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Biomedical subjects

F O Black

Publications and source records attributed to F O Black.

At least 19 recordsLinked to original sources
PubMed1992

Recovery of postural equilibrium control following spaceflight.

Decreased postural stability is observed in most astronauts immediately following spaceflight. Because ataxia may present postflight operational hazards, it is important to determine the incidence of postural instability immediately following landing and the dynamics of recovery of normal postural equilibrium control. It is postulated that postflight postural instability results from in-flight adaptive changes in central nervous system (CNS) processing of sensory information from the visual, vestibular, and proprioceptive systems. The purpose of the present investigation was to determine the magnitude and time course of postflight recovery of postural equilibrium control and, hence, readaptation of CNS processing of sensory information. Thirteen crew members from six spaceflight missions were studied pre- and postflight using a modified commercial posturography system. Postural equilibrium control was found to be seriously disrupted immediately following spaceflight in all subjects. Readaptation to the terrestrial environment began immediately upon landing, proceeded rapidly for the first 10-12 hours, and then proceeded much more slowly for the subsequent 2-4 days until preflight stability levels were reachieved. It is concluded that the overall postflight recovery of postural stability follows a predictable time course.

Adult↗
PubMed1992

Equilibrium.

Explore the source record for details and available documents.

Humans↗
PubMed1992

Surgical management of perilymphatic fistulas: a Portland experience.

A comprehensive review of our series of surgical perilymphatic fistula (PLF) repairs, as well as a review of published results from other otologists, suggested an unacceptably high rate of postoperative PLF recurrence. Some recurrences were related to specific events (i.e., coughing, strenuous activity, Valsalva-type maneuvers). However many cases had no apparent cause. Rather, the patients' symptoms recurred spontaneously, and at reoperation the graft was seen to have not "taken," suggesting graft failure rather than "patient failure." After a critical evaluation of current PLF surgical procedures and state-of-the-art concepts of wound healing, we developed a new surgical technique for PLF closure. Combining the use of laser graft-site preparation, an autologous fibrin glue "buttress," and a program of postoperative activity restriction, the new procedure allowed us to achieve statistically significant improvements in graft retention and surgical outcome, with recurrences dropping from 27 percent to 8 percent. In addition, complete resolution or significant symptomatic improvement occurred in 89 percent of patients with vertigo and/or dizziness and in 84 percent with disequilibrium. We conclude that this new surgical technique is an important addition to the otologic surgeon's arsenal for PLF management.

Adolescent↗
PubMed1992

Effects of vestibular rehabilitation on dizziness and imbalance.

Vestibular rehabilitation is a specific approach to physical therapy aimed at reducing dizziness and imbalance by facilitating central nervous system compensation for peripheral vestibular dysfunction. This article reports preliminary results of studies concerning the relative effectiveness of vestibular rehabilitation, general conditioning exercises, and vestibular suppressant medication on dizziness and imbalance in patients with chronic vestibular symptoms of at least 6 months duration. Patients with positional and/or movement-related dizziness and abnormal posturography were randomly assigned to the three treatment groups. Preliminary results suggest that although all three treatment approaches reduce dizziness, only vestibular rehabilitation also improves balance. This study takes the first step toward determining the efficacy of a specific exercise approach for reducing dizziness and imbalance in patients with chronic peripheral vestibular disorders.

Adolescent↗
PubMed1979

Dynamic evaluation of human vestibulo-ocular function using white noise rotation stimulus and linear system parameter estimation techniques.

White noise acceleration inputs were used to determine the human VOR transfer function both for normal subjects and for patients falling into two pilot categories: unilateral labyrinthectomy and reduced bilateral responses. The systematic patterns shown in the transfer function of the pilot abnormal categories as compared to the normal data suggests one method of classifying test results (table I). Frequency domain linear systems parameter fits were also made using the same data. The changes in these fit parameters, when pilot abnormal data is compared to normal data, suggests the use of the parameter fits themselves as a second classification scheme (fig. 1). The second scheme is not appropriate in cases where the response is unrelated to the stimulus.

Eye Movements↗
PubMed1978

Visualization of small extracanalicular neurilemomas by metrizamide cisternographic enhancement.

Metrizamide (Amipaque) computerized tomography cisternography (CTC) provides a rapid, simple, and accurate radiographic modality of intrathecal enhancement for detecting and morphologically characterizing cerebellopontine (CP) angle masses. The technique is of especial value in masses greater than 1.5 cm that are not detected on intravenously enhanced computerized tomography. Metrizamide CTC was used in six patients with no CP angle mass and in four patients with acoustic neurilemomas.

