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Query: UMLS:C0028738 (nystagmus)
 7,431 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Vestibular and optokinetic responses were recorded in three albino subjects with congenital nystagmus. Although an ice-water caloric stimulus did not elicit nystagmus, all patients showed a response to rotational stimuli containing high frequency components. Vestibular responses to a constant velocity rotation decremented with abnormally short time constants of 1-2 sec (normal 15-20 sec). For sinusoidal oscillation, in one subject, the cut-off frequency (where the amplitude of the response was 70% of maximum) was increased to 0.8 Hz (normal about 0.01 Hz). Full-field optokinetic stimulation generated no nystagmus response. These abnormalities may be due to defects in networks that act as mathematical integrators : either the final common neural gaze-holding network that converts velocity into position information for the ocular motor neurons or the "velocity-storage" mechanism that normally combines sensory inputs from both the labyrinths and visual system to generate appropriate (per-rotatory) nystagmus during rotation and to suppress inappropriate (post-rotatory) nystagmus after rotation.
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PMID:Vestibulo-ocular and optokinetic deficits in albinos with congenital nystagmus. 660 7

A 19-year-old man was a victim of near-drowning in fresh water. After he was resuscitated, examination showed nystagmus, absent gag reflex, diminished facial sensation, dysmetria of all limbs, and failure of automatic respiration. His intellect was perfectly preserved. Eight months later, he died suddenly, and the essential neuropathologic findings were limited to the lower brainstem. There was marked neuronal depletion bilaterally in the nucleus gracilis, nucleus cuneatus, nucleus of the tractus solitarius, nucleus ambiguus, and nucleus retroambiguus; several other lower-brainstem nuclei showed evidence of damage, but to lesser extent. The neuropathologic findings seem to have been an unusual consequence of anoxia-ischemia and support previous concepts of the anatomical localization of the human respiratory centers.
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PMID:Localized brainstem ischemic damage and Ondine's curse after near-drowning. 668 16

This study examined the effects of ice water caloric stimulation on H-reflex amplitude in normal subjects and three complete spinal cord-injured patients. H-reflexes were obtained by stimulating the tibial nerve at the popliteal fossa and recording the H-response from the gastrocnemius muscle. All normal subjects who experienced nystagmus or vertigo demonstrated significant augmentation in H-reflex amplitude with ice water irrigation of the ear canal. In the three spinal cord-injured patients, there was no significant change of H-reflex with the ice water stimulus. The results suggest that descending tracts in the anterior spinal cord must be functional to demonstrate caloric augmentation of H-reflexes. In patients with spinal cord injury, it may be possible to predict the recovery of motor function using this test together with other clinical signs of neurological function.
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PMID:Caloric stimulation-induced augmentation of H-reflexes in normal subjects, but not in spinal cord-injured patients. 672 62

The vestibulo-oculomotor reflex (nystagmus) was recorded by means of electronystagmography in 33 neurosurgical patients in dynamics prior to and after ventriculography. For contrasting the ventricular system a water-soluble medium (Conrey, dimer-X or Amipak) was used in 18 patients and contrast mixtures of water-soluble agents in combination with Myodil emulsion in 15. It was established that after ventriculography with water-soluble media the nystagmus hardly changed, while after the use of mixtures of radiocontrast media the trunk vestibular reactions in all types of nystagmus grew frequently and sharply and the vestibulovegetative reactions increased markedly.
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PMID:[Objective evaluation of tolerance of ventriculography with different x-ray contrast media (according to the results of nystagmography)]. 696 76

Auditory and vestibular function was monitored in 30 patients treated with netilmicin for urinary tract infection. During and after the treatment, no signs or symptoms appeared that could be ascribed to an ototoxic effect of the drug. Routine acoustico-vestibular tests as well as advanced, objective acoustic tests revealed no signs of impairment of the labyrinth function. Results of highly sensitive vestibular tests in 15 patients including computerized analysis of the nystagmus responses to caloric tests were compared with results obtained from a sample of normal individuals. Some of the results varied significantly more in the netilmicin group than in the reference group. The most characteristic variation was a decreased reaction to hot water stimulation.
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PMID:Netilmicin treatment followed by monitoring of vestibular and auditory function using highly sensitive methods. 697 Sep 82

