Noise exposure estimates of urban MP3 player users

Associations Between Recreational Noise Exposure and Hearing Function in Adolescents and Young Adults: A Systematic Review

PURPOSE

There is an increasing concern regarding hazardous recreational noise exposure among adolescents and young adults. Daily exposure to loud sound levels over a long period of time can increase the risk of noise-induced hearing loss. The full extent of the impact of recreational noise on hearing is not yet fully understood. The purpose of this review was to synthesize research that investigated hearing function in relation to recreational noise exposure in adolescents and young adults.

METHOD

A systematic literature search of five databases covering the years 2000-2023 was performed. The articles included investigated audiological measurements of hearing function in relation to recreational noise exposure.

RESULTS

Four hundred sixty records were identified, of which 20 met the inclusion criteria and were included in the results. This review showed that although some recreational noise activities can be potentially harmful, there is an unclear relationship between exposure and outcome. Some findings indicated hearing threshold shifts or reduced otoacoustic emission amplitudes after recreational noise exposure, but most changes were short term and in the extended high-frequency range.

CONCLUSIONS

There seemed to be inconsistencies regarding the utilization of methods of measuring exposure and outcome between studies. This might be one reason for the differing results in studies on the reported impact on hearing function from recreational noise exposure. To draw more certain conclusions about long-term effects, there is a need for longitudinal research that utilizes sound level measurements to assess low and high degrees of recreational noise exposure in relation to hearing function.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.25114193.

Toward a better understanding of nonoccupational sound exposures and associated health impacts: Methods of the Apple Hearing Study

Globally, noise exposure from occupational and nonoccupational sources is common, and, as a result, noise-induced hearing loss affects tens of millions of people. Occupational noise exposures have been studied and regulated for decades, but nonoccupational sound exposures are not well understood. The nationwide Apple Hearing Study, launched using the Apple research app in November 2019 (Apple Inc., Cupertino, CA), is characterizing the levels at which participants listen to headphone audio content, as well as their listening habits. This paper describes the methods of the study, which collects data from several types of hearing tests and uses the Apple Watch noise app to measure environmental sound levels and cardiovascular metrics. Participants, all of whom have consented to participate and share their data, have already contributed nearly 300 × 10⁶ h of sound measurements and 200 000 hearing assessments. The preliminary results indicate that environmental sound levels have been higher, on average, than headphone audio, about 10% of the participants have a diagnosed hearing loss, and nearly 20% of the participants have hearing difficulty. The study's analyses will promote understanding of the overall exposures to sound and associated impacts on hearing and cardiovascular health. This study also demonstrates the feasibility of collecting clinically relevant exposure and health data outside of traditional research settings.

Headphone Audio in Training Systems or Systems That Convey Important Sound Information

In the work environment, miniature electroacoustic transducers are often used in communication, for the transmission of warning signals or during training. They can be used in headphones or mounted in personal protective equipment. It is often important to reproduce sounds accurately. The purpose of this work was to assess audio strips by comparing the frequency response of the signal in the electrical outputs of six common-purpose devices. Based on the risk of hearing damage, the level of noise exposure was assessed. The following headphones were investigated: low-budget closed-back, open-back for instant messengers, open-back for music, and in-ear. A head and torso simulator with a transfer function was used. The most uniform shape of the frequency response of the signal at the electrical outputs was found to be in smartphones. Sound cards integrated into laptop motherboards had highly unequal characteristics (up to 23 dB). In the case of one of the laptops, the upper range of the transmitted frequencies was limited to the 12,500 Hz band. An external sound card or wireless headphones can improve the situation. In the worst-case scenario, i.e., rock music, the listening time was limited to 2 h and 18 min.

Acceptable Noise Levels and Preferred Signal-to-noise Ratios for Speech and Music

OBJECTIVES

The objective of this study was to evaluate the influence of music versus speech on a listener's signal-to-noise ratio (SNR) preferences when listening in a noise background. SNR preferences were quantified using acceptable noise level (ANL) and preferred SNR metrics. The measurement paradigm for ANL allows the listener to adjust the level of background noise while listening to the target at their most comfortable loudness level. A higher ANL indicates less tolerance for noise and a lower ANL indicates high tolerance for noise. The preferred SNR is simply the SNR the listener prefers when attending to a target in a fixed-amount (level) of background noise. In contrast to the ANL, the listener does not have control over the noise. Rather, they are only able to manipulate the target level. The first aim of the study was to determine if listeners' tolerances for noise, quantified using the ANL, when listening to music is different from that when listening to speech. The second aim of the study was to determine if listeners' tolerances for noise, quantified using their preferred SNR, when listening to music is different from that when listening to speech. The third aim of the study was to quantify the relationship between ANL and preferred SNR.

DESIGN

Ninety-nine normal-hearing, native-English speakers participated in this study. The ANL and preferred SNR were measured for speech and music targets. Music targets included two variations (with lyrics and without lyrics) of the song "Rocky Top." Measurements were made in the sound field at 0° azimuth, 1.5 m from a loud speaker. For both ANL and preferred SNR, targets were presented in 12-talker babble noise. The level of the noise was adjusted by the listener during ANL measurement but was fixed in level during the preferred SNR measurement (75 dB A). Repeated-measures analysis of variance was performed to identify any significant effect of target on the ANL and preferred SNR. Correlation analysis was performed to evaluate the relationship between ANL and preferred SNR.

RESULTS

Findings demonstrate a significant effect of target on ANL and preferred SNR. ANLs were highest for speech (mean = 7.2 dB), followed by music with lyrics (6.1 dB), and music without lyrics (2.5 dB). Preferred SNRs were highest for music with lyrics (mean = 2.3 dB), followed by speech (1.2 dB), and music without lyrics (-0.1 dB). A listener's ANL for a given target was strongly correlated with their ANL for a different target (the same was true for preferred SNR); however, ANL for a given target was not a statistically significant predictor of preferred SNR for the same target.

CONCLUSIONS

When listening in a background of noise, the listener's tolerance for noise depends on the target to which they are attending, whether music or speech. This dependence is especially evident for ANL measures, and less so for preferred SNR measures. Despite differences in ANL and preferred SNR across targets, a listener's ANL and preferred SNR for one target predicts their ANL and preferred SNR, respectively, for a different target. The lack of correlation between ANL and preferred SNR suggests different mechanisms underly these listener-preference metrics.

