otolaryngeology ENT audiology

2. Basic audiological evaluation

3. Basic audiological evaluation
-History taking
-Otoscopy
-Tuning fork testing
-Hearing and speech assessment (pure tone
audiometry and speech audiometry)
-Assessment of middle ear function (tympanometry
and stapedial reflex)

4. Conduction of sound : by 2 ways
 Air conduction(AC): sound energy is transmitted from
the tympanic membrane to the ossicular chain to the
oval window.
 Bone conduction(BC) : sound energy is transmitted to
the inner ear through the bone of the skull

5. Types of Hearing Loss
CHL SNHL
Mixed HL

6. Tuning fork tests
1-Rinne’s test
2-Weber’s test
3-Schwabach’s test
- Tuning fork 512Hz is used (preferred than the high
frequency Tuning forks) as:
A- lower frequency produce more bone vibration
b- Tuning forks of higher frequency have shorter decay
time (how fast the tuning fork loses vibratory energy)

7. 1-Rinne’s test
 Idea :It compares hearing by AC with BC in the same ear.
 Technique :
-The fork applied near the
external auditory canal
-When the patient no longer
hear its vibration put the fork
over the mastoid

8.  Interpretation :
Normal: AC is better than BC (Rinnie +ve)
In CHL: BC is better than AC(Rinnie -ve)
In SNHL: AC is better than BC but both reduced than
normal ( reduced Rinnie +ve)

9. 2-Weber’s test
Idea : compares BC of both ears
Technique :
-Put the tuning fork over
The midline of the vertex,
forehead, chin or upper incisor
teeth.
-Ask the patient which ear
hears the sound louder?

10. Interpretation:
(This test is useful in identifying unilateral
hearing loss)
Normal: sound is heard in midline or both ears equally
CHL: sound is heard in the diseased ear
SNHL : sound is heard better in the normal or better hearing
ear

11. 3-Schwabach’s test
 Idea : Compares the BC of the examiner with the patient
 Technique : Put the vibrating tuning fork over the mastoid
of the patient , and then over the mastoid of the examiner .
 Interpretation :
 Normal: duration of hearing of
the patient equal to the examiner.
 CHL: longer than the examiner.
 SNHL: less than the examiner.

12. Tympanometry
 When sound is introduced to the ear, some of sound
waves are reflected from tympanic membrane. The
amount of sound reflected is monitored by
tympanometer and give an idea about the compliance
of the middle ear.
 Complaince : the ease of passage of sound

13. Tympanometry
 Tympanometry is an objective measure of middle ear
compliance change as air pressure is varied in the
external ear(-400 to + 200mmH2o).
 Compliance is maximum when the air pressure on
both sides of TM is equal.
 Middle ear pressure is the pressure at which peak
occurred.
 Normal middle ear pressure : 0-50 mm H20

14. Tympanometry
 Measures the ossicular mobility and pressure of
middle ear.

15. Types of tympanogram
 Type (A) tympanogram

16. Type (B)
Examble : otitis media with effusion

17. Type (c)
Example : eustachian tube dysfunction

18. (
Type (As

19. Type Ad:

20. Acoustic Reflexes (Stapedial
Reflex).
 Loud acoustic stimulus will cause bilateral contraction
(reflex) of stapedius muscles
 loud stimulus delivered to one ear, can measure reflex
response on the ipsilateral or contralateral ear.
 Acoustic reflex thershold(ART): the minimum
intensity required to evoke the reflex
-In normal ear ART is 80 dB

21. Value of acoustic reflex:
 1- Diagnosis of hearing loss
a) CHL :ART absent
b) SNHL : ART(elevated) above 80 dB
2- Determine the level of facial nerve lesion:
if the lesion is above nerve to stapedius absent reflex
if the lesion is below nerve to stapedius present

22. Pure tone audiometry

23.  Pure tone audiometry is used to measure threshold of
hearing an individual.
 The instrument used in this measurement is known as
audiometer.
 This is a subjective investigation, the accuracy of
which dependent on the response of the patient.

24.  Air conduction
 Bone conduction

25.  humans can hear ~ 20 Hz - 20000 Hz. Typically tested
frequencies include 250 Hz - 8000 Hz.
 Bone conduction thresholds are tested across
frequencies include 500-4000Hz.
 The softest level at which the pt can hear a sound
is called the threshold

26. Environment
 SOUND TREATED .
 SINGLE ROOM / DOUBLE ROOM
 WELL ILLUMINATED &
AIR CONDITIONED.

27. 0
10
20
30
40
50
60
70
80
90
100
110
120
dBHL
0
10
20
30
40
50
60
70
80
90
100
110
120
250 500 1000 2000 4000 8000 Hz 250 500 1000 2000 4000 8000 Hz
Lt.
Rt.
Discrimination %
SRT
Ear
10
10
100%
100%
Normal Hearing Audiogram
Air conduction
Bone conduction

