Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “NOISE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources
PubMedDate not supplied

A comprehensive investigation of noise exposure in and around an integrated iron and steel works.

A comprehensive environmental noise exposure study was carried out in and around a major iron and steel works. The works was located in the central part of the city and was surrounded by residential, commercial, and sensitive receptors. Traffic activity near the plant was significant and added to the background noise level. Considering the variety of noise sources in the plant area and in the neighborhood, a practical approach to measure noise equivalent level in the plant and in the residential, commercial, industrial, and silence zone was adopted. A modular precision integrating sound level meter with statistical analyzer module, octave filter set, and calibrator were used during the measurements. The day and night level, Ldn, was determined. Worker exposure was assessed by determining the speech interference level (SIL), loudness level, and noise rating level at one of the major sources located in the power plant of the steel works. The results indicate that SIL was 94 dBA, loudness level was 112 phons, and the noise rating was in the range of 85-95. A traffic noise index also was determined near the works gates and was in the range of 68-96. The impact on the community is significant as observed from Ldn levels. Some mitigation measures for noise control are also discussed.

Environmental Monitoring↗
PubMedDate not supplied

Construction noise: exposure, effects, and the potential for remediation; a review and analysis.

More than one-half million construction workers are exposed to potentially hazardous levels of noise, yet federal and state Occupational Safety and Health Administration (OSHA) programs provide little incentive to protect them against noise-induced hearing loss. Construction noise regulations lack the specificity of general industry noise regulations. In addition, problems that characterize the construction industry, such as worker mobility and the large proportion of small businesses, make implementing hearing conservation measures more difficult. The apparent severity of exposure depends greatly on the measurement method, with the 3-dB exchange rate almost always showing higher average exposure levels than the 5-dB (OSHA) rule. Construction workers demonstrate hearing threshold levels that generally conform to those expected in manufacturing. The prevalence of hearing protection device (HPD) use among U.S. construction workers is very poor, partly because of perceived difficulties in hearing and understanding speech communication and warning signals. In addition, masking by noise of necessary communication and warning signals is of particular concern in construction, where recent research demonstrated the association between fatalities and the failure to hear reverse alarms. Judicial use of HPDs is of the utmost importance, along with avoiding overattenuation, selecting HPDs with uniform attenuation, and using noise-attenuating communication systems when possible. A successful hearing conservation program in British Columbia can serve as a model for the United States, with a long-standing positive safety culture, a high percentage of HPD use, improvement in average hearing threshold levels over the last decade, and a centralized record-keeping procedure, which helps solve the problem of worker mobility. However, controlling construction noise at the source is the most reliable way to protect worker hearing. U.S. manufacturers and contractors should benefit from the activities of the European Community, where noise control and product labeling in construction has been carried out for more than 20 years.

Ear Protective Devices↗
PubMed1990

The likelihood of detecting a significant hearing threshold shift among noise-exposed workers subjected to annual audiometric testing.

The ability of annual audiometric surveillance to detect significant deteriorations in hearing sensitivity is examined considering the time pattern of the growth of noise-induced hearing loss. The yearly rate of change in hearing level due to the effects of noise exposure and age is computed from a mathematical model put forward in the International Standard ISO 1999 (1989). The first-order derivative of hearing level associated with noise and age was compared with different criteria of significant threshold shift (STS). The results show that the potential annual variation in hearing level at 4 kHz, the audiometric frequency most affected by noise, is always less than the minimum margin of error of audiometry under exposure to 90 dBA-8 h. At 100 dBA it nearly equals the margin of error only for the very first year of exposure and for the most sensitive individuals. The rate of change in hearing threshold at 4 kHz is less than or equal to 1 dB per year for a major portion of a population exposed to an average noise level of 90 dBA-8 h (+/- 5 dB SD). For other audiometric frequencies, or for combinations of frequencies, this rate is even lower. It is also demonstrated that, using annual hearing tests, the likelihood of measuring an STS in a noise-exposed population is very small. It would be nearly equal to the likelihood of some workers being exposed to 100 dBA-8 h or more for a first year. Such results throw doubt on the validity of audiometric surveillance as a procedure for early detection of noise-induced hearing loss. They also imply that the detection by audiometric tests of true cases of significant threshold shift due to noise is excessively expensive.