Analysis of the Actual One-Month Usage of Portable Listening Devices in College Students

Although contemporary researchers are concerned about overexposure of portable listening devices (PLD) for adolescents and young adults who often prefer listening to music at high levels for a long time, many of these studies have focused on either comparing sound pressure levels of various kinds of earphones or evaluating the recognition of noise-included hearing loss and listening habits through surveys. Further still, current criteria were developed for occupational noise-induced hearing loss, so there are only a few published guidelines for hearing insults due to recreational noise exposure. The present study, therefore, measures actual listening levels and PLD time in college students using a real-time measurement system and applying that gathered scientific data to the internationally recommended noise exposure standards. Thirty-four college students were asked to listen to music similar to their daily lifestyles for 4-weeks. After installing the application, the Google account that linked to the user's mobile phone was logged into the server communication. When a subject listened to music, the average and maximum listening levels and listening time could then be recognized as his or her Google account ID and stored in the database for analysis. User data was measured at 1-s intervals and delivered to the main server system every 5 s. The data were analyzed as LZeq for mean levels and LCpeak for maximum levels, and also for PLD use time. The mean of the preferred listening level was 68-70 dB SPL for 4 weeks with long enough break times. That is, the listening levels of college students were not high enough to induce instant hearing loss when they used PLD. However, there was a large individual difference in the listening levels and use times. When applied to three recommended noise exposure criteria, the number of exceeded subjects also differed from 0 to 56.72% depending on the criterion. We thus suggest that appropriate and standardized criteria for music-induced hearing loss might be proposed for recreational PLD users.

Loud Music and Leisure Noise Is a Common Cause of Chronic Hearing Loss, Tinnitus and Hyperacusis

High sound levels capable of permanently damaging the ear are experienced not only in factories and war zones but in concert halls, nightclubs, sports stadiums, and many other leisure environments. This review summarizes evidence that loud music and other forms of "leisure noise" are common causes of noise-induced hearing loss, tinnitus, and hyperacusis, even if audiometric thresholds initially remain within clinically normal limits. Given the huge global burden of preventable noise-induced hearing loss, noise limits should be adopted in a much broader range of settings, and education to promote hearing conservation should be a higher public health priority.

Personal listening device usage among Canadians and audiometric outcomes among 6-29 year olds

OBJECTIVE

To describe personal listening device (PLD) usage and sociodemographic variables among a nationally representative sample of Canadians and examine audiometric outcomes among a subsample.

DESIGN

Audiometry and in-person questionnaires were used to evaluate hearing and PLD usage across age, sex, household income/education level. PLD exposure was quantified using a common occupational noise limit.

STUDY SAMPLE

A randomised sample of 10,460 respondents, aged 6-79, with audiometric analysis of a subsample (n = 4807), aged 6-29, tested between 2012 and 2015.

RESULTS

Loud PLD usage was reported by19.5% of Canadians. The highest prevalence was among teenagers (44.2%) and young adults (36.3%). Among children, 13.1% of users listened at loud volumes. High PLD usage (equivalent to or above 85 dBA, LEX 40) among 12-19 year olds was double that of 20-29 year olds: 10.2% versus 5.1%^E. Five years or more of loud PLD usage was associated with significantly higher mean hearing thresholds compared to less years. No association between loud or high PLD usage and mean thresholds were found.

CONCLUSION

The majority used PLDs safely, however a small proportion reported high risk usage which will impact hearing should this pattern persist over many years.

Associations between adolescents' earphone usage in noisy environments, hearing loss, and self-reported hearing problems in a nationally representative sample of South Korean middle and high school students

Few epidemiological studies have examined the relationship between earphone usage and hearing loss in adolescents. This study identified the prevalence of hearing loss in South Korean adolescents using representative national survey data and evaluated the relationship between earphone usage in a noisy environment and hearing loss. This study analyzed 532 subjects (12-19 years) who participated in a 2012 national survey and completed health and noise environment exposure questionnaires and pure tone audiometry (PTA) test. Hearing loss was defined as an average hearing threshold of 26 Decibel-A (dBA) or higher in PTA. The relationship between earphone usage and hearing loss was analyzed using a hierarchical logistic regression model. Adolescents who were exposed to high noise levels via headphones in a noisy environment had a hearing loss prevalence of 22.6% and adolescents who used earphones 80 minutes or more per day on average had the hearing loss prevalence of 22.3%. The results of the logistic regression analysis revealed that adolescents who used earphones in a noisy environment had a 4.5-fold higher risk of hearing loss and an 8.4 times higher risk of having a subjective hearing problem than those who did not use earphones (prevalence odds ratio (pOR) = 4.54, 95% confidence interval (CI): 1.35-15.24; pOR = 8.39, 95% CI: 1.12-62.83, respectively). Additionally, adolescents who used earphones more than 80 minutes per day in a noisy environment had a 4.7 times higher risk of hearing loss than those who used them less than 80 minutes per day (pOR = 4.68, 95% CI: 1.08-20.22). Longitudinal studies are needed to provide evidence of causality between earphone usage and hearing loss.

Personal Listening Device Use Habits, Listening Belief, and Perceived Change in Hearing Among Adolescents

PURPOSE

This study aimed to identify personal listening device (PLD) usage habits, listening belief, and perceived change in hearing, and to investigate how the variables related to perceived change in hearing among adolescents.

METHODS

The participants were 183 middle school students and 233 high school students from Ulsan. Data were collected by self-reported questionnaires from August 1, 2019, to October 22, 2019, and analyzed with descriptive statistics, χ² test, Mann-Whitney U test, and hierarchical multiple logistic regression.

RESULTS

Most students started to use PLDs from elementary school, and mean preferred listening level was 70.13 dB. Mean perceived susceptibility to music-induced hearing loss (MIHL) and perceived barriers to prevent MIHL were 5.18 and 3.40, respectively. Perceived change in hearing was reported on 14.2% of middle school students and 32.2% of high school students, and as the average score of perceived barriers to prevent MIHL increases by one point, the odds of decrease in hearing increase by 2.05 times (p < .001) and 1.35 times (p < .05), respectively.

CONCLUSION

Considering that most adolescents are exposed to PLD in elementary schools and about a quarter experienced a decrease in hearing after PLD use, educational programs on hearing conservation are required to start as early as in schools. Particularly, knowledge and skills to overcome barriers to prevent MIHL should be emphasized in educational programs.

