Ears 2 U: Hearing 101
 Stephen A.
Mitchell, MD
 Performance
Health Care
Committee
 Nashville, TN
Disclaimer
 Not selling anything
 Don’t care if you buy anything
 Not on payroll of any company that is
applicable to this presentation
 So there
Creds
 Otolaryngologist > 33 years
 Performance Health Care Committees
of NFA for MANY years (don’t ask)
 Performing Arts Medicine Association
since it started
 Wife her sister professional flutists
 I have ears
Why Should You Stay Awake For
This Talk?
 If you can’t hear, your career is over
 If you hurt your hearing, you will
suffer and be impaired forever
 Stupid things you do now may cause
irreversible damage to your ears with
no hope of restoration
 Things you do now can save your
ears
What’s the difference between:
 Using your $14,000 gold flute to
hammer a nail into the wall,
 or
 Sitting in the front row of a Smashing
Pumpkins Concert with no ear plugs?
 Answer:
 Not much, both are foolish and will
negate the time and effort and skill
you spent to learn your craft
What We Will Cover Today
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Anatomy
Physiology (how it works)
Testing
Causes of Hearing Loss
Prevention
Anatomy
 External ear
 Pinna
 Ear Canal
 Middle ear
 Ear bones
 Inner ear
 Cochlea
 Auditory nerve
 Brain
Physiology (how it works)
Pinna or Auricle
 Catches sound
wave vibrations in
air
 Funnel into meatus
of ear canal
 Permits directional
location
 Humans can’t
reposition to focus
Ear Canal
 Tube lubricated
with ear wax
 Amplifies 3 kHz to
12 kHz range
sounds 30-100 fold
 Voice centered
around 3 kHz
 Prone to acoustic
damage 3 kHz to
12 kHz
Ear Drum or Tympanic Membrane
 Membrane at end of ear canal
 Separates external from middle ear
 Converts air vibration of sound to
mechanical bone vibration of ossicles
(ear bones)
 Can rupture if air wave too intense,
protecting inner ear
Middle Ear: Ossicles or Ear Bones
 3 bones
 Mechanical lever
affect and ratio of
ear drum to oval
window amplifies
sound 25 dB
 Peak amp at 1 kHz
 Attached muscles
allow damping
Inner Ear or Cochlea
 Converts fluid waves into
membrane waves
 Hair cells convert fluid
waves into nerve
impulses
 Acoustic trauma and
diseases can injure hair
cell function
Auditory Nerve
 Pathway for electrical impulses from
cochlea to brain
 Preferred term is vestibulocochlear
nerve since it carries balance
information as well.
 Can be injured by skull fractures,
head trauma, or tumors
Brain: not as well understood
 Converts
electrical
signals into
sound as we
understand it
 Central
auditory
processing
 Psychoacoustics
Testing of Hearing System
 Establish baseline hearing
 Determine site and extent of damage
 Predict success of treatment or rate
of deterioration
 Rule out serious illness or tumors
Methods of Testing
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Clinical History and Exam
Audiogram
Tympanogram
Others: ABR, ECoG, OAE, CAP, ENG
Radiologic: CT, MRI, PET
Blood work: CBC, Glucose, Thyroid,
Lipids, etc
Clinical History and Exam
 Onset and
progression of
hearing problem
 Hx of contributing
illness, operations,
trauma, noise,
occupation
 Family history:
congenital/genetic
 Full ENT exam
Audiogram
 A map of how much
sound it takes at
different frequencies to
be heard.
