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Results 451 - 500 of 645
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Hamernik R P - - 1989
There is the suggestion in the literature that vibration may potentiate the effects of noise and may thus increase the risk of hearing loss in a variety of exposure situations. However, in human experimental studies, which, by necessity, are limited to low levels of exposure, the effects measured are relatively ...
Grenner J - - 1989
Sixty guinea pigs were exposed to a steady-state broadband noise with a falling frequency spectrum. The sound-pressure level was varied between 96 and 117 dB SPL, and the duration of the exposure was varied from 3 to 12 h. After 4-5 weeks, the auditory thresholds were determined by electrocochleography at ...
Borg E - - 1989
Rabbits were exposed to 2- to 7-kHz noise either for a short duration at a high sound-pressure level (15 or 30 min at 115 dB SPL), or a long duration at a low level (512 h at 85 dB SPL). The high-level exposure produced a hearing loss in the frequency ...
Rebert C S - - 1989
Acute effects of inhaled dichloromethane on the spontaneous electroencephalogram (EEG) and sensory-evoked potentials (EPs) were characterized and compared to previously observed effects of toluene; both solvents are common components of abused solvent mixtures. Twelve adult male Fischer-344 rats with chronic epidural electrode implants served as subjects. Each rat was exposed ...
McFadden E A - - 1989
We report the changes in auditory function that occurred at selected intervals following exposure to an intense pure-tone stimulus. One day old chicks were exposed to a 0.9 kHz tone for 48 h at 120 dB. At 0, 1, 3, 6, 9, 12 and 15 days after exposure, cochlear nucleus ...
Davis R I - - 1989
Evoked-potential tuning curves were obtained on over 150 chinchillas before and after acoustic overstimulation in order to relate the effects of changes in frequency selectivity to sensory cell loss over a wide range of hearing loss. Pre- and post-exposure measures of auditory thresholds and masked thresholds (simultaneous tone-on-tone paradigm) were ...
Champlin C A - - 1989
Overshoot refers to the poorer detectability of brief signals presented soon after the onset of a masking noise compared to those presented after longer delays. In the present experiment, brief tonal signals were presented 2 or 190 ms following the onset of a broadband masker that was 200 ms in ...
Zwick H - - 1989
Development of more sensitive human clinical visual function tests is required for early detection of both acute and chronic laser exposure effects. Detection of low-level laser light exposure depends upon the measure of visual function employed. Visual function measures may reflect physiological processes at the retina as well as those ...
Roberto M - - 1989
This paper reviews the results of several studies on the effects of blast wave exposure on the auditory system of the chinchilla, the pig, and the sheep. The chinchillas were exposed at peak sound pressure levels of approximately 160 dB under well-controlled laboratory conditions. A modified shock tube was used ...
Norton S J - - 1989
Following presentation of brief, intense pure tones spontaneous otoacoustic emissions (SOAEs) were reduced in frequency and/or amplitude. The effects were highly tuned with exposures between 1/8 and 5/8 of an octave below the SOAE producing the maximum changes. Exposure frequencies above the SOAE had no effect. The degree of tuning ...
Laroche C - - 1989
It is now recognized that temporary threshold shift (TTS) grows to an asymptotic level (ATS) after a prolonged exposure to steady-state and intermittent noise. Few studies have been conducted to verify this process of acquisition for impact noise. However, results obtained on animals have demonstrated that an asymptote is reached ...
Price G R - - 1989
Current methods of rating the hazard of weapons impulses for the ear have recently been challenged by electrophysiological data from experiments with animal ears which indicate that the hazard from low-frequency impulses is much lower than the hazard from higher frequency impulses (Dancer et al., 1981; Price, 1986b). To supplement ...
Wu Y X - - 1989
Audiograms were taken on 20 young men before and immediately after exposure to Fighter-6 ground running-up noise, and their course of recovery was followed. The sound levels at the engine hatch were 117-128 dB(A). The noise-induced temporary threshold shift was more than 13 dB. The maximum threshold shift occurred at ...
