Showing papers in "Noise & Health in 1999"

Personal and social variables as co-determinants of noise annoyance.

Abstract: This paper starts with the fact that noise annoyance is partly due to acoustic factors, partly due to so-called moderating variables, i.e. personal and social aspects of the residents. Noise annoyance is considered to be the (long-term) negative evaluation of living conditions with respect to noise. This evaluation is not simply dependent on past disturbances, but on attitudes and expectations, too. The personal factors influencing the evaluation and described here are: Sensitivity to noise, fear of harm connected with the source, personal evaluation of the source, and coping capacity with respect to noise. The social factors described here are: General (social) evaluation of the source, trust or misfeasance with source authorities, history of noise exposure, and expectations of residents. For most of these variables, data from different community studies are used in order to illustrate the respective moderating effect on annoyance. In addition, some of the moderators are presented as possible tools in order to reduce noise annoyance. It is expected that a significant decrease in a negatively moderating variable is as effective in reducing noise annoyance, as is a significant decrease in noise level.

Noise sensitivity as a factor influencing human reaction to noise

Abstract: Reaction (annoyance, dissatisfaction) to noise is itself an important health effect, as well as possibly contributing to other putative health effects of noise. Thus, factors such as noise sensitivity, which influence reaction, are of considerable importance. However, noise sensitivity is rarely clearly defined. This paper offers a formal definition of noise sensitivity, and reviews evidence relating to it. Noise sensitivity has been measured in various ways, but may be measured most directly by assessing reaction to many noise situations (other than those involving the noise source(s) which are the focus of the particular study). When noise sensitivity is measured in this way, factor analysis consistently reveals that noise sensitivity is not a unitary concept. Rather, two distinct factors appear: one related to loud noises (road traffic, lawn mower), and the other related to quieter noise situations which are nonetheless distracting (rustling papers at the movies, people talking while watching television). More research is needed to address the relationships between these factors, reaction and other health effects.

A theoretical framework for environmental noise annoyance.

Abstract: Noise annoyance is a phenomenon of 'mind and mood'. It is only partly determined by acoustic factors: typical noise metrics (LAeq and the like) allow only the prediction of aggregated annoyance scores (community levels) with moderate degree of precision. Many non-acoustic factors have been identified with varying degrees of association with annoyance. However, the proper identification and understanding of the role of non-acoustical factors can only be achieved on the basis of sound theories about rise and reduction of noise annoyance. This article discusses first the few systematic theories to understand the relative role of acoustic and non-acoustic factors. Then, it presents a theoretical perspective that places a major non-acoustic factor in the center: perceived control. It views noise annoyance as a form of psychological stress: disturbances may tax persons resources, and different people may use different ways of coping to deal with annoyance. The focus on perceived control also highlights that for residents exposed to environmental noise 'noise management at the source' often will be an equally important external stimulus to respond to as 'noise at the source'.

Noise and Stress - Salivary Cortisol as a Non-Invasive Measure of Allostatic Load.

Abstract: The psychobiology of stress has received increasing attention throughout the past two decades. Physiological pathways and subjective response patterns are described in more details aiming at a better understanding of the pathways leading to health or disease under prolonged periods of stress. Technical advances in the laboratory have significantly contributed to this development. One of these methodological advances is the measurement of cortisol in saliva which has promoted psychobiological stress research both in the laboratory and in the field. The present paper provides a brief methodological background and the use of salivary cortisol assessment as an indicator of stress in human studies from this research centre. It is suggested that research on health consequences of noise exposure should include salivary cortisol as a sensitive measure of allostatic load.