Personal Audio System: Hearing Symptoms, Habits, and Sound Pressure Levels Measured in Real Ear and a Manikin

Purpose The aims of this study were to characterize hearing symptoms, habits, and sound pressure levels (SPLs) of personal audio system (PAS) used by young adults; estimate the risk of developing hearing loss and assess whether instructions given to users led to behavioral changes; and propose recommendations for PAS users. Method A cross-sectional study was performed in 50 subjects with normal hearing. Procedures included questionnaire and measurement of PAS SPLs (real ear and manikin) through the users' own headphones and devices while they listened to four songs. After 1 year, 30 subjects answered questions about their usage habits. For the statistical analysis, one-way analysis of variance, Tukey's post hoc test, Lin and Spearman coefficients, the chi-square test, and logistic regression were used. Results Most subjects listened to music every day, usually in noisy environments. Sixty percent of the subjects reported hearing symptoms after using a PAS. Substantial variability in the equivalent music listening level (Leq) was noted (M = 84.7 dBA; min = 65.1 dBA, max = 97.5 dBA). A significant difference was found only in the 4-kHz band when comparing the real-ear and manikin techniques. Based on the Leq, 38% of the individuals exceeded the maximum daily time allowance. Comparison of the subjects according to the maximum allowed daily exposure time revealed a higher number of hearing complaints from people with greater exposure. After 1 year, 43% of the subjects reduced their usage time, and 70% reduced the volume. A volume not exceeding 80% was recommended, and at this volume, the maximum usage time should be 160 min. Conclusions The habit of listening to music at high intensities on a daily basis seems to cause hearing symptoms, even in individuals with normal hearing. The real-ear and manikin techniques produced similar results. Providing instructions on this topic combined with measuring PAS SPLs may be an appropriate strategy for raising the awareness of people who are at risk. Supplemental Material https://doi.org/10.23641/asha.12431435.

Use of Personal Listening Devices and Knowledge/Attitude for Greater Hearing Conservation in College Students: Data Analysis and Regression Model Based on 1009 Respondents

Given the concern regarding increased hearing loss in young people who use personal listening devices (PLDs), the present study analyzes the experience of PLDs among college students to identify their knowledge of and attitude toward hearing conservation. It also explains their relationship between knowledge of hearing loss and attitude-related hearing conservation as a questionnaire response using a regression model. A total of 1009 Korean college students responded to an online questionnaire. As a survey tool, the Personal Listening Device and Hearing Questionnaire was adapted as a Korean version with 78 modified items under 9 categories. Using principal component analysis, specific factors were extracted, and their relationships and paths were confirmed using multiple regression analysis. The results of the knowledge category of the questionnaire indicate that most respondents knew how to maintain healthy hearing and understood the signs of hearing loss. Regardless, many college students habitually use PLDs at high levels in noisy environments; they do not recognize how to prevent hearing loss. Even though they continue their current use pattern for PLDs, they also had a positive attitude toward receiving more information about hearing conservation. According to the regression model, the students' self-reported hearing deficits were due to the volume rather than the frequent use. Interestingly, knowledge about hearing loss may encourage students to develop a positive attitude toward reasonable restriction of PLD use. When PLD users have detailed knowledge about the hearing loss provided by professionals, we believe that most will avoid serious hearing problems and its risks and maintain a judicious attitude toward their own conservation.

Knowledge of the audiological effects, symptoms and practices related to personal listening devices of health sciences students at a South African university

OBJECTIVE

This study aimed to determine the knowledge of first year health sciences students at a South African university regarding hearing loss and symptoms attributable to personal listening devices and their practices concerning the use of personal listening devices.

METHOD

This was a cross-sectional study carried out using an anonymous self-administered questionnaire.

RESULTS

Of 336 students, 269 (80.1 per cent) completed the questionnaire. While most participants could identify symptoms that could be caused by extensive use of personal listening devices, almost 30 per cent did not know that it could cause permanent hearing loss. Personal listening devices were used by 90.7 per cent of participants, with 77.8 per cent having used them for more than five years. Use was at a high volume in 14.9 per cent of participants and for more than 2 hours per day in 52.7 per cent.

CONCLUSION

The findings indicate the need for an educational programme to inform students as to safe listening practices when using personal listening devices.

Prevalence of loud leisure noise activities among a representative sample of Canadians aged 6-79 years

This population-based study estimates the prevalence of loud leisure noise exposure and hearing protection usage among Canadians, as well as the population potentially at-risk using an occupational limit of 85 dBA, LEX 40 h, which denotes a typical occupational noise limit for a 40 hour work week. A total of 10 460 participants, aged 6-79 years, completed a Canadian Health Measures Survey household questionnaire. Loud leisure noise was defined by vocal effort required while communicating at arm's length except for loud personal listening device (PLD) usage with earbuds/headphones, which included both volume setting and vocal effort. The most prevalent loud leisure noise activities were amplified music, car/home stereo listening, and power tools, with 40% reporting each source, followed by sporting/entertainment (25%), gasoline engines (23%), and loud PLD listening (19.5%). Loud leisure noise was more prevalent among 12-39 year olds and males. Hearing protection usage was uncommon, from 44.2% (firearms) to 20.3% (power tools) and below 3% during amplified music and sporting/entertainment events. Calculations using self-reported duration of loud leisure noise activities estimated that 6.6 × 10⁶ Canadians were in the high cumulative noise exposure category. A large proportion of Canadians would be expected to develop some degree of noise-induced hearing loss should this pattern persist over years.

Collaborative Approaches to the Support of People with Disabilities: The Underserved and Unserved

BACKGROUND

Underserved and unserved people are individuals who lack necessary health services. They can be found in both high- and low-income countries with disabilities in areas such as speech, language, hearing, swallowing, physical, and neurological, as well as other health problems. In addition, academic programs that prepare students to serve underserved or unserved communities do not exist in some countries. Collaborative projects allow those with expertise to share their knowledge, strategies, methods, and technologies with health practitioners, administrators, educators, students, and families. The goal is to assist populations who require special services. Collaborative projects can be interdisciplinary, international, or involve academic institutions or organizations. It is also essential that collaboration projects consider the strengths and assets that are present in the environment and in the population. This asset-based approach supports sustainability as long-term solutions can take advantage of existing strengths. Sustainability is essential so that the goals of projects can continue to contribute to a population.

OBJECTIVES

The primary objective of this article is to present collaborative projects that positively impact underserved and unserved populations. The strengths of these projects are also presented as a model for further work.

SUMMARY

This article presents several collaborative projects, along with the impact of these efforts.

No Reliable Association Between Recreational Noise Exposure and Threshold Sensitivity, Distortion Product Otoacoustic Emission Amplitude, or Word-in-Noise Performance in a College Student Population

OBJECTIVES

The purpose of this study was to evaluate the relationship between recreational sound exposure and potentially undiagnosed or subclinical hearing loss by assessing sound exposure history, threshold sensitivity, distortion product otoacoustic emission (DPOAE) amplitudes, and performance on the words-in-noise (WIN) test.

DESIGN

Survey data were collected from 74 adult participants (14 male and 60 female), 18 to 27 years of age, recruited via advertisements posted throughout the University of Florida campus. Of these participants, 70 completed both the survey and the additional functional test battery, and their preferred listening level was measured in a laboratory setting.

RESULTS

There were statistically significant relationships between hearing thresholds and DPOAE amplitude. In contrast, performance on the WIN was not reliably related to threshold sensitivity within this cohort with largely normal hearing. The two most common exposures included bars or dance clubs, followed by music player use. There were no statistically significant relationships between individual or composite measures of recreational sound exposure, including preferred listening level, years of music player use, number of reported sound exposures, previous impulse noise exposure, or previous noise-induced change in hearing, and functional measures including threshold, DPOAE amplitude, and WIN measures. Some subjects were highly consistent in listening level preferences, while others were more variable from song to song.

