This is important because it is a potentially preventable cause of hearing loss.
NIHL occurs when there is overstimulation of the cochlear hair cells, leading to an overproduction of radical oxygen species (a response to metabolic exhaustion) and consequential loss of stiffness (they go floppy and unresponsive) of the hair cells. Usually this is due to overexposure to loud stimuli (chronically and repeatedly). In response to a single loud noise, this reaction will take a period of time to recover, during which the patient will be unable to hear very well (this is known as a temporary threshold shift). When this process is repeated, the recovery generally takes longer and will not fully resolve every time. This is thought to be due to some ‘floppy’ hair cells becoming stuck down and permanently unresponsive (known as permanent threshold shift).
Treatment is usually with hearing aids.