tremor. We collected 185 patients, being 120 with ID and 65 with SD. Tremor was seen in 27 (22.5%) of ID and 14 (21.5%) of SD. Tremor was present in either focal, segmental or generalized dystonia in both ID and SD. Family history for ET was absent in all patients. The similar frequency of tremor in ID and SD patients suggests that the pathophysiologic derangement resulting in dystonia can favor the development of tremor.

Adult↗
PubMed1999

Posteroventral pallidotomy for midbrain tremor after a pontine hemorrhage. Case report.

This 49-year-old man gradually developed a disabling action tremor in the proximal right upper extremity 8 months after suffering a pontine tegmental hemorrhage. The intraoperative microrecording in the nucleus ventralis intermedius (VIM) of the left thalamus revealed tremor-synchronous grouped discharges with a vigorous (2.7 Hz) action tremor predominantly in the shoulder and upper arm. High frequency electrical stimulation in the VIM did not affect the tremor. A posteroventral pallidotomy (PVP) was performed and resulted in the successful alleviation of all tremor activity. Posteroventral pallidotomy is known to alleviate parkinsonian tremors, especially those occurring in the contralateral lower extremity, trunk, and proximal segment of the contralateral upper extremity. The authors consider the pallidoreticular pathway to be an important tremor-mediating pathway for the proximal segment of the upper extremities and believe it can be controlled more effectively by PVP than by VIM thalamotomy, as demonstrated by the PVP-induced resolution of the midbrain tremor observed in this case.

Cerebral Hemorrhage↗
PubMed1975

Essential (hereditary or senile) tremor.

Sixteen cases (eight in males and eight in females) of essential (hereditary or senile) tremor were collected over a two-year period. Ten patients had near relatives with a similar disorder. All but one patient had a tremor of the upper limbs which was absent when the arms were at rest, but which appeared on movement, and was made worse by emotion. The severity of the tremor varied considerably from patient to patient, and often was temporarily lessened by alcohol. The tremor involved the head and neck in six subjects and the legs in two. One subject has associated neurological abnormalities probably due to cerebral arteriosclerosis. Otherwise no neurological abnormality except tremor was present in any patient. No patient showed evidences of Parkinsonism. To the time of collection of the series the tremor had been present for periods of between one and 62 years. Many patients with essential tremor are not severely enough affected to warrant therapy. Propranolol, a beta-adrenergic blocking agent, appears to reduce the tremor in at least some patients who need treatment.

Adolescent↗
PubMedDate not supplied

[Disappearance of essential tremor after thalamic infarction].

Stereotactic thalamotomy has been used with some benefit in the treatment of essential tremor. We report a 73-year-old woman whose essential tremor of the right hand spontaneously disappeared after thalamic infarction. She had suffered hand tremor of the right hand for seven years. One morning, she noticed mild muscular weakness in her right upper and lower extremities, numbness around her mouth and paresthesia in her right arm. Simultaneously, she noticed disappearance of the tremor of her right hand. Several days later, right hemiplegia and paresthesia completely resolved. Neurological examination revealed no postural tremor or resting tremor. T 2-weighted brain MR imaging showed a high-intensity signal in the left thalamus that involved the ventralis intermedius nucleus. Clinical recovery from the effect of the infarct on essential tremor was complete. Therefore, it seems that thalamic infarction in this patient had an effect on essential tremor similar to that achieved with thalamotomy.

Aged↗
PubMed2000

High-frequency synchronization of neuronal activity in the subthalamic nucleus of parkinsonian patients with limb tremor.

It has been hypothesized that in Parkinson's disease (PD) there is increased synchronization of neuronal firing in the basal ganglia. This study examines the discharge activity of 121 pairs of subthalamic nucleus (STN) neurons in nine PD patients undergoing functional stereotactic mapping. Four patients had a previous pallidotomy. A double microelectrode setup was used to simultaneously record from two neurons separated by distances as small as 250 micrometer. In the six patients who had limb tremor during the recording session (n = 76 pairs), the discharge pattern of 12 pairs of tremor cells (TCs) was found to be coherent at the frequency of the limb tremor. Both in-phase and out-of-phase relationships were observed between TCs. Interestingly, in these six patients, 63/129 single neurons displayed 15-30 Hz oscillations, whereas 36/76 pairs were coherent in this frequency range. Although the oscillatory frequencies were variable between patients, they were highly clustered within a patient. The phase difference between these pairs was found to be close to 0. High-frequency synchronization was observed during periods of limb tremor as well as during intermittent periods with no apparent limb tremor. In contrast, in the three patients without limb tremor during the recording session, only 1/84 neurons had high-frequency oscillatory activity, and no TCs or synchronous high-frequency oscillatory activity was observed (n = 45 pairs). These findings demonstrate that in PD patients with limb tremor, many STN neurons display high-frequency oscillations with a high degree of in-phase synchrony. The results suggest that high-frequency synchronized oscillatory activity may be associated with the pathology that gives rise to tremor in PD patients.

