The hearing threshold for low frequency (LF) tones was measured in a pressure field to investigate the effects of ageing on hearing sensitivity. Participants were young adults around 20 years old and older adults over 60. Measurement results showed that the older listeners had a higher threshold, on average, than the young listeners. The difference of median thresholds between these two groups was about 10 dB at every measurement frequency. Furthermore, hearing abnormalities other than age-related hearing loss showed no great effect upon the LF thresholds. Comparison of LF thresholds and audiograms (i.e. mid and high frequency hearing) of the older listeners revealed only moderate correlation between them. These results suggest that older people retain good hearing sensitivity in the LF region, in contrast to their often-degraded sensitivity at higher frequencies. Therefore, in LF noise evaluation, we should carefully regard the possibility that older listeners can perceive a low level LF noise.

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.

This study investigates the auditory capabilities of Golden Rabbitfish (Siganus guttatus) and the potential efficacy of sound-based deterrent methods for behavior control. Behavioral experiments were conducted on Golden Rabbitfish to assess their responses to sound stimuli. Sinusoidal pulses in the range of 100~800 Hz, based on previous research on auditory evoked potentials (AEPs), were utilized. An analysis of behavioral trajectories, swimming speed, and acceleration changes revealed the fish’s reactions to varying frequency sound stimuli. The results indicate that Golden Rabbitfish exhibited increased swimming activity and speed when stimulated by sound and notably moved away from the source under prolonged exposure to low-frequency acoustic signals. Specifically, the fish displayed the most significant response to 200 Hz sinusoidal pulses with a response threshold of 113~126 dB. These findings suggest that Golden Rabbitfish are particularly sensitive to low-frequency noise, aligning with AEP study outcomes. This study concludes that employing sound stimuli to deter Golden Rabbitfish in practical settings holds promise for mitigating economic losses in seaweed farming due to Golden Rabbitfish grazing. The results indicate that Golden Rabbitfish exhibited increased swimming activity and speed when stimulated by sound and notably moved away from the source under prolonged exposure to low-frequency acoustic signals. Specifically, the fish displayed the most significant response to 200 Hz sinusoidal pulses with a response threshold of 113~126 dB. These findings suggest that Golden Rabbitfish are particularly sensitive to low-frequency noise, aligning with AEP study outcomes. This study concludes that employing sound stimuli to deter Golden Rabbitfish in practical settings holds promise for mitigating economic losses in seaweed farming due to Golden Rabbitfish grazing. The letter (a) denotes a significant difference ( p < 0.05), a letter (b) denotes a non-significant trend (0.05 < p ). 4. Discussion Various fish species demonstrate diverse responses to noise exposure. Zebrafish ( Danio rerio ), for example, typically display startled reactions and an initial increase in swimming speed when exposed to noise, followed by a notable decrease in speed with prolonged exposure. In contrast, European minnows ( Phoxinus phoxinus ) initially exhibit a decrease in swimming speed in response to noise, which then rapidly increases over time [ 21 , 22 ]. The behavioral changes in Golden Rabbitfish are akin to those of zebrafish and European minnows. Following the abrupt cessation of acoustic stimuli, the fish display a notable increase in swimming speed ( Figure 6 , Figure 7 i and Figure 8 i,ii). This heightened behavior is most prominent after exposure to high-frequency sounds, with significant variations being observed in the speed of Golden Rabbitfish post-sound cessation at 600 Hz ( p = 0.024; F = 2.292), which are generally higher than the average swimming speed of fish treated under normal conditions ( Figure 11 B and Figure 12 ). The sound levels in the experimental environment can also impact the auditory perceptions of the fish, potentially leading to deviations in the experimental results obtained through behavioral methods. Golden Rabbitfish demonstrate negative phonotaxis, displaying heightened sensitivity to frequencies ranging from 100 to 400 Hz as indicated by two auditory threshold measurement experiments. When exposed to low-frequency sounds (100–200 Hz) over an extended period, the fish consistently moved away from the sound source, as evidenced by the notable behavioral changes observed ( Figure 10 C,D). Significant differences in the average swimming speed and acceleration of Golden Rabbitfish were particularly notable during exposure to 200 Hz of sound compared to other frequencies ( Figure 11 ), emphasizing their strong aversion to low-frequency sounds. In contrast, behavioral responses to frequencies in the range of 300–400 Hz varied among the experimental fish, with only some displaying a tendency to move away from the sound source ( Figure 10 E,F), while the others remained in close proximity. This suggests that not all fish exhibited escape reactions to sounds in this frequency range under the experimental conditions, possibly due to differences in perception or individual variability. However, not all fish exposed to prolonged sound stimuli exhibit behavioral changes such as distancing themselves from the sound source [ 26 ]. Studies have shown that zebrafish and Lake Victoria cichlids ( Haplochromis piceatus ) do not display a clear tendency to move away from sustained white noise or irregular intermittent pulses [ 21 ]. In contrast, the Convict cichlid ( Amatitlania nigrofasciata ) shows avoidance behavior in reaction to boat noise [ 27 Additionally, fish may demonstrate adaptive responses to prolonged noise exposure, potentially showing decreased reactions over time, indicating a level of habituation. Some fish may gradually acclimate to sound stimuli, which is linked to their tolerance levels [ 33 , 38 ]. Given the significant variability in response levels and behavioral changes across fish species, when implementing acoustic deterrence in natural aquatic settings, the potential impact on other species should be considered, including their physiological stress responses [ 39 , 40 ]. Furthermore, investigating the auditory thresholds of other fish species within the same marine environment is essential for a thorough selection of appropriate sound stimuli. 5. Conclusions Sound significantly influences fish behavior, and it is quite feasible to control or influence their actions through various auditory stimuli. Fish exhibit different tendencies to be attracted to sounds, with their responses differing based on sound frequency and intensity. Golden Rabbitfish are highly sensitive to low-frequency sine pulses, with a lower auditory threshold at these frequencies.

