Biomedical subjects

J Corvera

Publications and source records attributed to J Corvera.

At least 19 recordsLinked to original sources

PubMed1991

[Ethical and economical considerations on cochlear implants in developing countries].

An important factor that all cochlear implant teams have to deal with one way or another is the coast of the prostheses. This problem takes on very special characteristics in developing countries. This paper is based on the authors' experience in establishing the cochlear implant program of the "Hospital General Manuel Gea Gonzalez", a public hospital in Mexico City, and tries to determine which should be the optimal characteristics of an implant to be used in developing countries.

Cochlear Implants↗

PubMed1989

Long-term effect of acetazolamide and chlorthalidone on the hearing loss of Menière's disease.

A retrospective computerized analysis of the records of patients with Meniere's disease was made to evaluate the effect of acetazolamide and chlorthalidone on the rate of hearing loss. Three groups were compared as follows: (1) 79 patients treated with chlorthalidone for 5 to 13.4 years; (2) 42 patients medicated with acetazolamide between 5 and 7.8 years; and (3) a control group of 71 patients who received only intermittent symptomatic treatment for vertigo, followed for 5 to 24.1 years. In the short term, after 2 to 6 weeks of treatment, a statistically significant decrease of the average hearing loss was observed with both chlorthalidone and acetazolamide. In the long term, more than 5 years, no preventive effect on the deterioration of the hearing loss could be detected. Both acetazolamide and chlorthalidone can be useful for diagnostic purposes by causing a fluctuation of hearing, as well as for the management of the vertigo attacks, but it is not useful for the long-term prevention of the hearing deterioration in Meniere's disease.

Acetazolamide↗

PubMed1985

Neurotologic evidence of central and peripheral involvement in patients with vestibular neuronitis.

Quantitative vestibulo-oculomotor tests and auditory brain stem responses were studied in 22 patients with vestibular neuronitis in a search for evidence of CNS affection. Such evidence was found in 16 of the 22; only in the other six could the examination findings be regarded as the result of damage limited to vestibular neuroepithelium or nerve. It is concluded that vestibular neuronitis can cause CNS signs by itself, probably because of inflammation in the vicinity of the vestibular nerve.

Adolescent↗

PubMed1980

Oculomotor and oculovestibular functions in a hemispherectomy patient.

Oculomotor and oculovestibular functions in a patient who had undergone a left hemispherectomy were examined under a variety of visual and vestibular stimuli. The main findings were an inability to hold left eccentric gaze, resulting in gaze-evoked nystagmus to that side; inaccurate saccades to the right; defective smooth pursuit to the left; asymmetrical vestibulo-ocular responses (VOR) in the dark due to the interaction of the VOR with the "spasticity of conjugate gaze", decreased gain of the visuo-vestibulo-ocular reflexes to both sides, more marked to the right, when rotated fixating on a stationary wall target or the environment, due to abnormal smooth and optokinetic systems; and failure to inhibit the VOR when rotated to the left with visual fixation.

Adult↗

PubMed1979

Effects of cerebellectomy on eye movements in man.

A patient with a right hemicerebellectomy and recurrence of a tumor on the left cerebellar hemisphere was examined regarding oculomotor and vestibuloocular functions. The findings were as follows: inability to maintain eccentric gaze; defective smooth pursuit system; failure to suppress by visual fixation the nystagmus induced by sinusoidal horizontal rotations; moderate increase of the vestibulo-ocular reflex gain when rotated in the dark; relative preservation of the slow phases of the optokinetic nystagmus, as compared to the slow phases induced by tracking a pendulum; decreased gain of the vestibulo-ocular reflex when rotated with the lights on fixating the environment; square wave jerks; and no saccadic dysmetria.

Adult↗

PubMed1978

Endolymph flow-pressure patterns in models of semicircular canals. Effects of angular accelerations in one or two spatial planes.

The effects of angular accelerations in one or two spatial planes over the pressure exerted on the cupule of the semicircular canals, was studied using hydraulic models of the canals. The models were accelerated using a torsion pendulum and the resulting flow was monitored. The relative position of the model modifies the direction and magnitude of the flow in each canal and in the equivalent of the utricle where the canals join each other. When simultaneous accelerations in two spatial planes were used, a coriolic effect was observed, which could be significant to explain some vestibular symptoms that occur under similar conditions. From the information obtained with the models, the excitation-inhibition patterns in each of the six semicircular canals can be predicted for accelerations in any given spatial plane or combination of planes.

Acceleration↗

PubMed1972