Tremor Disease Research Articles

Long-term EMG recordings differentiate between parkinsonian and essential tremor

The differential diagnosis of tremor is mainly based on clinical criteria.Nevertheless, these criteria are in some cases not sufficient to differentiate between different tremor forms. Long-term EMG has proven to be a valid and reliable method for the quantification of pathological tremors. The aim of the study was to develop a long-term EMG-based automated analysis procedure that separates parkinsonian tremor from essential tremor. Using longterm EMG tremor was recorded in 45 consecutive patients, 26 with Parkinson's disease (PD) and 19 with essential tremor (ET). Eight tremor parameters were generated automatically. By stepwise backward regression a subset of these criteria was extracted to achieve an automated classification of the tremor by a mathematical model. The obtained model was then tested on a new group of 13 patients in early stages of the disease. Significant differences between groups were found for tremor occurrence, tremor asymmetry, mean tremor frequency and standard deviation of phase of antagonistic muscles. Due to data overlap a classification of the two tremor forms was not possible based on a single tremor parameter. Using logistic regression, a linear formula based on the three parameters tremor occurrence, mean tremor frequency and standard deviation of phase was established and predicted the correct diagnosis in 93% of patients. The validation of the model on the new group of patients in early stages of the tremor disease yielded a correct diagnosis in 100% of cases. We conclude that long-term EMG recording allows a rater-independent classification of parkinsonian versus essential tremor.

1.282 Is functional decline in essential tremor and Parkinson's disease alike?

1.282 Is functional decline in essential tremor and Parkinson's disease alike?

Genetic essential tremor in γ-aminobutyric acidA receptor α1 subunit knockout mice

Essential tremor is the most common movement disorder and has an unknown etiology. Here we report that gamma-aminobutyric acidA (GABA(A)) receptor alpha1-/- mice exhibit postural and kinetic tremor and motor incoordination that is characteristic of essential tremor disease. We tested mice with essential-like tremor using current drug therapies that alleviate symptoms in essential tremor patients (primidone, propranolol, and gabapentin) and several candidates hypothesized to reduce tremor, including ethanol; the noncompetitive N-methyl-D-aspartate receptor antagonist MK-801; the adenosine A1 receptor agonist 2-chloro-N6-cyclopentyladenosine (CCPA); the GABA(A) receptor modulators diazepam, allopregnanolone, and Ro15-4513; and the L-type Ca2+ channel antagonist nitrendipine. Primidone, propranolol, and gabapentin reduced the amplitude (power) of the pathologic tremor. Nonsedative doses of ethanol eliminated tremor in mice. Diazepam, allopregnanolone, Ro15-4513, and nitrendipine had no effect or enhanced tremor, whereas MK-801 and CCPA reduced tremor. To understand the etiology of tremor in these mice, we studied the electrophysiological properties of cerebellar Purkinje cells. Cerebellar Purkinje cells in GABA(A) receptor alpha1-/- mice exhibited a profound loss of all responses to synaptic or exogenous GABA, but no differences in abundance, gross morphology, or spontaneous synaptic activity were observed. This genetic animal model elucidates a mechanism of GABAergic dysfunction in the major motor pathway and potential targets for pharmacotherapy of essential tremor.

Illnesses of the Brain in John Quincy Adams

John Quincy Adams, the sixth and perhaps most scholarly American president, served courageously despite familial essential tremor, depression, and cerebrovascular disease. His cousin Samuel Adams and his father John Adams also had essential tremor, which the later called "quiveration". Alcoholism and depression affected several members of J.Q. Adams's family. Following his own time as president, J.Q. Adams returned to duty as the congressman who most assiduously fought slavery, a fight he continued even after he had suffered a major left hemispheric stroke. His fatal collapse in Congress, protesting the Mexican War, is legendary among the final illnesses of American statesmen.

A spiroplasma associated with tremor disease in the Chinese mitten crab (Eriocheir sinensis).

An epidemic of tremor disease has been a serious problem in Chinese mitten crabs, Eriocheir sinensis, in China in recent years. The disease-causing agent was previously considered to be a rickettsia-like organism. Here, analysis of the 16S rRNA gene sequence, light and electron microscopy and cultivation in vitro were used to identify the agent. Sequence analysis of the 16S rRNA gene found it to have 98 % identity with that of Spiroplasma mirum. The agent was able to be passed through membrane filters with pores 220 nm in diameter and could be cultivated by inoculating the yolk sac of embryonated chicken eggs and M1D medium. Rotary motion and flexional movement were seen by light microscopy, and electron microscopy showed that the organism had a helical morphology and lacked a cell wall. The organism produced small colonies with a diameter of 40-50 microm after 17-25 days of incubation on solid M1D medium. The agent was found in blood cells, muscles, nerves and connective tissues of crabs inoculated with a filtrate of yolk sacs or with cultures grown in M1D medium, and it was similar in structure to those grown in eggs and cultivation broth. Disease was reproduced by experimental infection with the cultivated organisms. This study has demonstrated that the causative agent of tremor disease in the Chinese mitten crab is a member of the genus Spiroplasma. This is believed to be the first time a spiroplasma has been found in a crustacean. These findings are not only significant for studies on pathogenic spiroplasmas, but also have implications for studies of freshwater ecology.

