pure tone audiometry

Card Set Information

pure tone audiometry
2014-02-01 17:35:43
355 aud

Show Answers:

  1. what are pure tone tests
    tests performed with an audiometer are extensions of the same concepts developed in tuning fork tests
  2. calibration
    • reliability of any test
    • test environment
    • patient performance
    • examiner sophistication
  3. what is being measured when pure tone is used
    • not actually measuring hearing but the response to a set of acoustic signals that we interpret as representing hearing
    • this is the only true hearing test
  4. audiometer
    • electronically driven tuning fork
    • electronically generated tones
    • vacuum tubes
    • transitors
    • integrated circuits
  5. specifications of audiometers
    • intensity range from -10 to 120 db
    • can have extensive high freq
    • air conduction of 125-8000 hz
    • earphone match
  6. testing suite
    • sound treated, not sound proof
    • different sizes
    • calibration important (if not calibrated, not getting a pure tone)
    • sound field measures
  7. expected patient responses
    • push button
    • hand raising
    • verbalization
  8. false positives
    • response when there is no signal 
    • usually from anticipating the signal
  9. hughson-westlake procedure for testing
    • ascend until tone is heard
    • decrease until tone is not heard
    • increase until tone is heard
    • repeat 3 times
  10. where do you start in hz when testing
    • 1000 hz because it is easily heard
    • has high test retest reliability
  11. asha says to start at ---- db
    • 30 db, if response decrease by 10db until no response, 
    • increase by 5 until a response
    • decrease by 10 db until no response
    • increase by 5 db until response
    • if no response at 30, increase by 20db until resonse then follow the above
  12. what are the major freqs used for speech
    5, 1, 2 hz
  13. what is used for high freq loss
    • fletcherian avg (500, 1000hz)
    • speech needs to match pure tone avg
  14. bone conduction
    max intensity levels
    • freq is from 250-4000hz
    • more power required for bc than for ac
    • max intensity levels a t50-70 db
    • more power causes distortion at higher freqs
    • low freqs may have feeling rather than hearing (vibrotactile)
  15. bone conduction arises from interactions of a least 3 different phenomenon
    • distortional
    • inertial
    • osseotympanic
  16. distortional bone conduction
    • skull set into motion
    • bones are distorted
    • activates certain cells
    • creates same electrochemical activity as by air conduction 
    • simultaneous with inertial and osseotympanic
  17. inertial bone conduction
    • because of inertia, ossicles lag behind so the stapes moves in and out of oval window just like in air conduction
    • simultaneous with distortional and osseotympanic
  18. osseotympanic bone conduction
    • oscillation of skull causes vibration of column of air in outer external canal
    •  sound waves move out of ear and toward tm like in air conduction
    • simultaneous with distortional and inertial
  19. bone conduction placement
    • mastoid process
    •     louder
    •     proximity to ear
    • forhead
    •     10db greater intensity needed
    • both ears must be uncovered
  20. what affects bone conduction
    • the condition of the outer and middle ear often affects the bone conduction thresh estimate because of the osseotympanic and inertial components
    • any pathologic condition that affects the conductive mech will also affect bone conduction
  21. thresh of audibility
    • the thresh of any stimulus is the lowest quantity that elicits a certain response
    • thresh of aud is the min effect sound pressure level that is capable of evoking an aud sensation
  22. aud thresh definition
    lowest intensity listener can identify 50% of the time
  23. at what db does crossover occur for bone?
    for air using headphones? for air using insert recievers?
    • 0db for bone
    • 40db for air earphones
    • 70db for air inserts
  24. what are some special considerations when getting pure tone
    • high freq like ototoxicity at 8000hz
    • stimulus length - 1-2 sec
    • patient variables include the ear shape and patient instructions
  25. sound field testing
    • stimulus through loud speaker, not a pure tone
    • freq modulated sounds for speech
    • difficulty knowing which ear is responding, OPEN AIR, NO HEADPHONES
    • no bone conduction scores
    • difficult to determine severe profound loss
    • sensitive to ambient noise
  26. when are children tested by regulation
    1,2 , 5, 8, and 10 and those in special ungraded classes and new students with no record
  27. —The Regulations of the Department of Health mandates Hearing Screening in the 11th grade because:
    • 1. 4/5 years have passed since the last mandated hearing test
    • 2. any identification of permanent hearing loss at that age may impact upon their ability to perform in a job and or advanced training
    • 3. of the ability to be referred to another program for assistance before the age of 21
    • 4. adolescents have more exposure to noise levels in school at that age
    • 5. hobbies and sports activities
    • 6. it may be their last opp to get state assistance
    • 7. hearing loss due to otosclerous may begin to become evident in the teen years