Supra-threshold deficits in normal hearing military recruits exposed to impulse noise.

The aim of this study was to determine the effect of impulse noise exposure on various proxy measures of cochlear synaptopathy in young military recruits. A total of 27 military recruits with exposure to firearm and artillery noise and 13 non exposed participants were recruited. All presented with normal hearing thresholds and the presence of distortion product otoacoustic emissions (DPOAEs). The Noise Exposure Structured Interview (NESI) was used to quantify noise exposure. Speech perception in noise (SPiN), equivalent rectangular bandwidth (ERB) of auditory filters, auditory brainstem response wave I amplitude, wave I amplitude growth function, wave I/V amplitude ratio, wave V latency, wave V latency shift with ipsilateral noise, and the summating potential/action potential ratio of the electrocochleography were measured. In military participants, SPiN was worse, ERB at 4 kHz was larger, wave I amplitude at 75 dBnHL was reduced, and wave V latency was delayed. However, no significant correlations were observed between NESI and auditory measures, once multiplicity of tests was controlled for. These results suggest that military recruits may exhibit supra-threshold deficits, despite presenting with normal hearing thresholds and presence of DPOAEs. Future studies should include a measure of auditory filters in their test battery.

French-Canadian translation and validation of four questionnaires assessing hearing impairment and handicap.

OBJECTIVE: Questionnaires evaluating hearing impairment are available in English but there is a need for French standardised questionnaires for researchers as well as for audiologists and other clinicians. The objective of this study is to describe the translation and validation of four questionnaires that assess different aspects of hearing impairment and handicap among elders with hearing loss, by comparing the main score and psychometric evaluation of original and French-Canadian (FC) versions of the World Health Organization Disability Assessment Scale II (WHO-DAS II), the Screening Test for Hearing Problems (STHP), the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Measure of Audiologic Rehabilitation Self-Efficacy for Hearing Aids (MARS-HA). DESIGN: Vallerand method: translation and back-translation by two translators, revision by a committee of experts and pre-tested with five bilingual older participants. STUDY SAMPLE: Participants (n = 29) were 65 years of age or older including 21 with hearing aids. RESULTS: The psychometric properties (internal consistency, temporal stability after four weeks) indicate good reliability for most of the translated questionnaires and their subscales, especially the WHO-DAS II. CONCLUSIONS: The translations in FC of two hearing loss and two hearing aid questionnaires were validated. It is recommended to pursue the demonstration for temporal stability for the STHP.

Adverse effects of pesticides on central auditory functions in tobacco growers.

OBJECTIVE: To investigate the effects of exposure to pesticides on the central auditory functions (CAF) of Brazilian tobacco growers. DESIGN: This was a cross-sectional study carried out between 2010 and 2012. Participants were evaluated with two behavioural procedures to investigate CAF, the random gap detection test (RGDT) and the dichotic digit test in Portuguese (DDT). STUDY SAMPLE: A total of 22 growers exposed to pesticides (study group) and 21 subjects who were not exposed to pesticides (control group) were selected. RESULTS: No significant differences between groups were observed for pure-tone thresholds. A significant association between pesticide exposure and the results for RGDT and DDT was found. Significant differences between pesticide-exposed and nonexposed subjects were found for RGDT frequency average and DDT binaural average, when including age and hearing level as covariates. Age was significantly associated with RGDT frequency average, DDT left ear score, DDT binaural average and DDT right ear advantage. Hearing levels were not significantly associated with any of the test scores. The relative risk of failing the DDT and RGDT for the study group was 1.88 (95% CI: 1.10-3.20) and 1.74 (95% CI: 1.06-2.86), respectively, as compared with the control group. CONCLUSIONS: The results showed that tobacco growers exposed to pesticides exhibited signs of central auditory dysfunction characterised by decrements in temporal processing and binaural integration processes/abilities.

Wind turbine sound pressure level calculations at dwellings.

This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada's Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2-Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson's linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada.

Personal and situational variables associated with wind turbine noise annoyance.

