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Results for “Ear Protective Devices”

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PubMed2000

Assessment of the influence of background noise on escape-maintained problem behavior and pain behavior in a child with Williams syndrome.

We examined the influence of background noise on levels of problem behavior and pain behavior under functional analysis conditions for a child with a diagnosis of Williams syndrome and hyperacusis. Background noise was associated with increases in escape-maintained problem behavior and increases in pain behavior such as clasping ears and crying. When the child was fitted with earplugs, there were substantial reductions in both problem and pain behavior under the background noise condition.

Child Behavior Disorders↗
PubMed1976

Practice effects for auditory localization: a test of a differentiation theory of perceptual learning and development.

Practice and transfer of practice in an auditory localization task were observed for three different information conditions (normal, transformed and reduced) to examine four aspects of Gibson's (1969) differentiation theory of perceptual learning and development. Support was found for the propositions that: (i) dimensions of difference, rather than prototypes, are learned; (ii) specificity is a more appropriate response measure than number of correct responses; (iii) perceptual learning will occur regardless of whether feedback is given or not; (iv) transfer of practice will be greater if dimensions of difference (as opposed to prototypes) are learned. It was also found that feedback during practice did not affect transfer. In an apparent contradiction though, specificity increased in the absence of dimension of difference. This increase was interpreted as being associated with the detection of non-task-related information and was seen as lending support to Gibson's hypothesis that, perceptual learning is motivated by intrinsic cognitive drive and is terminated by a reduction in subjective uncertainty.

Auditory Perception↗
PubMed1994

Using incentives to promote workers' participation in worksite research.

We designed this study to examine the effects of two types of incentives on the participation rate of workers from two plants in worksite research. There were 186 workers in the study, some of whom received chances for savings bonds. Given reductions in funding and concerns of management, no comparison could be made between the incentives; however, the study provided valuable information regarding planning for incentives in worksite research.

Adult↗
PubMed1996

Effects of earplugs on catecholamine and cortisol excretion in noise-exposed textile workers.

To investigate physiological and psychological effects of industrial noise, a survey was performed on 50 female workers exposed to machinery noise [93-100 dB(A)] (noise group) and 25 female workers in less-noisy environments [71-75 dB(A)] (control group) in a textile factory in Vietnam. Urine was collected for analysis of catecholamines and cortisol. The subjects were also asked to fill out a questionnaire. Each subject was examined over 2 working days. The workers in the noise group were asked to put earplugs in their ears during the working hours of the 2nd day. On the 1st day without earplugs, urinary excretion of catecholamines in the noise group were greater than those in the control group. Cortisol in urine showed a similar tendency. Differences in catecholamine excretion between the noise group and the control group decreased on the 2nd day when the earplugs were used for attenuation of noise level in the noise group. Frequency of subjective fatigue symptoms was lower on the 2nd day than that on the 1st day in noise group, while the control group showed almost no day-difference. The results indicate that the catecholamine response to noise in workers was reduced through the use of earplugs.

Adult↗
PubMed1979

Military audiological aspects in noise-induced hearing losses.

The sound pressure of a single shot ranges from about 165 up to 190 dB, depending on the type of weapon. In general, most shooting practice is carried out from a sheltered shooting gallery. Groupshooting and multiple reverberations from sheltered galleries maximize the acoustic strain. Clinically the acoustic trauma can be considered to be a combination of both acute and chronic noise injury, because very intense impulse noise, such as gunfire, can injure the inner ear both mechanically and by mean of disturbances in metabolism. When the ears are not protected, acoustic trauma develops in about 10% of military conscripts and 60% of regular army personnel.

Audiometry↗
PubMed1989

How could canal-pluggings result in intensive direction changing type of positional nystagmus?

The objectives of this study in Rhesus monkeys is to observe the sequences which appear in the oculo-spinal-motor system after selected semicircular canals had been plugged. The left anterior and the right posterior canals in a monkey "LARP", the left anterior and posterior canals in "LALP", and the left lateral canal in "LL" were plugged under intubation general anesthesia. Three-dimensional eye recordings were performed, using two scleral coils. Behavior, posture, and vestibulo-ocular reflex were studied. Compensation was established in the light within 2 days. In darkness, no spontaneous nystagmus was recorded in the sitting position. The monkey "LALP" developed marked positional nystagmus. When the head position was changed up to 360 degrees in 15 degrees steps, horizontal, vertical and torsional eye movements showed remarkable changes. Spontaneous direction changing nystagmus in darkness was also recorded in "LALP". To conclude, direction changing positional nystagmus, which was seen for several months after the canal plugging, was difficult to explain by the damage to the adjacent ampullary and/or otolithic endorgans, but may be explained by the limited otolithic compensation in the earth parallel plane for the defective dynamic canal inputs. These observations and conclusions were from experiments using three monkeys only and should still be confirmed in more extended experiments.