Kral K - - 1989
Insects are frequently assumed to have hard-wired nervous systems that fail to demonstrate functional plasticity. We have produced changes in synaptic frequency, and analysed their developmental time course, dynamics and reversibility, in the lamina underlying the compound eye of the fly, by exposing young adults to different visual stimuli. The ...
Dolan T G - - 1989
The recoveries of whole-nerve action potential (AP) thresholds, AP amplitudes and AP tuning curves in gerbils were monitored following two weeks of exposure to band-pass noise at 85 dBA. Recordings were made by means of electrodes chronically implanted in the subjects' bullas. The noise exposure caused threshold elevations in all ...
Kamal A A - - 1989
Hearing threshold was reexamined in a group of forge hammering workers investigated 8 years ago with consideration of the age effect and of auditory symptoms. Workers were exposed to impact noise that ranged from 112 to 139 dB(A)--at an irregular rate of 20 to 50 drop/minute--and a continuous background noise ...
Thorne P R - - 1989
The oxygen tension (pO2) of endolymph of the guinea pig cochlea was measured during exposure to loud sound (12 kHz or high-pass noise; 110 dB SPL up to 1 h duration). A small, but significant, steady decline in mean pO2 was observed after both pure tone and high-pass noise exposure. ...
Mack C A - - 1988
A review of the theory of absorption on microscopic and macroscopic levels is given. This theory is then applied to the absorption of UV light by diazo-type positive photoresist during exposure. A formal treatment of the properties of polychromatic light is given. Using these analyses, the effects of polychromatic exposure ...
Fischer B - - 1988
Adverse effects of simultaneous exposure to visible light and room temperature were investigated in rabbit early cleavage stages and morulae. Routine laboratory conditions were mimicked as close as possible. Embryonic development was assessed by cell proliferation via incorporation of tritiated thymidine, by gross morphology, and by electron microscopy. Damage was ...
Monroy A F - - 1988
Two-dimensional (2-D) gel electrophoresis has been used to follow changes in cell type specific and organelle localized polypeptides upon exposure of etiolated sorghum shoots and dark-grown resting Euglena to light. Total protein extracted from isolated bundle sheath strands and mesophyll protoplasts was resolved by 2-D gel electrophoresis. The cell type ...
Hamernik R P - - 1988
An analysis of the pure-tone threshold recovery functions obtained from 118 chinchillas exposed to high-level impulse noise showed that there are at least three distinctly different types of recovery function: type I--a recovery function for which the initial threshold shift recovers monotonically with increasing postexposure time; type II--a delayed recovery; ...
Redding G M - - 1988
Aftereffect measures of visual shift and proprioceptive shift were obtained for prism exposure conditions in which, at the end of a sagittal pointing movement, most of the arm was visible (concurrent exposure) or only the first finger joint was visible (terminal exposure). Intermediate exposure conditions permitted view of the hand ...
Canlon B - - 1988
Guinea pigs were pre-exposed to a low level acoustic stimulus prior to exposure to a stimulus known to yield a permanent threshold shift. This pre-treatment resulted in: 1) approximately a 20 dB reduction in the threshold shift relative to animals not pre-exposed, and 2) complete recovery from the threshold shift ...
Champlin C A - - 1988
Gap detection thresholds (GDTs) were obtained from human listeners before and after exposure to a brief 0.4- or 1.7-kHz tone. The temporary threshold shift (TTS) produced 2 min after an exposure was approximately 10 dB. GDT stimuli were octave-band noises centered at one of three frequencies: the exposure frequency, one-half ...
Fechter L D - - 1988
Previous studies have determined that severe systemic hypoxia disrupts cochlear function acutely, but have suggested that augmentation of cochlear perfusion may successfully protect cochlear function under all but the most profound hypoxic treatments. In the current study we report on the chronic effects of simultaneous exposures to noise and carbon ...
