Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In a Torsion Swing Chair (TSC) test for nystagmus, S is oscillated sinusoidally around the vertical axis with successive cycles diminishing in extent. Channel II of a standard recording ENG traces the chair's movement (differing among Ss according to their weight) while Channel I records S's ENG. A method was devised to quantify S's nystagmus by calculating, for each pair of succeeding cycles, the ratio of the decline in amplitude of the slow phase nystagmic velocity to the decline in amplitude of chair movement. This ratio, relatively constant across cycles, is greater with labyrinthine pathology. Ratios were established with 15 normal young adults as cut-offs for normalcy. The method was applied to 30 patients with peripheral hearing loss whose only complaint was slight vertigo following an acute stage of vertigo. The TSC test was validated by comparing it to the severity of vertigo and to the presence/absence of abnormal results on a standard clinical caloric test in ENG and on standard clinical ECoG. All but 1 of the 30 pts exhibited abnormal results on the TSC test, as compared with 18 for the caloric and 16 for the ECoG. Furthermore, abnormality on the TSC test was more likely to be associated with abnormal results on one or both of the other two tests than were either of the other two tests. It can be concluded that the TSC test is a valid and objective tool useful in ENG practice.
 ...
PMID:The Torsion Swing Chair test: a ratio method for quantifying nystagmus. 361 Sep 87

This study was performed on a material of 70 patients, who fulfilled the criteria of definitive MS. All the patients were examined by an otologist, a neurologist and a neuro-ophthalmologist. A wide range of audiologic and otoneurologic tests were used to obtain a good understanding of the respective disorders in MS, to gain a better knowledge of the role of otology in MS, to correlate the results with the clinical findings in order to find the most useful tests to detect MS lesions and to describe pathophysiologic aspects of central lesions using MS as a model. The material consisted of MS cases representing mild or moderate stages of disability (Hyllested classification 1.-4); 32 belonged to Hyllested group 1., 19 to group 2., 7 to group 3. and 12 to group 4. The age and sex distribution were similar with materials described earlier, as were most of the clinical neurologic findings. The material can thus be considered representative. The neuro-ophthalmologic examination served to rule out causes other than MS for abnormalities observed in the tests. Besides the clinical neurologic and otoneurologic evaluation a number of additional tests were performed. The ENG tests consisted of registration for spontaneous and positional nystagmus, of smooth pursuit and saccadic eye movements, optokinetic nystagmus and caloric reactions. The audiologic evaluation was based on the following tests: pure tone audiograms, speech reception thresholds, discrimination scores, filtered speech test, stapedius reflex thresholds, stapedius reflex decay and auditory brainstem responses. The clinical otologic examination revealed little abnormalities, which is well in accordance with the pathophysiology of MS. In addition the clinical examination ruled out peripheral lesions as reasons for observed abnormalities. Numerous abnormalities were found during the otoneurologic examination of the cranial nerves. The amount of abnormal findings in the otoneurologic examination were surprisingly high: only one patient exhibited normal results in all the tests used. The abnormalities most often encountered were those of smooth pursuit (96%), followed by saccadic eye movements (76%), optokinetic nystagmus (53 %), and abnormalities in the caloric reactions such as dysrhythmia (40%) and defective visual suppression of the nystagmus (43%). When comparing the results obtained with ENG with those of clinical findings seen during the neuro-ophthalmologic examination, a good intercorrelation was found. Yet, in many ENG tests a number of cases with subclinical abnormalities only, were observed, which stresses the importance of exact and objective methods for the registration of eye movements.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Involvement of the audiovestibular system in multiple sclerosis. An otoneurologic and audiologic study. 387 51

One hundred and ninety-nine child patients with blunt head injury were examined. Spontaneous and/or positional nystagmus (greater than or equal to 7 degrees/s) was observed immediately after trauma in 46% of cases, 6-12 months (average 10.2 months) later in 20%, and 2-8 years (average 4.7 years) later in 18%. Central ENG disturbances were found immediately after trauma in 43% of cases, 6-12 months later in 24%, and 2-8 years later in 12%. Only 1.5% of the child patients suffered from vertigo more than 6 months after trauma. The results of the study led to the conclusion that head injuries cause about as many similar objective vestibular lesions in children as in adults but fewer subjective symptoms.
 ...
PMID:Vestibular disorders following head injury in children. 387 87

Astemizole, a new H1 antihistamine, was tested on 10 patients with chronic dizziness and either spontaneous or positional nystagmus. Patients with Meniere's disease were excluded from the study. The patients took 10 mg of astemizole per day for 30 days. Four ENGs were performed; one pre-drug, one after 2 weeks of drug, one after 4 weeks of drug and one post-drug ENG. Six of the 10 patients showed a clear decrease in spontaneous and/or positional nystagmus at the second and third ENG and a rebound of nystagmus when the drug was stopped. There was a positive relation between subjective symptoms and nystagmus. No side-effects were observed.
 ...
PMID:Astemizole: its use in patients with chronic vertigo and eng signs--a pilot study of a new drug. 613 21

