This document discusses the assessment of hearing. It describes the anatomy of the hearing pathway and types of hearing loss. Key clinical tests to assess hearing are described, including tuning fork tests like Rinne's test and Weber's test. Pure tone audiometry is explained as the method to measure hearing thresholds at different frequencies and classify levels of hearing loss. Different patterns on audiograms can indicate conductive, sensorineural or mixed hearing loss. Otoscopy is also briefly mentioned as an examination technique.

1. THE ASSESSMENT
OF HEARING - Revision
M. DIN
THE ASSESSMENT
OF HEARING - Revision
M. DIN

2. ANATOMY

3. HEARING PATHWAY
AIR CONDUCTION (WHOLE PATH)
EAC  TM  ME  COCH  CN   Br
SKULL BONES
BONE CONDUCTION
NB AC>BC
AIR CONDUCTION (WHOLE PATH)
EAC  TM  ME  COCH  CN   Br
SKULL BONES
BONE CONDUCTION
NB AC>BC

4. • External Ear- Conduction & some
amplification
• Middle Ear – Conduction and amplification
• Inner ear ( Cochlea)- Transduction
• Cochlear nerve- Transmission
• External Ear- Conduction & some
amplification
• Middle Ear – Conduction and amplification
• Inner ear ( Cochlea)- Transduction
• Cochlear nerve- Transmission

5. HEARING LOSS
– CONDUCTIVE- if conduction is
affected- EE & ME
– SENSORI-NEURAL- If the transduction or
transmission is affected- Cochlea & Cochlear
Nerve
– MIXED- Both
– CONDUCTIVE- if conduction is
affected- EE & ME
– SENSORI-NEURAL- If the transduction or
transmission is affected- Cochlea & Cochlear
Nerve
– MIXED- Both

7. Hearing assessment
• Presence of hearing loss
• Type of hearing loss
• Amount of hearing loss
• Cause of hearing loss
• Presence of hearing loss
• Type of hearing loss
• Amount of hearing loss
• Cause of hearing loss

8. Basic clinical tests:
Finger friction/watch ticking test
• Measure distance at which a normal person
hears watch ticking or finger friction
• This distance can be compared with the
distance which a patient hears the same
sound
• Measure distance at which a normal person
hears watch ticking or finger friction
• This distance can be compared with the
distance which a patient hears the same
sound

9. TUNING FORK TESTS

10. PRINCIPLE’S OF
TUNING FORK TESTING
• IN NORMAL HEARING
– AC >BC
– BOTH EARS BC ESSENTIALLY EQUAL
• IN CHL
– BC >AC (> 25-30 dB)
– BC better than normal persons BC because
ENVIORNMENTAL NOISE NOT HEARD
• IN SNHL
– AC >BC (BOTH PATHWAYS AFFECTED)
• IN NORMAL HEARING
– AC >BC
– BOTH EARS BC ESSENTIALLY EQUAL
• IN CHL
– BC >AC (> 25-30 dB)
– BC better than normal persons BC because
ENVIORNMENTAL NOISE NOT HEARD
• IN SNHL
– AC >BC (BOTH PATHWAYS AFFECTED)

11. SCHWABACH’S TEST
• COMPARE BONE CONDUCTION OF
SUBJECT WITH EXAMINER
– NORMAL- SAME
– CHL- SUBJECT PROLONGED
– SNHL- SUBJECT SHORTENED
• COMPARE BONE CONDUCTION OF
SUBJECT WITH EXAMINER
– NORMAL- SAME
– CHL- SUBJECT PROLONGED
– SNHL- SUBJECT SHORTENED

12. RINNE’S TEST
Compare AC and BC of each ear

13. RINNE’S TEST
• NORMAL- AC >BC: RINNE’S POSITIVE
• CONDUCTIVE HEARING LOSS(>25 dB)
BC>AC: RINNE’S NEGATIVE
• SENSORI-NEURAL HEARING LOSS
AC>BC: RINNE’S POSITIVE
• !!! RINNE’S FALSE NEGATIVE
IN UNILATERAL SNHL
Subject answers from the non- tested ear
• NORMAL- AC >BC: RINNE’S POSITIVE
• CONDUCTIVE HEARING LOSS(>25 dB)
BC>AC: RINNE’S NEGATIVE
• SENSORI-NEURAL HEARING LOSS
AC>BC: RINNE’S POSITIVE
• !!! RINNE’S FALSE NEGATIVE
IN UNILATERAL SNHL
Subject answers from the non- tested ear

