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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Effect of Coretal Polfa (Oxprenolol) on parkinsonian tremor and benign essential tremor].

Coretal -- an agent blocking the beta-adrenergic receptors -- was given to 12 patients with Parkinson's syndrome with evident tremor and to 4 patients with benign essential tremor. In the group of Parkinson's syndrome the effectiveness of this treatment was evaluated by the blind method. The whole period of observation was 6 weeks, during 3 weeks the patients received Coretal 60-120 mg daily, during the next 3 weeks they were given placebo. The intensity of tremor was assessed by means of a scoring system. Improvement was achieved in 7 patients with Parkinson's syndrome and in 3 out of 4 cases of idiopathic tremor. Complete disappearance of tremor was never observed. Transient side effects were observed in 2 causes. The authors think that Coretal may be used with good result in treatment of parkinsonian tremor and benign essential tremor.

Clinical Trials as Topic↗
PubMed1975

Application of an objective method of assessing intention tremor - a further study on the use of weights to reduce intention tremor.

Thirty-one patients with intention tremor due to a variety of causes were subjected to measurements of their intention tremor. The effect of varying amounts of lead weights on the amount of limb tremor recorded was noted. It is concluded that simple methods of treatment may be of benefit, and that an objective method of measuring intention tremor overcomes many of the difficulties of a clinical trial of this type. The method described yields quantifiable data which can be subjected to statistical analysis to help overcome the problem of variability. Bias in the results due to practice or fatigue effects has proved negligible. An optimum amount of lead, which was usually between 600 and 840 g, has been noted.

Adolescent↗
PubMed1979

Tremor in the tension developed isometrically by soleus during the tonic vibration reflex in the decerebrate cat.

1. Irregularities in the development of tension during the tonic vibration reflex of the soleus muscle of the decerebrate cat have been analysed into their frequency components. The reflex was recorded isometrically and elicited by longitudinal vibration, normally at 150 Hz. The amplitude of vibration was set so as to elicit a maximal reflex response, suggesting 1:1 driving of the majority of the Ia afferents at the frequency of vibration. 2. The resulting power spectrum regularly showed a well marked tremor peak separated by a trough from any slow irregularities. The predominant frequency of this tremor varied from 4 to 11 Hz in different preparations, with a mean of 7.4 Hz; on average, frequencies within 1.7 Hz on either side contained over half the power of the predominant frequency. Altering the frequency of vibration did not alter the distribution of tremor frequencies. 3. The root mean square value of the tension irregularities, over the range 4-14 Hz, varied from 12 to 110 mN in different preparations (median value, 23 mN); this was superimposed on mean active reflex tensions varying from 2 to 10 N. 4. The 'tremor' due to a single motor unit was estimated from spectral analysis of tetanic contractions of the whole muscle and decreased with increasing frequency of activation. Comparison of the single unit values with the tremor seen during vibration in the same preparations showed that equivalent amounts of tremor to the latter could typically have been produced by the continued synchronous contraction of about five 'average' motor units firing at the predominant tremor frequency. 5. When a tonic stretch reflex was present its tremor frequencies did not differ consistently from those of the tonic vibration reflex. On average, the tremor was smaller for the stretch reflex than for the tonic vibration reflex; the difference was usually slight and might have been related to the stretch refex tension being smaller. 6. Evidence was obtained that the tremor was not due to any insecurity of 1:1 driving of the Ia afferents by the vibration. First, the tremor did not increase when the amplitude of vibration was decreased sufficiently to ensure that the degree of 1:1 driving must have been reduced. Secondly, the introduction of a comparable 'artificial tremor' by sinusoidally oscillating the muscle at low frequency did not produce the e.m.g. response that would have been expected if the applied 'tremor' had been modulating the firing of the Ia or any other group of afferents. 7. It is concluded that the observed tremor cannot be attributed to 'oscillation in the stretch reflex arc', though without prejudice to the role of this mechanism under other conditions and especially when the recording is not isometric. However, the genesis of the tremor has not been established and much of it might result simply from the chance synchronization of motor units that are firing below their tetanic fusion frequency.

Action Potentials↗
PubMed1975

Beta-adrenergic mechanisms in action tremor.

