1. Pure tone audiometry is an objective test that measures air and bone conduction thresholds to evaluate the type and severity of hearing loss. It is helpful for documentation and diagnosis.
2. Impedance audiometry objectively measures middle ear function through tympanometry and acoustic reflex testing. It can detect middle ear pathologies and is a fast screening test.
3. Otoacoustic emissions are sounds originating from the cochlea that can help diagnose cochlear hearing loss through an objective, noninvasive test done in both children and adults.
2. FINGER FRICTION TEST
WATCH TEST
SPEECH /VOICE TESTS
Normal person hears a conversation at
12m/40ft
Hears whisper at 6m/20ft in quiet
surroundings
(disadv:lack of stardardisation of pitch,intensity)
TUNING FORK TESTS
3. It is the study of hearing disorders through
hearing evaluation and rehabilitation
Acoustics:refers to hearing and perception of
sound
Sound:is a form of energy,which is produced
by any vibrating object.
Velocity of sound in air is 344m/sec
Sound travels faster in solids >liquids>gas
4. Frequency:is the number of cycles /sec. Its unit is Hertz
(Heinrich Rudolf Hertz).
Ear is sensitive—20-20000Hz,
speech frequency-500-3000Hz,
audiometric testing-125-8000Hz
Pitch is the subjective sensation produced by frequency.
Intensity is the strength of sound and determines the
loudness of sound. Its unit is decibel (dB) (Alexander
Graham Bell)
whisper----30dB
conversation---60dB
shouting-----90dB
Pain in the ear---130dB
5. Pure tone: a single frequency sound
Complex sound: more than one frequency
Music : is a peroidic complex sound
Noise: is a aperoidic complex sound
1. White noise-all frequencies of sound
Narrow band noise – certain frequencies of sound
Speech noise-speech frequency sounds(300-3000Hz)
6. Loudness discomfort level:90-150dB.It is
important while prescribing a hearing aid.
Dynamic range :is the difference between the
most comfortable level and the loudness
discomfort level
Masking: is a phenomenon to produce inaudibility
of one sound by the presentation of another
Essential for bone conduction tests and air conduction tests when
the difference in hearing between the ears is>40dB
7. Measurement of hearing acuity
Types:
Pure tone audiometry (PTA)
Impedence audiometry
Speech audiometry
Otoacoustic emissions(OAE)
Brain stem evoked response audiometry (BERA)
8. Other audiological tests
Tests for recruitment
◦ ABLB(alternate binaural loudness balance test)
◦ , SISI(short increment sensitivity index)
Tone decay test
Eustachian tube function tests
9.
10. Measurement of hearing acuity by
estimation of air conduction and bone
conduction thresholds of hearing for
various frequencies using pure tones
Pure tone- 125-8000Hz(AC)
250-4000Hz(BC)
Threshold of hearing: Minimum
perceivable intensity of sound
11. Is an electronic device that generates pure
tones.The intensity of these tones can be
increased or decreased in 5dB steps
12.
13.
14.
15. Air conduction- sound is presented adjacent
to pinna- conduction through external and
middle ear.
Bone conduction- sound presented on the
mastoid process- directly stimulates the
inner ear.
16.
17. The threshold for air and bone conduction
for each frequency is noted .
Bone conduction is a measure of the cochlear
function
The difference in the thresholds of air and
bone conduction(A-B gap)is a measure of
degree of conductive deafness.
In a normal person,both air and bone
conduction is at 0dB and A-Bgap is absent
18. Pure tone average :is an average of the air
conduction thresholds at 500,1000 and
2000Hz (speech frequencies)
Masking :air conduction sounds cross over
when >40dB difference exists between the
AC thresholds of the two ears whereas BC
sounds may crossover at even 0dB
difference.A narrow band noise is given to
the non test ear (better ear).This is called
masking.
