2 How Sound Travels Hammer Anvil Stirrup First, sound is collected by the pinna (the visible part of the outer ear)Then, it is directed into the outer ear canalNext, sound makes the eardrum vibrateNow, the vibration causes three tiny bones in the inner ear to vibrateHammerAnvilStirrup
4 How Sound TravelsFinally, the vibration is transferred to the snail-shaped cochlea in the inner earThe cochlea is lined with sensitive hair cells (cilia)The hair cells (cilia) trigger the generation of nerve signals that are sent to the brain
5 Anatomy of the Ear Outer Ear Pinna Ear Canal Outer layer of the eardum Middle EarHammerAnvilStirrupInner EarCochleaNervesSemicircular Canals
6 Outer EarPinna- the visible part of the outer ear. It collects sound and directs it into the outer ear canal.Ear Canal- the tube through which sound travels to the eardrumOuter layer of eardrum- (tympanic membrane) vibrates when sound waves reach it
7 Middle Ear Hammer (Malleus)- a tiny bone that passes vibrations Anvil (Incus)- a tiny bone that passes vibrations from the hammer to the stirrupStirrup (Stapes)- a tiny, U-shaped bone that passes vibrations from the stirrup to the cochlea. This is the smallest bone in the human body. (.25 to .33 cm long)Eustachian tube- a tube that connects the middle ear to the back of the nose; it equalizes the pressure between the middle ear and the air outside.
8 Inner EarCochlea- a spiral-shaped, fluid-filled inner ear structure; it is lined with cilia (tiny hairs) that move when vibrated and cause a nerve impulse to form.Nerves- these carry electro-chemical signals from the inner ear (the cochlea) to the brain.Semicircular Canals- Fluid filled tubes attached to the cochlea that help us maintain our sense of balance.
9 Can you label the ear? Semicircular Canals Stirrup Nerves Anvil Hammer PinnaCochleaEardrumEustachian TubeOuter Ear Canal
10 There are three kinds of hearing loss: Sensorineural Conductive Mixed hearing loss
11 Sensorineural Hearing Loss Also known as nerve deafnessthe inner ear or actual hearing nerve itself is damagedAbout 90% of all people with hearing impairments suffer from sensorineural hearing lossMost common
12 Conductive Hearing Loss outer and/or middle part of the ear fail to work properlySounds become "blocked" and are not carried all the way to the inner ear (where hearing is still normal)Not permanent; temporary hearing loss
13 Mixed Hearing LossA combination of a conductive and sensorineural hearing lossBoth the middle and inner ear are involved
14 Causes of Conductive Hearing Loss a buildup of fluid in the middle earwax in the ear canalpuncturing of the eardrumproblems or injury to the bones or membrane — which carry sound from the external ear through the middle ear to the inner ear.
15 Sensorineural Hearing Loss Usually permanentnot medically or surgically treatableIn most cases, the cillia or the nerves from the inner ear to the brain are irreparably damaged.wearing hearing aids may be of significant benefit
16 Causes of Sensorineural Hearing Loss the natural aging processexposure to loud noisesinfection or other diseasea genetic disorderTinnitus, or ringing in the ears, is usually associated with sensorineural hearing loss
17 Causes of a Mixed Hearing Loss This hearing disorder can also occur when a person first just has a permanent sensorineural hearing loss and then also develops a conductive hearing loss.For example, a person who already has a sensorineural loss gets a middle ear infection, and the two types of loss combine to create a greater hearing loss.Some other instances of mixed hearing loss are the result of the outer and inner ear being malformed, which causes both types of hearing loss
18 TreatmentConductive hearing loss can be easier to remedy than sensorineural or mixed hearing loss.It is usually treatable with either medical or surgical interventionIn cases where medical/surgical intervention is not an option, a hearing aid can be very helpful.
19 Treatment Sensorineural hearing loss is usually permanent no medically or surgically treatable. In most cases, the nerves from the inner ear to the brain are irreparably damaged.However, most people with this hearing loss find wearing hearing aids to be of significant benefit
20 Treatment for Mixed Hearing Loss With mixed hearing loss, the conductive part may be treated, but the sensorineural part is usually permanent.
21 Levels of Hearing Loss Bilateral- both ears are impaired Unilateral- one ear is impaired
22 Bilateral Hearing Loss MildModerateSevereProfound
23 Mild Hearing LossA 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.
24 Moderate Hearing LossA 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
25 Severe Hearing LossPeople 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 speech reading).
26 Profound Hearing LossProfound 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 speech reading (also commonly referred to as "lip-reading")
27 How Hearing Loss is Measured Decibels (dB)- the intensity (volume or loudness) of a soundA whisper is about 20 dBloud music (some concerts) is around 80 to 120 dBand a jet engine is about 140 to 180 dBUsually, sounds greater than 85 dB can cause hearing loss in a few hours; louder sounds can cause immediate pain, and hearing loss can develop in a very short time
28 How Hearing Loss is Measured Hertz- a range of frequenciesThe tone of sound is measured in cycles per second (cps) or Hertz.Low bass tones range around 50 to 60 HzShrill, high - pitched tones range around 10,000 Hz or higherThe normal range of human hearing is about 16 Hz to 16,000 HzSome people can hear within a slightly higher rangeAnimals can hear up to about 50,000 Hz.
29 Identifying Hearing Loss Ranges have been established to help people identify how much difficulty they should expect from their hearing loss. The typical ranges for an adult are:-10dB to 25dB = Normal range26dB to 40 dB = Mild hearing loss41 dB to 55 dB = Moderate hearing loss56 dB to 70 dB = Moderately Severe hearing loss71 dB to 90 dB = Severe hearing lossover 90 dB = Profound hearing loss
30 Audiogram Hearing loss is plotted on an audiogram Right ear is representedby a red circleLeft ear isrepresented bya blue X
31 Audiogram 10dB to 25dB = Normal hearing 26dB to 40 dB = Mild hearing loss41 dB to 55 dB = Moderatehearing loss56 dB to 70 dB = ModeratelySevere hearing loss71 dB to 90 dB = Severeover 90 dB = Profound