Adult↗
PubMed1994

Management and motivational factors in the control of noise induced hearing loss (NIHL).

This paper describes a study investigating attitudes to noise as an occupational hazard. The objectives of the study were to understand the individual and organizational factors which affect attitudes towards noise induced hearing loss (NIHL) and to relate these to the standards of hearing conservation achieved in industry as demonstrated by compliance with the Noise at Work Regulations. The study comprised a survey of 48 organizations across Britain, and a more detailed examination of 10 of these as case studies. Methods used included desk research, audits of hearing conservation programmes, questionnaires and interviews. Whilst there is widespread acceptance that industrial noise is a hazard, it is one that is frequently taken for granted, and measures to deal with it are often inadequate. Most organizations place the onus on the workforce to protect their own hearing through the use of personal hearing protectors. Workers reactions to noise tended however to be passive and much of the time neither managers nor the workforce are concious of the noise hazard. This is the case even where some managers are committed to good industrial housekeeping and accident prevention. As effective hearing conservation programme requires three management attributes: leadership from senior management, the ability of middle management (particularly in production and engineering) to put hearing conservation measures into practice, and specialist technical knowledge of noise and of the legislation. The study points to the need for more education and motivation of senior managers as the priority in improving standards of hearing conservation and noise control.

Attitude to Health↗
PubMed2004

Retrospective noise estimates for British nuclear workers using an alternative approach.

Exposure estimates were required to support an epidemiological study of occupational noise and cardiovascular disease. The study cohort consisted of male industrial workers employed at two nuclear facilities in England between 1945 and 1999 (n=2412). Historical noise exposure data were available from 6850 sound pressure measurements collected since 1965. Additional information was obtained from interviews with retired and long-term company personnel. Partly due to the lack of information provided by job title, coupled with the fact that noise behaves differently compared with chemical agents, an unusual approach was used to estimate noise exposure. Rather than grouping homogeneous exposure groups by job title or task, the assessors first used historical sampling data to estimate average area noise levels in each workplace where a survey had been performed. Noise contours were then estimated in the work area and, finally, individual estimates of exposure were further refined based on job title. Estimates were extrapolated to areas where noise surveys were not performed and adjustments were made for potential bias. Overall, noise exposure estimates ranged from 60 to 97 dBA, with a median of 86 dBA. For use in subsequent exposure-response analysis, cohort work histories were used to calculate exposure indices of cumulative, average intensity and exposure duration above 85 dBA. Validation exercises are discussed.

Cardiovascular Diseases↗
PubMed2001

A follow-up study of effects of chronic aircraft noise exposure on child stress responses and cognition.

BACKGROUND: Children are a high-risk group vulnerable to the effects of chronic aircraft noise exposure. This study examines the effects of aircraft noise exposure on children's health and cognition around London Heathrow airport and tests sustained attention as an underlying mechanism of effects of noise on reading and examines the way children adapt to continued exposure to aircraft noise. METHODS: In this repeated measures epidemiological field study, the cognitive performance and health of 275 children aged 8-11 years attending four schools in high aircraft noise areas (16-h outdoor Leq > 66 dBA) was compared with children attending four matched control schools exposed to lower levels of aircraft noise (16-h outdoor Leq < 57 dBA). The children first examined at baseline were examined again after a period of one year at follow-up. Health questionnaires and cognitive tests were group administered to the children in the schools. RESULTS AND CONCLUSIONS: At follow-up chronic aircraft noise exposure was associated with higher levels of annoyance and perceived stress, poorer reading comprehension and sustained attention, measured by standardized scales after adjustment for age, social deprivation and main language spoken. These results do not support the sustained attention hypothesis previously used to account for the effects of noise on cognition in children. The reading and annoyance effects do not habituate over a one-year period and do not provide strong evidence of adaptation.

Adaptation, Psychological↗
PubMed1996

Prospective study of noise exposure during pregnancy on birth weight.

