Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The familial occurrence of essential tremor combined with (congenital) nystagmus, duodenal ulceration and a narcolepsy-like sleep disturbance caused by an autosomal dominant gene with high penetrance and fairly uniform expressivity is reported in a family of Swedish-Finnish ancestry. Twelve of 17 affected family members had essential tremor which began between 30-40 years of age and which could be controlled temporarily by alcohol; this resulted in alcoholism in several affected individuals. The most severly affected persons showed cerebellar signs which may reflect a possible pathogenetic relationship of the syndrome to the genetic cerebellar atrophies. Nystagmus, observed in 12 of 17 affected family members (eight of whom were also affected with tremor) usually was congenital and accompanied by refractive errors. Duodenal ulcers occurred almost exclusively in individuals with the neurological syndrome, and preceded its onset in some cases. The ulcer disease therefore seems to be a component manifestation of the syndrome and is interpreted as a pleiotropic effect of the gene which also causes the nystagmus, tremor and sleep disturbance.
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PMID:Essential tremor, nystagmus and duodenal ulceration. A "new" dominantly inherited condition. 124 68

Nystagmus evoked after rapid horizontal head-shaking is believed to be a sensitive indication of the existence and location of a unilateral vestibular lesion. Its origin is the directional asymmetry in vestibular responses of the healthy labyrinth (Ewald's second law). For nystagmus to appear after the head has stopped moving, however, the directionally asymmetric responses must have been stored during the head-shaking to be discharged afterwards. Our results confirm the notion that head-shaking nystagmus is most likely generated by a directional preponderance in vestibular responses but only in combination with a functioning central velocity-storage mechanism. If velocity-storage is lost completely, as may occur during the acute phase of a unilateral peripheral vestibular lesion, even a large vestibular preponderance does not lead to head-shaking nystagmus. Thus, to interpret the results of the head-shaking test the condition of the velocity-storage mechanism must be taken into account.
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PMID:Head-shaking nystagmus during vestibular compensation in humans and rhesus monkeys. 223 4

Nystagmus after rapid head-shaking (post-headshake nystagmus) is often seen in patients with vestibulopathy. Post-headshake nystagmus is transient and is frequently associated with symptoms of dizziness, dysequilibrium, or vertigo. The phenomenon presumably reflects headshake-induced asymmetry in vestibulo-ocular reflex pathways, which persists after head-shaking stops. We postulated that the same vestibular imbalance that underlies post-headshake nystagmus might produce an equivalent in postural instability. To test this hypothesis, we investigated the effect of headshake on postural control and eye movements in patients who exhibited post-headshake nystagmus, vestibulopathy, or both. Postural instability was quantified with a dynamic platform device, whereas eye movements were recorded with electrooculography. Ten normal controls and 21 patients with a history of post-headshake nystagmus or unilateral vestibulopathy were evaluated. Subjects were tested for 20 seconds before and immediately after passive horizontal headshake (+/- 30-degree amplitude) at 2 Hz for 20 seconds. Postural stability was assessed while subjects stood with eyes closed, and the floor was modulated proportionally with sway. The difference in normalized peak-to-peak sway (equilibrium score) before and after headshake was assessed in all subjects and compared between groups. Post-headshake nystagmus was documented by electro-oculography recorded during posturography. Results for normal controls and vestibulopathic subjects without post-headshake nystagmus showed only a small transient decline in postural stability after headshake. Those with post-headshake nystagmus (regardless of caloric asymmetry) showed a robust decline in postural stability.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Nystagmus and postural instability after headshake in patients with vestibular dysfunction. 787 Apr 39

In cases of central and/or peripheral vestibular system asymmetry, Head-Shaking test-induced Nystagmus (H.S.-Ny) can appear after a cycle of 20 horizontal head oscillations. Four types of H.S.-Ny have been described, all of which are horizontal: 1) deficit Ny; 2) recovery Ny; 3) biphasic Ny; 4) triphasic Ny. None of these forms are specific for any given vestibular asymmetry site, whether central or peripheral. The authors report another low vertical type of H.S.-Ny found in 13 of the 1500 cases where the test was performed. Ten of these cases are discussed here. Vertical H.S.-Ny was found in 7 cases of N.M.R.-confirmed central pathologies, in 1 case of complications from epidemic parotitis and in 2 cases for which N.M.R. did not confirm the presence of an organic pathology. Vertical H.S.-Ny was often associated with other vestibular signs (Gaze-Ny, Rebound Ny, variable direction Ny, down-beat positional Ny, labyrinthine hyper reflexia). The authors consider this form of nystagmus a simple, easily determined signal of great importance in diagnosing the presence of a central, tronco-encephalic and cerebellar pathologies.
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PMID:[Vertical nystagmus induced by the head-shaking test: 10 cases]. 1087 52

