Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fifty-eight patients, 36 with essential tremor (ET) and 22 with Parkinson's disease (PD), received deep brain stimulation (DBS) in the thalamic ventral intermediate (Vim) nucleus. The mean follow-up was 17 months for ET and 21 months for PD patients. Stimulation parameters were adjusted as needed, at various intervals after surgery. Results were assessed using routine clinical evaluation and established outcome scales. All patients needed incremental increase in stimulation parameters at various intervals during the first 6-12 months after surgery. The mean voltage 1 week postoperatively was 1. 45 V in PD patients, and 1.37 V in ET patients. Twelve months later, the figures were 2.14 V in PD and 2.25 V in ET patients. At 1 year, the Essential Tremor Rating Scale (ETRS) improved from 54 to 28 (p < 0.0001). The motor part of the Unified Parkinson's Disease Rating Scale (UPDRS) improved from 37 to 26 (p < 0.01). Tremor items of the UPDRS improved more markedly (p < 0.0001). One week postoperatively 90% of PD, and 89% of ET patients were tremor free. One year later, 70% of PD and 60% of ET patients remained mostly tremor free. Upon switching off stimulation, there was a clear tendency for tremor rebound (p = 0.07) in the PD group, requiring continuous 24-hour stimulation in some patients. Permanent non-adjustable ataxia was induced by stimulation in 2 PD patients.
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PMID:Tolerance and tremor rebound following long-term chronic thalamic stimulation for Parkinsonian and essential tremor. 1085 80

Essential tremor (ET) is the most common movement disorder. However, only a small percentage of people affected by this genetically transmitted neurologic disorder seek medical attention. Lack of consensus on the diagnostic criteria for ET is an impediment to accurate diagnosis and leads to difficulty in accessing accurate prevalence data. Although a positive family history, alcohol sensitivity, and propranolol responsiveness are characteristic of ET, these factors should not be considered necessary for the diagnosis of ET. ET can produce substantial physical and psychosocial disabilities. The occasional coexistence of ET and Parkinson's disease (PD) in the same individual may present a diagnostic challenge.
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PMID:Essential tremor: clinical characteristics. 1085 48

Implantable devices that interact directly with the human nervous system have been gaining acceptance in the field of medicine since the 1960's. More recently, as is noted by the FDA approval of a deep brain stimulator for movement disorders, interest has shifted toward direct communication with the central nervous system (CNS). Deep brain stimulation (DBS) can have a remarkable effect on the lives of those with certain types of disabilities such as Parkinson's disease, Essential Tremor, and dystonia. To correct for many of the motor impairments not treatable by DBS (e.g. quadriplegia), it would be desirable to extract from the CNS a control signal for movement. A direct interface with motor cortical neurons could provide an optimal signal for restoring movement. In order to accomplish this, a real-time conversion of simultaneously recorded neural activity to an online command for movement is required. A system has been established to isolate the cellular activity of a group of motor neurons and interpret their movement-related information with a minimal delay. The real-time interpretation of cortical activity on a millisecond time scale provides an integral first step in the development of a direct brain-computer interface (BCI).
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PMID:Work toward real-time control of a cortical neural prothesis. 1089 85

Essential tremor (ET) is the most common type of movement disorder, although its etiology and neurophysiological substrates remain unclear. While thought to be a benign condition, it has yet to be studied from a neuropsychological perspective. We examined the neurocognitive functioning of 13 nondemented subjects with severe ET, including aspects of memory, cognitive flexibility, and attention. Results revealed that 12/13 subjects demonstrated impairment on 1 or more cognitive measures in comparison with published normative data. The pattern of findings was suggestive of relative dysfunction of frontal-mediated processes not unlike that seen in Parkinson's disease. These deficits were found in subjects irrespective of the presence of cognitive complaints, depression, or the existence of other potential neurocognitive risk factors. These findings suggest that mild cognitive deficits are not uncommon in association with severe ET and may be related to subcortical systems.
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PMID:Cognitive functioning in individuals with "benign" essential tremor. 1184 70