To study the mechanisms by which propranolol suppresses essential tremor, accelerometric recordings were made from four normal subjects and eight patients with that tremor, and small amounts of isoproterenol and propranolol were infused intravenously or into one brachial artery. Intra-arterial isoproterenol increased tremor amplitude selectively in that arm in normal subjects and in patients with essential tremor (range, 1.85 to 3.50 with mean 2.74 times the base-line level). Intra-arterial or intravenous propranolol quickly blocked the enhanced action tremor in both groups. It did not simultaneously affect the underlying essential tremor, whereas long-term oral propranolol therapy did diminish the amplitude of the essential tremor in each patient. Peripheral beta-adrenergic tremorogenic receptors function normally even in patients with essential tremor; their function is not necessary for the production of essential tremor, and the efficacy of chronic propranolol therapy in the suppression of essential tremor is not mediated via its peripheral beta-adrenergic blocking action.

Administration, Oral↗
PubMed1992

Alterations of benzodiazepine receptor binding in tremor rats with absence-like seizures.

Tremor rats begin to exhibit clinical or electrical absence-like seizures after 6 weeks of age, and by 14 weeks of age, all have seizures. Central-type benzodiazepine receptor binding was investigated in tremor rats and control rats, aged 4 weeks and 16 weeks. Significantly lower benzodiazepine receptor density and no differences in affinity were found in the hippocampus of the tremor rats in comparison with that of control rats at both ages. This abnormality is considered to be due to a tremor gene and may be the cause of absence-like seizures in tremor rats. A significantly lower receptor density was found in the cerebellum at 4 weeks of age in the tremor rats than in the control rats. These changes may be related to tremorous movements in the tremor rats. Receptor density was significantly lower in the brainstems of tremor rats and control rats at 16 weeks of age than at 4 weeks of age, and the decrease was more marked in control rats. These facts may reflect a reduced decrease in the response to the dysfunction of gamma-aminobutyric acidergic neurons, or the function of the gamma-aminobutyric acid/benzodiazepine receptor system may be secondarily increased to suppress seizures in 16-week-old tremor rats.

Animals↗
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↗
PubMed1975

Semiology of Tremors.

Since the description by Galen in the 2nd Century, A.D., clinical neurology has acknowledged the existence of two types of tremor: that which occurs at rest and that occuring during the execution of movement. With the help of refined methods of analysis, E.M.G. and cinephotography, the authors have carried out a detailed clinical assessment in more than 400 patients. The basic criterion used to define a tremor was the classical definition of Dejerine: "An involuntary, rhythmical and symmetrical movement about an axis of equilibrium." As a result of this study, the conclusion has been reached that there are two types of tremor: postural tremor and tremor of attitude. Both are present while the limb remains immobile, whether by wilful design or when at rest in a position of posture and subject only to the action of gravity. During voluntary movement, tremor is not present. Irregular, asymmetrical and non-rhythmic oscillations may appear however - as in so-called intention tremor, of cerebellar origin - but this abnormal movement can hardly be called a real tremor. It is merely a manifestation of ataxia. As a consequence of this study, it is suggested that further understanding of the basic mechanism of tremor can be reached by the investigation of the central neural structures which are involved in the physiology of posture and attitude.

Adolescent↗
PubMed1976

Physiological and pharmacological aids in the differential diagnosis of tremor.

Physiological and pharmacological studies of more than 150 patients with movement disorders are reported. Particular attention is paid to the differentiation of various types of tremor on the basis of rate, rhythm, and pattern of EMG activity in antagonistic muscles. The typical 'tremor-at-rest' of Parkinson's disease--3-7 Hz activity which alternates between antagonistic muscles--is suppressed, at least briefly, during voluntary activity, at which time typical 8--12 Hz 'physiological tremor' may be seen. Essential tremor and its familial or senile variants also have a characteristic EMG pattern during voluntary activity--5-8 Hz bursts of activity which are synchronous in antagonistic muscles. This type of tremor may also be present in patients with Parkinson's disease and in certain kinships with a Charcot-Marie-Tooth polyneuropathy. Other tremors in association with polyneuropathy ('neuropathic tremor') have different physiological characteristics. Myoclonus is of essentially two types ('positive' with EMG bursts and 'negative' with brief pauses in ongoing activity, as with asterixis) and may, at times, mimic tremor. Certain specific tremors respond predictably to specific pharmacological therapy.