CONCLUSIONS

No reliable relationships between common recreational sound exposure or previous noise-induced changes in hearing were found during analysis of threshold sensitivity, DPOAE amplitude, or WIN performance in this cohort. However, the study sample was predominantly female and Caucasian, which limits generalizability of the results.

The effect of brief subway station noise exposure on commuter hearing

Objective

To demonstrate that brief exposure to subway noise causes temporary threshold shift and is preventable with noise protection.

Methods

The study was conducted as a randomized crossover trial. Twenty subjects were randomly assigned to two groups, one with hearing protection and one without. Subjects were exposed to subway platform noise for 15 minutes. Pre‐ and post‐exposure pure tone audiometry (PTA) and otoacoustic emissions were compared. After a washout period, subjects switched hearing protection groups and repeated the process.

Results

A statistically significant reduction in PTA thresholds after subway noise exposure was identified, for subjects with and without hearing protection (P < .001). For exposure without hearing protection, the mean threshold was 5.19 dB pre‐exposure and 3.91 dB post‐exposure (decrease of 1.28 dB; 95% confidence interval, 0.82–1.74). For exposure with hearing protection, the mean threshold was 4.81 dB pre‐exposure and 3.47 dB post‐exposure (decrease of 1.34 dB; 95% confidence interval, 0.89–1.79).

Conclusion

Brief exposure to subway noise did not cause hearing loss with or without noise protection. Though clinically insignificant, the unexpected finding of reduction in PTA suggests that there are complex heterogeneous short‐ and long‐term cochlear responses to noise exposure that should be further explored.

Level of Evidence

1b

Analysis of Output Levels of an MP3 Player: Effects of Earphone Type, Music Genre, and Listening Duration

Background and Objectives

To prevent noise induced hearing losses caused by listening to music with personal listening devices for young adults, this study was aimed to measure output levels of an MP3 and to identify preferred listening levels (PLLs) depending on earphone types, music genres, and listening durations.

Subjects and Methods

Twenty-two normal hearing young adults (mean=18.82, standard deviation=0.57) participated. Each participant was asked to select his or her most PLLs when listened to Korean ballade or dance music with an earbud or an over-the-ear earphone for 30 or 60 minutes. One side of earphone was connected to the participant’s better ear and the other side was connected to a sound level meter via a 2 or 6 cc-couplers. Depending on earphone types, music genres, and listening durations, loudness A-weighted equivalent (LAeq) and loudness maximum time-weighted with A-frequency sound levels in dBA were measured.

Results

Neither main nor interaction effects of the PLLs among the three factors were significant. Overall output levels of earbuds were about 10-12 dBA greater than those of over-the-ear earphones. The PLLs were 1.73 dBA greater for earbuds than over-the-ear earphones. The average PLL for ballad was higher than for dance music. The PLLs at LAeq for both music genres were the greatest at 0.5 kHz followed by 1, 0.25, 2, 4, 0.125, 8 kHz in the order.

Conclusions

The PLLs were not different significantly when listening to Korean ballad or dance music as functions of earphone types, music genres, and listening durations. However, over-the-ear earphones seemed to be more suitable to prevent noise induce hearing loss when listening to music, showing lower PLLs, possibly due to isolation from the background noise by covering ears.

Personal Listening Devices in Australia: Patterns of Use and Levels of Risk

Personal listening devices (PLDs) have the potential to increase the risk of noise-induced hearing loss (NIHL) for users. The present study aimed to investigate the nature and extent of the risk posed, by describing the user profile of a PLD population, identifying listening habits of that population, and examining whether PLD risk status is associated with hearing damage. A sample of 4,185 Australian PLD users completed an online survey about listening behaviors and hearing health. Listeners were characterized as low, high, or very high-risk based on daily noise dose estimates calculated from self-reported listening volume and durations. Listening patterns and hearing difficulties were examined in relation to risk status. Results indicated differences in listening volumes and durations with respect to age, with higher listening volumes reported for environments with greater background noise. Fifteen percent of participants' usage was classified as posing a potential risk to hearing, with a significantly greater proportion of younger people in higher-risk categories. Forty-one percent of participants reported feeling they have a hearing loss, with ∼20% reporting difficulties with speech in noise. For 18- to 35-year-olds, higher-risk status was associated with a greater proportion of self-reported hearing difficulties, including perceived poorer speech perception. These results have implications for hearing health promotion activities and suggest that messages should focus on either volume levels or durations depending on the particular activity in which the PLD is used. In addition, the results underline the importance of placing PLD exposure in the context of individuals' wider noise exposure. Although PLD use alone is not placing the majority of users at risk, it may be increasing the likelihood that individuals' cumulative noise exposure will exceed safe levels.

Application of the online hearing screening test "Earcheck": Speech intelligibility in noise in teenagers and young adults

Objective:

The objective was to describe the speech intelligibility in noise test results among Dutch teenagers and young adults aged 12–24 years, using a national online speech reception threshold (SRT) test, the Earcheck. A secondary objective was to assess the effect of age and gender on speech intelligibility in noise.

Design:

Cross-sectional SRT data were collected over a 5-year period (2010–2014), from participants of Earcheck. Regression analyses were performed, with SRT as the dependent variable, and age and gender as explaining variables. To cross-validate the model, data from 12- to 24-year olds from the same test distributed by a hearing aid dispenser (Hoorscan) were used.

Results:

In total, 96,803 valid test results were analyzed. The mean SRT score was −18.3 dB signal-to-noise ratio (SNR) (standard deviation (SD) = 3.7). Twenty-five percent of the scores was rated as insufficient or poor. SRT performance significantly improved with increasing age for teenagers aged 12–18 years by 0.49 dB SNR per age-year. A smaller age-effect (0.09 dB SNR per age-year) was found for young adults aged 19–24 years. Small differences between male and female users were found.

Conclusion:

Earcheck generated large quantities of national SRT data. The data implied that a substantial number of users of Earcheck may have some difficulty in understanding speech in noise. Furthermore, the results of this study showed an effect of gender and age on SRT performance, suggesting an ongoing maturation of speech-in-noise performance into late adolescence. This suggests the use of age-dependent reference values, but for this purpose, more research is required.

Perceptions of public primary school teachers regarding noise-induced hearing loss in South Africa

Background

Noise-induced hearing loss (NIHL) is an increasingly growing problem in young children. This is attributed to recreational noise being the most common cause of this problem. In young children, hearing problems can delay language development and reduce academic achievements. South Africa, in particular, has limited information and protective measures regarding the conservation of hearing in school-aged children.

