Ecog

Question 1

What is electrocochleography?

Answer 1

Measures an auditory evoked potential is obtained in response to sound stimuli by an extratympanic electrode.

Question 2

What is measured?

Answer 2

The cochlea microphonic and the summating potetnial are created by hair cells SP and the compund action potential of the auditory nerve is the response of many nerve fibres AP

Question 3

Ratios?

Answer 3

The SP compared to AP ratio is calculated. With changes in SP as a result of changes fluid pressure of the scala media and vestibuli. Criteria change according to which ecog system used

Question 4

Results..

Answer 4

An enlarged SP to AP ration may be indicative of Menieres disease