The Ear and Hearing

The Ear

How the Ear Works - videos

Statistics: Developed by HLA-Wake County, Raleigh, NC U.S. population 320+ million 2.5 million Deaf 34 million Hard of Hearing 1 of every 10 people has a hearing loss Over age 65, 1 in every 3 persons has some degree of hearing loss Understanding Hearing Loss

How Sound Travels  First, sound is collected by the pinna (the visible part of the outer ear)  Then, it is directed into the outer ear canal  Next, sound makes the eardrum vibrate  Now, the vibration causes three tiny bones (the ossicles) in the inner ear to vibrate  Hammer AnvilStirrup

How Sound Travels  Finally, the vibration is transferred to the snail-shaped cochlea in the inner ear  The cochlea is lined with sensitive hair cells  The hair cells trigger the generation of nerve signals that are sent to the brain

Hearing Loss * Unilateral loss: hearing loss in one ear. *Bilateral loss: hearing loss in both ears. *There are three kinds of hearing loss: Sensorineural Conductive Mixed hearing loss

Conductive Hearing Loss outer and/or middle part of the ear fail to work properly Sounds become "blocked" and are not carried all the way to the inner ear (where hearing is still normal) Not permanent; temporary hearing loss

Causes and Treatment of Conductive Hearing Loss a buildup of fluid in the middle ear wax in the ear canal puncturing of the eardrum problems or injury to the bones or membrane Conductive hearing loss can be easier to remedy than sensorineural or mixed hearing loss.sensorineuralmixed It is usually treatable with either medical or surgical intervention In cases where medical/surgical intervention is not an option, a hearing aid can be very helpful.

Sensorineural Hearing Loss Also known as nerve deafness the inner ear or actual hearing nerve itself is damaged About 90% of all people with hearing impairments suffer from this type of loss Most common Usually permanent not medically or surgically treatable In most cases, the hair cells or the nerves from the inner ear to the brain are irreparably damaged. wearing hearing aids may be of significant benefit

Causes of Sensorineural Hearing Loss the natural aging process exposure to loud noises infection or other disease a genetic disorder Tinnitus, or ringing in the ears, is usually associated with sensorineural hearing loss

Mixed Hearing Loss A combination of Conductive and Sensorineural

Noise! A major contributor to hearing loss in teenagers and adults. It can be prevented. Levels 85 and up are considered unsafe Interactive Sound Ruler City or freeway traffic 70 dB Hair dryer/alarm clock 80 dB Mowing the lawn- 90 dB Riding a motorcycle – 90 dB Race car/dance club- 110 dB Firecracker 140 dBInteractive Sound Ruler

Degree of Hearing Loss Normal Mild Moderate Severe Profound

Mild Hearing Loss A mild hearing loss may cause you to miss 25-40% of the speech signal. Usually this results in problems with clarity since the brain is receiving some sounds but not all of the information. Symptoms of mild hearing loss include problems understanding someone farther away than a normal distance for conversation, or even up close if the background environment is noisy. Weak voices are also difficult to understand for people with mild hearing losses.

Moderate Hearing Loss A moderate hearing loss may cause you to miss 50-75% of the speech signal. This means you would not have problems hearing at short distances and understanding people face-to-face, but you would have problems if distance or visual cues changed. Symptoms of moderate hearing loss include problems hearing normal conversations and problems hearing consonants in words

Severe Hearing Loss People with severe hearing loss have difficulty hearing in all situations. Speech may be heard only if the speaker is talking loudly or at close range. A severe hearing loss may sometimes cause you to miss up to 100% of the speech signal. Symptoms of severe hearing loss include inability to have conversations except under the most ideal circumstances (i.e., face-to-face, in quiet, and accompanied with speechreading).

Profound Hearing Loss Profound hearing loss is the most extreme hearing loss. A profound hearing loss means that you may not hear loud speech or any speech at all. You are forced to rely on visual cues instead of hearing as your main method of communication. This may include sign-language and/or speechreading (also commonly referred to as "lipreading")

Measuring your hearing Hearing threshold

How is hearing measured: Decibels (dB)- the intensity (volume or loudness) of a sound A whisper is about dB loud music is around 80 to 120 dB and a jet engine is about 140 to 180 dB Hertz – unit of frequency of sound waves Low bass tones range around 50 to 60 Hz Shrill, high - pitched tones range around 10,000 Hz or higher The normal range of human hearing is about 16 Hz to 16,000 Hz Animals can hear up to about 50,000 Hz.

Audiogram 10dB to 25dB = Normal hearing 26dB to 40 dB = Mild loss 41 dB to 70 dB = Moderate 71 dB to 90 dB = Severe over 90 dB = Profound

Speech Banana

What Causes Hearing Loss? Birth defects Premature birth Illness with high fever Meningitis Measles Scarlet fever Medications and drugs Genetic Usher syndrome Down syndrome RH incompatibility Injury to ear Loud noises! Ear infections Injuries to middle ear Head injury Old Age