28. Tests various frequencies
Both qualitative and quantitative (type and
severity of hearing loss)
Documentation
Compare serial audiograms/ pre and post
treatment audiograms
May give clue to diagnosis
29. Subjective test
Patient should understand instructions-
cannot be done in children and psychiatric
patients
Not accurate for medico-legal purposes if
malingering suspected
Masking to be done to avoid involvement of
non-test ear in the test
30. Impedance = resistance
Impedance X compliance
Measurement of the compliance of the middle
ear structures to the sound impulse
More compliance= middle ear structures
vibrate more freely
Less compliance= middle ear structures
vibrate less freely (more stiff)
31.
32. Tympanometry: measurement of compliance
of middle ear structures to sound impulse at
varying external ear pressures
Stapedial reflex/ Acoustic reflex :can be
documented as there is reduced compliance
during contraction of stapedius muscle
(normal stapedial reflex threshold: 90dB)
33.
34.
35.
36. Objective test
Easy to perform even in children
Fast results- best screening test
Diagnose various middle ear diseases
Stapedial reflex studies help in
◦ Facial nerve lesions
◦ Auditory acuity in children
◦ Recruitment
◦ Malingering
37. Speech reception threshold(SRT)
◦ Minimum intensity at which 50% of spondee words
(bisyllables with equal stress on each syllable )are
repeated correctly
◦ Normal:10dB of PTA
Speech discrimination score(SDS)
◦ Percentage of correctly repeated phonetically
balanced words(single syllable words)given at an
intensity 30-40dB above the SRT.
◦ Normal: 95-100%
◦ Conductive hearing loss:90-100%
◦ Sensorineural hearing loss: is poor
38.
39. Are sounds
Originate from cochlea
Two types
1. Spontaneous
2. Evoked
- Transient
- Distortion
40. Done in quite room
No patient preparation
Requires 10 -15 minutes
Probe placed in the ear canal
Not painful
Non-invasive
41. Uses:
Screening test in neonates,uncooperative and
mentally challenged patients
Helps to distinguish between cochlear and
retrocochlear hearing loss
42. Recording of the electrical activity of the
auditory pathway till the brain stem evoked
by a sound stimulus
1 2 3 4
5
43. .
Brain stem evoked response
audiometry (BERA)
• Objective way of eliciting brain stem
potentials in response to audiological click
stimuli
• Waves are recorded by electrodes
placed over the scalp
• BERA is resistant to the effects of
sleep, sedation and anesthesia
44.
45. Objective measure auditory acuity
Can be done even in new born children
Authentic for medico-legal purposes-
malingering
Site of the lesion in auditory pathway can be
detected depending on the latency of
individual waves
46.
47.
48. What is Bing’s test?
What is Gelle’s test?
Why do we use 512Hz tuning fork for
TuningFork Tests?
What is roll over phenomenon?
What is the significance of acoustic reflex?
What is carhart’s notch?
Which frequency is most affected in noise
induced hearing loss?
49. 1)In impedence audiometry:
1. “A” wave denotes otosclerosis
2. Patient’s cooperation is essential
3. A 220Hz frequency probe is used
4. “C” wave denotes ossicular discontinuity
5. “B” Wave is seen in serous otitis media
50. 2) Tuning fork tests:
1. Is a subjective test
2. Quantifies the hearing loss
3. Can detect maligering
4. Are clinical tests
5. Detects the type of hearing loss
51. 3) Rinnes test is
1. Negative in acoustic neuroma
2. Positive in Meniere’s disease
3. Negative if minimum deafness is 15-20dB
4. Positive in normal individual
5. Done with 512Hz tuning fork
52. 4)Pure tone audimetry is:
1. Objective test
2. Helps in documentation
3. Ideally performed in a sound proof room
4. “X” symbol is used to mark air conduction in
left ear
5. Can differentiate between cochlear and
retrocochlear hearing loss
53. 5)Otoacoustic emissions is:
1. invasive
2. an objective test
3. Done in only adults
4. Used to screen for hearing loss
5. Helpful to diagnose cochlear deafness
