Sensorineural hearing loss (SNHL) is a kind of loss of hearing attributed to problems in vestibulocochlear nerve, and sometimes the inner ear or the central processing centres of the brain. The loss may vary from mild to total deafness.
Most often, SNHL is due to abnormalities in the hair cells of the organ of Corti in the cochlea. Other rare SNHL involve the vestibulocochlear nerve or the auditory portions of the brain. In very cases, only the auditory centres of the brain are affected, leading to cortical deafness. This results in poor quality of sound received.
Majority of SNHL is due to improper hair cell function. This may be due to abnormality at birth or damage caused later in life. Both external causes like noise trauma and infection and intrinsic factors like genes are responsible for SNHL. Neural hearing loss is attributed to damage to the cochlear nerve that affects initiation or transmission of the nerve impulse along the nerve. Although rare, hearing loss may also may occur from abnormalities of the central auditory system in the brain. This condition, called central hearing impairment, is very rare because auditory pathways cross back and forth on both sides of the brain, enabling proper hearing. Prolonged exposure to very loud noise without hearing protection or using headphones for a long period set to high volumes can also cause hearing loss. Whether congenital or acquired, SNHL can be managed using hearing aids and cochlear implants.