Coping with stress: neuroendocrine reactions and implications for health

Abstract: A new stress model, the Allostatic Load Model, refers to the ability to achieve stability through change. The various biological functions activated during stress serve an important role in the organism's adaptation to the environment by protecting and restoring the body but may, under certain conditions, also have health damaging consequences. Two different psychoneuroendocrine stress systems are of particular interest: (1) the sympathetic adrenal medullary (SAM) and (2) the hypothalamic pituitary adrenocortical (HPA) systems. Sustained activation of the SAM system with overexposure to epinephrine (adrenaline) and norepinephrine (noradrenaline) is considered to contribute to the development of cardiovascular disease (CVD). Chronic stress exposure influencing the HPA-axis is associated with metabolic changes which also increase the risk of CVD but, in addition, also contribute to impaired immune function, diabetes, depressive symptoms and cognitive disturbances. The present paper is focused on the possible biological pathways between environmental stress and somatic illness, including the role of environmental stress for the development of musculoskeletal disorders. It is concluded that the SAM and the HPA systems play an important role in linking environmental stress to various negative health outcomes and that knowledge about these psychobiological pathways is of considerable importance for the possibilities to prevent and treat environmentally induced ill health.

Noise-Induced Endocrine Effects and Cardiovascular Risk.

Abstract: Noise has the potential to cause stress reactions. Chronic noise-induced stress accelerates the ageing of the myocardium and thus increase the risk of myocardial infarction. The involved pathomechanisms include acute increase of catecholamines or cortisol under acute noise exposure and an interaction between endocrine reactions and intracellular Ca/Mg shifts. Chronic noise exposure of animals on a diet with suboptimal magnesium content led to increase of connective tissue and calcium, and decrease of magnesium in the myocardium. These changes were correlated to noradrenaline and normal ageing. Post mortem studies of hearts from victims of ischemic heart diseases confirmed the importance of Ca/Mg shifts in humans. Recent epidemiological studies support the importance of noise as a risk factor in circulatory and heart diseases, especially in myocardial infarction.

Sound-Induced Cochlear Ischemia/Hypoxia as a Mechanism of Hearing Loss.

Abstract: This review will briefly examine evidence supporting the hypothesis that sound causes changes in cochlear blood flow, intracochlear oxygen levels, and the morphology of cochlear blood vessels. A survey of the literature shows that traditional histopathological studies provided such evidence and that decreased cochlear blood flow can be demonstrated and measured by laser Doppler flowmetry and by direct observation of cochlear microvessels. Oxygen levels also decline and possibly to a greater degree than blood flow. There is also evidence that in certain circumstances sound can increase blood flow. Reduced blood flow, or reduced oxygenation, is critically important in an organ system with high energy needs like the cochlea. Therefore, a second hypothesis, that sound-induced reduction in CBF represents a functional ischemia, will be explored in examining the relevance of traditional ischemia/reperfusion models to cochlear damage. It is found that reactive oxygen species (free radicals and oxidizing ions) are present in sound-induced hearing loss and thus there is evidence that an ischemia/reperfusion type of injury occurs during loud sound exposures.

Absence of otoacoustic emissions in subjects with normal audiometric thresholds implies exposure to noise.

Abstract: Otoacoustic emissions and contra-lateral sound activated efferent suppression of emissions were examined to determine whether they provide any early indication of auditory damage from exposure to noise. Three groups were studied: noise exposed workers (n=50, mean age 42 years), patients with Meniere's disease (n=24, mean age 48 years) and normal subjects (n=24, mean age 41 years). All subjects underwent routine pure tone audiometry, tympanometry and otoacoustic emission testing. As a number of studies have shown that with hearing threshold better than 30 dB HL, emissions are almost always present and are generally absent with hearing loss greater than 30 dB HL, subjects in this study were sub grouped into these two categories in order to examine the incidence of emissions. Absence of emissions in subjects with mean hearing thresholds better than 30 dB HL varied from 0% in normal controls, 8% in patients with Meniere's disease and a significantly high 56% in noise exposed workers despite similar mean hearing thresholds for all groups. The mean transient emission levels for the noise exposed workers was significantly lower than the controls and Meniere's groups. This study clearly indicates that in the noise-exposed group there is sub clinical and sub audiometric damage to the outer hair cells responsible for generation of otoacoustic emissions. Of those with normal otoacoustic emissions, the efferent suppression was absent in 60% of noise exposed workers but in only 3.8% of control subjects implying that the efferent control may also be affected in a significant proportion despite normal hearing thresholds and emissions.

Hearing ability in Danish symphony orchestra musicians.