The possibility that wind turbine noise (WTN) affects human health remains controversial. The current analysis presents results related to WTN annoyance reported by randomly selected participants (606 males, 632 females), aged 18-79, living between 0.25 and 11.22 km from wind turbines. WTN levels reached 46 dB, and for each 5 dB increase in WTN levels, the odds of reporting to be either very or extremely (i.e., highly) annoyed increased by 2.60 [95% confidence interval: (1.92, 3.58), p < 0.0001]. Multiple regression models had R(2)'s up to 58%, with approximately 9% attributed to WTN level. Variables associated with WTN annoyance included, but were not limited to, other wind turbine-related annoyances, personal benefit, noise sensitivity, physical safety concerns, property ownership, and province. Annoyance was related to several reported measures of health and well-being, although these associations were statistically weak (R(2 )< 9%), independent of WTN levels, and not retained in multiple regression models. The role of community tolerance level as a complement and/or an alternative to multiple regression in predicting the prevalence of WTN annoyance is also provided. The analysis suggests that communities are between 11 and 26 dB less tolerant of WTN than of other transportation noise sources.

Occupational noise exposure and noise-induced hearing loss are associated with work-related injuries leading to admission to hospital.

OBJECTIVE: This study focuses on work-related injuries that required admission to hospital in a population of male workers exposed to occupational noise (≥80 dBA) which some displayed a hearing loss due to their exposure. METHODS: The study population count 46 550 male workers, 1670 (3.6%) of whom incurred at least one work-related injury requiring admission to hospital within a period of 5 years following hearing tests conducted between 1987 and 2005. The noise exposure and hearing loss-related data were gathered during occupational noise-induced hearing loss (NIHL) screening. The hospital data were used to identify all members of the study population who were admitted, and the reason for admission. Finally, access to the death-related data made it possible to identify participants who died during the course of the study. Cox proportional hazards model taking into account hearing status, noise levels, age and cumulative duration of noise exposure at the time of the hearing test established the risk of work-related injuries leading to admission to hospital. RESULTS: For each dB of hearing loss, a statistically significant risk increase was observed (HR=1.01 dB 95% CI 1.006 to 1.01). An association (HR=2.36 95% CI 2.01 to 2.77) was also found between working in an occupational ambient noise ≥100 dBA and the risk of injury. CONCLUSIONS: From a safety perspective, this issue is highly relevant; especially when workers are exposed to intense ambient noise and NIHL.

Cardiovascular disease mortality among retired workers chronically exposed to intense occupational noise.

OBJECTIVE: The aim of this study, conducted among retired workers (≥65 years), is to estimate the association between long-term risk of cardiovascular disease (CVD) death and (1) duration of occupational noise exposure in career and (2) noise-induced hearing loss (NIHL), the latter being used as an indicator of adverse effects for long-term exposure to occupational noise. METHODS: Data from screening activities of occupational NIHL were paired to data from death records and were used for this study. A nested case-control analysis was performed. Each case was matched with three controls for length of follow-up and economic sector. A total of 161 CVD deaths occured during an average follow-up of 6.8 years. Conditional logistic regression models were used to estimate the risk (OR) of CVD death by tertiles of duration of noise exposure and of NIHL. RESULTS: Conditional logistic regression models indicated that prolonged duration of noise exposure (≥36.5 years) (3rd tertile) was associated with an increased risk of CVD death (OR 1.70; 95 % CI 1.10-2.62), as compared with shorter duration (<27 years) (first tertile). Moderate NIHL (2nd tertile) (OR 1.64; 95 % CI 1.04-2.6) and severe NIHL (3rd tertile) (OR 1.66; 95 % CI 1.06-2.60) were also associated with an increase in risk of CVD death. CONCLUSIONS: Results are consistent with recent findings on the chronic effects of occupational noise exposure persisting after retirement although it is less than during active working life.

Noise as an explanatory factor in work-related fatality reports.

Noise exposure in the workplace is a common reality in Québec, Canada as it is elsewhere. However, the extent to which noise acts as a causal or contributive factor in industrial work-related accidents has not been studied thoroughly despite its plausibility. This article aims to describe the importance or potential importance, during investigations looking into the specific causes of each work-related fatal accident, of noise as an explanatory factor. The written information contained in the accident reports pertaining to contextual and technical elements were used. The study used multiple case qualitative content analysis. This descriptive study was based on the content analysis of the 788 reports from the Commission de la santé et de la sécurité du travail du Québec [Workers' Compensation Board (WCB)] investigating the fatal work-related accidents between 1990 and 2005. The study was descriptive (number and percentages). Noise was explicitly stated as one of the explanatory factors for the fatal outcome in 2.2% (17/788) of the fatal accidents, particularly when the work involved vehicular movement or the need to communicate between workers. Noise was not typically considered a unique cause in the accident, notably because the investigators considered that the accident would have probably occurred due to other risk factors (for example, disregard of safety rules, shortcomings in work methods, and inadequate training). Noise is an important risk factor when communication is involved in work. Since noise is ubiquitous and may also interfere with vigilance and other risk factors for accidents, it may be a much more important contributing factor to accidents than is currently recognized.

