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We studied a family with essential tremor of the arms. Some members also had tremor of the trunk and legs on standing, but not on walking, sitting, or reclining. Tremor was evoked, regardless of body or limb position, by strong tonic contraction of the appropriate muscles; it was a type of static postural tremor. Beta-adrenergic blockers had no effect on the tremor of the trunk or legs, but clonazepam was beneficial.
It was discovered by serendipity that a combined application of chlorpromazine (3.5 mg/kg) and pentobarbitone (20.0 mg/kg) induced intermittent tremor-bursts in four extremities of guinea pigs. This tremor with a prominent extensor activity disappeared after spinalization, indicating a supraspinal process. Biperiden reduced the frequency and amplitude of the tremor, which was further diminished by amantadine. Baclofen was found to be most potent drug in suppressing tremor. It was suggested that the cortico-striato-pallido-thalamo-cortical feedback loop may be impaired by a combined action of chlorpromazine and pentobarbitone. This new animal model for drug-induced tremor would be of considerable importance with regard to physiological, biochemical, pharmacological and pathological aspects of motor control.
The irregular rhythm, presence at rest and acceleration during posture and active movements, low frequency and focal signs are its main features. A case of 49 years old male with tremor of left arm lasting five years is reported. The patient has been suffering from rheumatoid arthritis from 1987.8 years ago a chronic lymphoblasic leukemia was revealed. In upper left arm irregular rest, postural and kinetic tremor occurs, with increasing amplitude and frequency 3.5 Hz. Physical examination revealed pyramidal syndrome and deliberative symptoms. MRI showed vasculitis-like subcortical changes and leukoarajosis-like signs. Neuropsychological examination indicates slight impairment of cognitive functions. Treatment with benzodiazepins and L-dopa was ineffective. Described above symptoms fulfill Holmes' tremor criteria. Only few studies confirmed correlation between tremor and presence of autoimmune diseases. Our case is the first study describing Holmes' tremor, which occurred during rheumatoid arthritis or chronic lymphoblastic leukemia.
Tremor measurements were obtained from 12 male volunteers before and during ethanol intoxication. The tremor recorded during extension and flexion of the hand is called physiological action tremor (PAT) and shares many of the same frequency, amplitude, and electromyographic characteristics reported for withdrawal tremor (WT). This report focuses on the relationships of these two tremors and presents further evidence to consider that PAT and WT might be controlled by the same mechanisms.
We have recently developed a method of long-term EMG recording (Bacher et al., 1989), which has proven suitable for the quantification of pathological tremor. In the present paper we show that (1) the principal parameters of the method (tremor occurrence, tremor intensity, tremor frequency) are highly reproducible with intraclass correlation coefficients in the order of 0.9, (2) that the method has both a high specificity (87.5%) and sensitivity (96%) for detection of pathological tremor, and (3) that it can be useful for examining agonist-antagonist muscle activation under everyday conditions.
Six patients undergoing stereotactic procedures for essential tremor received microinjections of muscimol (a gamma-aminobutyric acid-A [GABA(A)] agonist) into the ventralis intermedius thalamus in areas where tremor-synchronous cells were identified electrophysiologically with microelectrode recordings and where tremor reduction occurred with electrical microstimulation. Injections of muscimol but not saline consistently reduced tremor in each patient. The effect had a mean latency of 7 minutes and lasted an average of 9 minutes. We propose that GABA-mediated thalamic neuronal inhibition may represent a mechanism underlying the effectiveness of surgery for tremor and that GABA analogues could potentially be used therapeutically.
While voluntary movement blocks Parkinsonian rest tremor (PT), essential tremor (ET) is enforced by postural and/or kinetic action. We studied the effect of contralateral externally- and internally triggered hand movement on PT and ET to investigate the transhemispheric influences on tremor genesis. We measured the changes of tremor peak frequency power after flash signal (F), flash triggered (FM) and self-paced (SPM) movement of the contralateral hand in nine PT and seven ET patients using accelerometer. PT significantly decreased both during FM and SPM tasks, suggesting that it is generated by a constant subcortico-cortical network, which includes higher order motor areas. Intensity of ET showed a remarkable intra- and interindividual variability both during FM and SPM reflecting a different generator circuitry with variable functional connections.
