Audiology is defined as the evaluation, treatment and management of hearing and balance disorders in both adults and children. An Audiologist is a person with a master’s or doctorate degree in the specified field of audiology. An audiologist is able to perform diagnostic testing and provide treatment for hearing and balance disorders.
How We Hear
Hearing is the perception of sound waves in the environment. Sound waves are the mechanical movement of air particles. This movement occurs when a vibrator such as the speaker of a radio or a person’s vocal cords moves the air in the environment. Human ears are shaped to funnel and amplify this sound in to the ear canal and present it to the eardrum. The eardrum shakes in response to the sound waves, and sends the vibration through three bones in the middle ear called the malleus, incus and stapes. The stapes is attached to the oval window of the inner ear, and the sound is sent into the inner ear by the vibration of the stapes footplate. In the inner ear, sound now vibrates fluid and stimulates nervous tissue corresponding to the frequency of the sound. The nervous tissue then sends this sound to the brain in the form of electrical impulses.
How Hearing Loss Occurs:
Hearing loss is divided in to two categories based on its cause. Hearing loss may often be a mixture of the two types.
(1) Conductive hearing loss: Occurs when something interferes with the transmission of sound through the outer, middle or inner ear as described above. A conductive loss can be described as easily as sticking an earplug in your ear, which gives a mild hearing loss. Other causes for conductive hearing loss include fluid in the middle ear, otosclerosis, or a hole in the ear drum. Conductive hearing loss is often medically correctable, meaning that it may be repaired through surgical or other medical means. People with conductive hearing loss usually only lose sensitivity to soft sounds and retain the clarity of speech as long as it is loud enough.
(2) Sensorineural hearing loss: Occurs when there is no problem with the sound conduction, and the only cause for the hearing loss is damage to inner ear nervous tissue due to noise, medication or just the natural aging process. The sound is conducted as above through the outer and middle ear, but it is not carried to the brain as electrical impulse because there is damaged nervous tissue present. Sensorineural hearing loss is not able to be corrected surgically and relies upon generally making sound louder with a hearing aid or another assistive device in order to correct for the loss caused by this damage.