Introduction: Tinnitus, the perception of the sound in the absence of an external acoustic source, disrupts the daily life 1 out of every 200 adults, yet its physiological basis remains largely a mystery. The generation of tinnitus is commonly linked with the impaired functioning of the outer hair cells (OHC) inside the cochlea. Otoacoustic emissions are the objective test used to assess their activity. Objective: The objective of the investigation was to study the features of Distortion product OtoAcoustic emissions (DPOAE) in a group of tinnitus patients with normal hearing and to find out whether there is any difference in DPOAE findings in the tinnitus patients with normal hearing and in persons with normal hearing with no complaint of tinnitus. Materials and Methods: The participants consisted of two groups. The subject group consisted of 16 ears of patients, in which 6 subjects were having tinnitus in both ears while 4 subjects were having tinnitus only in one ear. All subjects were aged between 20 to 60 years with complaint of tinnitus with audiometrically normal hearing. Control group was comprised of 16 audiometrically normal hearing ears of persons who were age and gender matched with the subject groups and had no complaint of tinnitus. Both the subject group as well as control group was subjected for DPOAE test. Findings of both the groups were compared using the unpaired t test. Result and conclusion: It was observed that the amplitudes of DPOAE were significantly lower in tinnitus patients than that of persons without complaint of tinnitus, at a frequency of 1281-1560, 5120-6250, 7243-8837 Hz, which imply that decrease of DPOAEs amplitudes may be related to the presence of tinnitus. It can be concluded that there is association between tinnitus and reduced OHC activity which indicate the OHC of cochlea are involved in the generation of tinnitus.

Although tinnitus is a very common symptom, risk factors related to behavior and habits have not been sufficiently investigated. As no investigation on this problem has been performed in Serbia, the aim of our study was to establish the prevalence of tinnitus among Serbian adolescents and to investigate the relationship between their behavior and habits and tinnitus. This investigation was designed as a cross-sectional interview study among secondary school students in Belgrade, Serbia (277 boys and 494 girls). An anonymous questionnaire was self-administered at classes. The investigated variables were: The presence of tinnitus, sources of noise, night outs at noisy places, use of personal music players, smoking, second hand smoke (SHS), substance abuse, coffee and alcohol consumption. Spearman's rank-order correlations and multiple logistic regressions were performed with variables related to behavior and habits as independent ones and tinnitus as a dichotomized dependent variable. Tinnitus was reported by 99 students (12.8%), more frequently among girls compared with boys (P = 0.009). Multivariate logistic regression analysis in boys revealed a significant independent effect of a regular drug abuse on the onset of tinnitus. The chances of tinnitus were 13 times higher among drug addicts compared with non-drug users (odds ratio [OR] and 95% confidence interval [CI] for tinnitus = 13.072; 1.335-127.946). In girls, the significant independent effect on tinnitus was found for daily duration of exposure to SHS (OR and 95% CI for tinnitus = 1.328; 1.073-1.644 /per 2 hours of exposure/).

The aim of the following study was to examine the relationship between working memory capacity (WMC), executive functions (EFs) and perceived effort (PE) after completing a work-related task in quiet and in noise in employees with aided hearing impairment (HI) and normal hearing. The study sample consisted of 20 hearing-impaired and 20 normally hearing participants. Measures of hearing ability, WMC and EFs were tested prior to performing a work-related task in quiet and in simulated traffic noise. PE of the work-related task was also measured. Analysis of variance was used to analyze within- and between-group differences in cognitive skills, performance on the work-related task and PE. The presence of noise yielded a significantly higher PE for both groups. However, no significant group differences were observed in WMC, EFs, PE and performance in the work-related task. Interestingly, significant negative correlations were only found between PE in the noise condition and the ability to update information for both groups. In summary, noise generates a significantly higher PE and brings explicit processing capacity into play, irrespective of hearing. This suggest that increased PE involves other factors such as type of task that is to be performed, performance in the cognitive skill required solving the task at hand and whether noise is present. We therefore suggest that special consideration in hearing care should be made to the individual's prerequisites on these factors in the labor market.

