Ears 2 U: Hearing 101

1. Ears 2 U: Hearing 101 • Stephen A. Mitchell, MD • Performance Health Care Committee • Nashville, TN

2. 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

3. 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

4. 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

5. 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

6. What We Will Cover Today • Anatomy • Physiology (how it works) • Testing • Causes of Hearing Loss • Prevention

7. Anatomy • External ear • Pinna • Ear Canal • Middle ear • Ear bones • Inner ear • Cochlea • Auditory nerve • Brain

8. Physiology (how it works)

9. Pinna or Auricle • Catches sound wave vibrations in air • Funnel into meatus of ear canal • Permits directional location • Humans can’t reposition to focus

10. 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

11. 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

12. 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

13. 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

14. 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

15. Brain: not as well understood • Converts electrical signals into sound as we understand it • Central auditory processing • Psychoacoustics

16. 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

17. Methods of Testing • Clinical History and Exam • Audiogram • Tympanogram • Others: ABR, ECoG, OAE, CAP, ENG • Radiologic: CT, MRI, PET • Blood work: CBC, Glucose, Thyroid, Lipids, etc

18. 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

19. 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

20. 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

21. Tympanogram • Measure of middle ear function • Position and flexibility of TM • Mobility or stiffness of ossicles • Fluid or air in middle ear space

22. Other Basic Hearing/Ear Tests • 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

23. 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

24. Causes of Hearing Loss • Hereditary (bad parental selection) • Can be present at birth • Most show up later in life • Nonhereditary • Conductive • Sensorineural • Central: brain has problems processing • Functional: faking for psychological or financial gain

25. 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

26. 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 • Cochlea and hair cells • Unilateral or bilateral • Sudden or gradual onset • Congenital or acquired

27. Acquired Causes of SNHL • 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

28. 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.

29. NIHL • Structural damage to hair cells can cause distortion or reduction of sound perception • Hearing loss can become PERMANENT

30. 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

31. 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

32. 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

33. 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

34. Music-Induced Hearing Loss • 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

35. Damage = intensity + timeProblem: both variable in music

36. 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.

37. 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 sound-level exposure is critical: just as important as learning fingerings

38. 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

39. 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

40. Your Homework • Download and read the NASM-PAMA drafts • Check out Hearnet.com • Hearing Education Awareness for Rockers

41. Wear hearing protection in ALL noisy situations

42. Prevention • Avoid any hazardous noise not required for your occupation

43. “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

44. Thank you, “enjoy” the exhibit hall