14. Rinne’s
test
Normal
CHL
SNHL

15. WEBER’S TEST
Compare the BC of both ears ( with each other)

16. WEBER’S TEST
• NORMAL- CENTRAL
• CONDUCTIVE HEARING LOSS
LATERALISES TO AFFECTED EAR
• SENSORI-NEURAL HEARING LOSS
LATERALISES TO BETTER EAR
NB- lateralisation occurs > 5dB difference -
-May have central Weber‘s if both sides
have equal hearing loss
• NORMAL- CENTRAL
• CONDUCTIVE HEARING LOSS
LATERALISES TO AFFECTED EAR
• SENSORI-NEURAL HEARING LOSS
LATERALISES TO BETTER EAR
NB- lateralisation occurs > 5dB difference -
-May have central Weber‘s if both sides
have equal hearing loss

17. Normal
R CHL
L SNHL

18. SOUND LEVEL
MEASUREMENT
DECIBEL SCALE
SOUND PRESSURE IN dB
=20 x Log10 measured SP/ reference SP
Reference SP is the least amount of sound that
can be heard by a normal hearing person at a
specific frequency
= 20mPa (20 x 10-6 N/m2 )
DECIBEL SCALE
SOUND PRESSURE IN dB
=20 x Log10 measured SP/ reference SP
Reference SP is the least amount of sound that
can be heard by a normal hearing person at a
specific frequency
= 20mPa (20 x 10-6 N/m2 )

19. PURE TONE AUDIOMETRY
• AC & BC TESTED FOR EACH EAR
– At different frequencies
• CALLIBRATED SOUND IN DECIBELS
– 0 dB - 20 dB NORMAL
– 21dB - 40 dB MILD HL
– 41dB - 60 dB MODERATE HL
– 61dB - 80 dB SEVERE HL
– >80 dB PROFOUND HL
• AC & BC TESTED FOR EACH EAR
– At different frequencies
• CALLIBRATED SOUND IN DECIBELS
– 0 dB - 20 dB NORMAL
– 21dB - 40 dB MILD HL
– 41dB - 60 dB MODERATE HL
– 61dB - 80 dB SEVERE HL
– >80 dB PROFOUND HL

20. Pure tone audiometry
• Masking
– Delivery of wide band noise the non-tested ear
– Always needed in BC measurements
– Needed if > 50-60 dB AC measurements
• Masking
– Delivery of wide band noise the non-tested ear
– Always needed in BC measurements
– Needed if > 50-60 dB AC measurements

21. PTA- nomenclature
• O Right ear AC
• X Left ear AC
• [ Right ear BC with masking
• ] left ear BC with masking
• If no masking BC-Δ
• Air conduction readings linked, BC left
unatttached
• O Right ear AC
• X Left ear AC
• [ Right ear BC with masking
• ] left ear BC with masking
• If no masking BC-Δ
• Air conduction readings linked, BC left
unatttached

22. AUDIOGRAMS
Normal- AC=BC CHL- BC<AC

23. AUDIOGRAM
SNHL- BC&AC
affected equally
SNHL- BC&AC
affected equally

24. -
1
0 0.25 0.5 1 2 4 8
1
6
0
10
20
30 [ [ [ [ [
40 [
50
60 o o o o o o
Mixed hearing
Loss- both
conductive and
sensorineural
components
60 o o o o o o
70
80
90
10
0
11
0
Mixed hearing
Loss- both
conductive and
sensorineural
components

25. EXAMINATION
OTOSCOPY
OTOSCOPY

26. Summary
• Know the technique and expected results of
the clinical tests of hearing.
• Know the method of audiometry, masking,
the nomenclature and the common types of
audiograms
• Know the technique and expected findings
in otoscopy
• Know the technique and expected results of
the clinical tests of hearing.
• Know the method of audiometry, masking,
the nomenclature and the common types of
audiograms
• Know the technique and expected findings
in otoscopy

28. .
THANK
YOU
THANK
YOU