Current insights in noise-induced hearing loss: a literature review of the underlying mechanism, pathophysiology, asymmetry, and management options

Abstract

BackgroundNoise-induced hearing loss is one of the most common forms of sensorineural hearing loss, is a major health problem, is largely preventable and is probably more widespread than revealed by conventional pure tone threshold testing. Noise-induced damage to the cochlea is traditionally considered to be associated with symmetrical mild to moderate hearing loss with associated tinnitus; however, there is a significant number of patients with asymmetrical thresholds and, depending on the exposure, severe to profound hearing loss as well.Main bodyRecent epidemiology and animal studies have provided further insight into the pathophysiology, clinical findings, social and economic impacts of noise-induced hearing loss. Furthermore, it is recently shown that acoustic trauma is associated with vestibular dysfunction, with associated dizziness that is not always measurable with current techniques. Deliberation of the prevalence, treatment and prevention of noise-induced hearing loss is important and timely. Currently, prevention and protection are the first lines of defence, although promising protective effects are emerging from multiple different pharmaceutical agents, such as steroids, antioxidants and neurotrophins.ConclusionThis review provides a comprehensive update on the pathophysiology, investigations, prevalence of asymmetry, associated symptoms, and current strategies on the prevention and treatment of noise-induced hearing loss.

Endoplasmic Reticulum Stress in Hearing Loss

“…Several mechanisms have been proposed to contribute to DIHL, NIHL, and ARHL, including oxidative stress, calcium overload, inflammatory responses, and hereditary susceptibility [38,[107][108][109][110]. Recent research has added ER stress and UPR to this list, although more details await further investigation (Table 1).…”

Recent Advancements in Gene and Stem Cell‐Based Treatment Modalities: Potential Implications in Noise‐Induced Hearing Loss

“…Steroids reduce inflammation by interacting with DNA‐binding receptor proteins and inhibiting gene expression of pro‐inflammatory proteins, most notably via the NF‐κB complex (McKay and Cidlowski, ; Adcock and Mumby, ; Patil et al, ). Steroids are considered as an essential component of current NIHL management but have been associated with extensive side effect profile and limited efficacy (Sakat et al, ; Le et al, ). Antioxidants such as N‐acetyl cysteine (NAC) mediate their effect through replenishment of glutathione species, thereby reducing the concentration of ROS that damages cellular integrity (Sha and Schacht, ).…”

“…In a 2011 report by US Government Accountability Office, hearing loss was the most prevalent occupational health disability in the Department of Defense (Fallavollita et al, ). Moreover, Department of Veteran Affairs incurred $1,102 billion in cost for hearing loss‐related compensation in 2005 alone (Le et al, ; McDait et al, ). It is safe to presume that the public socioeconomic burden due to hearing loss is even more, considering its large impact on the quality of life in a given person with NIHL (Alamgir et al, ).…”

Implications and Prevention of Noise Hazards on Board Ships

“…Intense exposures may even lead to the loss of hair cells. Reduced O 2 supply as a result of vasoconstriction may be a basic mechanism for temporary threshold shift (TTS) induced by noise [27][28][29][30][31][32][33][34][35] . On the preventive aspect, recent studies in this Institute have shown that inhaling a mixture of 5 per cent CO 2 and 95 per cent O 2 , known as Carbogen, for a brief period of 5 min effectively controls the effect of vasoconstriction by causing vasodilatation, which maintains the O 2 supply and increased metabolic demand.…”