Objectives

The main aim of the study was to determine the perception of primary school teachers regarding NIHL. The study also aimed to determine if any hearing conservation programmes are being implemented in schools and the need for training of primary school teachers regarding NIHL.

Method

A survey was conducted. In order to cover the population of interest, the sampled schools in Pretoria were clustered into urban, semi-urban and rural areas.

Results

The majority of the teachers included in this study are aware of NIHL and its effects. They, however, lack the necessary resources and knowledge to effectively use this information. Most (67.5%) of the teachers indicated that they have never been exposed to children with NIHL in a school setting. It was also found that the majority (84%) of the schools included in the study do not implement hearing screening and conservation programmes.

Conclusion

Although the sample size was limited, the results correlate with other research in this field indicating a need for planning and implementation of hearing conservation programmes in schools, including training of teachers in order for these programmes to be effective.

Listening to music with personal listening devices: monitoring the noise dose using a smartphone application

OBJECTIVES

To monitor listening habits to personal listening devices (PLDs) using a smartphone application and to compare actual listening habits to self-report data.

DESIGN

Two stages: self-report listening habits questionnaire, and real-time monitoring of listening habits through a smartphone application.

STUDY SAMPLE

Overall 117 participants aged 18-34 years (mean 25.5 years) completed the questionnaire, and of them, 40 participants (mean age: 25.2 years) were monitored for listening habits during two weeks.

RESULTS

Questionnaire main findings indicated that most of the participants reported listening for 4-7 days a week, for at least 30 min at high listening levels with volume control settings at 75-100%. Monitored data showed that actual listening days per week were 1.5-6.5 d, with mean continuous time of 1.56 h, and mean volume control setting of 7.39 (on a scale of 1-15). Eight participants (22%) were found to exceed the 100% noise dose at least once during the monitoring period. One participant (2.7%) exceeded the weekly 100% daily noise dose. Correlations between actual measurements and self-report data were low to moderate.

CONCLUSIONS

Results confirmed the feasibility of monitoring listening habits by a smartphone application, and underscore the need for such a tool to enable safe listening behaviour.

The Effects of Earphone Use and Environmental Lead Exposure on Hearing Loss in the Korean Population: Data Analysis of the Korea National Health and Nutrition Examination Survey (KNHANES), 2010-2013

BACKGROUND

Although previous studies have reported that frequent earphone use and lead exposure are risk factors for hearing loss, most of these studies were limited to small populations or animal experiments. Several studies that presented the joint effect of combined exposure of noise and heavy metal on hearing loss were also mainly conducted on occupational workers exposed to high concentration.

OBJECTIVES

We investigated both the individual and joint effects of earphone use and environmental lead exposure on hearing loss in the Korean general population.

METHODS

We analyzed data from 7,596 Koreans provided by the Korea National Health and Nutrition Examination Survey (KNHANES) during the period 2010-2013. The pure-tone average (PTA) of hearing thresholds at 2, 3, and 4 kHz frequencies was computed, and hearing loss was defined as a PTA ≥ 25 dB in one or both ears.

RESULTS

A dose-response relationship in hearing loss with earphone use time and blood lead level is observed after adjustment for confounding factors. With a 1-hour increase in earphone use time and 1 μg/dL increase in blood lead concentration, the odds of hearing loss increased by 1.19 and 1.43 times, respectively. For hearing loss, the additive and multiplicative effect of earphone use and blood lead level were not statistically significant.

CONCLUSIONS

Earphone use and environmental lead exposure have an individual effect on hearing loss in the general population. However, the estimated joint effect of earphone use and lead exposure was not statistically significant.

Influence of Hearing Risk Information on the Motivation and Modification of Personal Listening Device Use

PURPOSE

The purpose of this study was (a) to investigate the behaviors, knowledge, and motivators associated with personal listening device (PLD) use and (b) to determine the influence of different types of hearing health risk education information (text with or without visual images) on motivation to modify PLD listening use behaviors in young adults.

METHOD

College-age students (N = 523) completed a paper-and-pencil survey tapping their behaviors, knowledge, and motivation regarding listening to music or media at high volume using PLDs. Participants rated their motivation to listen to PLDs at lower volume levels following each of three information sets: text only, behind-the-ear hearing aid image with text, and inner ear hair cell damage image with text.

RESULTS

Acoustically pleasing and emotional motives were the most frequently cited (38%-45%) reasons for listening to music or media using a PLD at high volume levels. The behind-the-ear hearing aid image with text information was significantly (p < .0001) more motivating to participants than text alone or the inner ear hair cell damage image with text.

CONCLUSIONS

Evocative imagery using hearing aids may be an effective approach in hearing protective health campaigns for motivating safer listening practices with PLDs in young adults.

The influence of subway station design on noise levels

OBJECTIVES/HYPOTHESIS

To investigate the impact of subway station design on platform noise levels.

STUDY DESIGN

Observational.

METHODS

Continuous A-weighted decibel (dBA) sound levels were recorded in 20 New York City subway stations, where trains entered on either a straight track or curved track in 10 stations each. Equivalent continuous noise levels (L_eq ) at various locations on the boarding platform (inbound end, midplatform, and outbound end) during train entry and exit were compared between the straight and curved stations in broadband as well as narrow one-third octave bands.

RESULTS

Overall, curved stations trended louder than straight stations, although the difference in broadband L_eq did not reach statistical significance (curve, 83.4 dBA; straight, 82.6 dBA; P = .054). Noise levels were significantly louder at the inbound end of the platform during train entry (inbound, 89.7 dBA; mid, 85.5 dBA; outbound, 78.7 dBA; P < .001) and at the outbound end during train exit (inbound, 79.7 dBA; mid, 85.3 dBA; outbound, 89.1 dBA; P < .001). Narrow band analysis showed that curved stations were significantly louder than straight stations at 100 Hz and high frequencies from 8 to 20 kHz. Peak impact levels ranged from 104 to 121 dBA.

CONCLUSIONS

Curved stations have a different noise profile compared to straight stations and are significantly louder than straight stations at high frequencies. Designing stations with straight tracks within the platform can help reduce commuter noise exposure.

LEVEL OF EVIDENCE

NA Laryngoscope, 127:1169-1174, 2017.

Dietary supplement comprised of β-carotene, vitamin C, vitamin E, and magnesium: failure to prevent music-induced temporary threshold shift

This study examined potential prevention of music-induced temporary threshold shift (TTS) in normal-hearing participants. A dietary supplement composed of β-carotene, vitamins C and E, and magnesium was assessed using a randomized, placebo-controlled, double-blind study design. Dosing began 3 days prior to the music exposure with the final dose consumed approximately 30-min pre-exposure. There were no group differences in post-exposure TTS or music-induced decreases in distortion product otoacoustic emission (DPOAE) amplitude. Transient tinnitus was more likely to be reported by the treatment group, but there were no group differences in perceived loudness or bothersomeness. All subjects were monitored until auditory function returned to pre-exposure levels. Taken together, this supplement had no effect on noise-induced changes in hearing. Recommendations for future clinical trials are discussed.