Raynaud's phenomenon is characterized by constriction in blood supply to the fingers causing finger blanching, of white fingers (WF) and is triggered by cold. Earlier studies found that workers using vibrating hand-held tools and who had vibration-induced white fingers (VWF) had an increased risk for hearing loss compared with workers without VWF. This study examined the occurrence of Raynaud's phenomenon among men and women with noise-induced hearing loss in relation to vibration exposure. All 342 participants had a confirmed noise-induced hearing loss medico legally accepted as work-related by AFA Insurance. Each subject answered a questionnaire concerning their health status and the kinds of exposures they had at the time when their hearing loss was first discovered. The questionnaire covered types of exposures, discomforts in the hands or fingers, diseases and medications affecting the blood circulation, the use of alcohol and tobacco and for women, the use of hormones and whether they had been pregnant. The participation rate was 41% (n = 133) with 38% (n = 94) for men and 50% (n = 39) for women. 84 men and 36 women specified if they had Raynaud's phenomenon and also if they had used hand-held vibrating machines. Nearly 41% of them had used hand-held vibrating machines and 18% had used vibrating machines at least 2 h each workday. There were 23 men/6 women with Raynaud's phenomenon. 37% reported WF among those participants who were exposed to hand-arm vibration (HAV) and 15% among those not exposed to HAV. Among the participants with hearing loss with daily use of vibrating hand-held tools more than twice as many reports WF compared with participants that did not use vibrating hand-held tools. This could be interpreted as Raynaud's phenomenon could be associated with an increased risk for noise-induced hearing loss. However, the low participation rate limits the generalization of the results from this study.

Noise pollution is still a growing public health problem with a significant impact on psychological health and well-being. The aim of this study was to investigate the impact of noise on displaced aggression (DA) in different subgroups of residents in one of the neighborhoods of Plovdiv city. A cross-sectional semi-structured interview survey was conducted using specially designed data registration forms and 33 close-ended and open-ended questions, divided into two major panels - one original and a modified version of the Displaced Aggression Questionnaire (DAQ). The mean score for DA was 61.12 (±19.97). Hearing noises above the perceived normal threshold, higher noise sensitivity and continuous noises were associated with higher levels of DA. Low frequency and high intensity noises were also associated with higher DA scores. Multiple regression model supported these findings. Contradictory to previous research age was positively correlated with noise sensitivity and aggression. We speculated that this might be due to the relatively lower socio-economic standard and quality of life in Bulgaria. Therefore, social climate might be modifying the way people perceive and react to environmental noise. Finally, the DAQ proved to be a viable measurement tool of these associations and might be further implemented and modified to suit the purposes of psychoacoustic assessment.

Competing theories exist about why asymmetry is observed in noise-induced hearing loss (NIHL). We evaluated these theories using a cohort of young workers studied over 16 years. The study aim was to describe and evaluate patterns of hearing loss and asymmetry by gender, agricultural exposure and gunfire exposure. This was a secondary analysis of data collected from young adults during follow-up of a randomized controlled trial. This follow-up study evaluated long-term effects of a hearing conservation intervention for rural students. The sample consisted of 392 of 690 participants from the original trial. In total, 355 young adults (aged 29-33 years) completed baseline and follow-up noise exposure surveys and clinical audiometric examinations. Data are displayed graphically as thresholds by frequency and ear and degree of asymmetry between ears (left minus right). In the primary group comparisons, low and high frequency averages and mean high frequency asymmetry were analyzed using mixed linear models. At frequencies >2000 Hz, men showed more hearing loss, with greater asymmetry and a different asymmetry pattern, than women. For men with documented hearing loss, there was a trend toward increasing asymmetry with increasing levels of hearing loss. Asymmetry at high frequencies varied substantially by level of shooting exposure. While "head shadowing" is accepted as the primary explanation for asymmetric hearing loss in the audiologic and related public health literature, our findings are more consistent with physiological differences as the primary cause of asymmetric hearing loss, with greater susceptibility to NIHL in the left ear of men.

