Acute Recreational Noise-Induced Cochlear Synaptic Dysfunction in Humans With Normal Hearing: A Prospective Cohort Study.

OBJECTIVES: The objective of the study was to identify the acute high-intensity recreational noise-induced effects on auditory function, especially the cochlear synaptopathy-related audiological metrics, in humans with normal hearing. METHODS: This prospective cohort study enrolled 32 young adults (14 males and 18 females); the mean age was 24.1 ± 2.4 years (ranging from 20 to 29). All participants with normal hearing (audiometric thresholds ≤25 dB HL at frequencies of 0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz for both ears) had already decided to participate in the outdoor music festival. Participants were asked to measure the noise exposure dose and complete auditory examinations, including the air-conduction pure-tone audiometry (PTA), distortion product otoacoustic emission (DPOAE), contralateral suppression (CS) on transient evoked otoacoustic emission (TEOAE), auditory brainstem response (ABR) test and Mandarin Hearing in Noise Test (MHINT), at baseline and 1 day and 14 days after music festival noise exposure. RESULTS: The mean time of attending the music festival was 7.34 ± 0.63 h (ranging from 6.4 to 9.5), the mean time-weighted average (TWA) of noise exposure dose was 93.2 ± 2.39 dB(A) (ranging from 87.9 to 97.7). At neither 1 day nor 14 days post exposure, there were no statistically significant effects on PTA thresholds, DPOAE amplitudes, CS on TEOAEs, or MHINT signal-to-noise ratios (SNRs) of acute outdoor music festival noise exposure, regardless of sex. While the ABR wave I amplitudes significantly decreased at 1 day after exposure and recovered at 14 days after exposure, the exposed/unexposed ABR wave I amplitude ratio was significantly correlated with MHINT SNR change at 1 day after exposure, although it was not correlated with the noise exposure dose. CONCLUSION: In young adults with normal hearing, we found the self-compared decrement of ABR wave I amplitudes at 1 day post acute recreational noise exposure at high intensity, which also contributes to the change in speech perceptual ability in noisy backgrounds. This study indicated that auditory electrophysiological metric changes might be a more sensitive and efficient indicator of noise-induced cochlear synaptic dysfunction in humans. More attention should be paid to the recreational noise-induced cochlear synaptopathy and auditory perceptual disorder.

Music level preference and perceived exercise intensity in group spin classes.

CONTEXT: Sound levels in fitness classes often exceed safe levels despite studies that show many participants find high sound levels stressful. AIMS: The objective is to determine if lower sound levels in spinning classes significantly impact exercise intensity and to determine if class participants prefer the music played at lower levels. SETTINGS AND DESIGN: Observational study of 1-hour group spin classes. METHODS AND MATERIALS: Sound levels were measured in 18 spin classes over two weeks. No adjustments were made in week-1 and sound levels were decreased by 3 dB in week-2. Participant preferences and data on post-class hearing changes were collected via post-class questionnaires (n = 213) and divided into three terciles based on the total sound exposure of corresponding classes. STATISTICAL ANALYSIS USED: Unweighted survey generalized linear models are used to sort the causal relationships between different variables simultaneously and participant responses. The Chi-square test is used to reveal statistically significant relationships between two or more categorical variables. RESULTS: When mean sound levels exceeded 98.4 dBC, respondents were 23 times more likely to report the music as too loud than too quiet (P < 0.05), and four times more likely to prefer a decrease, rather than an increase, in sound level (P < 0.05). There was no significant difference in respondents reporting high exercise intensity between the middle (95.7-98.1 dBC) and upper (98.4-101.0 dBC) terciles, 67.1% and 71.8%, respectively (P = 0.53). Overall, 25.9% of respondents reported auditory symptoms following classes. Analysis in the context of dBA and dBC produced congruent conclusions and interpretations. CONCLUSIONS: Sound levels in many fitness classes remain dangerously high. However, music level can be lowered without a significant impact on perceived exercise intensity and many participants prefer lower sound levels than current levels.

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.

Young Adults' Knowledge and Attitudes Regarding "Music" and "Loud Music" Across Countries: Applications of Social Representations Theory.