Preferred listening levels of mobile phone programs when considering subway interior noise

Today, people listen to music loud using personal listening devices. Although a majority of studies have reported that the high volume played on these listening devices produces a latent risk of hearing problems, there is a lack of studies on “double noise exposures” such as environmental noise plus recreational noise. The present study measures the preferred listening levels of a mobile phone program with subway interior noise for 74 normal-hearing participants in five age groups (ranging from 20s to 60s). The speakers presented the subway interior noise at 73.45 dB, while each subject listened to three application programs [Digital Multimedia Broadcasting (DMB), music, game] for 30 min using a tablet personal computer with an earphone. The participants’ earphone volume levels were analyzed using a sound level meter and a 2cc coupler. Overall, the results showed that those in their 20s listened to the three programs significantly louder with DMB set at significantly higher volume levels than for the other programs. Higher volume levels were needed for middle frequency compared to the lower and higher frequencies. We concluded that any potential risk of noise-induced hearing loss for mobile phone users should be communicated when users listen regularly, although the volume level was not high enough that the users felt uncomfortable. When considering individual listening habits on mobile phones, further study to predict total accumulated environmental noise is still needed.

Reducing the risk of music-induced hearing loss from overuse of portable listening devices: understanding the problems and establishing strategies for improving awareness in adolescents

Hearing loss from the overuse of portable listening devices (PLDs), such as MP3 players or iPods, is of great concern in the popular media. This review aims to discuss the current state of scientific knowledge about music-induced hearing loss from PLD use. This report evaluates the literature on the risk to hearing from PLD use, the individual and psychological factors that influence PLD usage, and strategies for reducing exposure to music through PLDs. Specific interventions are reviewed, and several recommendations for designing interventions and for individual intervention in clinical practice are presented. Clinical recommendations suggested include the “80–90 rule” and the use of isolator-style earphones to reduce background noise.

The music listening preferences and habits of youths in Singapore and its relation to leisure noise-induced hearing loss

INTRODUCTION

Noise-induced hearing loss (NIHL) is a preventable condition, and much has been done to protect workers from it. However, thus far, little attention has been given to leisure NIHL. The purpose of this study is to determine the possible music listening preferences and habits among young people in Singapore that may put them at risk of developing leisure NIHL.

METHODS

In our study, the proportion of participants exposed to > 85 dBA for eight hours a day (time-weighted average) was calculated by taking into account the daily number of hours spent listening to music and by determining the average sound pressure level at which music was listened to.

RESULTS

A total of 1,928 students were recruited from Temasek Polytechnic, Singapore. Of which, 16.4% of participants listened to portable music players with a time-weighted average of > 85 dBA for 8 hours. On average, we found that male students were more likely to listen to music at louder volumes than female students (p < 0.001). We also found that the Malay students in our study listened to louder music than the Chinese students (p < 0.001).

CONCLUSION

We found that up to one in six young persons in Singapore is at risk of developing leisure NIHL from music delivered via earphones. As additional risks due to exposure to leisure noise from other sources was not taken into account, the extent of the problem of leisure NIHL may be even greater. There is a compelling need for an effective leisure noise prevention program among young people in Singapore.

College students' personal listening device usage and knowledge

OBJECTIVE

To determine the usage and knowledge of safe limits on personal listening devices (PLD) among college students.

DESIGN

First, information on health history was collected. Second, microphone in real ear techniques determined eardrum to free-field correction factors. Third, hearing levels were evaluated and information gathered about knowledge of safe listening behaviors.

STUDY SAMPLE

180 college students participated in a one-hour session using their PLDs and earphones set to their personal preference.

RESULTS

Virtually all participants reported knowledge of hearing loss risk due to PLD use and accurately recognized their own PLD listening levels (p = .01) as either within or exceeding safe sound limits. Forty-four subjects listened at greater than 80-dBA free-field equivalent levels. Only 7% of these participants were aware of these hazardous levels and 15% of participants' exposure surpassed free-field equivalent levels normalized to eight hours.

CONCLUSIONS

Despite reported knowledge of hearing loss risk due to PLD use in virtually all college students, 1 in 4 were found to listen to their PLDs at free-field equivalent levels greater than 80-dBA, with 94% unaware of their potential risk. Further research is needed to provide accurate PLD listening information and evaluate the possibility of long term PLD intensities that surpass recommended safety levels on hearing loss in adults over time.

Otoacoustic emissions before and after listening to music on a personal player

Background

The problem of the potential impact of personal music players on the auditory system remains an open question. The purpose of the present study was to investigate, by means of otoacoustic emissions (OAEs), whether listening to music on a personal player affected auditory function.

Material/Methods

A group of 20 normally hearing adults was exposed to music played on a personal player. Transient evoked OAEs (TEOAEs) and distortion product OAEs (DPOAEs), as well as pure tone audiometry (PTA) thresholds, were tested at 3 stages: before, immediately after, and the next day following 30 min of exposure to music at 86.6 dBA.

Results

We found no statistically significant changes in OAE parameters or PTA thresholds due to listening to the music.

Conclusions

These results suggest that exposure to music at levels similar to those used in our study does not disturb cochlear function in a way that can be detected by means of PTA, TEOAE, or DPOAE tests.

Cultural and demographic factors influencing noise exposure estimates from use of portable listening devices in an urban environment

PURPOSE

This study examined listening levels and duration of portable listening devices (PLDs) used by people with diversity of ethnicity, education, music genre, and PLD manufacturer. The goal was to estimate participants' PLD noise exposure and identify factors influencing user behavior.

METHOD

This study measured listening levels of 160 adults in 2 New York City locations: (a) a quiet college campus and (b) Union Square, a busy interchange. Participants completed a questionnaire regarding demographics and PLD use. Ordinary least squares regression was used to explore the significance of demographic and behavioral factors.

RESULTS

Average listening level was 94.1 dBA, with 99 of 160 (61.9%) and 92 of 159 (57.5%) exceeding daily (L A8hn) and weekly (L Awkn) recommended exposure limit, respectively. African American participants listened at the highest average levels (99.8 dBA).

CONCLUSIONS

A majority of PLD users exceeded recommended exposure levels. Factors significant for higher exposure were ethnicity and age; factors not significantly associated with exposure were gender, education, location, awareness of possible association between PLD use and noise-induced hearing loss, mode of transportation, device manufacturer, and music genre. Efforts to effect behavior changes to lessen noise-induced hearing loss risk from PLD use should be sensitive to the cultural differences within the targeted population.