 Help determine if loss
conductive,
sensorineural, central,
functional, or a mix
Decibel (dB): measurement of
sound level power relative to 0 dB
 Used for telephone
circuits in 1920’s
 A ratio of sound
relative to arbitrary
soft standard noise
(0 dB)
 Log scale (10x)
 120 dB = 1 trillion
 Range of ear so big
Tympanogram
 Measure of middle
ear function
 Position and
flexibility of TM
 Mobility or stiffness
of ossicles
 Fluid or air in
middle ear space
Other Basic Hearing/Ear Tests
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ABR: nerve function from ear to brain
ECoG: inner ear pressure (Meniere’s)
OAE: hair cell health
CAP: central auditory processing
ENG: balance testing, inner ear and
brain contribution
Radiologic Tests
 CT scan temporal bone (contains ear)
 Look for infection, tumor, congenital
defects
 MRI Brain and internal auditory canal
 Look for tumor, stroke, degenerative
disorders
 PET scan
 Tumor
Causes of Hearing Loss
 Hereditary (bad parental selection)
 Can be present at birth
 Most show up later in life
 Nonhereditary
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Conductive
Sensorineural
Central: brain has problems processing
Functional: faking for psychological or
financial gain
Conductive Hearing Loss
 External ear
 Wax, foreign body, canal infection
(swimmers ear), tumor
 Ear Drum
 Perforation, scarring
 Middle ear
 Fluid (otitis media)
 Ossicles stiff, fracture, eroded,
otosclerosis
Sensorineural Hearing Loss (SNHL)
 Neural: auditory nerve damage
 Tumor (acoustic neuroma)
 Trauma after temporal bone fracture or
shearing force to nerve and brain
 Sensory: inner ear
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Cochlea and hair cells
Unilateral or bilateral
Sudden or gradual onset
Congenital or acquired
Acquired Causes of SNHL
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Inflammatory (measles, mumps, HIV)
Ototoxic drugs (chemotx, ASA, Lasik)
Autoimmune (SLE, RA, Lortab)
Trauma and Tumor
Meniere’s (multiple causes)
Sudden SNHL (vascular, idiopathic)
Presbycusis (aging ear)
Noise induced
Noise Induced Hearing Loss (NIHL)
 Too much sound
hits hair cells for
too long a time
creates heavy
concentrations of
reactive oxygen
species (oxygen
ions, peroxides),
causing cell injury,
degeneration, and
eventual cell death.
NIHL
 Structural damage to hair cells can cause
distortion or reduction of sound perception
 Hearing loss can become PERMANENT
Types of NIHL
 Acute: permanent from one time
exposure to excessive sound pressure
 Explosion, gunfire, open hand slap to
ear, drum, air horn
 Gradual noise induced hearing loss
 Repeat exposure to loud sounds over
long period of time
 Heavy equipment, aircraft, personal
media players, MUSIC-INDUCED hearing
loss
Gradual NIHL (aka: threshold shift)
 Initial injury causes Temporary
Threshold Shift (TTS) of hearing
after injury, returning to normal after
few hours away from noise
 After sufficient injury over time, shift
becomes Permanent Threshold Shift
(PTS) and is irreversible
Result of PTS
 Ringing in ear
 Distortion of pitch and
quality of sound
 Hypersensitivity (pain)
 Psychological
pressures
 Hearing aids help
 But do NOT restore
normal hearing
How Much Noise Is Too Much?
 Controversial
 Depends on fragility of
individual ears
 Level of noise (dB) and
duration of exposure
(time)
 Types of noise
(instruments)
 $ = work comps =
lawyers = OHSA
Music-Induced Hearing Loss
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Occupational hearing loss accepted
Music-induced hearing loss debated
Rock music loss accepted
Classical music loss controversial
 Hard to determine which individuals or
groups are consistently at risk with
defined classical music exposure
 Not all research studies in agreement
Damage = intensity + time
Problem: both variable in music
Problem: Apples and Oranges
 Scand Audiol. 1983;12(4):257-64.
 The hearing of symphony orchestra
musicians.
 Karlsson K, Lundquist PG, Olaussen T.
 We suggest that the sound exposure
criteria for industrial noise are not
valid when discussing such sounds as
are produced by acoustic instruments
in a symphonic environment.
Musicians and NIHL: Now What?
 Fact: Musicians must hear good
 Fact: Noise can injure your hearing
 You are responsible for your health
 Not some Washington drone
 YOUR management of your soundlevel exposure is critical: just as
important as learning fingerings
Prevention of NIHL
 Education
 Self education
 Teacher provided education
 Your application above (“Just Do It”)
 Modify lifestyle
 Modify practice habits
 Modify workplace
 Spread the word to others
 Lobby for appropriate standards
Self Education
 If you’re awake, you’re self educated
 Internet search: “NASM-PAMA Draft”
 Draft by National Association of Schools
of Music (NASM) and Performing Arts
Medicine Association (PAMA)
 Recommendation to Faculty and
Students in Schools of Music
 Kris Chesky at UNT held NASM-PAMA
conference July 2004 to jump start
Your Homework
 Download and
read the
NASM-PAMA
drafts
 Check out
Hearnet.com
 Hearing
Education
Awareness for
Rockers
Wear hearing protection in ALL
noisy situations
Prevention
 Avoid any
hazardous noise
not required for
your occupation
“I’m from the government and I’m
here to help you”
 Do NOT count on OSHA
standards to protect
your ears
 Regulations are based
on industrial noise
 Represent minimum
allowable standards that
politicians can agree on
 We are NOT clones
Thank you, “enjoy” the exhibit hall