Vertigo and dizziness are common complaints encountered in clinical practice. The patient's history and a thorough otoneurological evaluation are essential for identifying the specific pathology behind the patient's complaints. If the patient reports an illusion of movement (vertigo), this most likely indicates an imbalance within the vestibular system. A sensation of rotatory movement together with a spontaneous nystagmus suggests a lesion involving the semicircular canals, while an illusion of linear movement indicates a disturbance of the otoliths. Nystagmus of central origin or caused by a peripheral vestibular lesion can usually be distinguished by other features in the history or on clinical examination. While peripheral vestibular lesions usually lead to a mixed horizontal-torsional or vertical-torsional nystagmus, a pure vertical or pure torsional nystagmus is always caused by a central lesion. With simple bedside tests such as head-shaking nystagmus and rapid head impulses deficits in labyrinthine function can clearly be detected. For a more thorough investigation of vestibular function at the level of individual semicircular canals and the otoliths, modern techniques are now available such as three-dimensional eye movement vector analysis for the evaluation of individual semicircular canal function, measurement of the subjective visual vertical for utricular, and click-evoked myogenic potentials for saccular testing.
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PMID:Assessing vestibular function: which tests, when? 1089 64

Nystagmus signaling vestibular dysfunction was observed after vibratory stimulation with a 100 Hz ABC stimulator in a population of 36 patients with unilateral labyrinthine pathology (ULP) (pre and postoperative neuromas, vestibular neurectomies) and 10 patients with vestibular neuritis. The stimulus was applied on 3 bony points of the skull (vertex and 2 mastoids) and 2 muscular points of the neck (right and left posterior cervical region). These results were compared with those in 95 normal subjects and 19 cases of central disease and were correlated on the same day with results of the caloric test and head shaking test (HST). A consistent nystagmus was found in only 6 % of the normal subjects (specificity 94 %) and in 10 % of the central lesions, but in 94 % of the 36 peripheral ULP. The sensitivity of the test was equivalent to the HST. The signal was optimized in 30 patients: stimulus frequency, amplitude, stimulator mass, form of the contact, patient tolerance. The best results were obtained for a frequency of 100 Hz and an amplitude of 0.5 mm (there was no response under 0.1 mm vibration amplitude). Under videoscopy and 3D videonystagmography, the direction or side of the nystagmus was constant, but its axis (horizontal, oblique or rotational) changed according to the location of the stimulator: on the mastoid (elective location of stimulation with responses in 94 % of cases) the axis was most often horizontal or horizontal rotational. On the vertex location (where nystagmus was observed in 60 % of cases) the axis of nystagmus was most often rotational or oblique and sometimes horizontal-rotational. The nystagmus showed short latency (less than 200 ms). It started and stopped as stimulation was initiated and interrupted. Nystagmus persisted for the duration of patient tolerance. This nystagmus generally signifies unilateral vestibular weakness rather than vestibular predominance. It is a good indicator of unilateral vestibular dysfunction and could serve as a useful test in clinical practice. We discuss the origin of the nystagmus which may originate in muscle proprioception (by propagation of the vibration to neck muscles) or in the labyrinth (simultaneous excitation of 3 canals on each side).
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PMID:[Semiologic value and optimum stimuli trial during the vibratory test: results of a 3D analysis of nystagmus]. 1108 4