Achados audiológicos em jovens usuários de fones de ouvido

Objetivos analisar a relação entre o uso de fones de ouvidos e os comprometimentos auditivos e extra-auditivos provocados pelos tocadores portáteis de música. Métodos a proposta foi coletar dados, por meio de um questionário respondido pelos participantes. Realização dos exames audiométricos: audiometria tonal e vocal; imitânciometria e pesquisa dos reflexos acústicos; emissões otoacústicas transientes e emissões otoacústicas produto de distorção, posteriormente os dados foram comparados entre os indivíduos de um mesmo grupo e os grupos foram comparados entre si (grupo experimental e grupo controle). Para a análise estatística foi utilizado o teste Qui-Quadrado e exato de Fisher. Resultados algumas das variáveis investigadas, tais como o uso de fones de ouvido de 1 a 2 horas diárias, a presença de queixas auditivas e extra-auditivas, exposição a níveis de pressão sonora elevados extra-ocupacional uma vez por semana, ser não fumante, não usar medicamentos controlados e não apresentar zumbido possuíram frequência estatisticamente significante para o grupo experimental. Em relação às queixas auditivas houve diferença estatisticamente significante entre os grupos experimental e controle para sensação de ouvido abafado e sensação de rebaixamento auditivo. Conclusão os sintomas temporários indicam os potenciais efeitos nocivos de ouvir tocadores portáteis de música por uma hora ao dia. Pesquisas ainda são necessárias para avaliar os prejuízos de longo prazo ao sistema auditivo.

Assessment of Noise Exposure to Children: Considerations for the National Children's Study

Evidence has been accruing to indicate that young children are vulnerable to noise in their physical environment. A literature review identified that, in addition to hearing loss, noise exposure is associated with negative birth outcomes, reduced cognitive function, inability to concentrate, increased psychosocial activation, nervousness, feeling of helplessness, and increased blood pressure in children. While increasing attention has been given to the health effects of noise in children, research about noise exposure is sparse and often the measure of exposure is simply proximity to a noise source. The U.S. National Children's Study (NCS) provides a unique opportunity to investigate noise exposures to pregnant women and children using a number of assessment modalities at different life stages. Measurement of noise levels in homes and other environments, personal dosimetry measurements made over a period of days, and questionnaires addressing sources of noise in the environment, annoyance to noise, perceived noise level, use of head phones and ear buds, noisy activity exposures, and occupational exposures, are planned for evaluation within the NCS Vanguard pilot study. We describe the NCS planned approach to addressing noise exposure assessment in study visits over a child's lifetime.

Digital music exposure reliably induces temporary threshold shift in normal-hearing human subjects

OBJECTIVES

One of the challenges for evaluating new otoprotective agents for potential benefit in human populations is the availability of an established clinical paradigm with real-world relevance. These studies were explicitly designed to develop a real-world digital music exposure that reliably induces temporary threshold shift (TTS) in normal-hearing human subjects.

DESIGN

Thirty-three subjects participated in studies that measured effects of digital music player use on hearing. Subjects selected either rock or pop music, which was then presented at 93 to 95 (n = 10), 98 to 100 (n = 11), or 100 to 102 (n = 12) dBA in-ear exposure level for a period of 4 hr. Audiograms and distortion product otoacoustic emissions (DPOAEs) were measured before and after music exposure. Postmusic tests were initiated 15 min, 1 hr 15 min, 2 hr 15 min, and 3 hr 15 min after the exposure ended. Additional tests were conducted the following day and 1 week later.

RESULTS

Changes in thresholds after the lowest-level exposure were difficult to distinguish from test-retest variability; however, TTS was reliably detected after higher levels of sound exposure. Changes in audiometric thresholds had a "notch" configuration, with the largest changes observed at 4 kHz (mean = 6.3 ± 3.9 dB; range = 0-14 dB). Recovery was largely complete within the first 4 hr postexposure, and all subjects showed complete recovery of both thresholds and DPOAE measures when tested 1 week postexposure.

CONCLUSIONS

These data provide insight into the variability of TTS induced by music-player use in a healthy, normal-hearing, young adult population, with music playlist, level, and duration carefully controlled. These data confirm the likelihood of temporary changes in auditory function after digital music-player use. Such data are essential for the development of a human clinical trial protocol that provides a highly powered design for evaluating novel therapeutics in human clinical trials. Care must be taken to fully inform potential subjects in future TTS studies, including protective agent evaluations, that some noise exposures have resulted in neural degeneration in animal models, even when both audiometric thresholds and DPOAE levels returned to pre-exposure values.

Mass transit ridership and self-reported hearing health in an urban population

Information on prevalence and risk factors associated with self-reported hearing health among mass transit riders is extremely limited, even though evidence suggests mass transit may be a source of excessive exposure to noise. Data on mass transit ridership were collected from 756 study participants using a self-administered questionnaire. Hearing health was measured using two symptom items (tinnitus and temporary audiometric threshold shift), two subjective measures (self-rated hearing and hearing ability), and two medical-related questions (hearing testing and physician-diagnosed hearing loss). In logistic regression analyses that controlled for possible confounders, including demographic variables, occupational noise exposure, nonoccupational noise exposure (including MP3 player use) and use of hearing protection, frequent and lengthy mass transit (all forms) ridership (1,100 min or more per week vs. 350 min or less per week) was the strongest predictor of temporary threshold shift symptoms. Noise abatement strategies, such as engineering controls, and the promotion of hearing protection use should be encouraged to reduce the risk of adverse impacts on the hearing health of mass transit users.

Noise levels of neonatal high-flow nasal cannula devices--an in-vitro study

BACKGROUND

Excessive ambient noise levels have been identified as a potential risk factor for adverse outcome in very preterm infants. Noise level measurements for continuous positive airway pressure (CPAP) devices demonstrated that these constantly exceed current recommendations. The use of high-flow nasal cannula (HFNC) as an alternative non-invasive ventilation modality has become more popular in recent years in neonatal care.

OBJECTIVE

To study noise levels of two HFNC devices commonly used in newborns. As a comparison, noise levels of a continuous flow CPAP device were also studied.

METHODS

In-vitro study. The noise levels of two contemporary HFNC devices (Fisher & Paykel NHF™ and Vapotherm Precision Flow®) and one CPAP device (Dräger Babylog® 8000 plus) were measured in the oral cavity of a newborn manikin in an incubator in a quiet environment. HFNC flows of 4-8 l/min and CPAP pressures of 4-8 cm H2O were applied. The CPAP flow was set at 8 l/min as per unit practice.

RESULTS

Vapotherm HFNC generated the highest noise levels, measuring 81.2-91.4 dB(A) with increasing flow. Fisher & Paykel HFNC noise levels were between 78.8 and 81.2 dB(A). The CPAP device generated the lowest noise levels between 73.9 and 77.4 dB(A).