Hashino E - - 1988
The effects of intense noise exposure on hearing in the budgerigar were examined by behavioral audiometry. After binaural exposure to an intense broadband noise, auditory threshold shifts (TS) of the birds were continuously measured at frequencies between 0.125 and 8 kHz using an avoidance conditioning technique. Temporary threshold shifts (TTS) ...
Ylikoski J - - 1988
Sixty patients with varying degrees of noise-induced hearing loss (NIHL) after long-term exposure to intense impulse noise from firearms, but without manifest clinical symptoms of vestibular pathology, were tested for body sway using a stable platform. The results were compared with those from 115 healthy referents examined in the same ...
Campbell S S - - 1988
Exposure to light was recorded from 10 healthy elderly adults and 13 age-matched subjects with senile dementia of the Alzheimer's type (SDAT). Data were recorded in the home, for an average of 5 days, while subjects continued their normal daily activities. Subjects were exposed to remarkably small intervals of illumination ...
Hansson H A - - 1988
Exposure to electromagnetic fields may cause various types of effects on nervous tissue, in severe cases even irreversible damage. The exposure conditions, i.e. frequency including type and extent of modulation, time, intensity, wave form, as well as shape, size and position of exposed subject and possible treatment with drugs, are ...
Seidel H - - 1988
This study was carried out in order: (1) to examine the effects of isolated and combined prolonged exposures to noise and whole-body vibration on hearing, vision and subjectively experienced strain, and (2) to check the combined effects with repeated exposures. Six male subjects were exposed twice to noise (N) at ...
Johnson A C - - 1988
Rats were exposed to toluene (1000 ppm, 16 h/d, 5 d/w, 2 w), or noise (100 dB Leq, 10 h/d, 7 d/w, 4 w) or toluene followed by noise. Auditory function was tested by brainstem audiometry using a 1/3 octave filtered sine wave stimulus at the frequencies 1.6, 3.15, 6.3, ...
Canlon B - - 1988
The aim of the present investigation was to determine: 1) the relationship between changes in auditory sensitivity and alterations in stereocilia micromechanics and tectorial membrane morphology after acoustic overstimulation; 2) the rate of growth of a threshold shift in stereocilia following in vitro overstimulation; and 3) if the damaging effects ...
Sinex D G - - 1987
Whole nerve action potential (AP) and single auditory-nerve fiber thresholds were measured in chinchillas exposed to noise. The exposure stimulus was a 500-Hz octave band of noise presented at 95 dB SPL for 15 min/h, for 4 or 40 days. The AP thresholds were elevated by about 40 dB on ...
Clark W W - - 1987
Changes in hearing sensitivity and cochlear damage were determined in two groups of chinchillas exposed to an octave band of noise (OBN) centered at 0.5 kHz, 95 dB SPL on two different schedules: 6 h per day for 36 days, or 15 min/h for 144 days. Hearing sensitivity was measured ...
Calixto S - - 1987
A dry polymeric mixture rendered red sensitive with a dye has been used to record interference gratings and holograms. Diffraction efficiencies of ~10% can be attained with exposures of ~94 mJ/cm(2). If necessary the reading step can be done just after the exposure or after a fixing step performed with ...
De Sano C F - - 1987
12 male and 12 female volunteers were evaluated for their suggestibility before and after an approximately 15-min. exposure to either sham, 1-Hz or 4-Hz magnetic fields that were applied across their mid-superior temporal lobes. During the field-application subjects were instructed to view a green light that was pulsating at the ...
Fernández-Ballesteros R - - 1987
In this study we assessed the influence of duration of exposure of the Rorschach stimuli on the response determinants when the information processing is interrupted using a patterned mask or visual noise. Analysis shows that increasing duration of exposure does not yield a parallel increase in the production of more ...
Ylikoski J - - 1987
Guinea pigs were exposed to the impulse noise from 90-300 rifle shots (peak 158 dB SPL, maximal energy content at 1.1 kHz). This exposure induced severe cochlear damage. The vestibular end organs also showed damage of varying degree. The ampullary cristae were most severely damaged, but changes were also seen ...
