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Yapa Wijeratne
Faculty of Medicine
University of Peradeniya
• Loud sounds and hearing loss
• Intense sounds can cause
1. hair cell death
2. nerve fiber degeneration
• What is Hearing...
Types of deafness/ hearing loss
1. Sensorineural (SN) hearing loss/ Nerve Deafness – impairment of
the cochlea or impairme...
1. Sensorineural (SN) hearing loss
• destruction of the cochlear or the auditory nerve
• the person becomes permanently de...
• It results from lesions of the cochlea (sensory type) or
• VIIIth nerve and its central connections (neural type).
• The...
2. Conductive hearing loss
• destruction of tympanum-ossicular system
• sound can still be heard via bone (ossicular) cond...
Conductive hearing loss
• It is caused by any disease process interfering with the conduction of
sound from the external e...
3. Mixed hearing loss
• In this type, elements of both conductive and sensorineural deafness
are present in the same ear.
...
While assessing the auditory function it is
important to find out:
A. Type of hearing loss
A. (conductive, sensorineural o...
Bedside Testing of Hearing
• Three different sized tuning forks. The higher pitched forks (such as
the 256 or 512 Hz fork)...
Rinne’s Test
• The single most common office test is a tuning fork test called the
Rinne, named after Adolf Rinne, who des...
• Normal findings
• The sound is louder at the ear, that is, air conduction is better than bone
conduction.
• Record this ...
Normal Hears vibration in air after bone conduction is over
Conduction deafness of
one ear
Vibration in air is not heard a...
Weber’s Test
• In the Weber test, a 512 Hz tuning fork is placed on the patient's
forehead.
• If the sound lateralizes (is...
• Normal findings
• The noise is heard in the middle or equally in both ears.
• Abnormal findings
• The noise is louder in...
Normal Hears equally on both sides
Conduction deafness of one ear Sound louder in the diseased ear
Partial nerve deafness ...
Tuning fork tests and their interpretation
Test Normal Conductive deafness SN deafness
Rinne AC > BC (Rinne positive) BC >...
Audiometry
• Audiometry is the term used to describe formal measurement of hearing.
The measurement is usually performed u...
• Air conduction is tested by having the subject wear earphones
attached to the audiometer.
• Pure tones of controlled int...
Audiogram
• The minimum intensity (volume) required to hear each tone is
graphed, and the results are called an audiogram....
Audiogram for a Patient with Normal Hearing
• When there is a hearing loss, the next step is to try and determine
whether the loss is caused by a sensory problem (sen...
Interpretation of audiogram
• When air conduction tests show a hearing loss, but there is no loss
identified with bone con...
Audiogram of right ear showing conductive hearing loss with
Air-Bone gap
Sensorineural hearing loss with no A-B gap
Early case of noise-induced hearing loss (NIHL).
Note dip at 4000 Hz.
Mixed hearing loss
Conductive hearing loss Sensorineural hearing loss (SNHL)
1. Negative Rinne test, i.e. BC > AC.
2. Weber lateralised to po...
Hearing tests in children
• These ages are important to select the appropriate test to assess
patients with suspected hear...
Test your knowledge
1. What is the investigation shown in this picture?
2. Identify the tracing
3. Comment on the findings
OSCE STATION-1
1. What is the investigation shown in this picture?
• Pure tone audiometry (PTA)
2. Identify the tracing
• Audiogram
3. Co...
Comment on the hearing in following cases.
OSCE STATION-2
Comment on the hearing in following cases.
• Positive Rinne in each ear & Weber test referred equally to each ear
indicati...
OSCE STATION-3
• Positive Rinne test on both sides & the Weber test is referred to the
left ear indicating sensorineural deafness in the ...
OSCE STATION-4
• Rinne test is negative on the right, positive on the left & the Weber
test is referred to the right ear indicating condu...
T/F MCQ
1. Tuning folk tests are best performed with the 128 Hz tuning folk.
2. Non lateralized Weber test always indicate...
T/F MCQ
1. Tuning folk tests are best performed with the 128 Hz tuning folk.
2. Non lateralized Weber test always indicate...
Assessment of hearing (with self assessment questions).
Assessment of hearing (with self assessment questions).
Assessment of hearing (with self assessment questions).
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Assessment of hearing (with self assessment questions).

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Assessment of hearing. with self assessment questions.
Guide for the tests of hearing physiology practical.

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Assessment of hearing (with self assessment questions).

  1. 1. Yapa Wijeratne Faculty of Medicine University of Peradeniya
  2. 2. • Loud sounds and hearing loss • Intense sounds can cause 1. hair cell death 2. nerve fiber degeneration • What is Hearing Testing? • Hearing testing is a means of evaluating an individual's overall hearing function. • Hearing can be impaired due to lesions in the external ear canal, the middle ear, or the inner ear. • The purpose of hearing testing is to evaluate hearing function and, if it is impaired, to attempt to localize the site of lesion.
