We examine the possibility that physiological effects of noise may result not only from noise exposure per se, but also from people's beliefs about the noise. Due to widely publicised changes to the runway configuration at Sydney Airport, aircraft noise levels in nearby areas were expected to either increase, decrease or remain the same. As part of the Sydney Airport Health Study, residents in each of these 3 expected-change areas (N=1015) completed a structured interview which included indices of noise reaction (including annoyance) and physical and mental health, prior to the anticipated changes. Concurrent (pre-change) measures of aircraft noise levels were taken. Self-reported physiological/health effects differed across areas with the same aircraft noise level consistently with differences in psychological reaction across these areas. Expected change in noise level added to the level of self-reported physiological symptoms predicted by noise level in regression analyses. Dose-response functions differed across the expected-change areas. These results are consistent with the hypothesis that noise exposure produces physiological symptoms, but that expectations regarding future noise levels also contribute to the physiological impact of noise, which may be reduced by addressing psychosocial factors related to noise reaction.

This retrospective cross-sectional study of median hearing threshold levels of males employed in two specific occupations shows that the trend with decreasing noise-induced hearing loss in Sweden during the 1970s and 1980s continues into the 1990s. In the occupational categories mechanical work and wood processing men in age groups 30-39, 40-49 and 50-59 years old examined during the time period 1971-76, 1981-86 and 1991-96 were compared. Possible explanations to the improvement might be a wider use of hearing protectors at work and less exposure to noise during military service. The results show that the awareness of noise-induced occupational hearing loss has improved but the hearing conservation programs are still necessary as hearing threshold levels in these occupational groups continue to be poorer than expected in relation to age.

Firearms are a common source of impulse noise that may potentially damage a hearing organ. It is not easy to predict soldiers' personal susceptibility to noise exposure. The purpose of this study was to evaluate of the transient evoked otoacoustic emission (TEOAE) and distortion-product otoacoustic emission (DPOAE) before and after shooting and compare it with conventional pure tone audiometry. Standard pure tone audiometry, tympanometry, TEOAE and DPOAE measurements were recorded before and 10-15 minutes after shooting. Ten male soldiers (20 ears) were exposed to impulse noise from automatic gunfire (15 single rounds of live ammunition). They did not use any earplugs. The reduction in amplitude of the TEOAE after shooting was 3.1 and 5.1 as SPL for 3 and 4 kHz respectively for the right ear and 4.3 dB SPL for 1 kHz and 0.6 dB SPL at 2 kHz for the left ear. The greatest reduction in DPOAE occurred at frequencies of 1.0 kHz (3.8dB SPL) and 3.0 kHz (2.9 dB SPL) for the left ear. There were no differences in the audiometric thresholds before and after shooting. Emissions appear to be more sensitive for monitoring early cochlear changes after shooting, than pure tone audiometry.

The Nottingham Health Profile (NHP) has been used to investigate the health profiles in different medical conditions. It has, however, never been applied to tinnitus sufferers. The present study aimed at investigating relationships between the perceived severity of tinnitus, audiometric data, age, gender and non-disease specific health-related quality of life measured with the NHP divided into two sections; NHP I (topics related to health status) and NHP II (health induced problems in daily life). These parameters were statistically analysed to identify predictive factors to the perceived severity of tinnitus, described by the Tinnitus Severity Questionnaire (TSQ). A total of 186 consecutive tinnitus patients (57 females and 129 males) attending an audiological specialist clinic in Sweden were included in the study. The stepwise regression model used explained 37.8 per cent of the variance in the perceived severity of tinnitus, and the significant predictors were: "Emotions", "Sleep", and "Pain", three of the six dimensions of the NHP I. Differences between gender were found in NHP II and age-related differences emerged in NHP I when male and female patients were compared to normal controls.

A questionnaire was used to collect data from 545 students of the Manchester Metropolitan University. The aim of the study was to investigate associations between the attendance of university students at night-clubs (NCs) that play loud music and the incidence and duration of post exposure tinnitus (PET) and spontaneous tinnitus (ST). The possible effects of taking social drugs in NCs on tinnitus was also investigated. Descriptive analyses and Chi squared association analyses were carried out. The study showed that 87% of students attended noisy NCs and there was a significant association between the attendance at NCs and the duration of PET. There was no significant association between frequency of attendance and the incidence of tinnitus, however non attendees were significantly less likely to get ST. The amount of social drug-taking was not as high as expected, only 19% taking drugs more than rarely, although the incidence may be under-reported. Taking drugs while at night-clubs would appear to exacerbate the effects of noise exposure on tinnitus. Non drug taking males were less susceptible to PET lasting longer than 2 hours and ST than non drug taking females, whereas drug taking males were more susceptible than drug taking females. Whereas PET has yet to be proved to be related to auditory damage, this study would suggest the effect of night­club noise exposure impedes tinnitus recovery and could prove to be an early sign of permanent damage.

The large intersubject variability observed in demographic studies of noise-induced hearing loss illustrates how difficult it can be to estimate with precision the risk posed by exposure to noise. One possible source of the variability is the result of evaluating a diverse set of acoustic conditions with a simple metric A-weighted energy. In this paper the limitations of the energy­based criteria are reviewed. The benefits of evaluating a noise exposure in terms of energy and the metrics of frequency and time-domain kurtosis are discussed. A second source of variability in industrial noise studies may be related to non-acoustic factors such as chemical exposures that contribute to hearing loss acquired on the job