To understand the causes of hearing loss, it is helpful to know how the ear functions. The ear consists of three parts: outer, middle, and inner ear. Sound enters through the outer ear, causes vibration of the tympanic membrane (or eardrum). The vibrations set the middle ear bones (malleus, incus, stapes) into motion. This motion causes movement of the fluid in the cochlea (or inner ear). The fluid causes a traveling wave that moves the tiny sensory hair cells encapsulated in the cochlea. The hair cells translate sound vibrations into electrical signals that are passed on to the auditory nerve, which sends the signal to the brain to be processed into sound. What a complicated process for a seemingly small part of the body!
There are three types of hearing loss: sensorineural, conductive, or mixed. Sensorineural hearing loss occurs when there is a disruption in the function of the inner ear or auditory nerve. Sensorineural hearing loss is typically permanent. Conductive hearing loss is caused when sound is prevented from traveling through the outer or middle ear. Conductive hearing loss can sometimes be treated with medicine or surgery. Mixed hearing loss includes both sensorineural and conductive components.
Hearing loss may be caused by several different factors. These factors include gradual buildup of earwax, abnormal bone growths or tumors, ear infections, ruptured ear drum, ear diseases (e.g., Otosclerosis, Meniere’s, autoimmune, etc.), genetics, viruses (e.g., measles, mumps, meningitis, etc.), ototoxic medications, loud noise, physical head injury, or simply, age.
Symptoms of hearing loss include perceiving speech as “muffled” or the belief that all speakers are mumbling; difficulty understanding speech, especially when competing against background noise; feeling that you can hear but cannot understand; frequently asking for repetition; increasing TV or radio volume; withdrawal from conversations; and avoidance of some social settings.
If you or a loved one is concerned about your hearing health, contact our office to schedule a hearing evaluation.
– Dr. Brie Noud, AuD, CCC-A