To examine the effect of noise exposure during pregnancy on infant birth weight, a well-characterized cohort of 200 pregnant women in the first trimester participating in prenatal care clinics was followed throughout gestation (in Taiwan, 1991). Individual 24-hour noise exposure of all women was prospectively measured, and information regarding possible noise exposure from traffic and occupation was also obtained. Noise exposure during pregnancy was correlated with the birth weights of the women's babies. No association between personal noise exposure measured in decibels (less than 85 dBALeq during pregnancy) and birth weight was found. Possible occupational noise exposure (indicated by working in a manual job), traffic noise exposure (indicated by distance between the home and main streets), and a history of listening to amplified music and using personal listening devices during pregnancy also showed no effect on infant birth weight. Maternal weight, maternal weight gained during pregnancy, gestational age, and infant's sex were the four factors that correlated significantly with birth weight. The noise exposure experienced by women during pregnancy may not be great enough to affect their infants' birth weight.

Adolescent↗
PubMed1996

Noise in the signal-averaged electrocardiogram and accuracy for identification of patients with sustained monomorphic ventricular tachycardia after myocardial infarction.

Late potentials are detected at various noise levels in clinical studies. The aim of this study was, in a case-control design, to assess the effect of residual noise level on the identification of patients with sustained monomorphic ventricular tachycardia after myocardial infarction. Electrocardiograms from 16 patients with prior myocardial infarction and documented sustained monomorphic ventricular tachycardia and 41 patients with prior myocardial infarction and without ventricular tachycardia, were analysed by two signal averaging procedures to noise level 0.2 and 0.4 muV. Standard time domain parameters were measured. Two definitions of late potential were analysed: (1) if any two of the following criteria were present (signal-averaged QRS duration > 120 ms, late potential duration > 40 ms, and root-mean-square voltage of the terminal 40 ms of the filtered QRS < 25 muV); or (2) if the signal-averaged QRS duration > or = 120 ms. Overall the signal-averaged electrocardiogram performed better at noise level 0.4 muV compared to noise level 0.2 muV with respect to identification of patients with or without ventricular tachycardia after myocardial infarction. Reducing noise level from 0.4 to 0.2 muV increased the sensitivity, but the consequence was a substantial decrease in specificity. Our data indicate that when a high sensitivity is the goal, the definition based only on signal-averaged QRS duration > or = 120 ms should be applied; sensitivity was 88% and specificity 59% at noise level 0.4 muV. If a high specificity is the goal, the definition should be based on the definition with two abnormal parameters; sensitivity was 69% and specificity 68% at noise level 0.4 muV.

Adult↗
PubMed1989

Effect of broadband noise on the human brain stem auditory evoked response.

The purpose of this paper is to describe the effect of broadband continuous noise on brain stem auditory evoked responses elicited from normal-hearing and hearing-impaired individuals. The motivation for this study derives from the increasing use of noise masking paradigms in diagnostic electrophysiology, the universal presence of background noise in everyday listening environments, and the frequent observation that background noise is more detrimental to the performance of the hearing-impaired individual than to the normal-hearing individual. Four studies were designed to evaluate: (1) the sensitivity and specificity of the latency-intensity series, (2) the sensitivity and specificity of the latency-noise series, (3) the dependence of the latency-noise series on signal-to-noise ratio near electrophysiologic threshold, and (4) the dependence of the latency-noise index on the signal level at which the test is performed. The results of the studies reported herein show that the electrophysiological response to increasing masker levels is more sensitive for identifying inner ear pathology than previously used latency-intensity series measures, without compromising specificity. It is suggested that simultaneous broadband masking should be considered as a test for localization of pathology in those subjects for whom routine behavioral measurements are not possible or when the results of such measurements are equivocal.

Adolescent↗
PubMed1996

Word recognition in continuous and interrupted broadband noise by young normal-hearing, older normal-hearing, and presbyacusic listeners.