Ataxia↗
PubMed1976

Frequency and displacement amplitude relations for normal hand tremor.

Spectral analysis of hand tremor records obtained from normal subjects during continuous extension of the hand for 15-45 min revealed that the root-mean-square (rms) displacement amplitude of the tremor increased from control levels of about 30 mum to levels on the order of 100-1,000 times control. Associated with this increase in the displacement was a systematic decrease in the hand tremor frequency from control values of 8-9 Hz to values of 4-6 Hz. Spectral analysis of demodulated extensor EMG records indicated a consistent relation between EMG modulation amplitude at the tremor frequency and the tremor displacement amplitude for tremor records with rms displacement above about 100 mum. No consistent relation was found between these two variables for tremor records with displacements below 100 mum. Consideration of both mechanical and neural reflex effects indicated that a viscoelastic-mass mechanism primarily determined the small-amplitude (less than 100 mum) tremors, while the large displacement tremors may have involved both mechanical and neural feed back factors.

Computers↗
PubMed1976

Correlation between the dischanges of two simultaneously recorded motor units and physiological tremor.

Simultaneous recording was performed from pairs of motor units either in a small intrinsic hand muscle (first dorsal interosseus, 6 subjects, 37 records) or in two synergistic calf muscles (gastrocnemius and soleus, 6 subjects, 50 records). The two motor units were recorded by means of two electrodes inserted into the muscle during stationary isometric contractions of different strengths. Cross-correlograms were calculated in two ways: (1) between spike trains of two motor units; (2) between either spike train and the peaks of the tremor record. The cross-correlation between pairs of motor units showed a consistent tendency to synchronization in the hand as well as in the calf muscles. This synchronization was higher than could be expected from the random activity of asynchronously firing motor units. The amount of synchronization was correlated with the amplitude of physiological tremor: the stronger the tremor, the higher the synchronization coefficient. The cross-correlation between a spike train and the peaks of the tremor records showed a higher probability of unit firing 30-60 msec prior to the tremor beats. It is concluded that the tremor force produced by one muscle or a pair of synergistic muscles is the result of the synchronized activity of motor units. This hypothesis is supported by some characteristic changes in the amplitudes and rates of tremor in Parkinson's disease and myopathies. In these diseases the pathological changes in tremor rates simply reflect underlying changes of the motoneuronal firing rates.

Action Potentials↗
PubMed1992

Effect of stereotactic thalamic lesion on essential tremor.

The cause of essential (low-frequency) tremor is unknown and its relation to physiological (high-frequency) tremor is unclear. We assessed essential tremor in one patient before and after a stereotactic thalamic lesion. The procedure changed the size of the tremor in the right hand but not in the left. Persistence of a low-frequency component suggested that essential tremor was an additional feature superimposed on physiological tremor in this patient. The focus of essential tremor seems to be an autonomous central generator that is independent of physiological tremor mechanisms.

Adult↗
PubMed1975

Relative efficacy of alcohol and propranolol in action tremor.

Thirty-nine patients with a variety of diseases, including essential tremor, Parkinson's Disease, olivopontocerebellar degeneration, ataxia telangiectasia, and cervical cord injury with action tremor, were evaluated for the effect of one ounce of absolute alcohol ingestion. Tremor significantly subsided in 61.9% of E.T.; 46.6% of P.D.; one patient with A.T.; and one patient with C6 lesion. The tremor became worse in one patient with O.P.C.D. Twenty of these patients were treated with propranolol, an average dose of 92 mgm. per day, and re-evaluated three to six months later. All those who improved on alcohol improved on propranolol and the one whose tremor accentuated with alcohol had a similar response to propranolol. It is concluded that the tremorilytic effect of alcohol is neither specific for, nor limited to, essential tremor and is of no value in differentiating various neurological disorders which manifest as action tremor. It is recommended that one ounce of absolute alcohol by mouth be used as an office procedure to predict the response of patients' tremor to propranolol.

Adult↗
PubMed1976

A mechanical-reflex oscillator hypothesis for parkinsonian hand tremor.