CONCLUSIONS

Both HFNC devices generated higher noise levels than the CPAP device. All noise levels were far above current recommendations of the American Academy of Pediatrics. In light of the long duration of non-invasive respiratory support of very preterm infants, less noisy devices are required to prevent the potentially adverse effects of continuing excessive noise exposure in the neonatal intensive care unit.

A suggested model for decision-making regarding hearing conservation: towards a systems theory approach

OBJECTIVE

The aim of the study was to investigate potential health promotion variables associated with adolescents' hearing protection use at concerts.

STUDY SAMPLE

The sample consisted of 242 upper secondary school students aged 15-19 years.

DESIGN

Variables defined by the theory of planned behaviour (TBP) and health belief model were tested in this quantitative study.

RESULTS

Fifty-three percent of the adolescents reported that they used hearing protection at concerts to some degree, and 33 individuals (14%) reported that they used hearing protection in 50% of cases or more. The average degree of hearing protection use was reported to be 17% of the visits at concerts. Norms, perceived control, barriers, and noise sensitivity were associated with attitudes towards loud music. In addition, norms, barriers, permanent tinnitus, and noise sensitivity were significantly correlated with hearing protection use. However, intention was not significantly correlated with hearing protection use.

CONCLUSIONS

From a systems theoretical approach it can be suggested that preventive strategies must consider more levels than just the individual, in order to achieve long lasting behavioural changes in adolescents' listening habits. To be able to get useful knowledge about preventive strategies, it is necessary to add context-specific variables into generic models such as TPB.

Self-reported hearing difficulties, main income sources, and socio-economic status; a cross-sectional population-based study in Sweden

BACKGROUND

Hearing difficulties constitute the most common cause of disability globally. Yet, studies on people with hearing difficulties regarding socio-economic status (SES), work, long-term unemployment, sickness absence, and disability pension are scarce. The aim of the present study was to investigate the main income sources of men and women of working ages with and without self-reported hearing difficulties and associations with gender, age, SES, type of living area, and country of birth.

METHODS

A cross-sectional population-based study, using information on self-reported hearing difficulties and SES of 19 045 subjects aged 20-64 years participating in Statistics Sweden's annual Living Conditions Surveys in any of the years 2004 through 2008. The information was linked to a nationwide database containing data on demographics and income sources. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated, using binary logistic regression analysis.

RESULTS

Hearing difficulties increased with age and were more common in men (age-adjusted OR: 1.42 (95% CI: 1.30-1.56)) with an overall prevalence of 13.1% in men and 9.8% in women. Using working men as reference, the OR of having hearing difficulties was 1.23 (0.94-1.60) in men with unemployment benefits and 1.36 (1.13-1.65) in men with sickness benefits or disability pension, when adjusting for age and SES. The corresponding figures in women were 1.59 (1.17-2.16) and 1.73 (1.46-2.06). The OR of having sickness benefits or disability pension in subjects with hearing difficulties was 1.36 (1.12-1.64) in men and 1.70 (1.43-2.01) in women, when adjusting for age and SES and using men and women with no hearing difficulties as reference.

CONCLUSIONS

Hearing difficulties were more prevalent in men. After adjustment with age and SES as well as with type of living area and country of birth, a significant association with unemployment benefits was found only in women, and the associations with long-term sickness absence and disability pension tended to be stronger in women.

Listening Levels of Teenage iPod Users: Does Measurement Approach Matter?

The main objective of this study was to determine the influence of background noise levels and measurement approach on user-selected listening levels (USLLs) chosen by teenaged MP3 player users. It was hypothesized that the presence of background noise would (i) increase the USLL across all measurement approaches, (ii) result in no significant USLL differences between survey reports, objective lab measures or calibrated self-report field measures, and (iii) cause no interaction effect between level of background noise and measurement approach. There were two independent variables in this study: the level of background noise and measurement approach. The first independent variable, level of background noise, had two levels: quiet and transportation noise. The second independent variable, measurement approach, had three levels: survey, objective in-ear lab measurement and calibrated self-report field measurement. The dependent variable was ear canal A-weighted sound pressure level (dBA SPL). A 2 × 3 repeated-measures ANOVA was used to determine the significance of the main and interaction effects. USLLs increased in the presence of background noise, regardless of the measurement approach used. However, the listening levels estimated by the participants using the survey and self-report field measure were significantly lower than those recorded using in-ear laboratory measurements by 9.6 and 3.3 dBA respectively. In-ear laboratory measures yielded the highest listening levels. Higher listening levels were observed in the presence of background noise for all measurement approaches. It appears that subjects' survey responses underestimate true listening levels in comparison to self-report calibrated field measures, and that both underestimate listening levels measured in the laboratory setting. More research in this area is warranted to determine whether measurement techniques can be refined and adjusted to accurately reflect real-world listening preferences.

The challenge of detecting minimal hearing loss in audiometric surveys

PURPOSE

This tutorial provides framework and context for understanding the complex interaction of hearing measurement methodology and cohort social factors, as well as their relation to approaches to data interpretation and identification of minimal hearing loss (HL) in audiometric surveys.

METHOD

Pertinent archival studies were reviewed, and an original analysis on U.S. Centers for Disease Control and Prevention (CDC) audiometric survey data from children (ages 6-19) was performed.

CONCLUSION

The definition of an otologically normal individual, the pass-fail criterion representing the upper limit of the range of normal hearing, and the quality of the audiometry affect the percentage of persons who are falsely identified as having a minimal HL. An upper limit of normal hearing of 15 dB HL yields an unacceptably high false-positive rate, particularly when the more variable higher audiometric frequencies are examined. When air-conduction thresholds are assessed in isolation to estimate potential noise damage, the failure to exclude persons who have possible middle and external ear problems, including earwax, results in high false-positive rates. When these factors and other limitations are considered, audiograms from teens from a recent CDC survey do not show evidence consistent with widespread noise-induced HL. Suggestions are made to improve the effectiveness of pure-tone audiometry and the identification of minimal HL.

Exposures to transit and other sources of noise among New York City residents

To evaluate the contributions of common noise sources to total annual noise exposures among urban residents and workers, we estimated exposures associated with five common sources (use of mass transit, occupational and nonoccupational activities, MP3 player and stereo use, and time at home and doing other miscellaneous activities) among a sample of over 4500 individuals in New York City (NYC). We then evaluated the contributions of each source to total noise exposure and also compared our estimated exposures to the recommended 70 dBA annual exposure limit. We found that one in ten transit users had noise exposures in excess of the recommended exposure limit from their transit use alone. When we estimated total annual exposures, 90% of NYC transit users and 87% of nonusers exceeded the recommended limit. MP3 player and stereo use, which represented a small fraction of the total annual hours for each subject on average, was the primary source of exposure among the majority of urban dwellers we evaluated. Our results suggest that the vast majority of urban mass transit riders may be at risk of permanent, irreversible noise-induced hearing loss and that, for many individuals, this risk is driven primarily by exposures other than occupational noise.