Abstract Background Prolonged earphone use is routine among young adults and may contribute to early changes in auditory thresholds. However, the specific usage patterns that predict auditory threshold elevation remain unclear. Hence, the present study evaluated frequency-specific auditory thresholds in young earphone users and usage-related predictors influencing auditory thresholds. A cross-sectional study was conducted among 110 medical students. Data on daily duration of earphone use, weekly frequency, years of exposure, preferred output volume, and gender were collected using a structured questionnaire. Pure-tone audiometry was performed for both the ears at frequencies from 0.25 to 8 kHz. Multiple linear regression analyses were applied separately for each frequency and ear to identify significant predictors of auditory thresholds shifts. Results Daily hours of earphone use emerged as a significant predictor of increased thresholds at low and mid frequencies (0.25–1 kHz, p < 0.01) in the right ear. Output volume was the most consistent predictor for left ear thresholds across multiple frequencies (0.5–8 kHz; p < 0.05). Weekly use showed a limited association, reaching significance only at 8 kHz in the right ear. Overall model fit was modest, with adjusted R² values ranging from − 0.03 to 0.11. Gender differences in mean thresholds were not statistically significant across frequencies. Conclusion Higher daily earphone use and increased output volume are associated with s Gender differences in mean thresholds were not statistically significant across frequencies. Conclusion Higher daily earphone use and increased output volume are associated with subtle, frequency-specific elevations in hearing thresholds in medical students. Although thresholds remained within normal limits, findings suggest early auditory stress. Adoption of safe listening practices may help prevent future noise-induced hearing loss. For adults, the WHO recommends a total weekly dose of 80 dB (for children 75 dB) for 40 h as safe exposure and as the volume increases, the safe duration drops significantly [ 4 ]. Clinically, permanent hearing loss is defined by hearing thresholds of 25 dB HL or worse, while normal hearing is defined as thresholds of 20 dB HL or better in both ears [ 5 ]. Although occupational noise exposure has been widely studied, growing body of evidence suggests that recreational listening through PLDs may cause similar cochlear stress and contribute to early manifestations of subclinical hearing damage [ 6 , 7 ]. Recreational NIHL resulting from PLD exposure often progresses gradually and is associated with early changes occurring at lower or mid-frequencies before progressing to the typical high-frequency notches which are characteristic of classical occupational noise exposure [ 1 , 8 ]. Studies have reported association between prolonged exposure to high-intensity sound with temporary threshold shifts (TTS) and permanent threshold shifts (PTS) [ 9 ]. These auditory shifts primarily involve damage to outer hair cells in the cochlea. Most of the prior studies have analysed general associations rather than frequency-specific regression modelling [ 8 , 10 ]. This has potentially obscured the subtle effects at lower frequencies and exact contribution by the various predictors. Young adults, especially college students, represent a particularly vulnerable group due to their prolonged earphone use and often at high-volume. They are prone for lifelong cumulative exposure risk [ 14 ]. This warrants the need for identification of modifiable risk factors and their role in auditory threshold shifts which is crucial for targeted preventive strategies and to promote hearing conservation in medical students. Gender showed modest associations at 0.5 kHz and 1 kHz however these effects were secondary to usage-related variables. The predominance of low-frequency associations in this study contrasts with the classical high-frequency involvement typically associated with 4 K dip in NIHL [ 1 , 12 , 22 ]. Jha et al. and Ramya et al., have also reported significant high-frequency hearing loss associated with prolonged earphone use [ 23 , 24 ]. While noise-induced hearing loss is classically associated with high-frequency notches, recreational exposure via PLDs often impacts speech frequencies (0.5–2 kHz) due to unique spectral, anatomical, and behavioral factors [ 7 , 25 ]. Additionally, increasing PLD volume to overcome ambient noise in urban environments results in intense, prolonged stimulation of the cochlea in the 0.5 kHz to 2 kHz range, where the auditory system is most sensitive [ 25 , 26 ]. These differences may reflect early cochlear changes, where metabolic stress and reversible functional alterations occur before the development of the classical high-frequency notch associated with NIHL [ 4 , 7 , 27 ]. The findings suggest that earphone use is associated with threshold changes at lower and mid frequencies; however, no consistent association was observed at higher frequencies in the present study. Overall, daily duration of earphone use was the strongest and most consistent predictor of hearing threshold elevation at lower frequencies in the right ear, while output volume emerged as the most consistent predictor These findings support the concept that threshold shifts may begin subtly and at lower frequencies before progressing to classical high-frequency loss. The study reinforces the importance of promoting safe listening practices with “60/60 rule” where one should use earphone at no more than 60% of maximum volume and not more than 60 min at a time. Public health initiatives targeting young adults should emphasize that normal audiograms do not necessarily indicate absence of auditory damage, especially with chronic recreational noise exposure. Strengths and limitations A major strength of this study is the use of frequency-specific regression modelling rather than pooled hearing outcomes.

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. Th

Fish’s hearing is sensitive to the frequency of underwater sound generated by offshore wind turbines, ranging from tens to hundreds of hertz. Marine organisms living near these turbines experience prolonged exposure to underwater sound. In this study, we developed a system for measuring underwater sound pressure levels and analyzed the effects of low-frequency sound on the behavior of Pagrus major (red sea bream). Low-frequency sound (100 Hz pure tone) was emitted at 15-min intervals from an underwater speaker installed in the experimental tank. Prior to low-frequency sound emission, the fish