BERA

Question 1

What is BERA?

Answer 1

Brain stem Evoked Response Audiometry

Question 2

Other names for BERA

Answer 2

BAER(Brain-stem Auditory Evoked Response)
BAEP(Brain-stem Auditory Evoked Potential)
ABR(Auditory Brain-stem Response)

Question 3

How is the response of Electrocochleography produced?

Answer 3

It is produced in the form of waves

3 waves are produced

1st wave : cochlear microphonics (produced by outer hair cells)

2nd wave : summation potential (SP) - produced by both outer and inner hair cells

3rd wave : action potential (AP) - produced by cochlear nerve

Question 4

What does summation potential denote ?

Answer 4

It denotes the amount / extent of both outer and inner hair cells that is getting activated / responds to the given auditory stimulus

Question 5

What does action potential denote ?

Answer 5

It denotes whether the nerve gets activated in response to signal from the hair cells

Question 6

What does the Electrocochleography measures?

Answer 6

It measures the entire activity of the cochlea

Question 7

What value of Electrocochleography is suggestive and diagnosed of Ménière’s disease?

Answer 7

> 30% - suggestive
45% - diagnostic = this indicates that there’s irritative stimulation of hair cells but the nerve is not stimulated adequately that’s why SP increases and no increase in AP is seen

Question 8

What does BERA record?

Answer 8

It records the wave produced by each part of the auditory pathway in response to the stimulus given

Question 9

What is the auditory pathway ?

Answer 9

Cochlear nerve
Cochlear nuclei
Superior olivary nucleus
Lateral Lemniscus
Inferior colliculus
Medial geniculate body

Question 10

How many waves are recorded in BERA ?

Answer 10

Only tests the first 10 milliseconds of the transmission of sound

7 waves are obtained but only 5 are considered

Question 11

What does each wave denote in BERA ?

Answer 11

Wave 1 - distal part of cochlear nerve
Wave 2 - proximal part of cochlear nerve
Wave 3 - cochlear nucleus
Wave 4 - superior olivary nucleus
Wave 5 - lateral lemniscus (largest , most consistent wave always present )
Wave 6 & 7 - inferior colliculus

Question 12

At what interval does the wave occur ?

Answer 12

1 ms

Question 13

Does BERA helps to differentiate cochlear and retrocochlear lesion?

Answer 13

Yes

If the first wave is delayed by one millisecond and other waves appears at 1ms interval , this indicates that the problem is in front of the distal part of the nerve i.e the organ of Corti

Question 14

What is the best audiometric test for retrocochlear hearing loss?

Answer 14

BERA

Since it can exactly identify the site of lesion

Question 15

Best audiometric test for acoustic neuroma ?

Answer 15

BERA ; acoustic neuroma arises from the proximal part of cochlear nerve and hence all the nerves from 2 - 5 gets delayed

Diagnostic feature

⚡️Increased inter aural latency >0.2ms
⚡️latency between wave 1 and wave 5 increases

Best test for acoustic neuroma - MRI

Question 16

Best investigation for hearing loss in infants and screening of neonates in ICU

Answer 16

BERA

Question 17

Threshold of hearing is identified how in BERA

Answer 17

The loudness at which wave 5 appears is called the threshold of hearing

Important test for malingering ; objective test

Question 18

Drawback of BERA

Answer 18

Does not detect hearing loss >80-90db ; for identifying this extent of hearing loss we do ASSR(Auditory Steady State Response)

Question 19

What is ASSR ?

Answer 19

EEG activity is recorded in response to sound
Done with pure tones ( made of a single frequency)

Question 20

Components of speech audiometry

Answer 20

Speech reception threshold - loudness at which 50% of spoken words are identified

Discrimination score - ability to discriminate between words
0-20% indicates retro-cochlear /neural hearing loss

Question 21

Roll over phenomenon seen in

Answer 21

Retro - cochlear hearing loss in speech audiometry