ABSTRACT
Permanent Noise-induced hearing loss (NIHL) most commonly follows repeated noise exposure over a long period of time, but can occur following a single loud noise exposure, known as acoustic trauma. Noise that is sufficiently loud to cause injury can broadly be categorised as occupational, environmental or recreational. While the exact mechanism of NIHL is incompletely understood, it is well recognised that in most cases NIHL is multifactorial, with a complex interaction between genetic and environmental factors. Tinnitus and hyperacusis are also common and their onset related to noise exposure supports the diagnosis of NIHL. In the UK, some occupations may be eligible to claim social benefits for NIHL from the Industrial Injuries Disablement Benefit or the Armed Forces Compensation Scheme. In the NIHL field, sound pressure levels are most commonly described using the A-weighted decibel scale, which accounts for the relative loudness of low level sounds perceived by the human ear at different frequencies.