Patients with nonparkinsonian tremors are the second largest group treated with functional neurosurgery. We summarize the present pathophysiological knowledge of these conditions. Essential tremor (ET) may be due to oscillations within the olivocerebellar circuit. There is experimental evidence from animal models for such a mechanism, and clinical data indicate an abnormal function of the cerebellum in ET. Cerebellar tremor may be closely related to the tremor seen in advanced ET. The malfunction of the cerebellum causes a pathological feed-forward control. Additionally an oscillator within the cerebellum or its input/output pathways may cause cerebellar tremor. Almost nothing is known about the pathophysiology of dystonic tremor. Holmes tremor is based on a nigral and a cerebellar malfunction and presents clinically as the combination of tremor in Parkinson's disease and cerebellar tremor. Neuropathic tremor can be extremely disabling and is thought to be due to an abnormal interaction of the disturbances within the periphery and abnormal cerebellar feedback. Unlike the case of Parkinson's disease, functional neurosurgery of nonparkinsonian tremors is not yet based on a solid pathophysiological background.
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PMID:Pathophysiology of nonparkinsonian tremors. 1194 54

Based on the hypothesis that rhythmical, tremor-like movements produced by normal subjects might be influenced by similar central oscillatory neuronal networks believed to determine the features of the pathologic tremors of Parkinson's disease (PD) or Essential Tremor (ET) patients, we examined the neurophysiological characteristics of a tremor mimicked by normal volunteers and compare this data with those from PD or ET tremors. Voluntarily simulated tremor (VST) was studied in 47 neurologically intact subjects, resting tremor in 10 patients with PD and postural tremor in 10 patients with ET. Using a tremor analysis system based on a solid state gyroscopic sensor sensitive to angular rate, the following parameters were determined: frequency, amplitude (angular displacement) and regularity (Q coefficient of constancy). We also performed an inertial loading test and a test-retest analysis. Nearly all normal subjects were able to simulate a tremor that was indistinguishable, in frequency and regularity, from that of PD or ET, although the amplitude was significantly higher in normal subjects. As in pathological tremors, the VST frequency was significantly influenced by age, but not by gender, handedness or previous knowledge of tremor. Inertial load did not modify the tremor frequency, suggesting that mechanical factors were minor. We also found a logarithmic inverse relationship between frequency and amplitude of the VST. We concluded that VST shares many similarities with pathological tremors. It is therefore possible that all tremors are somehow influenced by the same central oscillators which may become disinhibited and clinically apparent in pathological conditions such as PD or ET.
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PMID:Voluntarily simulated tremor in normal subjects. 1203 89

Thalamic deep brain stimulation (DBS) is proven to suppress tremor in Parkinson's disease (PD) and essential tremor (ET). However, there are few reports on its long-term efficacy. We studied the efficacy of DBS at 2 years and 6-7 years after electrode implantations in the ventrointermediate nucleus of the thalamus in 39 patients (20 PD, 19 ET) with severe tremor. Twenty-five of the patients completed the study. Evaluations were done in a double-blind manner with the Unified Parkinson's Disease Rating Scale (UPDRS) and Essential Tremor Rating Scale (ETRS). DBS decreased tremor sum scores in PD (P < 0.025) compared to the preoperative baseline (median, 7; Q25-75, 6-9) both at 2 years (median, 2; Q25-75, 2-3.5; n = 16) and at 6 to 7 years (median, 2.5; Q25-75, 0.5-3; n = 12). Stimulation on improved tremor sum as well as sub scores (P < 0.025) compared to stimulation off conditions. In ET, thalamic stimulation improved (P < 0.025) kinetic and positional tremor at both follow-up periods (n = 18 and n = 13, respectively) with significant improvements (P < 0.025) in hand-function tests. PD but not ET patients showed a general disease progression. Stimulation parameters were remarkably stable over time. We conclude that high-frequency electric thalamic stimulation can efficiently suppress severe tremor in PD and ET more than 6 years after permanent implantation of brain electrodes.
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PMID:Long-term efficacy of thalamic deep brain stimulation for tremor: double-blind assessments. 1253 9