OBJECTIVE: Word recognition performance in continuous and interrupted broadband noise was examined in young normal-hearing (YNH), older normal-hearing (ONH), and presbyacusic (older hearing-impaired [OHI]) listeners. DESIGN: Participants (N = 36) were presented with identical Northwestern University Auditory Test No. 6 stimuli at 30 dB sensation level re their respective speech reception thresholds. The speech stimuli were presented in quiet and in both competing noise conditions with signal to noise ratios (S/Ns) of 10, 5, 0, -5, -10, -15, and -20 dB. RESULTS: In general performance was superior in quiet, improved with increasing S/N, and was greater in the interrupted broadband noise than in the continuous broadband noise. Significant main effects of group and S/N were found in both competing noises (p < 0.0001). Post hoc pairwise comparisons revealed all groups performed differently, with superior performance being displayed by the YNH group followed by the ONH and OHI groups, respectively (p < 0.05). A significant group by S/N interaction was observed in only the interrupted noise condition (p = 0.019). The degree of change in word recognition performance as a function of S/N was greatest in the OHI group followed by the ONH group and the YNH group. CONCLUSIONS: Group effects observed in the interrupted noise would imply that the two older groups of listeners had an auditory temporal deficit relative to the YNH listeners. The paradigm reveals the patency of the temporal processes that are responsible for the perceptual advantage (i.e., a release from masking) a listener has in interrupted competing stimulus.

Adult↗
PubMedDate not supplied

Cortical activation response to acoustic echo planar scanner noise.

PURPOSE: Our goal was to determine the distribution of auditory and language cortex activation in response to acoustic echo planar scanner noise with functional MRI (fMRI). METHOD: Acoustic scanner noise and spoken text, reproduced on high output cassette tape, were separately delivered at equivalent intensities to six normal hearing adult volunteers through earphones during fMRI data acquisition. In nine other subjects, taped scanner noise was delivered in five successive iterations of the task to assess the consistency of cortical activation to the noise stimulus. Gyri of the auditory and language system were divided into 10 different subregions for analysis of cortical activation. The number of activated pixels and proportion of volunteers activating each cortical subregion were determined using a cross-correlation analysis. RESULTS: Cortical activation to taped acoustic scanner noise was present within the transverse temporal gyrus (primary auditory cortex) in all subjects, but activation was highly variable between subjects in auditory association and language relevant cortex. Auditory association cortex activation was seen in the planum polari, planum temporali, and middle temporal gyrus/superior temporal sulcus regions in one-half to two-thirds of the volunteers. There was no significant difference in the distribution of cortical activation within individual subjects across five successive iterations of the scanner noise task. Listening to spoken text consistently activated primary and association auditory cortex bilaterally as well as language relevant cortex in some cases. The mean number of activated pixels was significantly greater for text listening than acoustic scanner noise in auditory association and language relevant cortical subregions (p < 0.01), although the distribution of activity was similar between the two tasks. CONCLUSION: This preliminary investigation suggests that the complex sounds produced by the echo planar pulse sequence can activate relatively large regions of auditory and language cortex bilaterally, with the extent of activation outside the primary auditory cortex being variable between subjects. However, the distribution of activation within individual subjects was relatively constant across several iterations of the scanner noise stimulus.

Adult↗
PubMed1997

Calcium channel blockade reduces noise-induced vascular permeability in cochlear stria vascularis.

Exposure to noise results in multiple perturbations of cochlear microcirculation, including increases in vascular permeability. There is evidence that these events are mediated, in part, by calcium channels. The current study examined the effects of calcium channel blockade on the diameter and permeability of cochlear vessels during noise exposure. Subjects were exposed to either noise alone or noise after verapamil pretreatment. Vessels of the cochlear stria vascularis were imaged using intravital microscopy. Animals exposed to noise showed decreases in diameter and increased permeability above baseline levels. Animals pretreated with the calcium channel blocker verapamil and exposed to noise demonstrated increases in vessel diameter and no changes in permeability. These data indicate that calcium channel blockade reduces noise-induced microvascular permeability. Treatment strategies designed to protect from increases in vascular permeability due to noise exposure may reduce temporary threshold shifts.

Analysis of Variance↗
PubMed1996

The effects of chronic industrial noise exposure on urinary cortisol, fatigue and irritability: a controlled field experiment.

