Pure Tone Audiometry - Cochlea Hearing Loss

Cochlea Hearing Loss

Cochlea hearing loss is also known as sensorineural hearing loss (SNHL), and is most prevalent in the elderly. In this situation, the hearing loss is acquired through the ageing process, and is referred to as presbyacusis. SNHL is most commonly caused by damage to the OHCs and the IHCs. There are two methods by which they might become damaged. Firstly, the entire hair cell might die. Secondly, the stereocilia might become distorted or destroyed. Damage to the cochlea can occur in several ways, for example by viral infection, exposure to ototoxic chemicals, and intense noise exposure. Damage to the OHCs results in either a less effective active mechanism, or it may not function at all. OHCs contribute to providing a high sensitivity to quiet sounds at a specific range of frequencies (approximately 2–4 kHz). Thus, damage to the OHCs results in the reduction of sensitivity of the basilar membrane to weak sounds. Amplification to these sounds is therefore required, in order for the basilar membrane to respond efficiently. IHCs are less susceptible to damage in comparison to the OHCs. However, if they become damaged, this will result in an overall loss of sensitivity.