Animals↗
PubMed1993

Monitoring the effects of noise exposure using transiently evoked otoacoustic emissions.

One possible alternative to conventional pure-tone testing for screening and monitoring cochlear changes is the measurement of otoacoustic emissions. The aims of this study were to determine the feasibility of using transiently evoked otoacoustic emission (TEOAE) measurements as an objective field procedure and to compare the sensitivity of the measurements indirectly to pure-tone thresholds. The test groups were 117 male recruits and 30 male career cadets in compulsory military service in Switzerland. Transiently evoked otoacoustic emissions were measured before and at the end of a 17-week training period that included exposure to noise from firearms. Results revealed significant changes in response amplitudes in the frequency range from 2 to 4 kHz, whereas changes in the frequency range from 0.5 to 2 kHz were not significant for either group. The changes in relative amplitude did not exceed 15% when spectra containing the lower frequencies were considered. However, they were always greater than 83% within the higher-frequency range. All mean changes were in the direction expected from cochlear damage. Comparison of TEOAE results with pure-tone thresholds measured for a similar sample of subjects indicated that TEOAE testing may be more sensitive than pure-tone audiometry in detecting early cochlear damage from noise. The testing of TEOAEs is feasible as a screening procedure. It offers objective and repeatable information and is substantially less time consuming than pure-tone audiometry.

Adult↗
PubMedDate not supplied

Speech intelligibility and the use of hearing protectors.

On theoretical grounds, it is usually assumed that the use of hearing protectors in a noisy working environment has no influence upon speech intelligibility - in fact, may even increase it. In practice, however, people often do not wear hearing protectors, since these are widely believed to reduce speech intelligibility. In the present article, a description is given of an investigation, carried out among 537 subjects, into the influence of hearing protectors upon the speech intelligibility of people suffering from noise-induced hearing loss. From this analysis, it has become clear that the use of ear-muffs only leads to an improvement in speech intelligibility in persons who, according to their pure-tone audiogram, suffer from relatively small hearing losses. In general, it may be said that an increase in the severity of hearing losses will result in a reduced speech intelligibility.

Adolescent↗
PubMed1990

Speech recognition in a noisy and reverberant environment with and without earmuffs.

The effect of earmuffs on speech recognition in conditions comparable to an actual environment was studied with the use of sentences, words and nonwords. The speech level was adjusted to 60 and 85 dBA. White noise was used at signal-to-noise ratios (S/N) of 0, +5, and +10 dB. The reverberation times were 2.1 and 1.6 s. In quiet conditions at normal speech level (60 dBA), the perception was better without earmuffs than with them. At a high noise level, equal or better scores were achieved with ear protectors. At high speech and noise levels (85 dBA, S/N 0), the benefit of earmuffs was clearly demonstrated. Also with longer reverberation, the use of ear protectors increased the perception scores, especially at high speech and noise levels.

Acoustics↗
PubMed1978

Aspects on personal noise protection.

Two groups of noise-exposed workers were compared with respect to their use of ear protectors. One group had a severe, noise-induced hearing loss; the other group had normal hearing. Both groups were composed of workers of similar age and total duration noise-exposure. It was found that those with normal hearing had used ear protectors considerably more than those with severe hearing loss. Interestingly, quite a few workers had normal hearing in spite of working in noise for many years without ear protectors. Also, quite a few workers had a severe hearing loss in spite of frequent use of ear protectors. The reasons for not using ear protectors were analysed as also was the condition of the protectors and frequency with which they were replaced. Plastic ear plugs were preferred by 44%, vinyl foam ear plugs by 26%, fibreglass down by 18%, and ear muffs by 11% of the workers. In general, the condition of the ear protectors was good. Surprisingly, one-third of the workers did not use ear protectors, many of them because they had not realized that the environment they worked in had a noise intensity level above the injury risk level.

Auditory Threshold↗
PubMed1980

Custom-molded earplug performance: a retrospective study.

The purpose of this study was to determine the effectiveness of custom-molded earplugs in preventing hearing threshold shifts over a long period of time. A stepwise regression analysis was employed to accomodate job related variables including workplace noise level, demographic elements including age, and factors related to hearing including ear history. These variables would be expected to exert considerable influence on hearing threshold shifts. However, workplace noise level absorbed unexpected small amounts of variation in hearing threshold shifts for the textile worker subjects (N = 1517) even when noise level was entered as the only variable on the first step for each analysis. And, baseline hearing values absorbed unexpected large amounts even when entered on the last step. An argument based on these findings is presented suggesting that custom-fitted hearing protection was effective in preventing substantial changes in hearing threshold level during the period of this investigation.