Action Potentials↗
PubMedDate not supplied

[Primary orthostatic tremor: slow harmonic component as responsible of inestability].

BACKGROUND: Orthostatic tremor (OT) is clinically defined as a tremor of the lower limbs and trunk on walking. It bears a significant functional impairement. Although the term orthostatic tremor was first used by Heilman in 1984, Pazzaglia et al had previously described some cases in 1970. Despite the fact that the pathophysiology of this entity is not fully known, the presence of a central oscillator is generally accepted as being responsible. A high frecuency tremor, between 13 and 18 Hz, constitutes an almost patognomonic finding, and treatment with clonazepam usually improves the symptoms. PATIENT AND METHOD: We present a patient who described his symptoms as "cramps" in lower limbs and trunk on standing up, which were relieved on walking or resting. RESULT: This clinical presentation together with a neurophysiological recording of the tremor showing an activity of lower frequency (8 Hz) combined with the usual higher frequency (16 Hz) and above all the clear amelioration of symptoms when treated with gabapentin, i.e. resolution of the low frequency tremor without changes in the 16 Hz tremor, were the peculiar features of this case which merits discussion. CONCLUSIONS: The slow component of the orthostatic tremor is crucial in this case. The improvement with gabapentin is explained by the disappearance of this slow c

Acetates↗
PubMedDate not supplied

Clinical and electromyographic examinations of patients with psychogenic tremor.

The diagnosis of psychogenic tremor is difficult, as it is based on exclusion of all possible causes for organic tremor. The aim of this examination was to evaluate some typical clinical and electromyographic features of the psychogenic tremor. Twenty-nine patients with psychogenic tremor were examined and followed up for more than 36 months. Surface electromyographic recordings of the most involved limb in all positions were performed. The tremor was assessed also during different distractive methods. We found that typical symptoms are the sudden onset from more than one limb and in more than one limb position and the lack of progression. Tremor was accompanied by muscle contraction of both agonistic and antagonistic muscles. EMG recorded tremor was with alternating pattern and variable amplitude and frequency. In conclusion there are typical clinical and EMG symptoms that are useful for the early diagnosis of psychogenic tremors, while with the progression of the disease these symptoms are no more evident.

Adult↗
PubMedDate not supplied

[Orthostatic tremor induced by pharmaceuticals].

INTRODUCTION: Dopamine blocking agents can induce gravel types of 'tardive syndromes' (buccolinguomasticatory syndrome, dystonia, akathisia, and less frequently tremor, tourettism, and myoclonus). To our knowledge, orthostatic tremor has not been previously described as a complication of exposure to these drugs. CASE REPORTS: We report four patients who developed orthostatic tremor after exposure to dopamine blocking drugs. Two of them had orthostatic tremor as the predominant but not exclusive type of tremor, and the other two had 'pure' high-frequency orthostatic tremor. Tremor disappeared completely in 3 patients and improved markedly in the other one after gradual withdrawal of the offending drugs (metoclopramide in case 1, sulpiride and thyethylperazine in case 2, and sulpiride in cases 3 and 4). CONCLUSIONS: We propose that this 'tardive orthostatic tremor' could be considered into the spectrum of drug-induced movement disorders.

Aged↗
PubMed2005

Integrative re-organization mechanism for reducing tremor in Parkinson's disease patients.