Essential tremor is the most common of the movement disorders, being 20 times more common than Parkinson's Disease. It is characterised by postural and kinetic tremor which maximally affects the hands. It can be assessed by physiological techniques, subjective clinical methods, objective clinical methods and handicap/disability scales. Accelerometry, spirography and handwriting assessment, volumetry and handicap/disability questionnaires are commonly used methods. Primidone and propranolol are the first-line drugs. Several second-line drugs have been identified. Surgical techniques include lesioning or stimulation of the ventral lateral thalamus. Alcohol and botulinum toxin A are found to reduce tremor amplitude as well.
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PMID:Clinical features, assessment and treatment of essential tremor. 1283 51

Parkinson's disease patients frequently have symptoms and signs of autonomic nervous dysfunction that are the source of considerable disability. Recent studies have revealed that most patients with Parkinson's disease, and all with Parkinson's disease-associated orthostatic hypotension, have a loss of cardiac sympathetic innervation. Familial Parkinson's disease, caused by mutation of the gene encoding alpha-synuclein, also features orthostatic hypotension, sympathetic neurocirculatory failure and cardiac sympathetic denervation. We have recently described a whole-gene triplication of alpha-synuclein causing Lewy body parkinsonism in a large, well characterized family called the 'Iowa kindred'. Here we report the results of cardiac PET scanning using the sympathoneural imaging agent, 6-[18F]fluorodopamine in affected and unaffected members of this kindred. Four family members were studied, two with parkinsonism, one clinically normal and one with benign essential tremor alone. Both affected members had obvious loss of cardiac sympathetic innervation; the unaffected member had normal innervation, as did the member with isolated essential tremor. The results indicate that, in this family, where disease is caused by overexpression of normal alpha-synuclein, cardiac sympathetic denervation cosegregates with parkinsonism. Post-mortem studies have demonstrated synuclein-positive Lewy body formation in the brains of individuals with parkinsonism who were also in the family described here and who also carry this triplication. These results indicate that both parkinsonism and cardiac sympathetic denervation can result from an excess of normal synuclein.
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PMID:Association between cardiac denervation and parkinsonism caused by alpha-synuclein gene triplication. 1473 56

To investigate the prevalence of Essential Tremor (ET) in Singapore and compare the rates between Singaporean Chinese, Malays, and Indians, a community-based survey among a disproportionate random sample of 15,000 individuals (9000 Chinese, 3000 Malays, 3000 Indians) aged 50 years and above was conducted. In phase 1, trained interviewers conducted a door-to-door survey using a screening questionnaire for Parkinson's disease. In phase 2, medical specialists examined participants who screened positive to evaluate for the presence of postural or kinetic tremor of the upper limbs, or head tremor. Participants with suspected ET had their diagnosis confirmed in phase 3 by a movement disorders specialist and fellow based on the latest core diagnostic criteria. Forty participants with classic ET were identified. The prevalence rate (PR) of ET was 2.37 per 1000 (95% CI: 1.65-3.32), age-adjusted to UICC world standard population. The PR was significantly higher in males (p=0.01) and increased significantly with age (p<0.001). Indians (PR=4.94 per 1000, 95% CI: 2.63-9.04) were 1.8 times more likely to have ET than Chinese (PR=2.77 per 1000, 95% CI: 1.78-4.17) (p=0.08). No Malays with ET were identified. The data suggest that the prevalence of ET increases with age, is higher in males and may be higher amongst Indians.
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PMID:Prevalence of essential tremor in Singapore: a study on three races in an Asian country. 1587 84


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