Understanding the initial signature of noise-induced auditory damage remains a significant priority. Animal models suggest the cochlear base is particularly vulnerable to noise, raising the possibility that early-stage noise exposure could be linked to basal cochlear dysfunction, even when thresholds at 0.25-8 kHz are normal. To investigate this in humans, we conducted a meta-analysis following a systematic review, examining the association between noise exposure and hearing in frequencies from 9 to 20 kHz as a marker for basal cochlear dysfunction. Systematic review and meta-analysis followed PRISMA guidelines and the PICOS framework. Studies on noise exposure and hearing in the 9 to 20 kHz region in adults with clinically normal audiograms were included by searching five electronic databases (e.g., PubMed). Cohorts from 30 studies, comprising approximately 2,500 participants, were systematically reviewed. Meta-analysis was conducted on 23 studies using a random-effects model for occupational and recreational noise exposure. Analysis showed a significant positive association between occupational noise and hearing thresholds, with medium effect sizes at 9 and 11.2 kHz and large effect sizes at 10, 12, 14, and 16 kHz. However, the association with recreational noise was less consistent, with significant effects only at 12, 12.5, and 16 kHz. Egger's test indicated some publication bias, specifically at 10 kHz. Findings suggest thresholds above 8 kHz may indicate early noise exposure effects, even when lower-frequency (≤8 kHz) thresholds remain normal. Longitudinal studies incorporating noise dosimetry are crucial to establish causality and further support the clinical utility of extended high-frequency testing.

Many pieces of the literature showed that the potential risk of hearing loss was increasing among the general public, especially in adolescents and young adults, caused by prolonged exposure to loud music. Users tended to listen to music with a higher volume in noisy environments (e.g., intersections and subways) than in quiet ones. According to the WHO-ITU standard level for adults (80 dBA for 40 hours a week), the listening habits worse than the recommended standard might cause hearing damage. At present, the increasingly popular Noise-canceling headphones (NCHs) can reduce environmental noise to a certain extent. Whether users would lower the volume of music when using an NCH is a concern of the research. NCHs have different listening modes for dealing with ambient noise. Hence, the primary purpose of this study was to investigate the effect of different NCHs modes on pedestrians’ preferred listening levels (PLLs) in a noisy environment and to evaluate whether their listening levels were in a safe range.Methods: Fifteen male graduate students with normal-hearing ability participated in the study. The independent variable was the modes of NCHs, including Noise Cancellation (NC), Off, and Transparency modes. The PLLs were determined by each participant and recorded as the dependent variable. Before the experiments, participants were asked to report their headphone-use habits for assessing whether they exceeded a safe listening level. During the experiments, the ambient noise of heavy traffic intersections was played through two speakers. Participants were asked to put on the headphone with a specific mode by random orders. Subsequently, each participant was requested to adjust the volume of the music until it “sounded best.” The measurements were repeated twice for the three modes. A one-way repeated measure ANOVA with Bonferroni pairwise comparisons was used for statistical analysis. Results: The results indicated that the headphone modes significantly impacted the PLLs (p<0.001). Based on the Bonferroni pairwise comparisons, participants selected the highest PLLs with the Transparency mode (67.21 dBA), followed by the Off mode (60.77 dBA), and NC mode (55.83 dBA). Besides, the self-reported results showed that the usage of headphones was five days per week and three hours per day on average. From the results, the PLLs selected by the subjects were all lower than 80 dBA, and the average listening time did not exceed 40 hours per week. It implied that the participants' listening habits were at safe listening levels. Conclusion: In a noisy environment, different headphone modes have impacted on PLLs adjustment. The PLLs selected with the NC mode are significantly lower than those with Off mode and Transparency mode. The findings of this study suggested that using NC mode in a noisy environment could reduce the risk of hearing loss compared to the other headphone modes.

This study evaluates the sound pressure at the ears of users of personal digital audio players, equipped with in-ear earbuds. More than 50 devices were measured, provided by students aged 15/18. EN standard 50332 specifies the techniques for measuring the sound pressure level at the ears employing an head and torso simulator equipped with binaural microphones, when the gain control of the device is set to maximum. In this study, however, two measurmenets were performed on each device, one at maximum level, and another at the level at which the device had been left by the user after last listening. This way, on a statistical basis, it is possible to relate the effective exposure in daily usage with the maximum loudness of which the device is capable. Furthermore the study did also analyze the spectrum of the test signal: whilst the EN standard mandates for the IEC programme simulation noise, the analysis of thousands songs taken from the players under test revealed a slightly different spectrum, characterized by more boost at low frequencies and larger crest factor. The results of the study did show a relevant hearing risk for users of these personal digital audio players, which exceed noise exposure limits even when used for just one hour per day.

