dr bandar mohammed al qahtani m d ksmc n.
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AUDIOLOGY IN ORL PowerPoint Presentation
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  2. Tympanic mem & Ossicular Amplification22:1 in total 1.3:1 maleus to incus (lever action) 17 :1 TM surface to stapes footplateproblem in transmission leads to CHL

  3. Anatomy of hearing organTHE COCHLEA

  4. Traveling wave & Tonotopic organization Traveling wave & Tonotopic organization High frequency at base and low frequency at apexproblem inside the cochlea transmission leads to SNHL

  5. Auditory Assessment Clinical vs audiometric tests Clinical : - finger friction - watch test - speech test - tuning fork test

  6. Audiometric tests : subjective vs objective tests - pure tone audiometry - speech audiometry - impedance audiometry a-tympanometry b-acoustic reflex

  7. Anatomy

  8. AudiometricAssessment Pure Tone Audiometry Speech Audiometry Acoustic Immittance (impedance test ) Auditory Brainstem Responses Electrocochleography Otoacoustic Emissions

  9. Pure Tone Audiometry Most common ,subjective test Air conduction testing Frequencies 125,250,500,1000,2000,4000,8000 HZ Bone conduction testing 250,500,1000,2000,4000 HZ

  10. Pure tone audiometry

  11. USES • As baseline test (pre op and post op) • To differentiate the conductive vs sensorineural pathway • The degree of handicap or heaing loss and which frequencies

  12. Crossover Audiometric results are only valid when the results are actually of the test ear. Interaural attenuation reflects crossover. Air conduction from 40-80dB Bone conduction even at 0dB

  13. Masking The audiometric technique used to eliminate responses by the non-test ear. An appropriate noise is presented to the non-test ear while the test ear is being tested. Masking level must exceed the non-test ear threshold, but not create crossover.

  14. Speech Audiometry Determines how well a person hears and understands speech,subjective test. Spondee words SRT 50% of spondees SRT should be in close correlation with PTA +- 10 db of PTA. Discrimination score (DS) (90-100% in normal or conductive DS is 60-70 in sensory hearing loss


  16. USES-malingerer patients-for fitting Hearing Aids-for cochlear implant patients-to differentiate cochlear than retro-cochlear lesion

  17. Acoustic Immittance Impedance: resistance to acoustic flow,objective test Admittance: ease of acoustic flow Tested by: Tympanometry Acoustic Stapedial Reflex

  18. Tympanometryby Jerger

  19. A normal between 100-(-100) As stiff type otosclerosis or stiff TM. Ad flaccid type ossicular discontinuity B flat –fluid in ME or thick TM C more in negative –retracted TM

  20. Acoustic Stapedial Reflex to elicit a stapedial muscle contraction, objective test. 3 primary acoustic reflex characteristics Presence or absence of the reflex Reflex threshold Reflex Decay It tests VIII,brain stem ,VII Good for screening in infants and malingerer

  21. Acoustic Reflex Decay Measures the ability of the stapedius muscle to maintain sustained contraction. Lower frequency tone/noise for 10 seconds

  22. Facial Paralysis Absent or abnormal stapedial reflex when the recording probe is ipsilateral to the side of the lesion. Can also be helpful in locating lesions proximal or distal to the stapedial muscle.

  23. Eighth nerve lesions Absent reflexes when stimuli is presented to the affected ear. Reflexes in eighth nerve lesions are not dependent on the degree of hearing loss. Rapid reflex decay

  24. Auditory Brainstem Responses Impulses that are generated by the auditory neural pathway that can be recorded on the scalp. objective test Not affected by sleep, sedation, or attention.

  25. Bone Conduction ABR As reliable and repeatable as air conduction ABR. Particularly useful in structural abnormalities Canal Atresia or stenosis

  26. ABR Primary goal is a clear and reliable Wave I Wave I : distal 8th nerve Wave II : proximal 8th nerve Wave III : cochlear nuclei Wave IV : SOC Wave V : Lateral Lemniscus

  27. ABR

  28. Otoacoustic Emissions Low energy sounds produced by the cochlear outer hair cells,objective test. Cochlear amplification. Spontaneous emissions Not present in greater than 25dB hearing loss. Evoked Emissions Transient evoked Distorted Product

  29. OAE and middle ear pathology Transmission properties of the middle ear directly influence the OAE characteristics. Otitis media Newborns Tympanic membrane perforations