Adolescent↗
PubMed1980

The difference in protection efficiency between earplugs and earmuffs. An investigation performed at a workplace.

The hearing thresholds of shipyard workers have been measured with a Békésy sweep audiometer. The number of employees at different workplaces is so large that it is possible to select groups of workers of specified ages who have been employed by the shipyard for many years. These workers have used either earplugs of earmuffs for 5--10 years and have also been working all the time in almost the same noise environment. Three ways of investigation have been used to observe differences in the hearing levels between 'plug-men' and 'muff-men'. All three show a greater hearing impairment for 'muff-men' than for 'plug-men'. Under certain conditions earplugs provide the most effective protection although the attenuation is higher for earmuffs than for earplugs.

Adult↗
PubMed1981

The effect of hearing protectors on the attention demand of warning sounds.

A reason often given by noise-exposed workers for not wearing their hearing protection is that it impairs their ability to hear important sounds such as acoustic warning signals. An experiment was therefore conducted to assess the possible effect of wearing hearing protection on the attention demand of a typical industrial warning sound. Inattention was created by providing uncertainty as to the time occurrence of the signal, and a separate loading task. The results indicate that neither inattention, nor the combination of inattention and the wearing of hearing protection, need necessarily impair the perception of a warning sound. The experiment therefore found no basis for the attitude that hearing protectors impair the effectiveness of warning sounds. This conclusion may not however apply to warning sounds which are not distinct from the ambient noise, those which have to be recognized amongst other discrete sounds, or to users of hearing protection with an existing noise-induced hearing loss.

Adult↗
PubMed1983

Noise-induced hearing loss in shipyard workers with unilateral conductive hearing loss.

In a study of 6500 workers in the shipbuilding industry, 8 subjects were found to have unilateral conductive hearing impairment established before the noise exposure period and without recurrent attacks of acute or chronic infection or clinical diagnosis of otosclerosis. All subjects demonstrated a more pronounced sensorineural hearing loss at 4.0 kHz in the ear with normal middle ear function. The results show the value of even a small permanent conductive hearing loss for protection against noise-induced hearing loss. The observations are discussed in relation to the role of individual variations in sound transmission, the value of the acoustic reflex in noise-induced hearing loss and the efficiency of continuous use of hearing protectors.

Auditory Threshold↗
PubMed1985

Signal detection in industrial noise: effects of noise exposure history, hearing loss, and the use of ear protection.

The detection of one-third octave signals superimposed on backgrounds of steady-state and intermittent industrial noise of 84 dBA was investigated for observers with normal hearing or moderate to severe noise-induced hearing loss (NIHL). Variables included age, noise exposure history, configuration of the audiogram and the wearing of insert hearing protectors. Detection thresholds were obtained binaurally over headphones using a two- interval forced-choice procedure. For unprotected listening all observers showed a masked threshold of about 80 dBA for a one-third octave band cented at 3.15 kHz. Neither variation in noise exposure history nor configuration of the audiogram were significant factors. Using insert protectors in noise, observers with normal hearing showed an advantage on average of 3 dB. Those with NIHL gave masked detection thresholds greater than 100 dBA. Detection of a one-third octave band centred at 1 kHz by hearing-impaired observers with mild to moderate loss at 1 kHz was similar to that for normal observers. A model of the detection process was developed and evaluated.

Adolescent↗
PubMed1986

Development of hearing loss during long-term exposure to occupational noise. A 20-year follow-up study.

Occupational noise-induced hearing loss is still responsible for the majority of occupational ailments and injuries, with very large sums being paid in compensation. Repeated hearing tests over a 20-year period have been performed on 319 employees of a timber processing firm, working in sawmills and paper pulp production, exposed to mean noise levels of around 95-100 dB (A) and in a chemicals division with mean noise exposure levels of 80-90 dB (A). During the observation period, mean hearing levels deteriorated slowly, especially at 4 kHz, but no dramatic changes from one year to another were seen. We therefore propose 3-year intervals between regular hearing tests in this type of industry where noise exposure is predominantly of the continuous type, thus releasing resources for more active measures against noise-induced hearing loss. Cases of manifest hearing loss or otherwise at risk must of course be followed up at shorter intervals. A remarkably large proportion of the employees in the chemicals division suffered a hearing loss corresponding to 10% disablement according to Swedish criteria, which raises the question of a possible relation between exposure to industrial solvents and hearing loss.

Adolescent↗