Exposure to loud music, especially by young people, has significantly increased in recent years as a result of (a) advancements in technology in terms of personal music players and smart mobile phones, and (b) streaming of music through these devices. The World Health Organization (WHO) estimates that some 1.1 billion teenagers and young adults are at risk of developing hearing loss due to exposure to recreational noise such as music. It is suggested that knowledge and attitude of young adults toward music has bearing upon their music listening habits and thereby influences who is at risk of developing music induced hearing loss. Hence, researchers from various fields have tried to understand the knowledge and attitude of young adults regarding loud music. However, there is some criticism of attitude studies as there is little relation between expressed attitude and behavior. Some recent studies have explored the social representations of music and loud music using the Social Representations Theory (SRT). It has been suggested that social representation is more fundamental than attitude (or in other words social representation informs attitude), hence, it has a better relation to behavior. The current paper: (1) provides an overview of studies on knowledge and attitude of young adults toward loud music, (2) discusses the limitations of attitude theories and introduces SRT, and (3) provides a summary of social representation studies on "music" and "loud music" in young adults from different countries.

Noise levels at baseball stadiums and the spectators' attitude to noise.

BACKGROUND: Many public health professionals have expressed concern that regular participation in recreational settings with high noise levels might induce hearing loss. This study measures the noise levels in a baseball stadium and analyzes baseball fans' attitude of effect of recreational noise exposure on their hearing. METHODS: In the baseball stadium, noise levels from the beginning to the end of four games were measured in four seating sections, the red, blue, navy, and outfield sections using a sound level meter. For the survey sample, 344 randomly selected participants who visited the stadium and/or were baseball fans completed a 16-question survey on their noise exposure during the game and on the potential risk of hearing loss. RESULTS: The LAeq average of the 16 measures produced 91.7 dBA, showing a significantly high noise level in the red and navy sections. As a function of frequency by LZeq analysis, the noise levels of low frequencies between 0.05 and 1 kHz were significantly higher than other frequencies except for the outfield section, but the levels abruptly decreased above 1 kHz. Despite the very high noise levels, 70% of the respondents preferred sitting in either the red or the navy section to be closer to the cheerleaders and to obtain a good view. Most respondents reported that they did not consider wearing earplugs, and one-third experienced hearing muffled speech after the game. Notably, they agreed that an information announcement regarding loud noise and hearing protection was needed at the stadium. CONCLUSIONS: We conclude that the noise levels in baseball stadiums are high enough to cause hearing damage and/or tinnitus later when applying a rule of 85 dB LAeq for 8 hours with a 3-dB exchange rate. We expect these results to improve public education regarding safe noise exposure during popular sports activities.

A preliminary study on time-compressed speech recognition in noise among teenage students who use personal listening devices.

OBJECTIVE: To compare speech perception obtained with different time compression rates in teenagers that do or do not use personal listening devices (PLDs). DESIGN: Teenagers in a high school were recruited to complete questionnaires reporting their recreational noise exposure using PLDs. The dose of individual recreational noise exposure was calculated. The individuals with the most and least doses of recreational noise were selected and grouped into PLD users and non-PLD users. Normal rate and time-compressed (60% and 70%) speech recognition in quiet and noisy conditions was measured. STUDY SAMPLE: PLD user and non-PLD user group each included 20 participants. RESULTS: ANOVA analysis showed that the effect of group, background, compression rate, and interactions between any two factors are significant. Post hoc analysis showed that the speech recognition scores with normal rate in quiet and noise and those obtained from time-compressed speech in the quiet condition were not significantly different between PLD users and non-PLD users. However, differences in the time-compressed speech recognition scores (60% and 70%) in noisy conditions between the two groups were statistically significant. CONCLUSIONS: The fast-speed speech recognition in noise decreased significantly in PLD users compared with that in non-PLD users selected by extreme entertainment exposure.

A Hearing Loss Prevention Outreach Program for Farmers and Motorsports Enthusiasts.