The diagnostic importance of ENG depends on the neuro-otologist's knowledge of electrophysiology, vestibular pathophysiology and clinical experience. By no means can ENG replace a detailed neurological examination of the dizzy patient. Evaluation of ENG recordings is neither within the competence of the technical assistant who is in charge of this diagnostic method, nor can it be left to the computerised nystagmus analysator. ENG is a fundamental constituent of medical diagnosis in cases of neurootological diseases and should not be misused for diagnostic sophistries.
 ...
PMID:[Limits and possibilities of electronystagmography]. 633 10

Different parameters in use for quantitative analysis of ENG recordings are being discussed. Special importance can be attributed to the slow-phase velocity of the nystagmus and above all to the total amplitude. However, measurement of the total amplitude via digital computers is very expensive. Hence we present a device to measure amplitudes by means of a potentiometer. This is easy to handle, works accurately and is inexpensive.
 ...
PMID:[A simple measuring device for nystagmus amplitude. A contribution to rapid, exact and inexpensive evaluation of electronystagmograms]. 650 70

After introduction of the post caloric nystagmus frequency and amplitude measured on the ENG tracing, a BASIC program for pocket computer calculate, among others, the slow phase velocity, the PD, PL and ocular fixation indices.
 ...
PMID:[Caloric tests measured with ENG. Evaluation with the microcomputer]. 653 90

Sixty-five guinea pigs were used to investigate the influence of rotatostimulations on the lateral crista ampullaris. After repeated turning stimulations with the cupulometric mode (the terminal turning velocity: 180 degrees/sec) for 24-72 hours, the morphological changes in the crista ampullaris on the ampullopetal flow side were compared with those on the ampullofugal flow side by using scanning and transmission electron microscopy. Postrotatory nystagmus recorded by ENG during this experiment revealed the response decline phenomenon in all animals, and the caloric test performed after the rotatostimulation showed 'canal paresis' in the ear on the ampullopetal flow side. In a group stimulated for 24 hours, no particular damage on the crista ampullaris was noticed. However, in a group stimulated for 72 hours, local damage was dominant in the central part of the crista, which showed a tendency to extend towards the planum semilunatum according to an increment of changes. These findings were more remarkable on the ampullopetal flow side than on the ampullofugal flow side, suggesting the predominant effect of the ampullopetal endolymph flow in the lateral semicircular canal.
 ...
PMID:Influence of long-term repetitive rotatostimulations on lateral semicircular canals. 659 5

The optokinetic (OK) nystagmus induced by OK stimulus on the foveal area (foveal nystagmus) or on the peripheral retina (peripheral nystagmus) are discussed. Separation of the visual field can be achieved by a combination of a projection type OK stimulator and a masking cylinder driven by a d.c. ENG. Foveal and peripheral nystagmus became increasingly difficult to elicit in tact with narrowing of the visual field or increase in stimulus velocity. The influence of velocity was much more noticeable in the foveal nystagmus. The characteristics of foveal and peripheral OK nystagmus are elucidated by the overlapping method. The foveal nystagmus has a rather distorted form, but its slow-phase eye velocity is the same as the target velocity. It has a tendency to start and reverse with slow phase. Its beating field deviates in the direction of the slow phase. The peripheral nystagmus, on the contrary, has a typical saw-tooth form and its slow-phase eye velocity is slower than the target velocity, even at the low speed stimulus. It has a tendency to start and reverse with the quick phase. Its beating field deviates in the direction of the quick phase.
 ...
PMID:Role of the central and peripheral retina upon optokinetic nystagmus. Foveal and peripheral nystagmus. 659 31

Twenty subjects with no vestibular complaints and normal otoscopic exams were stimulated with 44 degrees C water for 5 minutes in one ear and their nystagmus was recorded by vertical and horizontal electro-oculography. Changes in vertical eye position and nystagmus inhibition were correlated during periods of mental tasking, relaxation, and voluntary eye elevation. The results showed an average of 42 degree eye depression with mental tasking during irrigation. In addition, mental arithmetic had a "releasing" effect on horizontal nystagmus. Elevation of the eyes on command, however, produced marked irregularity in the horizontal tracings, simulating inhibition. Almost every subject had an apparent vertical deflection on ENG with eye closure. These findings suggest a mechanical component to the phenomenon of inhibition as well as an active central mechanism.
 ...
PMID:Vertical eye deviation and nystagmus inhibition during mental tasking. 660 10


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>