This quasiexperimental field study explored the effect of noise attenuation on urinary cortisol excretion (sampled three times, at 6:30 and 10:30 AM and 1:30 PM) and reported fatigue and postwork irritability among 35 healthy industrial workers chronically exposed to high ambient noise levels (> 85 dB [A]) without using ear protectors. The results indicated that under conditions of chronic noise exposure the cortisol level at the end of the workshift was high and almost reached the morning level. This elevation in cortisol excretion was accompanied by high levels of accumulated fatigue and postwork irritability. Attenuating the noise reaching the eardrum by 30 to 33 dB, by fitting the same workers with earmuffs for a period of 7 working days, resulted in a significant improvement in both psychological and physiological stress reactions. Besides decreasing noise intensity, no other changes were made, either to ongoing work activities or to the other characteristics of the ambient noise. The cortisol level declined steadily during the workshift and exhibited the normal cortisol diurnal rhythm. At the end of the workshift, this level was significantly lower (P < .05) than that observed under the chronic noise-exposure condition. There was also a concomitant reduction in reported fatigue (P < .05) and postwork irritability (P < .01). These findings demonstrate the "net" contribution of ambient noise to elevating stress reactions to regular work demands.

Adult↗
PubMed2004

Predictability of speech-in-noise performance from real ear measures of directional hearing AIDS.

OBJECTIVE: Inability to understand speech in noise has been cited repeatedly as the principal complaint of hearing aid users. While data exist documenting the benefit provided by hearing aids with directional microphones when listening to speech in noise, little work has been done to develop a standard clinical protocol for fitting these hearing aids. Our goal was to evaluate a clinical measure of the acoustic directivity of a directional hearing aid, including its association with a test of speech perception in noise. DESIGN: The performance of two commercially available directional behind-the-ear (BTE) hearing aids was evaluated using the Hearing in Noise Test (HINT) and the Real Ear Aided Response (REAR) on 24 adult participants with symmetric, mild to moderately severe, sensorineural hearing loss. The HINT was conducted with the speech signal presented from 0 degrees and the noise from 180 degrees and either 135 degrees or 225 degrees, depending on the ear tested. REAR was measured at the above three angles using swept pure tones, and these measures were used to compute in situ directivity for each subject and hearing aid. CONCLUSIONS: Directional benefit for the HINT was greatest when noise was presented from the azimuth of the published polar diagram null of a given hearing aid in its directional mode (180 or 135/225 degrees). The only significant correlation between HINT and REAR results, however, was found when the noise source was at 180 degrees. These results confirm the validity of using real ear measures as a way to assess directionality in situ, but also indicate the complexity of predicting perceptual benefit from them. These data suggest that factors beyond acoustic directionality may contribute to improvement in speech perception in noise when such improvements are found.

Adult↗
PubMed2004

Effects of coexposure to noise and mixture of organic solvents on hearing in dockyard workers.

Questionnaire and audiometric data of 701 dockyard workers (517 noise and organic solvent mixture-exposed and 184 noise-only-exposed) were referred to 205 control subjects not exposed to either noise or solvents. The odds ratio (OR) of hearing loss was significantly increased by approximately 3 times in the noise-only group and by almost 5 times in the noise and solvent group. A moderate effect of solvent ototoxicity, in addition to noise, was observed on hearing threshold at a frequency 8 kHz. ORs for hearing loss were 1.12 for each increment of 1 year of age, 1.07 for every decibel of lifetime noise exposure (dB-A), and 1.004 for each increment of the index of lifetime exposure to solvents. The results suggest an additive damaging effect of coexposure to noise and organic solvents to the auditory organ.

Adult↗
PubMed1987

Hemodynamic effects of loud noise before and after central sympathetic nervous stimulation.