Palatal tremor has been subdivided into essential (EPT) and symptomatic palatal tremor (SPT). A subgroup of the SPT form has a syndrome of progressive ataxia and palatal tremor (PAPT). Published details of cases of PAPT are sparse and the disorder appears heterogeneous. We present clinical and MRI features of six patients with sporadic PAPT who attended The University Health Network between 1991 and 2002. Eye movements were recorded using a magnetic search coil technique. We review previously reported cases of PAPT from the English language literature and relate this disorder to EPT and SPT. PAPT may be divided into sporadic and familial forms. We identified 22 other prior reported cases of sporadic PAPT. Sporadic PAPT is a subtype of SPT in which progressive cerebellar degeneration is the most symptomatic feature. A combination of vertical nystagmus and palatal tremor was found in one of our cases. Internuclear ophthalmoplegia, a new finding, was present in two of our patients and indicated additional brainstem dysfunction. Inferior olivary high signal abnormalities were present on MRI in all of our cases. The cause of sporadic PAPT remains uncertain. In some previous reports of sporadic PAPT, the combination of brainstem or pontine atrophy, parkinsonism, autonomic dysfunction or corticospinal tract abnormalities suggests a diagnosis of multiple system atrophy, although pathological verification is lacking. Familial PAPT is associated with marked brainstem and cervical cord atrophy with corticospinal tract findings, but the typical olivary MRI abnormalities have not been reported. A substitution in the glial fibrillary acidic protein (GFAP) gene has been described in a family with PAPT, raising the possibility of Alexander's disease. One other familial syndrome of PAPT, termed 'dark dentate disease', has also been reported. PAPT is a subgroup of SPT in which ataxia progresses and is not usually the result of a monophasic illness. Eye movement abnormalities suggest a disorder of both the cerebellum and brainstem. Familial PAPT differs from sporadic PAPT in having marked atrophy of cervical cord and brainstem with corticospinal signs but without hypertrophic olivary appearance on MRI.
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.
A clinical and electrophysiological analysis of tremor in patients with essential tremor and tremulous form of Parkinson's disease as well as healthy subjects has been conducted. The method of accelerometry was used for assessing the variability of frequency and amplitude tremor. A comparison of the time-domain characteristics and spectral components of tremor was made between the two groups of patients that allowed to find the series of typical characteristics, which were important for understanding of its pathogenesis and differential diagnosis of this disease.
Detecting psychogenic tremors (PsychT) is often challenging. As there are no laboratory investigations or imaging techniques that can confirm the diagnosis, PsychT is identified on a clinical basis. We present a tree-based statistical algorithm derived from quantitative computerized tremor recordings as a novel method to help in the recognition of PsychT. The goal of this study was to show that objective data from computerized tremor recordings, when processed through a tree-based statistical algorithm, can be used to determine whether a patient can be classified as having PsychT.
To accomplish an objective quantification of tremor in conscious unrestrained rats, a registration device based on accelerometry was developed. Tremor intensity was continuously recorded by a small piezoresistive accelerometer (Egal 125-10D, Entran Devices) mounted on the back of the freely moving rat. The accelerometer was connected to a Grass Polygraph, where the analog signal was quantified as arbitrary marks/min by a 7P10 integrating unit. The integrated signals were then further analyzed by a desk-top computer (Luxor ABC-80). By analyzing tremor response to central serotonergic system activation, the reproductibility as well as the advantages and limitations of this recording system were demonstrated.
BACKGROUND: The extent to which essential tremor (ET) clusters within families (ie, the familial aggregation of ET) is not precisely known. In part, this is because studies assign disease status in relatives of patients with ET based solely on interviews without conducting physical examinations. This may lead to underascertainment of affected relatives with mild asymptomatic ET. OBJECTIVE: To determine the prevalence of asymptomatic ET among relatives of patients with ET. METHODS: Interview and examination of 25 patients with ET and 58 of their relatives. The interview included 12 questions that screened the patients for ET. Two neurologists who specialize in movement disorders reviewed the videotaped examinations. Based on standardized criteria, diagnoses included ET (definite, probable, or possible) on normal. RESULTS: Of the 8 relatives who received diagnoses of ET, 5 (62.5%) had asymptomatic ET. Hence, 5 (8.6%) of the 58 relatives (95% confidence interval 1.4%-15.8%) had asymptomatic ET. In those with asymptomatic ET, there was a preponderance of young individuals with mild tremor in the nondominant hand. CONCLUSIONS: The prevalence of asymptomatic ET in relatives of patients with ET was similar to that of symptomatic ET. Family studies that do not perform both an interview and a physical examination will underascertain the number of affected relatives. Therefore, future family studies should evaluate relatives of patients with ET with an interview supplemented by a physical examination.