Morphology of spiroplasmas in the Chinese mitten crab Eriocheir sinensis associated with tremor disease

The structure of spiroplasmas in the Chinese mitten crab associated with tremor disease was studied by transmission electron microscopy techniques, including both negative staining and ultrasectioning. A spiral structure, which is a typical form of spiroplasmas, could be detected and the observations showed for the first time the presence of spiroplasmas in the cells of the crab. Propagation of spiroplasmas within the cells presented various forms that could be sorted into three morphological types: rounded, regular helical, and pleiomorphic or intermediate forms. The spiroplasmas appeared as round bodies during the fallow stage of development or under poor conditions. They showed various shapes such as helices, saccate, branched, tadpole-like and tortoise-like structures while growing, and became long and congregated in late stages of development. When spiroplasmas were isolated from chicken eggs and cultured in M1D medium they appeared to undergo similar morphological changes to those in the crab. The spiroplasmas contained chromatin filaments and peripheral ribosome-like granules and were delimited by distinct unitary membranes. Average diameters were calculated at 0.1 to 0.35 μm for rounded forms and 0.1–0.2 μm for helical or long forms, and they varied in length from 3–12 μm.

Study on experimental infections of Spiroplasma from the Chinese mitten crab in crayfish, mice and embryonated chickens

Tremor disease (TD) of the Chinese mitten crab Eriocheir sinensi has become a serious disease in the Chinese freshwater culture industry in recent years. The agent, belonging to Spiroplasma, was purified from yolk and allantoic fluids of chicken embryos and was then inoculated into the body of crayfish, the abdominal cavity of ICR mice and the allantoid of chicken embryos, respectively. Thirty-eight days after the inoculation, the mice and crayfish were dissected and their tissues sampled and observed with both the light and electron microscope. No infection was detected in mouse or crawfish tissue. But when the different tissues from the inoculated embryonated chickens were tested, the agent was detected only in the brain of embryonated chickens. This indicated that the agent represented a neurotropic characteristic in embryonated chickens, just as it had in the crab. This infective characteristic may be due to the development and maturation of host immunity.

Rickettsia-like organism associated with tremor disease and mortality of the Chinese mitten crab Eriocheir sinensis.

We report the discovery of a rickettsia-like organism (RLO) in cultured freshwater Chinese mitten crab Eriocheir sinensis. The RLO caused tremor disease and was apparently responsible for a mass mortality (30 to 90%) in 2 provinces in southeast China. Moribund crabs were investigated from different districts during outbreaks in 1999 and 2000. With electron microscopy, 3 different pathogens were detected in moribund crabs: a rickettsia-like organism (RLO), virus-like particles (VLP) and a microsporidian-like protozoan (MLP). Based on the high prevalence, infection intensity and cytopathological signs, the RLO was considered to be the probable cause of the high mortality. Both VLP and MLP occurred at low prevalences and were considered secondary infections. The RLO was 0.22 to 0.35 microm in diameter, granular or clavate, bounded by a cell wall and membrane, and possessed no nucleus but a nucleoid was present. When dividing, RLOs occurred in irregular shapes, such as dumbbells, awls, and crescents. The RLOs exhibited a predilection for muscle and connective tissues and were probably transported to various tissues and organs by hemocytes.

Hand Tremor and Parkinson's Disease

Hand Tremor and Parkinson's Disease

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.

Inheritance and genetic mapping of the Campus syndrome (CPS): a high-frequency tremor disease in pigs.

A new progressive tremor disorder called Campus syndrome (CPS) was observed among the progeny of a normal boar of the Pietrain breed in Germany. Extensive backcross experiments indicate that CPS is inherited as an autosomal dominant trait, and the founder boar, Campus, is believed to be a gonadal mosaic. A linkage analysis of 57 animals mapped the CPS gene to a region on porcine chromosome 7 flanked by the markers SW1418 and SW352, which is homologous to a part of human chromosome (HSA) 14. Human dominant distal myopathy type 1 (MPD1) has been mapped to the homologous region of HSA14. As the myopathological findings in MDP1 show striking similarities to CPS, this porcine disorder may serve as an animal model for MPD1.