The hemodynamic effects of loud noise after central alpha 2-adrenoceptor stimulation were studied in 13 patients with mild (WHO 1) essential hypertension. The patients were randomized (double-blind) to treatment with either placebo or guanfacine 1-2 mg for four weeks and then crossed over and treated for another four weeks. All patients were exposed to a loud broad-band noise (105 dBA for 30 min) and all were studied both on placebo and guanfacine. Guanfacine significantly reduced the resting blood pressure from 141/92 to 134/88 mmHg (p less than 0.01) as well as heart rate at rest from 63 to 58 beats/min (p less than 0.05). Noise stimulation caused a significant increase in blood pressure and resistance in the placebo-treated group, while cardiac output decreased significantly. Pretreatment for one month with the central alpha 2-adrenoceptor stimulating agent guanfacine did not block the noise-induced pressor response nor the increase in peripheral resistance. A significant decrease in stroke volume was observed and cardiac output also tended to decrease in this group. It could be concluded that loud noise is a potent pressor stimulus which causes vasoconstriction and that the blood pressure response during noise could not be blocked by the centrally acting antihypertensive agent guanfacine. Since noise causes vasoconstriction it also induces an increased tone in the small arteries and, if the noise stimulus is sufficiently strong and repeated for a long time, it might cause structural changes in the resistance vessels and permanent arterial hypertension in humans.

Adrenergic alpha-Agonists↗
PubMed1989

The effect of intermittent noise on cardiovascular functioning during vigilance task performance.

This study was designed to investigate the effect of presentations of intermittent noise differing in predictability on cardiovascular functioning during task performance. Under a quiet condition and three conditions of intermittent noise, measures of blood pressure, heart rate (interbeat interval), and heart rate variability (variance, successive difference mean square, and the 0.1 Hz component of sinus arrhythmia) were obtained while subjects were occupied with a 55-min vigilance task. The results indicated that intermittent noise significantly increased diastolic and mean blood pressure. In addition, 0.1 Hz measures differed between the group working under quiet conditions and the groups working under noise. Although heart rate increased in all groups during the task, it increased significantly more in groups receiving unpredictable noise bursts. For the variables that were significantly affected by the noise presentations there was no evidence of response habituation over the task period. The results are discussed in relation to the effort required to maintain performance levels during noise, and attention is drawn to the implications of the present findings for cardiovascular health under conditions of chronic intermittent noise.

Adult↗
PubMed1999

Successful treatment of noise-induced cochlear ischemia, hypoxia, and hearing loss.

Cochlear blood flow (CoBF), perilymphatic partial pressure of oxygen (PL-pO2), cochlear microphonics (CMs), compound action potentials of the auditory nerve (CAPs), and auditory brainstem responses (ABRs) were studied in noise-exposed guinea pigs during and after the following treatments: intravenous infusion of isotonic saline (placebo); blood flow promoting drugs (hydroxyethyl starch = HES, pentoxifylline, betahistine, gingko biloba, naftidrofuryl); antiinflammatory agents (prednisolone, diclofenac sodium, histamine H1-receptor antagonist); isobaric oxygenation (IBO); and hyperbaric oxygenation (HBO) with and without supplements (simultaneous infusion of isotonic saline, pentoxifylline, prednisolone, or HES). It was found that PL-pO2 declined simultaneously with deterioration of CM, CAP, and ABR amplitudes after exposure to broad-band noise (bandwidth 1-12 kHz, 30 min, 106-dB SPL). CoBF decreased only 30 min after cessation of broad-band noise and progressed with cochlear hypoxia, while the hearing loss showed no further signs of deterioration and no recovery up to 3 h after exposure. Treatment (60 min) started 60 min after cessation of noise and was studied for a further 60 min. Isotonic saline did not influence the measuring parameters. Noise-induced cochlear hypoxia was compensated by IBO and more effectively by HBO with and without supplements, while other treatments had no sustained effect. A sustained therapeutic effect on noise-induced cochlear ischemia was achieved only by HES, HBO + HES, and pentoxifylline. However, the best therapeutic effect on noise-induced hearing loss was achieved with a combination of HBO and prednisolone, followed by monotherapy with prednisolone or HES with the result that not only did the CAPs and ABRs completely recover, the CMs also showed significant improvement, although full recovery did not occur. All other therapies were significantly less effective or did not improve noise-induced reduction of auditory evoked potentials.

Action Potentials↗