ICBEN review of research on the biological effects of noise 2011-2014.

The mandate of the International Commission on Biological Effects of Noise (ICBEN) is to promote a high level of scientific research concerning all aspects of noise-induced effects on human beings and animals. In this review, ICBEN team chairs and co-chairs summarize relevant findings, publications, developments, and policies related to the biological effects of noise, with a focus on the period 2011-2014 and for the following topics: Noise-induced hearing loss; nonauditory effects of noise; effects of noise on performance and behavior; effects of noise on sleep; community response to noise; and interactions with other agents and contextual factors. Occupational settings and transport have been identified as the most prominent sources of noise that affect health. These reviews demonstrate that noise is a prevalent and often underestimated threat for both auditory and nonauditory health and that strategies for the prevention of noise and its associated negative health consequences are needed to promote public health.

Validation of a French (Québec) version of the Tinnitus Handicap Inventory.

OBJECTIVE: To assess the psychometric properties of the Quebec French translation of the Tinnitus Handicap Inventory (THI-FQ). DESIGN: The original version of the THI was translated into French by two different people, and then revised before being administered to 221 study participants. A subgroup of 75 participants also completed the French versions of the Beck Depression Inventory II (BDI-II) and the Tinnitus Reaction Questionnaire (TRQ). STUDY SAMPLE: The study participants used French as their home language, had completed an otolaryngology (ENT) assessment, and had sought help with disabling tinnitus. RESULTS: No differences were found according to gender, age, or degree of hearing loss. The THI-FQ was very stable over a period of approximately 32 days. Internal consistency was 0.93 for the total score. Convergent validity with the TRQ was 0.81 (p < 0.001) while construct validity, as obtained with the BDI-II, was 0.74 (p < 0.001). As in other studies, the factor analysis did not confirm the structure proposed by Newman et al in the original study (1996). CONCLUSIONS: The THI-FQ presents very good reliability and validity, comparable to translations in other languages and the original version.

Exploring the effects of a repair strategies training program among children with auditory processing disorder: A pilot study.

OBJECTIVES: Children with hearing loss, as well as those with auditory processing disorder (APD), experience more communication difficulties than their normal-hearing peers. Receiving training on communication strategies has been shown to be beneficial for children with hearing loss, but little is known on the effect of such training on children with APD. The main purpose of this pilot study was to assess the effects of a repair strategies training program among children with APD. METHODS: Ten school-aged children with APD participated in a ten 60-min weekly repair strategies training program (experimental group) and ten did not receive any training (control group). In pre- and post-intervention, children were filmed while taking part in short scripted conversation situations in which communication breakdowns were introduced. Additionally, questionnaires on communication difficulties and repair skills, on life habits related to communication and education as well as on emotional well-being were filled by the children and their parents. RESULTS: In post-compared to in pre-intervention, children in the experimental group used significantly more of the repair strategies taught right after a communication breakdown occurred, used a greater variety of repair strategies, and overcame more communication breakdowns. The number of strategies needed to overcome a breakdown was not significantly different after the training compared to before. The level of difficulty to accomplish education-related life habits was generally lower, although not significantly, after entering the program than before. The individualized data showed that the studied training was more suited for children aged 9 years and older. The results of the children in the control group were not significantly different between the two measured times on all outcomes. CONCLUSION: Learning how to recognize and overcome communication breakdowns through a training program was beneficial for children with APD. The program enabled them to use a wider variety of repair strategies and to be more proactive in situations where communication is difficult. Studies are needed to further examine these findings in a larger sample of children with APD and in real-life settings.

Sensory Reweighting for Postural Control in Older Adults with Age-Related Hearing Loss.