28. Description of audiogram
Type of hearing loss
Degree
Configuration

29. Types of Hearing Loss
CHL SNHL
Mixed HL

30. Conductive Hearing Loss

31. Sensory neural hearing loss

32. Mixed hearing loss

33. Degree of hearing loss:
(depends on AC)
Mild H.L : <15-40 dB
Moderate H.L : >40-55 dB
Moderately severe>:55-70 dB
Severe H.L : >70-90 dB
Profound H.L : >90 dB

34. flat
Configuration:

35. Sloping (falling)

36. Rising

37. - Speech audiometry:
It is a speech subjective test which gives information
about the ability of the subject to communicate or
understand speech.
1-SRT
It is the intensity at which a patient can hear and correctly
repeat 50% of spondee words .
2- SDT :
It is the intensity at which the listener can just detect the
presence of a speech signal 50% of the time
It is used in :- neonates, infants and young children
- children with prelingual hearing loss

38. 3-Speech discrimination :
A standardized list of single syllable words are presented at 40
dB above the (SRT). The patient repeat the words. The score is
determined according to the percentage of words that are
correctly identified.
*Scores for speech discrimination:
 Excellent 88- 100%
 Good 72- <88%
 Fair 60- <72%
 Poor 40- <60%
 Very Poor < 40%

39. Speech discrimination:
-Normal ears: 100% discrimination score .
-Conductive hearing loss: 100% discrimination score,
but at higher intensity.
-Sensory hearing loss: 50-70% discrimination score
-Neural hearing loss: less than 40% discrimination
score.

40. Basic audiological evaluation for children:
1-subjective evaluation:
a- from 0 to 3 years : free field audiometry
b- from 3 to 5 years: play audiometry
2- objective evaluation:
a- Auditory brain stem response(ABR)
b-Otoacoustic emission (OAEs)

41. Auditory brain stem response(ABR)
 ABR are auditory evoked
response occurring with in
the first 10 -15 msec. post
stimulus onset.
 It represent synchronous
activity produced by neural
fibers of 8th cranial nerve
and brain stem.
 It consists of 5 positive
waves.

43. Clinical application of ABR
1-Screening tool
2- Diagnostic tool :
* For threshold detection( infant-young children-
uncooperative adults )
* Neuro-otologic : DD between cochlear and
retrocholear lesion
3-Intraoprative monitoring

44. Otoacoustic emissions(OAEs):
OAEs are acoustic energy produced by outer hair cells of
the cochlea and propagated through the middle ear to
be picked up in the external auditory canal
Types :
-Spontaneous: produced without
external stimuli
-Evoked : with external stimuli

45. Clinical application OF OAE:
1--Neonatal hearing screening: for all neonates for early
detection of congenital hearing loss
2--Cochlear function monitoring e g.
ototoxicity and noise exposure
3-- Diagnosis of retrochlear lesion (specially auditory
neuropathy): congenital hearing loss and normal OAE

46. Evaluation of vestibular function :
A-Vestibulo-spinal reflex:
- 1-Rombergs test:
- 2-Unterbergers test
- 3- Gait test
AII these tests the patient deviated to the affected
labyrinth

47. Evaluation of vestibular function(cont.)
b-Vestibulo-ocular reflex:
1-office test: e.g spontane0us nystagmus test ,gaze
test,…ect.
2- lab investigation:
*Videonystagmography (VNG)
*Rotational chair test
*Video head impulse test

48. Videonystagmography (VNG)
 Videonystagmography (VNG) is a complete diagnostic
system for recording, analyzing, and reporting eye
movements using video imaging technology, in which
hi-tech video goggles with infrared cameras are used.

49. Videonystagmography (VNG)
 VNG includes a series of tests used to determine
whether a vestibular disease may be causing a balance
or dizziness problem.
 It can differentiate between a central and
a peripheral vestibular lesion.
 If peripheral, it can decipher between unilateral and
bilateral vestibular loss.
 Determine the lesion compensated or not.

50. Videonystagmography (VNG)
It includes the following tests:
 Spontane0us nystagmus
 Gaze evoked nystagmus
 Oculomotor tests:
*Saccade
*Traking(smooth persuit)
*Optokinitic
 Dix-Hallpike (positioning) test
 Positional tests
 Caloric test

51.  Caloric test
-Patient lies supine and the head flexed forwards 30
degree ( lateral canal become vertical and maximally
stimulated)
- Each ear is irrigated : -cold water (30)
-warm water (44)
- Nystagmus is recorded

52. Results of caloric test :
 1- Normal ear:
- Nystagmus lasts for 2 mints
-The direction according to (COWS role)
2- Hypofunction of the labyrinth:
Nystagmus less than 1 mint
3- Dead labyrinth : No response