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

Studies were carried out on 32 persons between 38 and 54 years of age (average 45) with unilateral peripheral lesion function of the vestibular organ (among them 8 persons with complete lack of excitability) and 10 healthy persons between 23 and 42 years of age (average 32). All of the patients were examinated for vestibulo-visual interaction. With the help of electronystagmography, the eye movement was registered after visual stimulation, vestibular stimulation and simultaneous vestibulo-visual stimulation, with impulses evoking nystagmus of direction compatible and incompatible. Movement of black stripes on the white optokinetic screen with the velocity of 15 degrees/s, to the left and to the right, was visual stimulus. Vestibular organ was activated by cold water (30 degrees C), according to the Fitzgerald Hallpike's procedure. Nystagmus reaction was evaluated in the highest intensification on the basis of the mean velocity of the slow faze, amount of nystagmus deflexion, sum of amplitudes, as well as gain. We also took into account compatibility or incompatibility of the nystagmus directions which was induced by the simultaneous of the vestibulo-visual stimulation. It has been stated that the vestibulo-visual interaction in the unilateral peripheral lesion of vestibular organ does not differ in comparison with healthy persons. Besides, simultaneous vestibulo-visual stimulation induced by the impulses incompatible in their direction causes the decrease of the parameters value of the nystagmus in healthy persons and in persons with peripheral lesion of labyrinth. In the case of one-sided fall-out function of the vestibular organ an increase was observed of value gain of optokinetic nystagmus directed at the damaged side.
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PMID:[Vestibulo-visual interaction in peripheral lesion of vestibular organ]. 1039 Oct 44

The morbidity of benign paroxysmal positional vertigo (BPPV) was investigated from the functional standpoint by analyzing nystagmus elicited by the caloric test. As a result of an investigation of the three (horizontal, vertical and torsional) components of the nystagmus elicited by the caloric stimulus (cold water), the vertical nystagmus differed in direction between the left and the right ear in 3 out of the 4 BPPV cases. The vertical nystagmus elicited by the caloric stimulus reflected the functions of the anterior and posterior semicircular canals, and investigation of the difference in function between the anterior and posterior semicircular canal from the direction of the vertical nystagmus appeared to be feasible.
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PMID:Evaluation of vertical semicircular canal function by the caloric test--a study on patients with benign paroxysmal positional vertigo. 1041 26

In children with semicircular canal anomalies, vestibular compensation during their development and growth was studied. The damped rotation test elicited 'absence or poor per-rotatory nystagmus and absence of post-rotatory nystagmus in all cases. Development of gross motor and balance function was seriously delayed in each case during the first 2 or 3 years of life. Thereafter, during the pre-school age, all children could achieve most landmarks of motor development, such as head control, independent walking and running. However, balance functions at the age of entrance of the elementary school (6 years old) were variously impaired in each case. The better case could swim under water but the poor case could not maintain static balance with eyes closed. These motor skills due to vestibular compensation presumably depend on integration of the compensatory input from visual, somatosensory and proprioceptive senses, and the maturation of motor control systems in the cerebellum, basal ganglia and motor cortex.
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PMID:Vestibular compensation in infants and children with congenital and acquired vestibular loss in both ears. 1051 1

In 1905 Barany analyzed the nystagmus that appears during the irrigation of the ear with cold and hot water, justifying the phenomenon due to convectives currents in the horizontal semicircular canal. This hypothesis has been widely accepted until doubt was casted on it by the experiences carried out in the Skylab. Of the various mechanisms that could be responsible for the vestibular stimulation in the caloric tests, those which entail convection currents or endolymph expansion would need--we think--thermal gradients very superior to those occurring during these tests, that according to our calculations--always pro such hypothesis--seem insufficient.
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PMID:[Heat and vestibular stimulation]. 1052 Feb 72