Abstract: The audiograms of fifty-seven musicians from four Danish symphony orchestras were determined in connection with an interview about their working experience. Measurements of sound levels and noise dose were performed during rehearsal and during concerts in the four orchestras with the measurement equipment placed in various instrument groups. The average audiogram showed a decrease at higher frequencies similar to an age-related hearing loss. Each audiogram was corrected for the age of the person by means of the median from ISO 7029 and the average audiogram from these age-corrected individual audiograms showed no signs of hearing loss. The audiograms were also compared to the expected audiograms from ISO 1999, which takes account of the number of years at work, the number of playing hours per week, and the average sound level in the orchestra for the instrument group. In almost all cases the measured audiograms looked better than the predictions from ISO 1999. It may be concluded from this investigation that musicians cannot be expected to get pronounced audiometric hearing losses from playing in a symphony orchestra. It should be noted, though, that the data material is limited, and that the subjects have not been selected in a systematically or representative way.

Exposure to Nocturnal Road Traffic Noise: Sleep Disturbance and its After Effects.

Abstract: In this paper the disturbances to sleep caused by road traffic noise are reviewed in the light of the latest published findings. First, a short presentation is made of what noise is in general. Then an exposition is made of the different characteristics of road traffic noise and how it may be measured and rated with various descriptors. In general terms, the continuous exposure of people to road traffic noise leads to suffering various kinds of discomfort, thereby reducing the number of well-being elements. However, this conclusion is made more complex to attain when non-acoustical factors such as socio-economic situation, age and gender are taken into account. In broad terms, nocturnal road traffic activity leads to difficulties in falling asleep for people and to a reduction of their sleep quality. This, however, depends strongly on physical measures of noise like for instance the intermittency of loud single noise events, their level relative to that of the background noise and the frequency and time of their occurrence. Several studies have also confirmed the fact that mood, too, is strongly affected after spending a night with significant noise exposure. Other psychological and physiological functions affected by night-time exposure to road traffic noise, such as performance the following day and cardiovascular reactivity are also reviewed.

Industrial Noise Exposure and Risk Factors for Cardiovascular Disease: Findings from the CORDIS Study.

Abstract: Previous studies of the association between occupational noise exposure and cardiovascular disease (CVD) or risk factors for CVD are primarily either cross-sectional or retrospective, whereas the design of the CORDIS study was both cross-sectional and longitudinal It had three phases: Phase I was conducted during 1985-87 among 6,016 employees from 21 factories Recorded were medical, ergonomic, environmental (including noise levels at the various work stations) and psychological data Phase II was conducted during 1988-90, at 18 of the 21 original factories and included similar data collected from 3,509 subjects Phase III was conducted during the years 1995-96 and 4,995 workers who participated in Phases I and II completed questionnaires pertaining to medical, occupational and life style variables Mortality and cancer morbidity data were obtained over an 8 year follow-up period for all subjects Results from Phase I, revealed no association between noise exposure and resting blood pressure Positive association was found for serum lipids in women and in young men Noise annoyance had an additive effect on this outcome In addition, recurrent daily noise exposure was found to be associated with elevated acute resting heart rate Results of Phase II showed that chronic exposure to high noise levels during the 2-4 years of the follow-up resulted in changes of 39 mmHg in SBP and 33 mmHg in DBP, among workers performing complex jobs In workers performing simple jobs these changes were 03 and 04 mmHg Thus the type of work performed appears to be a significant factor Results of Phase III revealed that there was a trend for positive association between past noise exposure measured at Phase I and 8 years incidence of cardiovascular morbidity, mortality and total mortality This trend was statistically significant for total mortality (hazard ratio = 197, 95% CI 128-454) even after controlling for possible confounders In summary, tests for association between noise exposure and cardiovascular risk factors, or cardiovascular morbidity and mortality, and total mortality have yielded mixed results Reasons for this are discussed, as well as suggestions for further research

Effect of noise on the vestibular system - Vestibular evoked potential studies in rats.