Spectral analysis was performed on postural hand tremor records obtained from 22 parkinsonian subjects. Of these 22 subjects, 18 had postural hand tremor that occurred primarily at a single frequency during any one 16-s period. In general, this tremor occurred at different steady-state frequencies (each calculated over 16 s) between about 4 Hz and 8-9 Hz. This frequency decreased approximately 1 Hz for each 10-fold increase in displacement amplitude (root-mean-square, rms, amplitude determined at 16 cm from the wrist), decreasing from 8-9 Hz at about 30 mum to 3.75-4.0 Hz at about 30,000 mum. The major finding was that the frequency of parkinsonian hand tremor was nearly the same as that for hand tremor from normal subjects when these frequenceis were compared at similar rms displacement levels. This comparison, plus a comparison between other aspects of these two kinds of tremor, indicate that the mechanism for parkinsonian hand tremor is similar to that for large-displacement (greater than 100 mum) hand tremor of normal subjects, i.e., a mechanical-reflex oscillator mechanism.

Hand↗
PubMed1976

Motor-unit activity responsible for 8- to 12-Hz component of human physiological finger tremor.

Tremor of the extended third digit and bipolar surface and needle electromyograms of the extensor digitorum were recorded from six healthy volunteers for the purpose of elucidating the motor-unit activity responsible for the 8- to 12-Hz component of physiological finger tremor. Tremor was measured with a force transducer during steady voluntary contractions of approximately 200-250 g. The surface EMGs were full-wave rectified and low-pass filtered (-3 dB at 21 Hz), producing the envelope of the surface EMG (the demodulated EMG). Spectral analyses of simultaneous tremor and demodulated EMG records were performed. In four of six subjects, a pronounced 8- to 12-Hz amplitude modulation in the surface EMG was present, and coherency analysis demonstrated that this modulation was strongly correlated with the well-known 8- to 12-Hz tremor. In two subjects this amplitude modulation and tremor were barely detectable, despite the sensitive recording and analysis techniques used in this study. Spectral analysis was performed on 43 motor-unit spike trains. Twenty-two spike trains, having mean firing frequencies in the range of 10-22 spikes/s, produced statistically significant spectral peaks at 8-12 Hz, in addition to the expected spectral peaks at the mean firing frequencies. Of the 22 8- to 12-Hz-producing motor units, 12 had mean firing frequencies in the range of 17-22 spikes/s and exhibited the greatest 8- to 12-Hz activities of all motor units recorded. These motor units displayed transient sequences of double discharges in which interspike intervals (ISIS) of approximately 8-30 ms alternated with ISIS of 60-90 ms, thus producing an 8- to 12-Hz spectral peak. Adjacent ISIS of these motor units were correlated in the range of -0.5 to -0.9. Coherency analyses demonstrated that the 8- to 12-Hz activities of these motor units were correlated with the 8- to 12-Hz finger tremor and surface EMG modulation. The remaining 10 8- to 12-Hz-producing motor units had mean firing frequencies in the range of 10-17 spike/s. Although these motor units did not display the intense double-discharge firing pattern of the more rapidly firing motor units, a tendency toward action potential grouping was present and resulted in 8- to 12-Hz spectral activities which were correlated with the tremor and surface EMG modulation. .. ..

Adult↗
PubMed1979

Finger tremor and extrapyramidal side effects of neuroleptic drugs.

Finger tremor and extrapyramidal side-effects (EPSEs) were measured in seven patients before and during neuroleptic drug treatment to assess the relationship between the onset of EPSEs and changes in finger tremor spectra. Tremor and EPSEs were also measured in twelve patients stabilized on neuroleptic drugs to determine whether tremor could provide a reliable index of the presence and severity of extrapyramidal system disturbance. A downward shift in peak tremor frequently was noted within 48 hours of starting neuroleptic drug therapy, usually before the onset of EPSEs, and a significant negative relationship between the severity of EPSEs and tremor frequency (but not tremor amplitude). The peak frequency of finger tremor is thus a sensitive index of extrapyramidal disturbance and might be of value in predicting which patients taking neuroleptic drugs need anti-parkinsonian therapy.

Antipsychotic Agents↗
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↗