1. Bastaninejad, Shahin, MD, ORL-HNS
Auditory Assessment
Bastaninejad, Shahin, MD, ORL-HNS
Assistant Prof., TUMS
Amiralam Hospital
Acknowledgment: I would like to appreciate Prof. Borghei, for preparing this presentation

2. CHL
SNHL

3. Auditory Assessment Subjective tests Objective tests
Tuning fork tests (TFT)
Pure tone audiometry (PTA)
Speech audiometry
Objective tests
Impedance audiometry (Tym,AR)
Auditory Brainstem Response (ABR)
Otoacoustic Emission (OAE)
...

4. Tuning Fork Tests (TFT)
Rinne’s test
Weber’s test
Absolute Bone Conduction (ABC)

5. Rinne’s Test

6. Tuning Fork Tests (TFT)
Rinne’s Test
Principal: AC>BC
Rinne +: AC>BC, normal hearing or sensorineural hearing loss
Rinne -: AC<BC, conductive HL
False Rinne –: unilateral deep SNHL, due to cross over phenomena ,this can be avoided with masking

7. Weber’s Test

8. Tuning Fork Tests (TFT)
Weber’s Test
Principal: compares the BC of the two ears
Normal: hears equal on both sides or does not hear at all
Conductive HL: lateralized to the more affected side
SNHL: lateralized to the less affected side

9. Tuning Fork Tests (TFT)
Absolute Bone Conduction test
(Schwabach test)
Compares the BC of the examiner with the patient
Normal: equal to the examiner
CHL: longer than the examiner
SNHL: less than the examiner

10. Pure Tone Audiometry (PTA)
It is the graphic record of hearing Quantitatively & Qualitatively
Pure tones are delivered by head-phone for AC & by a vibrator for BC
X-Axis: Frequency range 125 – Htz (routinely depicted from Htz)
Y-Axis: Intensity of sound in decibels (dB)
A decibel is the smallest change in the intensity of sound which can be recognized by normal human ear

11. Pure Tone Audiometry (PTA)

12. Pure Tone Audiometry (PTA)
Normal Audiogram

13. Pure Tone Audiometry (PTA)
Range of hearing loss

14. Pure Tone Audiometry (PTA)
Conductive Hearing Loss (CHL)

15. Pure Tone Audiometry (PTA)
Sensori-Neural Hearing Loss (SNHL)

16. Pure Tone Audiometry (PTA)
Mixed Hearing loss

17. Masking To prevent ‘crossover’ phenomena Crossover happens with
40-60 dB AC difference in two ears
0-20 dB BC difference in two ears
Masking problem
Masking dilemma; in bilateral CHL or Bilateral Mixed HL
Overmasking  masking noise crosses over to the other side

18. Speech Detection threshold(SDT)
Speech Audiometry
Recorded voice is used
Speech Detection threshold(SDT)
An intensity level at which a listener can barely discern the presence of a speech signal in 50% of the time
It is equal to the PTA average obtained at 500,1000,2000Hz

19. Speech Reception Threshold (SRT)
Two syllabus words (Spondee)
With different intensities
The intensity at which 50% of the presented words can be repeated
Measured in dB (it is usually 8-9dB more than SDT)

20. Speech Discrimination Score (SDS)
Speech Audiometry
Speech Discrimination Score (SDS)
Mono syllable words
At 50dB higher than SRT
Percentage of words recognized correctly is noted
Normal: %
CHL: %
SNHL: low
Retro cochlear: very low

21. Impedance Audiometry Objective test Includes : Tympanometry
Acoustic Reflex
External Canal Volume (ECV)

22. Tympanometry
Record of resistance of conductive mechanism of ear against pressure changes of external canal
Type A: normal
Type B: OME, TM perforation, unfit probe, middle ear mass
Type C: Eustachian tube dysfunction
Type As: otosclerosis, tympanosclerosis
Type Ad: ossicular dislocation, or Atrophic TM
Type D: Scarred TM, or normal hypermobile TM

23. Tympanometry
Peak between -100 to +100

24. Tympanometry
Peak usually in-150 to -200

25. Tympanometry
Peak is under -300

26. Tympanometry

27. Acoustic Reflex Stapedial muscle contraction in response to loud noise
dB above hearing threshold
Particularly useful for DDx between Cochlear and Retrocochlear lesions
Afferent : cochlear (8th) nerve
Efferent : facial (7th)nerve

29. Acoustic Reflex Absent bilaterally when tested ear has CHL
BC must be better than 60dB to elicit this reflex
AR negative in tested ear but + in the contralateral  Retrocochlear lesion
AR Positive in Ipsi., but negative in Contra. Brain Stem lesion
It also demonstrate level of facial nerve lesion

30. ABR
Surface recording of the electrical activity of auditory pathway in response to sound  Sensitive for Retro-cochlear lesion
Wave 1 & 2: cochlear nerve
Wave 3: cochlear nucleus complex
Wave 4: Superior olivery complex
Wave 5: lateral leminiscus

31. Middle and Long Latency Response (MLR,LLR)
Lateral lemniscus
5th
Cochlear nucleus
ABR
3rd
4th
Sup. Olivary Complex
1st and 2nd

32. ABR

33. Oto-Acoustic Emission (OAE)
Normal cochlea generate a sound Due to the biological activity of outer hair cells
They are of 2 types:
Spontaneous emission (Spont.OAE50-70% of people)
Evoked otoacoustic emission

34. Any Question!?