Abstract: Studies have shown that in order for sound to affect the vestibular end organs in the inner ear, very high intensities are required. Furthermore, in patients with noise induced hearing loss, vestibular signs, if present, are subclinical. In order to study possible auditory-vestibular interactions in a more controlled fashion, using physiological sound intensities, the present study used short latency vestibular evoked potentials (VsEPs) to impulses of angular (15,000°/sec 2 , risetime 1.5 msec) and linear (3-5 g, rise time 1.5 msec) acceleration were used to study the possible effects of sound on peripheral vestibular function in rats. Four different paradigms were used: a - an intense (135 dB pe SPL) click stimulus was presented 5 msec before the linear acceleration impulse and the VsEP to 128 stimuli were recorded with and without this click stimulus. There was no effect of the preceding intense click on the first wave (reflecting end organ activity) of the linear VsEP. b - 113 dB SPL white noise "masking" was presented while the VsEPs were elicited. A 10-20% reduction in the amplitude of the first VsEP wave was seen during the noise exposure, but 5 minutes after this exposure, there was almost complete recovery to pre-exposure amplitude. c - 113 dB SPL noise was presented for one hour and VsEPs were recorded within 15 minutes of cessation of the noise. The auditory nerve-brainstem-evoked response showed a temporary threshold shift while there was no effect on the VsEP. d - 113 dB SPL white noise was presented for 12 hours per day for 21 consecutive days. Auditory nerve-brainstem-evoked responses and vestibular (VsEPs) function were studied one week after the conclusion of the noise exposure. Auditory function was severely permanently depressed (40 dB threshold elevation and clear histological damage) while the amplitude of wave 1 of the VsEP was not affected. It seems therefore that even though intense noise clearly affects the cochlea and may have a "masking" effect on the vestibular end organs, the intensities used in this study (113 dB SPL) are not able to produce a long-term noise induced vestibular disorder in the initially normal ear. These differences between the response of the cochlear and vestibular end organs to noise may be due to dissimilarities in their acoustic impedances and/or their electrical resting potential.

Hearing protection in the military environment

Abstract: The present state of passive (linear and non-linear) and active techniques for hearing protection in the military environment is reviewed. Solutions which allow to protect the ear from large continuous and high-level impulse noises while preserving the operational abilities of the personnel (detection, localization, communication...) are emphasised.

Comparing changes in transient-evoked otoacoustic emission and pure-tone audiometry following short exposure to industrial noise.

Abstract: It has been suggested that otoacoustic emissions, particularly transient-evoked otoacoustic emissions (TEOAE), might be more sensitive in assessment of changes to the cochlea caused by noise than pure-tone audiometry (PTA). The aim of the study was to compare temporary threshold shifts with the changes in TEOAE following a six-hour exposure to industrial noise at the intensity of 85-97 dB (A). Thirty two male employees of a metal factory were screened. TEOAE, PTA and tympanometry were included in the hearing test battery. Both, PTA and TEOAE showed significant reduction due to noise exposure, but no correlation between temporary threshold shifts and decreases in either the overall TOAE level or the level of otoacoustic emission in the frequency bands was found. Our results confirm the high sensitivity of TEOAE to short exposure to industrial noise. This study may recommend this measurement as a method of evaluation for TTS conditions for hearing conservation programme purposes, in addition to pure-tone audiometry.

Is there a gender difference in coping, perceived disability and handicap in patients with noise-induced hearing loss?

Abstract: Gender differences in coping strategies and self-rated disability and handicap were explored in individuals with noise-induced hearing loss. The study group consisted of 60 male and 33 female patients, consecutively presenting at the hearing clinics in two hospitals in the western part of Sweden. The females were older and had worse average hearing thresholds over the low frequencies (0.5, 1 and 2 kHz) in the better ear than the males. However, all subjects rated their hearing loss as "moderate" to "severe". The patients responded to the Communication Strategies Scale, CSS, measuring "maladaptive behaviour", "verbal strategies" and "non-verbal strategies" and the Hearing Disability and Handicaps Scale, HDHS, which is composed of four factorially derived subscales: "speech perception", "non-speech sounds", "interpersonal distress" and "threat to the self-image". Pure-tone audiometry and sociodemographic data was also assessed. Despite differences in pure-tone audiometry, there were no significant differences between gender in perceived disability or handicap. Significant gender differences in coping were found. The women used "maladaptive behaviour" and "verbal strategies" significantly more often than the men. This is in agreement with results of an interview-study of women with NIHL, showing that the perceived emotional temperature in a specific situation guided the choice of coping strategy. The gender difference in coping could also be related to, and explained by, the conversational goal (transactional or interactional).

