A Story About the Ear Mrs. Jameson

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A Story About the Ear Mrs. Jameson
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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 in the
  inner ear to vibrate
  
• Hammer
• Anvil
• Stirrup

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Vibration of the eardrum
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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
  (cilia)
  
• The hair cells (cilia) trigger the generation of
  nerve signals that are sent to the brain

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Anatomy of the Ear

• Outer Ear
• Pinna
• Ear Canal
• Outer layer of the eardum
• Middle Ear
• Hammer
• Anvil
• Stirrup
• Inner Ear
• Cochlea
• Nerves
• Semicircular Canals

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Outer Ear

• Pinna- 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 eardrum
  
• Outer layer of eardrum- (tympanic membrane)
  vibrates when sound waves reach it

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Middle Ear

• Hammer (Malleus)- a tiny bone that passes
  vibrations
  
• Anvil (Incus)- a tiny bone that passes vibrations
  from the hammer to the stirrup
  
• Stirrup (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.

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Inner Ear

• Cochlea- 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.

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Semicircular Canals
Stirrup
Nerves
Anvil
Hammer
Pinna
Cochlea
Eardrum
Eustachian Tube
Outer Ear Canal
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Hearing Loss

• There are three kinds of hearing loss
• Sensorineural
• Conductive
• Mixed hearing loss

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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 sensorineural hearing loss
  
• Most common

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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

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Mixed Hearing Loss

• A combination of a conductive and sensorineural
  hearing loss
  
• Both the middle and inner ear are involved

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Causes 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
  which carry sound from the external ear through
  the middle ear to the inner ear.
  

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Sensorineural Hearing Loss

• Usually permanent
• not medically or surgically treatable
• In 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
  

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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

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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

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Treatment

• Conductive hearing loss can be easier to remedy
  than sensorineural or mixed hearing loss.
  
• 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.
  

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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

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Treatment for Mixed Hearing Loss

• With mixed hearing loss, the conductive part may
  be treated, but the sensorineural part is usually
  permanent.
  

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Levels of Hearing Loss

• Bilateral- both ears are impaired
• Unilateral- one ear is impaired

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Bilateral Hearing Loss

• Mild
• Moderate
• Severe
• Profound

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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.

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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

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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).

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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")

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• Decibels (dB)- the intensity (volume or loudness)
  of a sound
  
• A whisper is about 20 dB
• loud music (some concerts) is around 80 to 120
  dB
  
• and a jet engine is about 140 to 180 dB
• Usually, 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

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How Hearing Loss is Measured

• Hertz- a range of frequencies
• The tone of sound is measured in cycles per
  second (cps) or Hertz.
  
• 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
  
• Some people can hear within a slightly higher
  range
  
• Animals can hear up to about 50,000 Hz.

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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 range
• 26dB to 40 dB Mild hearing loss
• 41 dB to 55 dB Moderate hearing loss
• 56 dB to 70 dB Moderately Severe hearing loss
• 71 dB to 90 dB Severe hearing loss
• over 90 dB Profound hearing loss

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Audiogram

• Hearing loss is plotted on an audiogram
• Right ear is represented
• by a red circle
• Left ear is
• represented by
• a blue X

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Audiogram

• 10dB to 25dB Normal
• hearing
• 26dB to 40 dB Mild hearing loss
• 41 dB to 55 dB Moderate
• hearing loss
• 56 dB to 70 dB Moderately
• Severe hearing loss
• 71 dB to 90 dB Severe
• hearing loss
• over 90 dB Profound
• hearing loss

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Hertz/Decibels

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Decibels

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Hertz
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Identify the Hearing Loss

• What type of hearing loss is it?

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Normal Hearing
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Moderate Loss
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Mild Hearing Loss
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Profound Hearing Loss
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Speech Banana

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What Causes Hearing Loss?

• You tell me!