Prevalence of tremor and Parkinson's disease

To determine the prevalence of essential tremor (ET) and Parkinson's disease (PD) in a retirement community, all residents of Carefree, Arizona, aged over 65 years were contacted. All participants completed validated questionnaires for PD and ET, and were examined using the Unified Parkinson's Disease Rating Scale. Of 356 individuals evaluated, 155 (43.5%) had tremor; 73 (20.5%) had ET; 26 (7.3%) had PD; and 56 (15.7%) had postural tremor (PT). Thus, a large percentage of individuals were found to have tremor, in the plurality of whom it could be classified as ET. The number of individuals with Parkinson's disease exceeded our expectations.

Clinical Study on the Accuracy of the Laitinen CT-Guidance System in Functional Stereotactic Neurosurgery

The accuracy, reproducibility and reliability of CT-guided functional stereotaxis using Laitinen's Stereoadapter were assessed in 19 patients who underwent 14 thalamotomies and 5 pallidotomies for the treatment of essential tremor or Parkinson's disease. The coordinates of the target were obtained from a CT study with the Stereoadapter. At surgery, the Stereoadapter was remounted to the patient's head and the CT coordinates were transferred to Laitinen's Stereoguide without ventriculography. 3-12 months after surgery, a postoperative CT study with Stereoadapter was done. The coordinates of the stereotactic lesion were compared to the preoperative target coordinates. A new similar target was simulated on the postoperative CT study and its coordinates were compared to those of the preoperative target. The coordinates of the lesion versus preoperative target showed a maximal difference of 3.5 mm for the lateral (x-) coordinate, 3.5 mm for the anteroposterior (y-) coordinate, and 3.75 mm for the height (z-) coordinate. The differences were statistically significantly only for the x-coordinate: The lesions lay 1.25 mm, on the average, medial to the preoperative target. This medial displacement of the lesions was presumably due to a 10% inborn magnification error of the CT picture for the lateral direction. The maximal differences between the coordinates of the 'new' simulated target on the postoperative CT and those of the preoperative target were 2.5 mm for the x-, 2.25 mm for the y- and 3.75 mm for the z-coordinates. The differences were not statistically significant.

Scrapie agent proteins do not accumulate in grey tremor mice.

The grey tremor mouse is an autosomal recessive mutant characterized by a phenotype of unusual pigmentation, neurological abnormalities and early death. These mice have a spongiform encephalopathy similar to scrapie and Creutzfeldt-Jakob disease. Although the disease is clearly heritable, the grey tremor mouse spongiform pathology has also been transmitted by inoculation of genetically normal mice with diseased brain homogenates. The possibility that a scrapie-like agent is involved has been proposed. We examined brain homogenates from grey tremor mice, scrapie-affected mice and normal mice for the presence of the mouse scrapie agent protein (MoSp33-37) and its normal cellular homologue. All untreated homogenates contained one or both isoforms of this protein as detected on immunoblots. Grey tremor mouse brain homogenates, when protease-treated, showed no evidence of MoSp33-37. A purification method for MoSp33-37 concentrated it in samples from scrapie-affected mice, but this protein was not detected in grey tremor or normal mice. These results suggest that it is unlikely that the scrapie agent is involved in grey tremor disease.

Arteriosclerosis, heredity, and some previous infections in the etiology of parkinson's disease. A case-control study

A case-control study was performed to investigate the significance of arteriosclerosis, heredity and some infections in the etiology of Parkinson's disease. The study group consisted of all traceable patients with Parkinson's disease living in a defined area, a total of 444 patients, and of control subjects for each patient, matched in sex and age, chosen from among the general population residing in the same area. No significant differences were found between the patients and the controls concerning the occurrence of cardiac insufficiency, coronary heart disease, or stroke. The Parkinsonian patients, however, had a significantly lower incidence of clinical arterial hypertension when compared with the controls. In addition, the patients more often had low systolic blood pressures and more rarely high pressures than the controls. Even the mean systolic blood pressure was significantly lower in the patients than in the controls. The low blood pressure seems to be an effect of Parkinson's disease itself with a minor contribution of levodopa therapy. The observations above are considered to indicate that arteriosclerosis and Parkinson's disease are probably only concurrent disorders and not in etiological relationship with each other. There was no statistically significant difference in the proportion of the patients and the controls with relatives with Parkinson's disease or essential tremor, which suggests that genetic factors do not have a significant role in Parkinson's disease and on the other hand that essential tremor and Parkinson's disease are two separate disease entities. No other encephalitis than a lethargic one was found to precede Parkinson's disease and the occurrence of meningitis was rare both among the patients and the controls. The history of Spanish influenza was found to be as frequent in the patients as in the controls, thus not supporting the idea that influenza has etiological importance in Parkinson's disease.