Sound levels from personal cassette players. Techniques have been devised whereby the levels at which users of personal cassette players listen to tape-recorded sounds through lightweight headphones may be measured and expressed in terms of free-field equivalent continuous A-weighted sound pressure levels. Data have been obtained on over 60 users of such devices who variously listened, in laboratory and field conditions, to music and speech against quiet and noisy backgrounds. The results have been interpreted in terms of noise exposure. Comparison with damage risk criteria indicates that 5% of the sample are listening in such a manner that habitual use would constitute a damage risk to hearing. Published in British journal of audiology (1987)

Hearing: the effects of noise. We live in a noisy world. The clamor and din of modern society has increased in variety, if not in prevalence and intensity, in the past decades, making noise America's most widespread nuisance. Excessive noise exposure annoys individuals, produces stress, impairs the ability to communicate, interferes with work and play activities, and, in high enough doses, produces permanent damage to the auditory system, which leads to significant hearing loss. Noise exposure associated with the workplace has been known to produce hearing loss for centuries. More than 20 years ago the U.S. Department of Labor promulgated regulations designed to protect the hearing of employees who work in noisy environments. However, these regulations failed to consider noise exposures outside the workplace, and recent evidence suggests that these exposures are potentially hazardous for millions of Americans. The most important sources of nonoccupational noise exposure are hunting and target shooting, listening to amplified music through headphones, and attendance at rock concerts. For each source, an assessment of risk of hearing loss is made.

Noise is all around you, from televisions and radios to lawn mowers and washing machines. Normally, you hear these sounds at safe levels that don't affect hearing. But sounds that are too loud or loud sounds over a long time are harmful. They can damage sensitive structures of the inner ear and cause noise-induced hearing loss. More than 30 million Americans are exposed to hazardous sound levels on a regular basis. Hazardous sound levels are louder than 80 decibels. That's not as loud as traffic on a busy street. Listening to loud music, especially on headphones, is a common cause of noise-induced hearing loss. You can protect your hearing by: Keeping the volume down when listening to music Wearing earplugs when using loud equipment NIH: National Institute on Deafness and Other Communication Disorders

Effects of listening to music with headphones on hearing--especially under noisy conditions. The purpose of this experiment was to clarify the effects of exposure to music using headphones under noisy conditions on hearing. The most comfortable loudness (MCL) for three kinds of music (Rock, Popular, Japanese songs) decided by two normal hearing subjects was measured under 6 noisy conditions (Train, Subway, Tram, Bus, Underground, Street) in a soundproof room. In the same manner, the MCL of favorite tunes of five subjects were measured. Temporary threshold shift 2 min after exposure (TTS2) to music for 30 min at the highest MCL was obtained. Furthermore, the characteristics such as spectral structures in one-third octave band or level fluctuations (coefficient of variation) were obtained for noise and music and compared. Statistical analysis revealed that MCL in Street was significantly higher than under other conditions and there was no significant differences in MCL among the various types of music. However, the highest MCL was found for Rock. About 20 dB of TTS was observed in one ear and the hazardous of headphones use in noisy conditions was suggested.

Unilateral hearing loss causes problems with directional hearing, affecting the ability to localize sound. PTS (Permanent Threshold Shift) is a permanent change Noise-induced hearing loss (NIHL) is a hearing impairment resulting from exposure to loud sound. People may have a loss of perception of a narrow range of frequencies or impaired perception of sound, including sensitivity to sound or ringing in the ears. When exposure to hazards such as noise occurs at work and is associated with hearing loss, it is referred to as occupational hearing loss. Hearin Noise-induced hearing loss (NIHL) is a hearing impairment resulting from exposure to loud sound. People may have a loss of perception of a narrow range of frequencies or impaired perception of sound, including sensitivity to sound or ringing in the ears. When exposure to hazards such as noise occurs at work and is associated with hearing loss, it is referred to as occupational hearing loss. Hearing may deteriorate gradually from chronic and repeated noise exposure (such as loud music or background noise) or suddenly from exposure to impulse noise, which is a short high intensity noise (such as a gunshot or airhorn). In both types, loud sound overstimulates delicate hearing cells, leading to the permanent injury or death of the cells. Once lost this way, hearing cannot be restored in humans. There are a variety of prevention strategies available to avoid or reduce hearing loss. Lowering the volume of sound at its source, limiting the time of exposure, and physical protection can reduce the impact of excessive noise. If not prevented, hearing loss can be managed through assistive devices and communication strategies. The largest burden of NIHL has been through occupational exposures; however, noise-induced hearing loss can also be due to unsafe recreational, residential, social and military service-related noise exposures. It is estimated that 15% of young people are exposed to sufficient leisure noises (i.e. concerts, sporting…

Hearing loss is increasingly recognized as a major public health concern among young adults, who are traditionally considered a low-risk group. This narrative review synthesizes recent evidence on risk and aggravating factors of early-onset hearing impairment, including recreational and occupational noise exposure, genetic susceptibility, infections, ototoxic medications, and lifestyle contributors. Pathophysiological mechanisms include cochlear synaptopathy, oxidative stress, excitotoxicity, vascular compromise, and immune-mediated injury. Global Burden of Disease data and World Health Organization reports indicate that more than one billion young people are at risk due to unsafe listening practices. Studies highlight emerging risk factors such as hidden hearing loss, extended high-frequency impairment and associations with COVID-19. Aggravating factors include delayed diagnosis, cumulative exposures and lack of preventive strategies. Early detection via advanced audiological assessments, such as extended high-frequency audiometry, otoacoustic emissions, speech-in-noise testing and auditory brainstem responses, is critical to prevent permanent damage. Public health interventions-particularly safe listening campaigns, early screening and monitoring in high-risk populations-are essential to reduce long-term disability.