Cochlea dead regions

Question 1

What are cochlea dead regions?

Answer 1

Where IHC’s are damaged and can no longer transmit that frequency

Question 2

What is off frequency listening?

Answer 2

If a signal is strong enough it will be detected at other regions of cochlea specific to another frequency. Confusing as 2 signals will be sent to the brain. the signal from the dead region but also the off frequency region.

Question 3

Speech outcomes in persons with dead regions…

Answer 3

Poorer understanding of speech in noise.

Amplification does not result in increased speech understanding.

Question 4

Dead regions can be found by…

Answer 4

Psychoacoustic tuning curves. If the tone can be masked most effectively by the same tone then it is not a dead, however if another frequency masks then is a dead region.

Question 5

What is the TEN test?

Answer 5

Threshold equalisation Test.
When a pure tone falls in a dead region it will be detected when there is sufficient BM vibration in an off frequency area where there are functioning IHC’s. Therefore any noise will mask it, does not need to be same as the stimulus.

Question 6

TEN test results (normal)

Answer 6

Masking signal is the same as the stimulus tone is normal.

Cochlear loss result in an increase of 2-3dB of threshold but same frequency.

Question 7

When do you often get dead regions?

Answer 7

Losses greater than 50dB.

Especially above 4kHz with 70+loss.