  3. 3. Types of deafness/ hearing loss 1. Sensorineural (SN) hearing loss/ Nerve Deafness – impairment of the cochlea or impairment of the auditory nerve 2. Conductive hearing loss/ Conduction Deafness– impairment of the physical structures that conduct the sound into the cochlea 3. Mixed hearing loss
  4. 4. 1. Sensorineural (SN) hearing loss • destruction of the cochlear or the auditory nerve • the person becomes permanently deaf
  5. 5. • It results from lesions of the cochlea (sensory type) or • VIIIth nerve and its central connections (neural type). • The term retrocochlear is used when hearing loss is due to lesions of VIIIth nerve, and • central deafness, when it is due to lesions of central auditory connections.
  6. 6. 2. Conductive hearing loss • destruction of tympanum-ossicular system • sound can still be heard via bone (ossicular) conduction
  7. 7. Conductive hearing loss • It is caused by any disease process interfering with the conduction of sound from the external ear to the stapediovestibular joint. • Thus the cause may lie in
  8. 8. 3. Mixed hearing loss • In this type, elements of both conductive and sensorineural deafness are present in the same ear. • There is air-bone gap indicating conductive element, and impairment of bone conduction indicating sensorineural loss. • Mixed hearing loss is seen in some cases of otosclerosis and chronic suppurative otitis media.
  9. 9. While assessing the auditory function it is important to find out: A. Type of hearing loss A. (conductive, sensorineural or mixed). B. Degree of hearing loss A. (mild, moderate, moderately severe, severe, profound or total). C. Site of lesion. A. If conductive, the lesion may be at external ear, tympanic membrane, middle ear, ossicles or eustachian tube. Clinical examination and tympanometry can be helpful to find the site of such lesions. B. If sensorineural, find out whether the lesion is cochlear, retrocochlear or central. Special tests of hearing will be required to differentiate these types. D. Cause of hearing loss. A. The cause may be congenital, traumatic, infective, neoplastic, degenerative, metabolic, ototoxic, vascular or autoimmune process. Detailed history and laboratory investigations are required.
  10. 10. Bedside Testing of Hearing • Three different sized tuning forks. The higher pitched forks (such as the 256 or 512 Hz fork) are more appropriate for hearing testing.
  11. 11. Rinne’s Test • The single most common office test is a tuning fork test called the Rinne, named after Adolf Rinne, who described this test in 1855. • In the Rinne test, a comparison is made between hearing elicited by placing the base of a tuning fork applied to the mastoid process (bone), and then after the sound is no longer appreciated, the vibrating top is placed one inch from the external ear canal (air).
  12. 12. • Normal findings • The sound is louder at the ear, that is, air conduction is better than bone conduction. • Record this as AC > BC; this is normal (Rinne positive). • Abnormal findings • If the sound is louder on the mastoid process, bone conduction is better than air conduction. • Record this as BC > AC (Rinne negative). • This applies in conductive deafness • A false-negative Rinne’s test may occur if hearing is very poor on one side. • Then, the sound travelling through the air is not perceived but, when the tuning fork is placed on the mastoid process of the ‘poor’ ear, the sound is conducted through the skull and heard in the ‘good’ ear. • In a mild conductive deafness, the Weber test is abnormal (lateralised) before the Rinne.
  13. 13. Normal Hears vibration in air after bone conduction is over Conduction deafness of one ear Vibration in air is not heard after bone conduction is over Partial nerve deafness of one ear Vibration in air is heard after bone conduction is over Complete nerve deaf-ness of one ear Vibration is not heard on the affected side
  14. 14. Weber’s Test • In the Weber test, a 512 Hz tuning fork is placed on the patient's forehead. • If the sound lateralizes (is louder on one side than the other), the patient may have either an ipsilateral conductive hearing loss or a contralateral sensorineural hearing loss. Weber Vertex
  15. 15. • Normal findings • The noise is heard in the middle or equally in both ears. • Abnormal findings • The noise is louder in an ear with conductive deafness (test on yourself by putting a finger in your outer canal to block out surrounding noise). • In unilateral sensorineural deafness the sound is heard better in the better-hearing ear. • In symmetrical hearing loss it is heard in the middle.
  16. 16. Normal Hears equally on both sides Conduction deafness of one ear Sound louder in the diseased ear Partial nerve deafness of one ear Sound louder in the normal ear Complete nerve deaf-ness of one ear Sound heard only in the normal ear
  17. 17. Tuning fork tests and their interpretation Test Normal Conductive deafness SN deafness Rinne AC > BC (Rinne positive) BC > AC (Rinne negative) AC > BC Weber Not lateralised Lateralised to poorer ear Lateralised to better ear
  18. 18. Audiometry • Audiometry is the term used to describe formal measurement of hearing. The measurement is usually performed using an "audiometer" by an "audiologist". • In audiometry, hearing is measured at frequencies varying from low pitches (125 Hz) to high pitches (8000 Hz). • Produces pure tones of different frequencies. Is used to determine the nature of hearing disabilities. • The audiometer is calibrated so that zero intensity level of sound at each frequency is the loudness that can barely be heard by the normal person (0 db). • Audiometry provides a more precise measurement of hearing.
