Analysis of Options to Reduce Noise Exposure to Shooters on Sport Shooting Ranges

The intensive development of sport shooting and the significant increase in the number of people using sport and recreational shooting ranges also increases the risk of hearing damage to shooters, due to exposure to impulse noise from the shots of firearms. This article discusses the methodology for assessing shooters’ exposure to noise and identifies and extensively discusses possible ways to minimise this exposure. It then describes a research experiment carried out to measure and calculate the effectiveness of noise reduction by means of acoustic silencers when shooting with typical weapons in the most popular sporting and hunting calibres. The experiment also included firing tests with subsonic ammunition. On this basis, conclusions were drawn regarding the possibility of reducing impulse noise during shooting and the possibility of eliminating the risk of hearing damage.

Priorities for occupational noise in Britain

Regulation of occupational exposure to noise in Britain for 50 years has reduced risk. However, statistics from around the globe (and in Britain alone) suggest that the range in harm is between around zero and more than 1 in 4 workers exposed to high noise. The uncertainty in statistics and the potential high incidence and prevalence of harm justifies investigation. In Britain, we will investigate the current risk of occupational hearing loss and the effectiveness of current noise control measures. We propose to gather data during inspections of industries that are known to have high levels of workplace noise. Finding high incidence of hearing damage will indicate a failure of immediate management of risk and likely result in enforcement action. We propose to review employers' control of noise propagation in the workplace through use and maintenance of noise controls supplied with machines and supplemented with acoustic barriers and noise havens. We propose to review suppliers design and build of noise control into their products and their reported noise emissions for noisiest typical use. We are looking to benefit from the experience of our global counterparts before finalising our plans.

Hearing protection and communication in high noise environments using vibration sensing and neural network voice transformation

In the United States alone, there are more than 9 million workers who are exposed to high levels of noise (> 85 dBA) that require hearing protection. Not only is there a risk of hearing damage due to these high noise levels, but it also prevents communication between people, leading to significant safety risks, including people not using hearing protection because of the desire to communicate. Workers in such high noise environments typically also wear safety glasses. This paper outlines an integrated system with safety glasses, hearing protection, and communication elements, using vibration sensing technology and a neural network based voice transformation routine. Data was collected to train the neural network based voice transformation. Recordings were made under various representative noise conditions, with some well exceeding sound pressure levels of 93 dBA, and Signal to Noise Ratios were extracted. In addition, experiments were conducted according to a modified ITU P.835 approach to determine intelligibility, naturalness and overall quality. The results demonstrate that with this approach, speech can be clearly understood in such high noise environments with this approach.

Predicting Parameters for Audiological Complications in Pediatric Patients Affected by Meningitis

Objective Meningitis is one of the most common causes of acquired sensorineural hearing loss in childhood. The aim of this study was to identify parameters predicting long-term audiological complications in meningitis. Methods Patients under 18 years admitted to the Bambino Gesù Pediatric Hospital between March 2001 and February 2019 with a diagnosis of meningitis entered the study. Audiological complications had been investigated during hospitalization and at follow-up. Results During the study period, 425 patients were enrolled. Sensorineural hearing loss was observed in 48 patients (11.3%). Multivariate analysis has shown that female gender predisposes to the development of permanent hearing loss after meningitis. Hearing impairment was associated with pneumococcal etiology (p < 0.001), lethargy (p = 0.027), reduced cerebrospinal fluid glucose level (26.18 mg/dL, p = 0.004), increase in both C-reactive protein (17.77 mg/dL, p = 0.001), and erythrocyte sedimentation rate (106.3 mm/h, p = 0.004). At follow-up, 19 patients had a persisting hearing damage, 7 recovered their hearing capacity and 20 were lost to follow-up. Among patients with permanent hearing damage, treatment was necessary in 16 patients. In details, 6 patients required external hearing aids and 10 patients required a cochlear implant. Conclusions Female gender, lethargy at onset, reduced cerebrospinal fluid glucose level, increased inflammation index, and pneumococcal etiology are correlated with sensorineural hearing damage in meningitis patients.