Lonsbury-Martin B L - - 1987
The findings of a number of studies investigating the effects of excessive sound on hearing have indicated that the correspondence between behavioral, physiological, and histological measures of noise-induced hearing loss may be markedly dependent upon the sensitivity of the particular measure. Recent studies demonstrating significant changes in the responses of ...
Hamernik R P - - 1987
Forty-one chinchillas, divided into seven groups, were exposed to 1, 10, or 100 noise impulses (one every 3s) having peak intensities of 131, 135, 139, or 147 dB. Hearing thresholds were measured in each animal before and after exposure using an avoidance conditioning procedure; a surface preparation of the cochlear ...
Lundorf E - - 1987
In a case-control study of 209 workers from a local railway maintenance and repair workshop, pleuropulmonary lesions were studied on chest radiographs. All workers were known to have been exposed to asbestos fibers of all kinds for a long period of time, but the exposure was light. A "dose index" ...
Popelár J - - 1987
Changes in the auditory nerve action potential (AP), evoked responses from the inferior colliculus (IC-ER) and auditory cortex (AC-ER) were assessed after exposure to white noise of 120 dB SPL for 1 h in awake guinea pigs. Auditory thresholds were estimated with the aid of averaged AP, IC-ER and AC-ER, ...
Miyakita T - - 1987
This experimental study was designed to determine whether a combination of noise and vibration produced more pronounced changes in temporary shifts of finger skin temperature and temporary threshold shift (TTS) of hearing than those resulting from exposure to either stress alone. Nineteen healthy subjects were exposed to six different combinations ...
Chermak G D - - 1987
Reversible tinnitus was induced in 10 male and 8 female normal-hearing subjects following a 5 min 110 dB SPL exposure to white noise. Temporary threshold shift (TTS) was measured at 2 and 4 kHz. Characteristics of the tinnitus were determined by means of a written questionnaire administered 5 min following ...
Liberman M C - - 1987
Single-unit recordings were made from populations of auditory-nerve fibers in 12 cats before and after acoustic overstimulation. Cats were killed 4 to 16 h after exposure, and the cochleas were analyzed at the light- and electron-microscopic levels. The exposures were designed to create 40 to 60 dB of acute threshold ...
Chermak G D - - 1987
Psychophysical tuning curves (PTCs) at 2 kHz and auditory thresholds (2 kHz and 4 kHz) were obtained from 18 normal-hearing listeners before and after exposure to a 5-min 110 dB SPL white noise. PTCs were quantified on five dimensions (Q10 tip, Q10 probe, d1oct, tip level and tip frequency). PTCs ...
Prazma J - - 1987
The effect of 60 minutes of exposure to high-frequency (10- to 40-kHz), high-intensity (115-dB) noise on the cochlear blood flow (CoBF) was investigated in adult gerbils. The CoBF was measured with a newly improved microsphere method. The number of microspheres in cochlear tissue that had been dissected by the surface ...
Bohne B A - - 1987
Four groups of chinchillas were exposed to an octave band of noise with a center frequency of 4 kHz and a sound pressure level of 80 or 86 dB SPL on interrupted schedules with 18, 42 or 162 h of rest between successive 6-h exposures. Damage in these ears was ...
Young J S - - 1987
Hypoxia has long been hypothesized to play a role in noise-induced hearing loss, and the disruption of auditory function by asphyxiation has been repeatedly demonstrated. Recent data, however, suggest that the cochlea is resistant to less extreme hypoxic events. The current report describes the combined effects of noise and hypoxia ...
Fredelius L - - 1987
A systematic study of the effects of acoustic overstimulation on the endolymphatic sac (ES) in the guinea pig was performed. The ES was studied with light and transmission electron microscopy after exposure of the animals to a 3.85 kHz pure tone of 108 dB SPL or 120 dB SPL for ...
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