This study tests the hypothesis that activation of protein kinase C (PKC) is a critical step for early recovery from spontaneous nystagmus after unilateral ablation of the vestibular periphery. Halothane-NO(2)-O(2)-anesthetized Long-Evans rats received a 5-microl intracerebroventricular bolus of vehicle (distilled water, six rats), PKC inhibitor [Iso-H-7 (10 mM, four rats; 50 mM, five rats) or bisindolemaleimide I (Bis-I, 10 microM six rats)], PKG and PKA inhibitor (A-3, 1 mM, six rats), or the serine-threonine protein kinase inhibitor H-7 (1 mM, five rats; 10 mM, five rats). Surgical unilateral labyrinthectomy (UL) was completed within 15 min. Sham control groups showed no nystagmus. Bis-I and Iso-H-7 significantly retarded the disappearance of spontaneous nystagmus quick phases for 8 h after UL (p<0.05). The effects of Iso-H-7 were dose-dependent: more nystagmus quick phases (p<0.05) were present in the 50 mM than the 10 mM group at 7 and 8 h post-UL. The rats given A-3 showed a delayed retardation of nystagmus loss, which differed significantly (p<0.05) from controls at 4-8 h after labyrinthectomy. The number of nystagmus quick phases was significantly greater than controls (p<0. 05) in the 10 mM H-7 group at 4, 5, 6 and 48 h post-UL, but only at 6 and 24 h post-UL in the 1 mM H-7 group. Thus, PKC activation is an important early requirement for vestibular compensation during the acute post-labyrinthectomy period, while cyclic-nucleotide dependent kinases may be important in a later time frame.
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PMID:Protein kinase C inhibition blocks the early appearance of vestibular compensation. 1052 48

The caloric test represents an essential part of each procedure evaluating vestibular function. The use of water has many contraindications: tympanic perforation, external otitis and mastoid diseases. Sometimes, nausea can make test execution very difficult. Several authors contributed to the study and diffusion of the caloric test for the evaluation of labyrinthine function using different types of otoalcorimeters. We compared two methods in the child--generally intolerant to the water test--and the results obtained were adapted to a mathematical model of air and water caloric nystagmus. Twenty-seven normal children, aged between 5 and 14 years, subdivided into three age groups (5-7, 8-10 and 11-14 years), underwent the water caloric test (250 cm3 at 31 and 43 degrees C for 40 s) and then the air test, together with another nine subjects undergoing only the air test (flow-rate 8 l/min at 25 and 49 degrees C) on different days. The comparison between the two stimulation methods showed a statistically significant difference (P < 0.002) between maximum slow speed component (max SSC) in degrees per second (degrees/s) of water (4.74 degrees/s) and air (2.98 degrees/s). The results of two caloric tests and the interindividual and intraindividual analysis of our electronystagmographic results are in agreement with the data obtained by other authors in studies on adults. Therefore, notwithstanding the differences between the two stimulation methods, the air caloric test can be applied in a larger number of cases, it is better tolerated and can thus be used even in children for the study of labyrinthine function.
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PMID:Comparison between air and water caloric tests in children. 1062 39

We report a case of optic glioma with bilateral optic atrophy. A 3-year-old girl presented with vomiting and left hemiparesis. She had hypothalamic dysfunction, right ptosis, right monocular nystagmus, left facial palsy, left hemiparesis, and left pes adductus. Neuroimaging studies showed obstructive hydrocephalus with a large suprasellar calcified tumor with a ring-like enhancement mimicking craniopharyngioma. Visual-evoked potentials showed delayed latency of N75 in the right occipital lead. The tumor, a pilocytic astrocytoma in the right optic tract and chiasma, was partially removed via a right frontotemporal craniotomy. The right optic nerve had shrunk to half the normal diameter and became twisted downwardly. Intracranial pressure (ICP) increased to 40 cm H2O. The fundus had bilateral optic atrophy without disc swelling. To our knowledge, this is the first report of a lamina/dot sign of the optic disc in a small child with a brain tumor and a normal neuroretinal fiber layer. These ocular findings may result from possible interruption of the axonal flow caused by the tumor and not increased ICP.
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PMID:Optic glioma with characteristic bilateral optic atrophy in a 3-year-old girl. 1070 32