Occupational Hearing Loss

Occupational hearing loss received attention after the Industrial Revolution and through World Wars I and II. It currently accounts for the largest portion of occupational diseases, and a third of all hearing loss is due to noise. Occupational hearing losses include noise-induced hearing loss (NIHL), hearing loss caused by ototoxic substances and hearing loss caused by their complex interactions. In the case of NIHL, even when exposed to the same noise, the degree of hearing damage and recovery may vary from person to person, and also be affected by other noise in daily life. Various organic solvents and some heavy metals exposed in workplace are important causes of ototoxic hearing loss, and they are known to have additive or synergistic effects when accompanied by noise. In Korea, NIHL is the most common occupational disease and has been increasing continuously since the 1990s. The number of claims for compensation has also been increasing steadily. However, the developed country including Korea almost never considered the effects of chemicals on the diagnosis and compensation for hearing loss workers. Occupational hearing loss can be prevented through hearing conservation programs. In this chapter, we will introduce the scientific basis of noise induced hearing loss, the impacts of ototoxic substance and co-existence impact on hearing loss.

Customised enriched acoustic environment for sound therapy of tinnitus

Tinnitus is an auditory disorder very difficult to treat. Whereas up until now there is not a “cure” for tinnitus, the most extended treatment combines counselling with sound therapy. When this sound is a broadband noise in the audio frequency band, this protocol is named tinnitus retraining therapy. Even though broadband noise was proposed at the beginning as the stimulus for sound therapy, many other sounds have been subsequently proposed and used, including tones, noise bands, music, and nature sounds. Although any sound, low enough to avoid annoyance, discomfort or hearing damage, is better than silence for tinnitus treatment, it is not still clear the relationship of the success of the therapy with the properties of the sound stimuli. The aim of this article is to propose an optimal sound treatment that provides a precise and selective stimulation of the whole auditory system. The proposed sound stimulus, Enriched Acoustic Environment, consists of sequential tones or broadband noise matched to the HL curves of the patients. The acoustical characteristics of these stimuli are analyzed and their positive effects in the treatment of subjects with tinnitus are reported.

SARS-CoV-2 infecting the inner ear results in potential hearing damage at the early stage or prognosis of COVID-19 in rodents

ObjectivesIn order to find out the association between the sensorineural hearing loss and COVID-19, we detected the expression ACE2 and TMPRSS2 in the mouse the hamster.DesignUsing the public data from NCBI and GISAID, we assessed the expression of ACE2 and TMPRSS2 at the transcriptomic, DNA, and protein levels of ACE2 in the brain, inner ear, and muscle from the golden Syrian hamster (Mesocricetus auratus) and mouse (Mus musculus).ResultsWe identified ACE2 and TMPRSS2 expressed at different level in the inner ear and brain at DNA and transcriptomic levels of both mouse and the hamster. The protein expression shows a similar pattern of the brain and inner ear, while the expression of ACE2 from the inner ear was relatively higher than it from the muscle.ConclusionSARS-CoV-2 could infect the hearing system potentially and SSNHL could be a characteristic to detect asymptomatic patients of COVID-19.

Deep Neural Network Model of Hearing-Impaired Speech-in-Noise Perception

Many individuals struggle to understand speech in listening scenarios that include reverberation and background noise. An individual's ability to understand speech arises from a combination of peripheral auditory function, central auditory function, and general cognitive abilities. The interaction of these factors complicates the prescription of treatment or therapy to improve hearing function. Damage to the auditory periphery can be studied in animals; however, this method alone is not enough to understand the impact of hearing loss on speech perception. Computational auditory models bridge the gap between animal studies and human speech perception. Perturbations to the modeled auditory systems can permit mechanism-based investigations into observed human behavior. In this study, we propose a computational model that accounts for the complex interactions between different hearing damage mechanisms and simulates human speech-in-noise perception. The model performs a digit classification task as a human would, with only acoustic sound pressure as input. Thus, we can use the model's performance as a proxy for human performance. This two-stage model consists of a biophysical cochlear-nerve spike generator followed by a deep neural network (DNN) classifier. We hypothesize that sudden damage to the periphery affects speech perception and that central nervous system adaptation over time may compensate for peripheral hearing damage. Our model achieved human-like performance across signal-to-noise ratios (SNRs) under normal-hearing (NH) cochlear settings, achieving 50% digit recognition accuracy at −20.7 dB SNR. Results were comparable to eight NH participants on the same task who achieved 50% behavioral performance at −22 dB SNR. We also simulated medial olivocochlear reflex (MOCR) and auditory nerve fiber (ANF) loss, which worsened digit-recognition accuracy at lower SNRs compared to higher SNRs. Our simulated performance following ANF loss is consistent with the hypothesis that cochlear synaptopathy impacts communication in background noise more so than in quiet. Following the insult of various cochlear degradations, we implemented extreme and conservative adaptation through the DNN. At the lowest SNRs (&lt;0 dB), both adapted models were unable to fully recover NH performance, even with hundreds of thousands of training samples. This implies a limit on performance recovery following peripheral damage in our human-inspired DNN architecture.