by Sara Adaes, PhD (c)
May 20, 2015
Hearing disorders are among the most common health problems. The World Health Organization estimated in 2012 that over 5.3% of the world’s population has disabling hearing loss, and the overall aging of the population will most likely keep increasing this number. In the older population, hearing impairment is also associated with the onset and progression of dementia. Hearing impairment in children can lead to communication disorders that affect the development of language having lifelong consequences.
Sensorineural hearing loss is the most common form of hearing impairment and typically occurs as a result of the loss of functional sensory hair cells within the cochlea. The sensory hair cells are responsible for converting sound vibrations into electrical stimuli that are them conveyed to the central nervous system via the auditory neurons, better known as spiral ganglion neurons.
The sensory hair cells are highly sensitive to ototoxic drugs, over-exposure to noise, and viral and bacterial infections. Sensorineural hearing loss can have a hereditary cause, but age-related hearing loss gradually occurs in most individuals as they grow older, with approximately 30% of adults between the ages of 65–74 years having some degree of hearing deficits.
Cochlear implants are a common solution to hearing impairment, allowing speech . . .