To investigate the feature and mechanism of delayed effect of ionizing radiation on the inner ear, the function and structure of the inner ear of the guinea pigs were observed during 8 month's period after exposure to fractional doses of gamma radiation (2 Gy per day) with a total dose of 60 Gy. Morphological study was performed using light microscopy, transmission and scanning electron microscopy while the function was measured with electrocochleography (ECochG) and electronystagmography (ENG). The results showed that the mean CAP response threshold was 35.67 +/- 6.78 dB before radiation, and 41.17 +/- 7.76 dB, 47.00 +/- 8.82 dB and 71.00 +/- 7.63 dB at 1st day, 3rd month and 8th months after completion of treatment, respectively. No significant change was demonstrated in the auditory responses at the 1st day of radiation (P > 0.05), but there was obvious hearing loss at 3rd and 8th month (P < 0.01). The nystagmus duration induced by ice water (ENG) was 40.00 +/- 5.44 seconds before radiation, 22.71 +/- 7.93 seconds at 8th month after radiation (P < 0.01). Histologic examination at 8th month after radiation revealed atrophy and degeneration of stria vascularis, a reduced number of capillaries, degeneration of endotheliocyte in vessels, outer hair cell and supporting cell of Corti's organ. The percentage of damaged hair cells in basal turn of the cochlea was significantly higher than those of the upper turn. Degeneration of vestibular hair cell was found. It is suggested that radiation from routine radiotherapy doses may result in a delayed impairment of the inner ear. The main mechanism of the radiation damage may be interference of oxygen supply and metabolism of the inner ear by radiation vascular lesion.
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PMID:[Delayed damage of ionizing radiation on the inner ear]. 1074 70

Evaluating the function of the vestibular part of the inner ear comprises more than the classic analysis of the lateral semicircular canal function. In healthy subjects, positional alcohol nystagmus may be seen after acute alcohol ingestion. Posturography has shown a deteriorated equilibrium after even moderate doses of alcohol, which speculatively could be an effect of otolith disturbance or a central integrative effect. We tested the possibility of an otolith effect by using linear acceleration in the lateral direction by means of eccentric rotation, stimulating mainly the outermost ear's otolith organ. The subject is seated eccentrically in a rotatory chair facing the direction of rotation. Thus, the otolith organs are stimulated in steady-state rotation. The subject experiences a lateral tilt and, in darkness, is instructed to put a short light bar in the position thought to be that of a water surface, which is identical to the perceived tilt. Twenty healthy subjects (10 men, 10 women) aged 20-29 years were tested before and approximately 1 hour after ingestion of alcohol, the amounts consumed corresponding to an approximate blood alcohol level of 0.05%, well above the maximum permissible level for driving in Sweden. No significant effects of alcohol were found. The otolith function probably is not affected by moderate alcohol intoxication levels. From this point of view, equilibrium deterioration due to alcohol ingestion in the erect position is caused by a central integrative deficit and not by an otolith effect.
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PMID:No Effects of Acute Alcohol Ingestion on Subjective Visual Horizontal Determination During Eccentric Rotation. 1075 89

A protocol is described for measuring responses to a broad-band (1-2 Hz) caloric step stimulus from which the vestibular ocular reflex (VOR) and adaptation time constants can be estimated. This novel stimulation is the caloric equivalent to a rotatory step of head acceleration. In this protocol, the ear is irrigated continuously for 5 min with water at a constant temperature. During the initial 2-min period of irrigation the subject is seated and leaning forward in a nonstimulable position (horizontal canals in a horizontal plane). This irrigation phase establishes a steady-state thermal gradient across the horizontal canal, effectively eliminating thermal dynamic properties of the caloric transmission as a confounding factor. At the end of this phase, the subject is rapidly reclined to a stimulable position (horizontal canals in vertical plane) that elicits the VOR nystagmus response to an on-step of force on the cupula. Consistent with adaptation processes, the VOR response first increases and then declines gradually over the 2-min period that the step of force is maintained. Four minutes after the onset of irrigation, the subject is rapidly returned to the nonstimulable position (off-step), which is then maintained for a final 1 min. The response after the off-step, which releases the force on the cupula, reveals reversed after-nystagmus due to adaptation. Five subjects provided caloric step responses for 26 caloric temperature conditions spanning the range from 28.4 to 43.0 degrees C. The resulting responses were fitted with an adaptation model similar to models applied to rotatory acceleration step responses. Estimates of the model parameters for robust caloric stimulation, including time constants for the VOR (18.3 sec) and for vestibular adaptation (153.2 sec), are considered in relation to corresponding values reported in the literature for rotatory and caloric vestibular stimulation. The results suggest that caloric step stimulation can be used successfully to probe VOR dynamics.
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PMID:Measurement of vestibular ocular reflex (VOR) time constants with a caloric step stimulus. 1079 31


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