A special movement therapy, called coordination dynamics therapy, has been reported to have the potential to improve central nervous system (CNS) functioning in Parkinson's disease patients. Electromyography using surface electrodes (sEMG) showed that the rhythmic muscle activity leading to Parkinsonian tremor was generated in the patients by the impairment of two kinds of inhibition. First, some premotor spinal oscillators organized themselves in the CNS neuronal networks without strong adequate input and second, the oscillators synchronized their firing to give rise to rhythmic muscle activity and tremor. In this paper it will be shown that highly coordinated arm and leg movements, generated when exercising on a special coordination dynamics therapy device, can reduce Parkinsonian tremor in amplitude and frequency and improve CNS functioning in the short-term memory. sEMG measurements showed upon exercising on the special coordination dynamics therapy device that the motor program improved in the short-term memory and tremor muscle activity became coordinated with the volitional motor program and reduced in size and frequency. Higher load exercising seemed to better reduce tremor muscle activity, probably because the physiologic CNS organization was more integrative then and could 'bind' stronger simultaneous pathologic tremor activity. Moreover, the rhythmic synchronized motor unit firing in different arm and leg muscles was synchronized or coordinated and changed in frequency and amplitude. It is concluded that the integrative re-organization mechanism to reduce Parkinsonian tremor is the phase and frequency coordination between neuron firing of the physiologic neuronal network state, generated by the highly coordinated arm and leg movements, and the simultaneous pathologic tremor network state, generated by the uninhibited neurons, firing synchronized oscillatory.

Aged↗
PubMed1985

Studies on the mechanism of chlordecone-induced tremor in rats.

Organochlorine insecticides such as DDT and chlordecone produce tremor in exposed individuals. Using a spectral analysis technique, chlordecone-induced tremor in rats was found to be dose- and time-related and could be distinguished from pharmacological agents (i.e., harmine, oxotremorine, and apomorphine) that produce tremor or stereotypic behavior. Drugs with known pharmacological effects were used to study the possible mechanism of chlordecone-induced tremor. Although no one neurotransmitter system appears necessary for tremor, the serotonergic, gabaergic, and cholinergic systems appear to contribute to chlordecone-induced tremor. The role of the catecholaminergic system is uncertain. Subsequent experiments indicated that supraspinal processes, possibly located in the brain stem, are important contributors to chlordecone-induced tremor. Activation of the cerebellum via the olivocerebellar tract to produce tremor cannot explain chlordecone's tremorgenic effects.

Animals↗
PubMed1989

[Essential tremor in the elderly: incidence in hospital admissions for non-neurologic reasons].

The frequency of essential tremor (ET) was determined in 102 unselected elderly patients aged 65 or over (average 73.9 +/- 9.1) admitted to the medical and surgical wards of a general hospital for non-neurological conditions. Patients bearing potential causes for symptomatic tremor were excluded. ET was observed in 10 individuals (9.8%) and in one a previously unrecognized Parkinson's disease (PD) was detected. The frequency of the ET increased linearly by age groups up to the age of 80 to decrease thereafter. In 30% of the cases the tremor did not involve the limbs, five had pathologically enhanced physiological tremor, one had type 2 ET and in one other a type 3 ET was combined with tremor of the head. No case had previously consulted because of the tremor and a positive family history for this was found in only 2 cases. In the overall group, a 4.9% affirmed to have a relative with tremor and in a further 3.9% a specific diagnosis of PD had been established in at least one relative. The occurrence of ET in first-degree family members was considerably lower, with a history of ET found in 1.5% out of 197 parents, 0.8% of 473 brothers and sisters and 0.3% out of 277 living sons and daughters. Our study indicates that a positive family history for tremor is commonly encountered in the general population, and a high percentage of elderly individuals may themselves exhibit ET albeit mild enough usually as not to warrant neurological consultation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

Cholinergic involvement in the modulation of oxotremorine-tremor in mice by propranolol.

Propranolol in low doses antagonized and in higher doses facilitated oxotremorine-induced tremor (Oxo-tremor) in mice. Atropine blocked Oxo-tremor, an effect that was reversed by propranolol. Atropine pretreatment also antagonized the potentiating effect of propranolol on Oxo-tremor. Propranolol inhibited mice brain cholinesterase at doses which enhanced Oxo-tremor. Timolol and sotalol produced a dose-dependent antagonism of Oxo-tremor, whereas practolol failed to produce a similar effect. None of these three agents produced any significant enhancement of Oxo-tremor. These results suggest the involvement of a peripheral mechanism for the antagonism and a central cholinergic mechanism for the facilitation of Oxo-tremor by propranolol.

Adrenergic beta-Antagonists↗
PubMed1987

Induction and reduction of muscle tremor upon acute and repeated administration of the beta 2-agonists terbutaline, salbutamol and tulobuterol.

