Clinical and audiological assessment of hearing
undergraduate level
MBBS
Presentation by Khair-Ullah and Sana-Ullah 4th year MBBS, Karachi, pakistan
ENT ward
1. ASSESSMENT OF HEARING
(clinical & audiological)
PRESENTED BY;
SANA -ULLAH
KHAIR-ULLAH
MBBS 4TH YEAR
HAMDARD UNIVERSITY
KARACHI, PAKISTAN
2. ASSESSMENT OF HEARING
Objectives:
To evaluate;
1] Type of hearing loss (conductive,sensorineural or
mixed)
2] Degree of hearing loss (mild,moderate,severe or
Profound/ total)
3] Site of lesion ( If conductive= external
ear,tympanic membrane,middle ear,ossicles or
Eustachian tube.
If sensorineural=cochlear,retrocochlear{VIII nerve} or
central)
5. CLINICAL TESTS OF HEARING
Rinne’s positive= AC>BC
Rinne’s negative =AC<BC= Conductive deafness (confirmed by performing
test in reverse direction)
Rinne’s reduced positive = Both AC and BC are reduced but still AC is
better than BC (sensorineural deafness)
Rinne’s false negative = sound may be perceived by other ear during test
(profound/total sensorineural deafness)
7. CLINICAL TESTS OF HEARING
Where is it heard?
Simultaneous in both ears=centeralized
Lateralized towards diseased ear=
Conductive deafness
lateralized towards normal ear=
Sensorineural deafness
8. CLINICAL TESTS OF HEARING
Schwabach’s test:
(test for nerve deafness)
compares the bone conduction of patient with that of examiner
ABC Test:
same as Schwabach’s test except
that external acoustic meatus is
closed
9. CLINICAL TESTS OF HEARING
IN CHILDREN
at 3 months= Stilling= child quietens in response to
a sound stimuli
at 5 months= moves eyes in response to a sound
stimuli
at 6 months= moves head in response to a sound
stimuli
at 7 months= Distraction Test= child tries to locate
the sound by moving his head
10. Audiological Tests for Assessment of hearing
Audiometry :
Audiometry is another method of assessing the patients hearing
levels. This test is normally carried out by an audiologist and is
conducted in a sound proof room. The audiometer will then
provide sounds at different frequencies to a set of headphones
that the patient is wearing. The head phones will be used to
assess AIR CONDUCTION. There is also a small metal vibrator
attached to the head unit which will be placed on the mastoid
to assess BONE conduction. When assessing bone conduction it
is important to mask the other ear so that the patient does not
misinterpret sounds heard from that ear. The audiologist then
"plots" the recorded sounds that the patient responds to on a
graph, known as an audio graph.
11.
12. Audiometry
Subjective:
Pure Tone Audiometry
Speech Audiometry
A) Speech reception threshold (SRT)
B) Speech discrimination score a.k.a Speech recognition or word
recognition score
Objective:
Bekesy Audiometry
Impedance Audiometry
A) Tympanography
B) Acoustic reflex
13. Pure Tone Audiometry
An audiometer that produces pure tones, the intensity of which can be inc or dec in 5
steps dB.
Air cond threshold are measured for tones of 125, 250, 500, 1000, 2000, 4000, 8000 Hz.
Bone cond thresholds are measured for tones of 250, 500, 1000, 2000 and 4000 Hz.
Uses:
To measure threshold of hearing by air & bone conduction and thus degree & type
of hearing loss.
To keep the record for future reference.
For prescription of hearing aid.
For medico legal purposes.
To predict speech reception threshold.
14.
15. Speech Audiometry
Ability to hear and understand speech is measured.
A) Speech reception threshold (SRT)
Min intensity at which 50% of the words are repeated
correctly by pt.
Spondee words are used i.e baseball, daydream, sunlight
etc. delivered in the form of recorded tapes or monitored
voice and their intensity varied in 5 dB steps till half of them
are correctly heard.
Normally SRT is within 10 dB of average of pure tone
threshold of thre frequencies (500,1000,2000 Hz) more than
that suggests functional hearing loss.
16. Speech Audiometry
B) Speech discrimination score (a.k.a speech recognition or
word recognition score.
It is measure of pt’s ability to understand
speech.
Phonetically balanced (PB) words ( single
syllable e.g pin, sin, day, bus etc. are
delivered to pt’s each ear separately at
30-40 dB above his SRT and the %age of
words correctly heard is recorded.
17.
18. Bekesy Audiometry
Self recording audiometry
Two tracings are seen.. Continuous tone and pulsed tone
To differentiate a cochlear from retro cochlear and an organic from non organic
hearing loss.
Various types of tracings are obtained
Type I = in conductive hearing loss
Type II = in cochlear loss
Type III = in retrocochlear / sensoryneural lesion.
Type IV = in retrocochlear / sensoryneural lesion.
Type v = in Non organic hearing loss
19. Impedance Audiometry
An objective test
A) Tympanography: Used to find compliance or stiffness of the tympano-ossicular system and
thus find the healthy or diseased status of middle ear.
20.
21. Impedance Audiometry
Acoustic Reflex:
It is based on the fact that when a loud sound of 70 to 100 dB above
the threshold of hearing of a particular ear, causes bilateral
contraction of the stapedius which can be detected by
tympanometry.
Uses:
Infants and young children
To find malingerers
To detect cochlear pathology
To detect VIII nerve lesion
Lesion of facial nerve
Lesion of brainstem