Many farmers and motorsports enthusiasts in rural areas attend tractor pulls, which are loud motorsport competitions using tractors and trucks with powerful, modified engines. The high noise levels experienced by farmers and motorsports fans in their recreational and occupational activities are not addressed by traditional hearing conservation programs. The University of Wisconsin-Madison audiology group has established an annual hearing loss prevention outreach project at the Dairyland Super National Truck and Tractor Pull in Tomah, Wisconsin. The objectives of the outreach are to provide hearing protection to those at the tractor pull, to document tractor pull noise levels, and to encourage tractor pull attendees to use hearing protection at work and in their other recreational activities. This study establishes that hearing loss prevention outreach at tractor pulls is necessary due to the high noise levels during the competitions. The number of earplugs distributed and the percentage of individuals who accept them indicates that this outreach is effective in the short term. It is yet to be determined if this type of hearing loss prevention project can create long-term shifts in cultural attitudes about rural noise and lead to increased hearing protection usage in the occupational and recreational lives of tractor pull attendees.

Decreased Speech-In-Noise Understanding in Young Adults with Tinnitus.

OBJECTIVES: Young people are often exposed to high music levels which make them more at risk to develop noise-induced symptoms such as hearing loss, hyperacusis, and tinnitus of which the latter is the symptom perceived the most by young adults. Although, subclinical neural damage was demonstrated in animal experiments, the human correlate remains under debate. Controversy exists on the underlying condition of young adults with normal hearing thresholds and noise-induced tinnitus (NIT) due to leisure noise. The present study aimed to assess differences in audiological characteristics between noise-exposed adolescents with and without NIT. METHODS: A group of 87 young adults with a history of recreational noise exposure was investigated by use of the following tests: otoscopy, impedance measurements, pure-tone audiometry including high-frequencies, transient and distortion product otoacoustic emissions, speech-in-noise testing with continuous and modulated noise (amplitude-modulated by 15 Hz), auditory brainstem responses (ABR) and questionnaires.Nineteen students reported NIT due to recreational noise exposure, and their measures were compared to the non-tinnitus subjects. RESULTS: No significant differences between tinnitus and non-tinnitus subjects could be found for hearing thresholds, otoacoustic emissions, and ABR results.Tinnitus subjects had significantly worse speech reception in noise compared to non-tinnitus subjects for sentences embedded in steady-state noise (mean speech reception threshold (SRT) scores, respectively -5.77 and -6.90 dB SNR; p = 0.025) as well as for sentences embedded in 15 Hz AM-noise (mean SRT scores, respectively -13.04 and -15.17 dB SNR; p = 0.013). In both groups speech reception was significantly improved during AM-15 Hz noise compared to the steady-state noise condition (p < 0.001). However, the modulation masking release was not affected by the presence of NIT. CONCLUSIONS: Young adults with and without NIT did not differ regarding audiometry, OAE, and ABR.However, tinnitus patients showed decreased speech-in-noise reception. The results are discussed in the light of previous findings suggestion NIT may occur in the absence of measurable peripheral damage as reflected in speech-in-noise deficits in tinnitus subjects.

Short-term music-induced hearing loss after sound exposure to discotheque music: the effectiveness of a break in reducing temporary threshold shift.

OBJECTIVE: To investigate the effect of a break in music exposure on temporary threshold shifts. DESIGN: A cross-over design where subjects are exposed to dance music for either two hours consecutively, or exposed to two hours of dance music with a one-hour break in between. Outcome measure was the change in hearing threshold, measured in 1-dB steps at different time points after ending the music. STUDY SAMPLE: Eighteen normal-hearing subjects participated in this study. RESULTS: Changes in pure-tone threshold were observed in both conditions and were similar, regardless of the break. Threshold shifts could be averaged for 1000, 2000, and 4000 Hz. The shift immediately after the ending of the music was 1.7 dB for right ears, and 3.4 dB for left ears. The difference between left and right ears was significant. One hour after the exposure, right ears were recovered to baseline conditions whereas left ears showed a small but clinically irrelevant remaining shift of approximately 1 dB. CONCLUSIONS: The advice to use chill-out zones is still valid, because this helps to reduce the duration to the exposure. This study does not provide evidence that a rest period gives an additional reduction of temporary threshold shifts.