Two single-blind placebo-controlled crossover studies on healthy volunteers were performed to compare typical adverse effects of the beta 2-adrenoceptor agonists salbutamol, terbutaline und tulobuterol in a daily period of eight h after acute oral administration of different doses. Assessments were repeated after six days of regular drug intake, to look for habituation phenomena. Finger tremor, integrated surface-EMG in relation to voluntary force, blood pressure and heart rate were measured. Tremor was recorded with a 3-dimensional accelerometer during three different states of hand extensor muscle activity: relaxed, lightly and maximally contracted. The tremor signal was submitted to power spectrum analysis (FFT). All drug effects depended on the dose and the type of drug used, 2 mg tulobuterol being about equivalent to 4 mg salbutamol and to 2.5 mg terbutaline. Cardiovascular adverse effects were weak and transient. The induction of resting tremor showed some habituation across subchronic medication, whereas cumulative and ceiling effects of the beta 2-agonists occurred in respect to tremor during both states of active muscle contraction. However, the beta 2-adrenergic effect during strong contraction consisted in a prominent reduction of tremor. This striking result did not seem to be related to a transient increase of force, relative to myoelectric activity, which was no longer seen after subchronic medication. In case of ceiling effects, the relative changes in tremor intensity decreased with continuous beta 2-sympathomimetic treatment. Therefore, tremor might become a tolerable though inevitable concomitant of bronchodilatory therapy. Its quantitative measurement seems to provide adequate means to assess dose- and time-efficacy as well as to estimate clinical benefit.

Adrenergic beta-Agonists↗
PubMed1995

[Continuous electric thalamus stimulation for the treatment of tremor resistant to pharmacotherapy].

OBJECTIVE: To determine the efficacy of continuous electrical thalamic stimulation in the treatment of pharmacotherapy-resistant tremor in patients with Parkinson's disease and essential tremor. DESIGN: Descriptive study. SETTING: Academic Medical Centre, Academic Hospital of the University of Amsterdam. METHOD: Five patients with Parkinson's disease and one with familial essential tremor suffering from pharmacotherapy-resistant tremor were treated by implantation of a four-polar stimulation electrode in the contralateral ventrolateral thalamic nucleus connected subcutaneously to a stimulator. Continuous electrical stimulation was applied in the daytime and switched off during the night. Three of the Parkinson patients were subjected to contralateral thalamotomy as well. RESULTS: Three patients (including the one with essential tremor) had complete tremor suppression during stimulation, and the other three had intermittent minimal tremor. There were no early complications (follow-up: 1 month-1 year). One patient had mild hemi-inattention and pyramidal signs due to the thalamotomy. CONCLUSION: Continuous thalamic stimulation appears to be a good alternative to thalamotomy. It renders possible bilateral surgical treatment for severe bilateral tremor.

Aged↗
PubMed1984

Spastic dysphonia and essential (voice) tremor treated with primidone.

Primidone has been reported to be effective in reducing tremor in patients with benign essential tremor. There is at least one report that suggests that the medication may reduce voice tremor, a frequent component of the essential tremor syndrome. Three patients with spastic dysphonia of essential (voice) tremor and one with more typical essential (voice) tremor were treated with primidone and experienced no alleviation in the voice signs. The side effects experienced by all patients were consistent with those noted in previous reports. Primidone does not seem to be effective in treating essential voice tremor or spastic dysphonia of essential voice tremor.

Aged↗
PubMed1997

Familial cortical myoclonic tremor as a unique form of cortical reflex myoclonus.

Previously it was reported that some patients with tremor had the same electrophysiological findings as those seen in patients with cortical reflex myoclonus, and consequently the tremor was named "cortical tremor." In the present study, we examined six patients from three families with cortical tremor of relatively late onset. The inheritance pattern of cortical tremor was compatible with autosomal dominant trait. Those patients had relatively rhythmic involuntary movements (tremor) in the distal upper and lower limbs, especially during posture and/or fine movements. There was no cerebellar ataxia or dementia, and fits of loss of consciousness occurred only infrequently. Electrophysiologically, they had generalized spikes on electroencephalogram (EEG), giant cortical components of somatosensory evoked potential, an enhanced long-loop reflex (C-reflex), and cortical spikes preceding the rhythmic jerk demonstrable by the jerk-locked back averaging method, thus fulfilling the criteria of cortical reflex myoclonus. Furthermore, they had slow negative EEG shift starting 1-2 s prior to voluntary movements, suggesting that, as opposed to the conventional form of progressive myoclonus epilepsy (PME), the cerebellar efferent input to the motor cortices was normal. These clinical and electrophysiological pictures are distinct from those of familial essential tremor, familial essential myoclonus, or the conventional form of PME, and the term "familial cortical myoclonic tremor" will represent the clinical and electrophysiological features of this unique entity most appropriately.

Adult↗