The objective of the current study was to evaluate the predictive role of the olivocochlear efferent reflex strength in temporary hearing deterioration in young adults exposed to music. This was based on the fact that a noise-protective role of the medial olivocochlear (MOC) system was observed in animals and that efferent suppression (ES) measured using contralateral acoustic stimulation (CAS) of otoacoustic emissions (OAEs) is capable of exploring the MOC system. Knowing an individual's susceptibility to cochlear damage after noise exposure would enhance preventive strategies for noise-induced hearing loss. The hearing status of 28 young adults was evaluated using pure-tone audiometry, transient evoked OAEs (TEOAEs) and distortion product OAEs (DPOAEs) before and after listening to music using an MP3 player during 1 h at an individually determined loud listening level. CAS of TEOAEs was measured before music exposure to determine the amount of ES. Regression analysis showed a distinctive positive correlation between temporary hearing deterioration and the preferred gain setting of the MP3 player. However, no clear relationship between temporary hearing deterioration and the amount of ES was found. In conclusion, clinical measurement of ES, using CAS of TEOAEs, is not correlated with the amount of temporary hearing deterioration after 1 h music exposure in young adults. However, it is possible that the temporary hearing deterioration in the current study was insufficient to activate the MOC system. More research regarding ES might provide more insight in the olivocochlear efferent pathways and their role in auditory functioning.

Throughout history, people have suffered from physical symptoms that they have attributed to modern technologies. Often these attributions are strongly held, but not supported by scientific evidence. Symptoms attributed to the operation of wind turbines (called "wind turbine syndrome" by some) may fit into this category. Several psychological mechanisms might account for symptoms attributed to wind turbines. First, the "nocebo effect" is a well-recognized phenomenon in which the expectation of symptoms can become self-fulfilling. Second, misattribution of pre-existing or new symptoms to a novel technology can also occur. Third worry about a modern technology increases the chances of someone attributing symptoms to it. Fourth, social factors, including media reporting and interaction with lobby groups can increase symptom reporting. For wind turbines, there is already some evidence that a nocebo effect can explain the attributed symptoms while misattribution seems likely. Although worry has not been directly studied, research has shown that people who are annoyed by the sound that turbines produce are more likely to report symptoms and that annoyance is associated with attitudes toward the visual impact of wind farms and whether a person benefits economically from a wind farm. Given that these mechanisms may be sufficient to account for the experiences reported by sufferers, policy-makers, clinicians and patients should insist on good-quality evidence before accepting a more direct causal link.

The First International Conference on Hyperacusis gathered over 100 scientists and health care professionals in London, UK. Key conclusions from the conference included: (1) Hyperacusis is characterized by reduced tolerance of sound that has perceptual, psychological and social dimensions; (2) there is a growing awareness that children as well as adults experience symptoms of hyperacusis or misophonia; (3) the exact mechanisms that give rise to hyperacusis are not clear, but the available evidence suggests that functional changes within the central nervous system are important and in particular, hyperacusis may be related to increased gain in the central auditory pathways and to increased anxiety or emotional response to sound; (4) various counseling and sound therapy approaches seem beneficial in the management of hyperacusis, but the evidence base for these remains poor.

In order to preserve their operational effectiveness and ultimately their survival, military personnel must be able to detect important acoustic signals and maintain situational awareness. The possession of sufficient hearing ability to perform job-specific auditory tasks is defined as auditory fitness for duty (AFFD). Pure tone audiometry (PTA) is used to assess AFFD in the UK military; however, it is unclear whether PTA is able to accurately predict performance on job-specific auditory tasks. The aim of the current study was to gather information about auditory tasks carried out by infantry personnel on the frontline and the environment these tasks are performed in. The study consisted of 16 focus group interviews with an average of five participants per group. Eighty British army personnel were recruited from five infantry regiments. The focus group guideline included seven open-ended questions designed to elicit information about the auditory tasks performed on operational duty. Content analysis of the data resulted in two main themes: (1) the auditory tasks personnel are expected to perform and (2) situations where personnel felt their hearing ability was reduced. Auditory tasks were divided into subthemes of sound detection, speech communication and sound localization. Reasons for reduced performance included background noise, hearing protection and attention difficulties. The current study provided an important and novel insight to the complex auditory environment experienced by British infantry personnel and identified 17 auditory tasks carried out by personnel on operational duties. These auditory tasks will be used to inform the development of a functional AFFD test for infantry personnel.