Our two ears act as a type of receiving station for the brain. One ear is directed to the left, the other to the right. When the ears pick up a sound, the brain calculates the angle from which the sound has arrived. The brain has this capability since the closest ear receives the sound microseconds earlier than the other ear.
With only one ear functioning properly, origin of sound is impossible to determine. Even more importantly, the quality of sound is better when it is heard with two ears. Speech received by only one ear sounds flat and devoid of its rich nuances. In most cases, two hearing instruments are fitted to those with impaired hearing in both ears.
The ear is a very complex organ comprised of three parts: the outer ear, the middle ear and the inner ear. Hearing loss can result from damage to any of these three parts. Hearing loss resulting from a problem located in the outer or middle ear is called a conductive hearing loss.
From the inner ear, the auditory nerve transmits information to the brain. Hearing loss caused by a damaged inner ear is called a sensorineural hearing loss. A combination of these is known as a mixed hearing loss.
In order to gain a better understanding of hearing loss, it is important to know how the ear functions.
The outer ear includes the pinna, the auditory canal and the eardrum. These structures channel sounds from the environment into the middle ear. The pinna helps to gather sound waves and the auditory canal directs them to the eardrum.
The middle ear is an air-filled cavity that contains the smallest bones in the human body - the malleus, incus and stapes, which are connected to the eardrum and the inner ear. The Eustachian tube keeps the air pressure in the middle ear equal to that of the surrounding environment.
In the inner ear, sound is processed by the cochlea, while information affecting balance is processed by the semicircular canals. There are tiny hair cells along the entire length of the fluid-filled cochlea. When the fluid in the cochlea is displaced by sound waves, the hair cells bend. This triggers a chemical response that transmits the message to the area of the brain in charge of processing and interpreting what we hear.
Typical problems include excessive accumulation of earwax and infections of the auditory canal (e.g.. 'swimmer's ear').
Perforation of the eardrum, infection of fluid in the middle ear and otosclerosis (a calcification around the stapes limiting its ability to move) are the most common causes. Many outer and middle ear problems can be treated successfully with medication or surgery. In cases where treatment is not effective, remaining hearing loss can usually be helped by using hearing instruments.
The majority of hearing problems result from damaged inner ear structures. Typical causes are the natural aging process, excessive exposure to noise, medication that is toxic to to the auditory system and head injuries. As a rule, this damage cannot be reversed but can be largely overcome with hearing instruments.
Unable to hear soft sounds and difficulty understanding speech in noisy environments.
Unabl to hear soft speech and moderately loud sounds, considerable difficulty in understanding speech, particularly with background noise.
Unable to hear most sounds. Speakers must raise their voice to be heard. Group conversation is possible only with considerable effort.
Some very loud sounds are audible but communication without a hearing instrument or through sign language is very difficult.
Hearing loss in the inner ear (sensorineural hearing loss) initially affects high frequency sounds. These high-pitched sounds such as "s", "f", "sh" and "t" play a key role in our ability to understand speech clearly. This is why a person with this type of hearing loss will often say, "I can hear but I don't understand what is being said."
Speech consists of vowels and consonants in different frequency (pitch) and loudness categories. A healthy ear easily registers these sounds. When hearing loss is present, a louder level is required. Depending on the degree and progression of the hearing loss, these elements of the speech are softer than normal hearing threshold and are not audible, at least not when spoken at a normal level.
A hearing test is conducted using an audiometer. This test precisely measures the extent of the hearing loss. As the extent of the loss may be different in each ear, they are tested separately using headphones. Both the perception of sound and the understanding of speech are evaluated.
Contact Andersen Eye Associates to schedule a hearing examination with a physician.
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Andersen Eye Associates proudly serves the Greater Saginaw region including Flint, Frankenmuth, Bay City, Midland, Bridgeport, Bad Axe, Mount Pleasant, and surrounding areas.