  19. 19. • Air conduction is tested by having the subject wear earphones attached to the audiometer. • Pure tones of controlled intensity are delivered to one ear at a time. • The subject is asked to raise a hand, press a button, or otherwise indicate when he/she hears a sound. • An attachment called a bone oscillator is placed against the bone behind each ear (mastoid bone) to test bone conduction.
  20. 20. Audiogram • The minimum intensity (volume) required to hear each tone is graphed, and the results are called an audiogram. • The hearing level is quantified relative to "normal" hearing in decibels (DB), with higher numbers of DB indicating worse hearing. • The DB score is not really percent loss, but nevertheless 100 dB hearing loss is nearly equivalent to complete deafness for that particular frequency. • A score of 0 is normal. It is possible to have scores less than 0, which indicate better than average hearing.
  21. 21. Audiogram for a Patient with Normal Hearing
  22. 22. • When there is a hearing loss, the next step is to try and determine whether the loss is caused by a sensory problem (sensorineural hearing loss) or a mechanical problem (conductive hearing loss). • This distinction is made by using a bone vibrator, which bypasses the mechanical parts of the middle ear. • If hearing is better using bone than air, this suggests a conductive hearing loss.
  23. 23. Interpretation of audiogram • When air conduction tests show a hearing loss, but there is no loss identified with bone conduction tests, there may be a conductive loss. • When both air and bone conduction results show hearing loss at the same level, the loss is considered sensorineural. • If different degrees of hearing loss are found via air and bone conduction testing, the loss is mixed.
  24. 24. Audiogram of right ear showing conductive hearing loss with Air-Bone gap
  25. 25. Sensorineural hearing loss with no A-B gap
  26. 26. Early case of noise-induced hearing loss (NIHL). Note dip at 4000 Hz.
  27. 27. Mixed hearing loss
  28. 28. Conductive hearing loss Sensorineural hearing loss (SNHL) 1. Negative Rinne test, i.e. BC > AC. 2. Weber lateralised to poorer ear. 3. Low frequencies affected more. 4. Audiometry shows bone conduction better than air conduction with air-bone gap. Greater the air-bone gap, more is the conductive loss. 5. Loss is not more than 60 dB. 1. A positive Rinne test, i.e. air AC > BC. 2. Weber lateralised to better ear. 3. More often involving high frequencies. 4. No gap between air and bone conduction curve on audiometry. 5. Loss may exceed 60 dB.
  29. 29. Hearing tests in children • These ages are important to select the appropriate test to assess patients with suspected hearing abnormalities. Test Minimum age Evoked otoacoustic emission (EOAE) Newborn Auditory brainstem response (ABR) audiometry Distraction testing 7–9 months of age Visual reinforcement audiometry 10 and 18 months can be used between the age of 6 months and 3 years Performance and speech discrimination testing 18 months to 4 years Audiometry from 4 years old
  30. 30. Test your knowledge
  31. 31. 1. What is the investigation shown in this picture? 2. Identify the tracing 3. Comment on the findings OSCE STATION-1
  32. 32. 1. What is the investigation shown in this picture? • Pure tone audiometry (PTA) 2. Identify the tracing • Audiogram 3. Comment on the findings • Normal intensity of hearing is between -10 to 20 dB. • In right ear • Air conduction & bone conduction both are reduced in high frequencies. • So sensorineural hearing loss of the right ear. • In left ear • Bone conduction is normal but air conduction is low. • Therefore conductive hearing loss is found in left ear.
  33. 33. Comment on the hearing in following cases. OSCE STATION-2
  34. 34. Comment on the hearing in following cases. • Positive Rinne in each ear & Weber test referred equally to each ear indicating symmetrical hearing in both ears with normal hearing or bilateral equally reduced sensorineural hearing loss. OSCE STATION-2
  35. 35. OSCE STATION-3
  36. 36. • Positive Rinne test on both sides & the Weber test is referred to the left ear indicating sensorineural deafness in the right ear. OSCE STATION-3
  37. 37. OSCE STATION-4
  38. 38. • Rinne test is negative on the right, positive on the left & the Weber test is referred to the right ear indicating conductive deafness in the right ear. OSCE STATION-4
  39. 39. T/F MCQ 1. Tuning folk tests are best performed with the 128 Hz tuning folk. 2. Non lateralized Weber test always indicates normal hearing. 3. Negative Rinne right ear & Weber test lateralized to right ear indicates conductive hearing loss of right ear. 4. In case of ruptured tympanic membrane, BC > AC. 5. Audiometry can be used to reliably assess the hearing of 6 year old child.
  40. 40. T/F MCQ 1. Tuning folk tests are best performed with the 128 Hz tuning folk. 2. Non lateralized Weber test always indicates normal hearing. 3. Negative Rinne right ear & Weber test lateralized to right ear indicates conductive hearing loss of right ear. 4. In case of ruptured tympanic membrane, BC > AC. 5. Audiometry can be used to reliably assess the hearing of 6 year old child. • Answers • FFTTT

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