We describe a patient with an unusual clinical presentation of progressive multiple cranial nerve palsies, cerebellar ataxia, and palatal tremor (PT) resulting from an unknown etiology. Magnetic resonance imaging showed evidence of hypertrophy of the inferior olivary nuclei, brain stem atrophy, and marked cerebellar atrophy. This combination of progressive multiple cranial nerve palsies, cerebellar ataxia, and PT has never been reported in the literature. We have also reviewed the literature of PT secondary to neurodegenerative causes. In a total of 23 patients, the common causes are sporadic olivopontocerebellar atrophy (OPCA; 22%), Alexander's disease (22%), unknown etiology (43.4%), and occasionally progressive supranuclear palsy (4.3%) and spinocerebellar degeneration (4.3%). Most patients present with progressive cerebellar ataxia and approximately two thirds of them have rhythmic tremors elsewhere. Ear clicks are observed in 13% and evidence of hypertrophy of the inferior olivary nucleus in 25% of the patients. The common neurodegenerative causes of PT are OPCA/multiple system atrophy, Alexander's disease, and, in most of them, the result of an unknown cause.
Familial cortical myoclonic tremor (FCMT) is a rare disorder often leading to a wrong clinical diagnosis of essential tremor. Electrophysiological data are usually considered to allow a correct diagnosis. We describe a FCMT French family with previously unreported clinical features such as sensitivity to glucose deprivation, vibration, repetitive visual patterns, and intense visual or auditory stimulation and contrasts. Electrophysiological studies of the propositus confirm the cortical reflex myoclonus elicited by photic stimulation and the absence of epileptic electroencephalographic discharges. We emphasize that a precise clinical analysis can lead to a correct diagnosis before electrophysiological confirmation. This is also the first-ever report of efficacy of levetiracetam in FCMT.
The purpose of this study was to examine H-reflex parameters among the pathophysiologic conditions of essential tremor (ET), Parkinson's disease (PD), combined essential tremor with Parkinson's disease (ETPD), and a control group. H-reflex latencies, amplitude of maximum H-reflex to maximum M-response ratio (H:M), vibration H-reflex to control H-reflex (Hv:Hc), and H-reflex recovery curves (HRRCs) were recorded and compared between a control group and patient groups with ET, early-stage PD, and with ETPD. No statistically or clinically significant differences were found between the patient groups and the control group for latency, H:M ratio, or Hv:Hc ratio. Significantly greater ratio values were observed for the PD group over the other groups for the HRRC tests at each interstimulus interval between 200 and 300 msec (p < 0.05), but values were not different between PD and ETPD patients for intervals between 350 and 1,000 msec. Patients with ET, PD, and ETPD apparently have different underlying pathologies. HRRC tests do not distinguish ET patients from normal, but differentiates specifically between PD and ETPD, and normal individuals. HRRC testing may be a useful method for evaluating pathologies between ET, PD, and ETPD patients.
OBJECTIVES/HYPOTHESIS: To evaluate the relative efficacy of unilateral and bilateral injections of botulinum toxin injection (BOTOX) in the treatment of essential tremor of the voice (ETV). STUDY DESIGN: Prospective open-label crossover study. METHODS: Patients referred to the Neurolaryngology Clinic at Toronto General Hospital with a diagnosis of ETV were eligible for the study. Patients were sequentially assigned to receive BOTOX as either a bilateral 2.5-U or a unilateral 15-U electromyography-guided injection, followed by the alternative injection 16 to 18 weeks later. Acoustic, aerodynamic, and nasopharyngoscopic data were collected approximately 2, 6, 10, and 16 weeks after each injection. Patients were asked to provide a perceptual evaluation of BOTOX effects at the conclusion of the study. RESULTS: Three of 10 patients demonstrated an objective reduction in tremor severity with bilateral injection, and 2 of 9 with unilateral injection. However, 8 of 10 patients wished to be re-injected at the conclusion of the study. A reduction in vocal effort appeared to be coincident with reduction in laryngeal airway resistance after BOTOX injection. CONCLUSIONS: Using objective acoustic measures, only a small proportion of patients achieved benefit from BOTOX injection for ETV. However, a majority of patients in our study benefited from a subjective reduction in vocal effort that may have been attributable to reduced laryngeal airway resistance.
The authors prospectively collected unblinded data from 27 consecutive patients following thalamic stimulation. A significant reduction of midline tremor was achieved after unilateral surgery, but a staged contralateral surgery had an additional effect. A subgroup analysis showed significant beneficial effects for head, voice, tongue, and face tremor. The most frequent reversible side effects were disequilibrium, dysarthria, and paresthesias. We observed more pulse generator adjustments for speech problems in the bilaterally implanted group.