Some medications cause irreversible damage to the ear, and are limited in their use for this reason. The most important group is the aminoglycosides (main member gentamicin ). A rare mitochondrial mutation, >G, can increase an individual's susceptibility to the ototoxic effect of aminoglycosides. Long term hydrocodone (Vicodin) abuse is known to cause rapidly progressing sensorineural hearing loss, usually without vestibular symptoms. Methotrexate , a chemotherapy agent, is also known to cause hearing loss. In most cases hearing loss does not recover when the drug is stopped. Paradoxically, methotrexate is also used in the treatment of autoimmune-induced inflammatory hearing loss.
Sensorineural hearing loss results from missing or damaged sensory cells (hair cells) in the cochlea and is usually permanent. Also known as “nerve deafness”, sensorineural hearing loss can be mild, moderate, severe or profound.
Mild to severe sensorineural hearing loss can often be helped with hearing aids or a middle ear implant . Cochlear implants are often a solution for severe or profound hearing loss.
Some individuals have a sensorineural hearing loss only in the high frequencies, also referred to as partial deafness. In these cases, only the hair cells at the base of the cochlea are damaged. In the inner part of the cochlea, the apex, the hair cells which are responsible for processing the low tones are still intact. Combined electric and acoustic stimulation, or EAS, was developed specifically for these cases.