Non-acoustical factors in noise management at Heathrow Airport.

Abstract: Non-acoustic factors in environmental noise can be broadly defined as all those factors other than noise level alone which contribute to noise annoyance and similar effects. Noise levels such as LAeq provide a good indication of the amount of physical noise present, and changes in physical noise level can be expected to correlate with changes in resident's perception, at least to some degree. On the other hand, a flexible approach to noise management based on wide consultation and communication can be extremely important. At Heathrow Airport over the last 20 to 30 years, overall aircraft noise levels have reduced because of the phasing out of the older noisier Chapter 2 aircraft types, but there are also other strategies in place which are clearly regarded as being effective both by airport management and by local community representatives and which are not as easily quantified in terms of noise level alone. This paper describes the background to noise management at Heathrow in some detail and draws a general conclusion that taking non-acoustic factors into account in addition to physical noise levels alone has been of considerable benefit over the years.

Evidence of a Common Pathway in Noise-Induced Hearing Loss and Carboplatin Ototoxicity.

Abstract: In spite of the differences in the nature of the insult, the hearing loss from ototoxic drugs and noise exposure share a number of similarities in cochlear pathology This paper explores the common factors between noise-induced hearing loss and ototoxicity by experimentally manipulating cochlear glutathione (GSH) In the first experiment, chinchillas were treated with a drop of saline (50 µl) on the round window of one ear and a drop of buthionine sulfoximine (BSO, 50 µl of 200 mM) on the other ear BSO is a drug that blocks GSH synthesis and it was hypothesized that GSH-depressed ears would be more vulnerable to noise Six hours after treatment, the animals were exposed to a 105 dB 4 kHz octave band noise for 4 hours, then a second dose of BSO was applied 2 hours later The BSO treated ears showed more temporary threshold shifts and reduced GSH staining at day 4 post exposure, but there was no BSO effect in terms of greater permanent threshold shift (PTS) or hair cell loss In the second experiment, chinchillas were pretreated with BSO and 3 days later were given either a single dose of carboplatin (25 mg/kg ip), a double dose (day 3 and 7) or only BSO Chinchillas that received BSO and the double dose of carboplatin had significantly greater loss of inner and outer hair cells than the carboplatin chinchillas In addition, the BSO and carboplatin chinchillas also had larger decreases in evoked response amplitudes suggesting that GSH depletion potentiated the ototoxicity of carboplatin These results are discussed in terms of the role of reactive oxygen species in creating hearing loss and the potential protective role of glutathione

Assessment of the effectiveness of aircraft noise regulation.

Abstract: A fundamental goal of aircraft noise regulation is control of the prevalence of noise-induced annoyance in airport communities. A common regulatory strategy is to identify values of long-term, time-weighted average aircraft noise exposure that may not be exceeded in the vicinity of airports without certain consequences. Noise exposure per se is neither the sole cause nor a perfect predictor of the annoyance of aircraft noise, however. Regulatory limitation of noise levels to certain values of favored noise metrics may therefore provide the appearance, rather than the substance, of a solution to problems of community reaction to aircraft noise. Response bias, as identified by Green and Fidell (1991), is a factor that exerts about as much influence on the observed prevalence of annoyance in communities as cumulative noise exposure. The importance of formal consideration of response bias in assessments of the adequacy of regulatory enforcement levels is addressed.

Long term effects of military jet aircraft noise exposure during childhood on hearing threshold levels.

Abstract: Some research suggests that young children may be relatively more susceptible to noise­ induced hearing loss (NIHL) than adults, and that the unique noise footprint associated with military jet aircraft is particularly damaging to hearing. This pilot study looked for evidence of NIHL in adults who have been exposed to military jet noise in early childhood, while living in Married Quarters on active RAF fast jet stations. Many Married Quarters lie within 70 dB(A) Leq contours, fewer in 83 dB(A) Leq contours. A cross-sectional pilot study was under­taken to examine the hypothesis that military jet noise exposure early in life is associated with raised hearing thresholds.