The role of the vestibular system during physical exercise has only been rarely analyzed by scientific investigations. An investigation was carried out with the purpose of obtaining information on vestibular regulation in rowers. The process of maintaining balance in the boat and the limiting factors were examined. Twenty beginners and 20 well-trained rowers participated in standardized vestibular tests in the laboratory as well as in the boat (single) on the water. The results suggest that several mechanisms in the physiologic field (torque of the body) are affected by training. The well-trained oarsmen showed a significant minor nystagmus frequency, and this criterion for general vestibular regulation also showed a relationship with the specific ability for maintaining balance in the boat.
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PMID:Physiologic and anthropometric aspects of vestibular regulation in rowing. 698 47

Salt poisoning/water deprivation has been described under various circumstances in adult cattle. The signs and lesions in cattle are somewhat different from those in swine, which are frequently affected. This report describes several cases of salt poisoning in veal calves. The calves were fed milk replacer and were housed without access to water. Presenting signs were mostly referrable to dysfunction of the central nervous system and included hyperesthesia, opisthotonus, nystagmus, muscle twitching and intermittent convulsions. Although the serum sodium concentration in some of these calves was over 200 mEq/1, no remarkable brain lesions were noted at necropsy. The salt content of the milk replacer was 10 times the level recommended by the National Research Council. This salt may have come from the whey included in the formula. The syndrome produced in the veal calves was similar to that seen in infant children given only a nursing formula containing too much salt, and limited water.
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PMID:A case of presumptive salt poisoning (water deprivation) in veal calves. 708 63

Recently we developed an analog model to simulate Alexander's law in nystagmus secondary to dysfunction of a semicircular canal. Alexander's law is based on the observation that the amplitude of the nystagmus grows with increasing gaze in the direction of the fast phase and diminishes with gaze in the opposite direction. To investigate the assumptions made in the model, we conducted quantitative experimental studies on the effect of gaze on caloric-induced nystagmus in human subjects. A weak stimulus (water at 26.5 degrees C and 240 ml/min) was administered for several minutes which caused the development of jerk nystagmus. Both the average slow phase velocity and frequency reached a steady state at about three minutes after the start of irrigation and remained stable until the flow of water was stopped. To investigate the effect of gaze, each subject was asked to hold gaze at various positions from center, to the right, to the left, and to repeat the cycle. Results indicated that the slow phase velocity of the nystagmus was greatest in the direction of the fast phase and decreased approximately linearly with gaze in the other direction in accordance with Alexander's law. Frequency was not a function of gaze. We speculate as to the biological advantages of the brainstem neural circuitry responsible for Alexander's law.
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PMID:Alexander's law: a model and resulting study. 709 55

The caloric response to either water or air stimulation has been compared in 10 normal subjects. The nystagmus signals have been analysed by digital signal processing. A statistical analysis of slow-phase velocity has been conducted. The variability of the single response appeared to be correlated with the level of response. Allowing for this correlation, no difference in variability could be detected when comparing both types of caloric stimulation. The consequences of error behavior for the current practice of calculating differences in labyrinthine sensitivity are discussed.
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PMID:Single-response variability of air and water caloric reactions. 719 Jun 64

Seventy five subjects ranging in age from 18 to 87 years received warm and cool caloric irrigations. Nystagmus was recorded and latency, duration, amplitude, frequency and speed of the slow component were measured. The effects of age, hearing loss, sex and water temperature were evaluated. Significant differences were found in cool water durations. Significant differences were found as a function of age for all parameters in warm water calorics. Response duration was not found to be significantly correlated to speed of the slow component in cool calorics.
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PMID:The effects of age, sex, hearing loss and water temperature on caloric nystagmus. 721 7


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