There is growing evidence linking hearing impairments and the deterioration of postural stability in older adults. To our knowledge, however, no study to date has investigated the effect of age-related hearing loss on the sensory reweighting process during postural control. In the absence of data, much is unknown about the possible mechanisms, both deleterious and compensatory, that could underly the deterioration of postural control following hearing loss in the elderly. The aim of this study was to empirically examine sensory reweighting for postural control in older adults with age-related hearing loss as compared to older adults with normal hearing. The center of pressure of all participants was recorded using a force platform and the modified clinical test of sensory interaction and balance protocol. The results suggest that individuals with age-related hearing loss displayed increased somatosensory reliance relative to normal hearing younger adults. This increased reliance on somatosensory input does not appear to be effective in mitigating the loss of postural control, probably due to the concomitant deterioration of tactile and proprioceptive sensitivity and acuity associated with aging. Beyond helping to further define the role of auditory perception in postural control, these results further the understanding of sensory-related mechanisms associated with postural instability in older adults.

Combined exposures: an update from the International Commission on Biological Effects of Noise.

International Commission on Biological Effects of Noise (ICBEN) Team 8 deals with the effects of combined "agents" in the urban and work place settings. Results presented at the ICBEN conference indicate that some pesticides, more specifically the organophosphates, and a wider range of industrial chemicals are harmful to the auditory system at concentrations often found in occupational settings. Effects of occupational noise on hearing are exacerbated by toluene and possibly by carbon monoxide. Several of the chemicals studied found to be potentially toxic not only to hair cells in the cochlea but also to the auditory nerve. In urban environments, team 8 focuses on additive and synergetic effects of ambient stressors. It was argued that noise policies need to pay attention to grey areas with intermediate noise levels. Noteworthy is also stronger reactions to vibrations experienced in the evening and during the night. An innovative event-based model for sound perception was presented.

Comparison of land use regression and random forests models on estimating noise levels in five Canadian cities.

Chronic exposure to environment noise is associated with sleep disturbance and cardiovascular diseases. Assessment of population exposed to environmental noise is limited by a lack of routine noise sampling and is critical for controlling exposure and mitigating adverse health effects. Land use regression (LUR) model is newly applied in estimating environmental exposures to noise. Machine-learning approaches offer opportunities to improve the noise estimations from LUR model. In this study, we employed random forests (RF) model to estimate environmental noise levels in five Canadian cities and compared noise estimations between RF and LUR models. A total of 729 measurements and 33 built environment-related variables were used to estimate spatial variation in environmental noise at the global (multi-city) and local (individual city) scales. Leave one out cross-validation suggested that noise estimates derived from the RF global model explained a greater proportion of variation (R2: RF = 0.58, LUR = 0.47) with lower root mean squared errors (RF = 4.44 dB(A), LUR = 4.99 dB(A)). The cross-validation also indicated the RF models had better general performance than the LUR models at the city scale. By applying the global models to estimate noise levels at the postal code level, we found noise levels were higher in Montreal and Longueuil than in other major Canadian cities.

Perception of the Quality of Life of Tobacco Growers Exposed to Pesticides: Emphasis on Health, Hearing, and Working Conditions.

Introduction Tobacco farming exposes workers to various health risks due to the high application of pesticides needed to control pests, weeds and fungal diseases that prevent the tobacco plant growth. Objective To analyze the perception of the quality of life of tobacco growers exposed to pesticides, with emphasis on general health, hearing, and working conditions. Method This is a descriptive, cross-sectional study using a quantitative approach with farmers from southern Brazil. Data were collected from November of 2012 to November of 2014. For data collection, we opted for the 36-item short form health survey (SF-36) questionnaire, and a questionnaire with closed questions about health, hearing and working conditions. We evaluated a total of 78 subjects; the study group, made up of 40 tobacco farmers exposed to pesticides, and a control group of 38 participants without occupational exposure to pesticides. Both groups are residents of the same municipality, and users of the federal public health system. Results The results showed that tobacco growers had lower quality of life scores compared with the control group. Significant differences were observed in the areas of pain and general health. There were correlations between physical elements and chronic diseases; hearing complaints and a lack of personal protective equipment use, occupation and hearing complaints, as well as general health and hearing complaints. Conclusion Tobacco farming is a risky activity for general and hearing health, and it can impact the quality of life of those working in this field.

Prevalence of Hazardous Occupational Noise Exposure, Hearing Loss, and Hearing Protection Usage Among a Representative Sample of Working Canadians.