Previously [The abstract has been shortened somewhat, and the headings removed, in order to conform to journal style], we have observed vestibular asymmetry in about one-third of healthy senior citizens and in about two-thirds of subjects with previous hip fractures and no other significant ailments. Wrist fractures are considered a harbinger of hip fractures. If vestibular asymmetry is correlated with falls and fractures among the elderly then it should also be reflected among subjects with wrist fractures. Sixty-six consecutive patients (mean age 67.8 years) who had sustained a fall-related wrist fracture during a 10-month period were included in the study. The frequency of head shake nystagmus among the patients was compared to that found among 49 healthy senior citizens (mean age 74.9 years). Nystagmus after head shaking, indicating asymmetric vestibular function, was found in 50 participants (76%) (p <0.001). Thirty-eight of these were graded with distinct or prominent nystagmus responses. Sixty percent of the subjects with horizontal nystagmus had a wrist fracture coinciding with the slow phase of nystagmus. Twenty-three subjects reported 30 previous fall-related fractures during the previous 10 years. Subjects with nystagmus after head shaking sustained 26 of these fractures. The frequency of signs of vestibular asymmetry was significantly higher (p < 0.001) among the subjects than among healthy senior citizens. These findings suggest that an asymmetric vestibular function could be an epidemiologically important contributory factor to falls and wrist fractures among the elderly population.
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PMID:Observation of vestibular asymmetry in a majority of patients over 50 years with fall-related wrist fractures. 1150 8

Leigh disease is a subacute neurodegenerative disorder characterized by symmetric necrotic lesions in the basal ganglia, cerebellum, thalamus, brain stem, and optical nerves and caused by altered oxidative phosphorylation. We describe the clinical, biochemical, neuroimaging, and molecular studies of a 19-year-old boy with early-onset Leigh disease manifesting as severe extrapyramidal disorder with generalized dystonia and choreoathetosis. He was born of healthy parents after an uneventful pregnancy and delivery. At the age of 2 1/2 years, after a minor respiratory infection, he developed unstable, broad-based gait and tremor of the hands. These symptoms persisted for the next several years, when ataxia became more prominent. Difficulty in swallowing, dysarthria, trunk dystonia, and marked dyskinesia of the arms and hands gradually developed. Nystagmus, transient ptosis, and strabismus also appeared. Abnormal laboratory findings included elevated plasma and cerebrospinal fluid lactate and pyruvate, with an abnormal lactate/pyruvate ratio. Cranial computed tomography and magnetic resonance imaging demonstrated signs of cerebellar atrophy, bilateral and symmetric hypodensities in the lentiform nucleus and thalamus, and transient hyperintensities of cerebral peduncles in T2-weighted sequences suggestive of Leigh disease. Muscle biopsy revealed isolated fiber atrophy, necrotic fibers undergoing phagocytosis, and no ragged-red fibers. The measured catalytic activity of cytochrome c oxidase in skeletal muscle homogenates demonstrated a partial cytochrome c oxidase deficiency No abnormalities in the mitochondrial genome and in the SURF-1 gene were found. The boy is currently receiving levodopa therapy, creatine monohydrate, and a high dosage of thiamine and lipoic acid, his condition is stabilized, and extrapyramidal symptoms are less pronounced.
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PMID:Cytochrome c oxidase partial deficiency-associated Leigh disease presenting as an extrapyramidal syndrome. 1151 Sep 39

The clinical picture of Positional Paroxysmal Vertigo (PPV) induced by vertical canal labyrintholithiasis has been clearly described, eliminating previous interpretations of pathogenesis of this disorder. The diagnosis of PPV is based on the well-known picture of positional paroxysmal Nystagmus. The Authors report a clinical sign which has not previously been reported in the literature: torsional Nystagmus induced by the Head-Shaking Test (HST). The Authors encoutered this sign in 30% of the cases of vertical canalolithiasis and in 50% of the cases diagnosed as vertical cupulolithiasis. This sign was also found in patients with a history of prior positional vertigo and in patients who, after treatment with release maneuver, no longer show clinical signs of positional vertigo. Such Nystagmus was not, however, found in the control group (normal subjects and patients suffering from other vestibular pathologies). In the present study the possible pathogenesis of this sign is discussed and some practical implications are considered.
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PMID:[Sign-report: torsional nystagmus from head-shaking in patients with labyrinth lithiasis of the vertical canal]. 1193 5

This study investigated 44 healthy elderly subjects aged between 64 and 87, who were analysed with videonystagmoscopy and quantitative videonystagmography, for establishing new standards for normal limits into this new diagnostic tool. 15.9% of the subjects were found to have spontaneous and provoked nystagmus at least in one position studied. Vertical nystagmus in head hanging position was the most frequent finding. In the Dix-Hallpike test we found one case of torsional nystagmus. No subject had seated position nystagmus. Nystagmus after head shaking and evoked nystagmus were not found.
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PMID:[Video-nystagmography findings in healthy elderly subjects]. 1282 44


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