Electrocochleography (ECochG)


Presentation:

Among the short latencies auditory evoked potential, auditory evoked potentials (AEP) and cochlear potential or electrocochleography (ECochG) are included. Historically, ECochG was performed under anesthesia through a trans-tympanic invasive electrode placed on the promontory. With its expertise in electrophysiology, ECHODIA Company developed a noninvasive technique for routine use, without anesthesia, using a gold coated electrode gently inserted into the ear canal.

 

User tips:

- Make sure that the ear canal is not obstructed by a wax plug.

- Clean the surface of the skin where the electrodes will be attached with abrasive gel. This decreases the impedance of the skin.

- The patient must be settled comfortably to avoid any excessive muscle tension.

- Use of saline water is recommended to improve the conductivity of the ear.

 

Measure specifications:

- 50 clicks/sec

- Alternating clicks / burst

- Contralateral masking

- 0 to 100dB HL

- Impedance tests

 

Aimed diseases:

- Search for auditory thresholds in addition to ABR.

- Search for a cochlear residual activity (as part of a review of cochlear implant, for example).

- Evaluation of the cochlear function in auditory neuropathy.

 

Method :

The cochlear potential include the microphonic cochlear potential (MPC), the summating potential (SP) and the action potential of the auditory nerve (AP). 

In addition to ABR, the ECochG can be used for the revealing of wave “I” which is difficult to identify on ABR tracing, search for hearing thresholds, search for residual cochlear activity (as within the framework of an assessment of cochlear implant), evaluation of the cochlear function within the framework of hearing neuropathies (existing MPC, flat ABR), per-operating monitoring in the surgery of the acoustic neuroma, intraoperative monitoring in surgery for acoustic neuroma. One of the common indications of ECochG is an assessment of the SP / AP, which is increased in diseases associated with endolymphatic hydrops.

 

Echodia devices allowing ECochG measurements: ELIOS and ELITE.