Cerebellar Neoplasms↗
PubMed1978

Galvanic disruption of vestibulospinal postural control by cochlear implant devices.

All subjects with implanted cochlear stimulators demonstrated evidence of abnormal postural stability without their stimulators activated. Instability increased when they were tested with cochlear stimulation units turned on, and additional instability was demonstrated in four of these subjects when tested in noise. These findings suggest that the electrical stimulation delivered by the cochlear prosthesis is not limited to the auditory system. The precise characteristics of electrical stimulation devices designed for stimulations limited to the cochlea and their spurious effects upon motor performance should be investigated. The design of future intralabyrinthine auditory electrical prostheses must include hardware designs and stimulus paradigms that avoid undesirable vestibular system stimulation.

Adult↗
PubMed1977

Surgical management of vagal chemodectomas.

Vagal chemodectomas (tumors of the vagal glomus body) are histologically benign and insensitive to radiation therapy. Unless properly managed, these tumors may become life-threatening because of their eventual impingement on surrounding structures, particularly contents of the cranial vault. Patients with chemodectomas of the skull base may be surgically treated without significant functional or cosmetic loss, provided the surgeon possesses the following surgical abilities: 1. temporal bone dissection capabilities; 2. microsurgical skills, including techniques of middle ear reconstruction and neurovascular anastomosis; 3. implementation of simultaneous multiple approaches to the skull base and infratemporal fossa; and 4. the capability of managing technically inherent intraoperative and postoperative problems. Experience from nine patients, all successfully treated surgically, will be summarized.

Adult↗
PubMed1975

Aural abnormalities in partial DiGeorge syndrome.

DiGeorge syndrome patients frequently have multiple anomalies of the craniofacial, cardiovascular, and visceral structures in addition to thymic and parathyroid hypoplasia. Gross and microscopic aural abnormalities occurring in a patient with partial DiGeorge syndrome are presented and compared with findings from the only other known temporal bone report.

Abnormalities, Multiple↗
PubMed1975

Effect of electronic filters on electronystagmographic recordings.

With the advent of digital computer measurement techniques for nystagmus parameter determinations, the need has arisen for careful quality control of nystagmus recording methods. For this study, electronic filter distortion of nystagmus waveforms was quantified, and the results were used to formulate guidelines for selection of appropiate band-widths depending on the user's requirements. For minimum distortion, a lower time constant of at least three seconds and an upper frequency cutoff of at least 60 hertz are recommended.

Computers↗
PubMed1975

Computer aided nystagmus analysis.

The electronystagmogram (ENG) is analyzed with the assistance of a PDP-8 minicomputer for calculating the instantaneous slope, average slope, lead frequency, lag frequency and cycle frequency of both the fast and slow wave components of the ENG. The ENG data is first digitized and displayed on a storage scope in order to permit the operator to select an epoch of data. The results are then displayed on the scope, and the mean and variance of the important parameters are outputted on the teletype. The programs include a system for storing a large library of records.

Computers↗
PubMed1975

Effect of coronal plane tilt on cat caloric nystagmus responses.

The nystagmus slope responses to vestibular stimuli are strongly dependent on eye position, while the frequency responses shift predictably and are relatively independent of the eye position. Spurious directional differences may be introduced in nystagmus slope parameters by small tilts in the roll plane in comparison to the more predictable frequency responses.

Animals↗
PubMedDate not supplied

Acrocephalosyndactly (Apert's syndrome): Temporal bone findings.

The middle ear and ossicular chain were not complete in the specimen, but the remnants present appeared normally developed except for the stapediovestibular joint region. The annular ligament was incompletely developed in two areas where fixation by undedifferentiated cartilage occurred. The subarcuate fossa, normally filled with fibrous tissue and usually narrowed by a rim of newly deposited periosteal bone at birth, was unusually large. Included in this fibrous tissue were remnants of the primary cartilaginous capusule undergoing absorption, as well as islands of partially removed endochondral bone. The abnormalities in both instances indicated a disturbance in maturation or resorption of the embryonal cartilaginous capsule.

Abnormalities, Multiple↗
PubMedDate not supplied

Auditory prostheses in perspective.

The results of the evaluation of subjects presently fitted with internal auditory prostheses are summarized. Based on these results, the role of single-channel prostheses as a treatment for acquired deafness is discussed in terms of the auditory expectation for a single channel and of subject selection.

Cochlea↗