OBJECTIVE: The aim of this study was to estimate the prevalence of hearing loss (HL), self-reported occupational noise exposure, and hearing protection usage among Canadians. METHODS: In-person household interviews were conducted with 3666 participants, aged 16 to 79 years (1811 males) with 94% completing audiometry and distortion-product otoacoustic emission (DPOAE) evaluations. Occupational noise exposure was defined as hazardous when communicating with coworkers at an arm's length distance required speaking in a raised voice. RESULTS: An estimated 42% of respondents reported hazardous occupational noise exposure; 10 years or more was associated with HL regardless of age, sex or education. Absent DPOAEs, tinnitus, and the Wilson audiometric notch were significantly more prevalent in hazardous workplace noise-exposed workers than in nonexposed. When mandatory, 80% reported wearing hearing protection. CONCLUSIONS: These findings are consistent with other industrialized countries, underscoring the need for ongoing awareness of noise-induced occupational HL.

[Ototoxic effects of carbon monoxide exposure: a review]. / Efeitos ototóxicos da exposição ao monóxido de carbono: uma revisão.

BACKGROUND: Ototoxic effects of carbon monoxide exposure: a review. AIM: To analyze the literature on hearing and Carbon Monoxide (CO). METHODS: To describe the physical properties, the absorption, distribution and metabolism of CO, as well as its origin, production, sources and the international standards for occupational exposure. Several studies about the effects of CO exposure to the auditory system of humans and experimental animals were discussed. The main economic sectors where the combined exposure to noise and CO takes place were identified. A description of the basic CO toxic mechanisms that are able to raise occupational noise-induced hearing loss was given. CONCLUSION: The review of the literature indicated the following: 1. Examples of CO exposure sources include air pollution, smoking and second-hand smoking, and occupational exposures. 2. CO's main toxic mechanism can lead to hypoxia due to the conversion of oxyhemoglobin to carboxyhemoglobin. 3. Rats have been the most used experimental animals in CO auditory effects studies, this group of studies has demonstrated the combined effects of acute exposure to CO and noise. 4. Studies about the negative effects of CO exposure over the human auditory system were mainly carried out after acute exposures to CO. These studies did not control or report exposure to noise as a contributor to the observed hearing deficits. Currently the available evidence indicates the need for further research on the effects of CO exposure to the auditory system, alone or in combination with noise.

Patients reported outcome post-cochlear implantation: how severe is their dizziness?

OBJECTIVES: The reported prevalence of vestibular dysfunction after cochlear implantation (CI) is varies between different scientific papers. The aim of this study is to determine the reported post-implantation outcome in terms of dizziness, and to measure its impact on quality of life using the Dizziness handicap inventory (DHI). METHODS: This was a prospective questionnaire based study of postoperative cochlear implant patients. The questionnaire assessed the type and onset of dizziness in addition to the DHI. RESULTS: 122 patients were recruited in this study, which is the largest sample size in the literature reported so far. Dizziness was evident in 45.9% of the population post-CI and in 27% pre-CI. The commonest subtype of the dizziness was unsteadiness followed by lightheadedness. The dizziness was mild in most of the patients. CONCLUSION: Although mild, dizziness is a common complaint post-cochlear implantation. An understanding of symptoms helps counsel patients preoperatively.

Falls risk and hospitalization among retired workers with occupational noise-induced hearing loss.

This study sought to ascertain whether occupational noise-induced hearing loss (NIHL) increased the risk of falls requiring hospitalization among retired workers. The study population consisted of males (age ≥ 65) with an average occupational noise exposure of 30.6 years and whose mean bilateral hearing loss was 42.2 dB HL at 3, 4, and 6 kHz. Seventy-two retired workers admitted to hospitals after a fall were matched with 216 controls from the same industrial sectors. Conditional logistic regression models were used to estimate the risk (odds ratio; [OR]) of falls leading to hospitalization by NIHL categories. Results showed a relationship between severe NIHL (≥ 52.5 dB HL) and the occurrence of a fall (OR: 1.97, CI95%: 1.001-3.876). Reducing falls among seniors fosters the maintenance of their autonomy. There is a definite need to acquire knowledge about harmful effects of occupational noise to support the prevention of NIHL and ensure healthier workplaces.