Electrophysiological examination of the ear

Like the eyes, the ear is one of the sense organs to be an electrophysiological examination. The principle is the same for all these types of examinations electrodes. But the important thing is to know what part of the head place ...
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The auditory evoked potential or PEA

Description and details

The electrical evoked response is the electrical activity of the auditory sensory channels, in response to a sound stimulation from outside.

The PEA study is part of electrophysiological examinations of the ear.

Recording of auditory evoked potential studies mainly electrical conduction from the sensory pathways to the brain. It is especially indicated for:

Verification threshold of hearing with assessment of hearing loss

Hearing loss (hearing loss)

Condition affecting the cochlea

Brain stem

Stroke

Head trauma

Coma (to assess the severity)

How's it going?

The study and recording of PEA require no special preparation. The test is not painful and takes only a few minutes (about 20 minutes).

The review takes place on a patient lying on his back, eyes closed. Electrodes are attached to the scalp, forehead and ears (in contact with the mastoid). Both ears being investigated one by one, a short noise at varying intensities (click) is output to a pair at each of the ears. Electrical waves are recorded by electrodes and displayed on a computer screen as a path.

The study of ECP is not dangerous and there are no complications in this review. The review can be achieved even in newborns.

The result

The plot is obtained along the course of the examination. The main parameter of interest is the time interval between the stimulus and the response of the auditory pathways and brain. However, the amplitude and shape of the curves can be interpreted.

If latency response to stimulation, the doctor may suspect the evolution of diseases that impede nerve conduction as:

The existence of a tumor or neuroma

The evolution of multiple sclerosis with impairment of the myelin sheath of the auditory nerve.

The électrocohléographie or ECoG

The ECoG is an electrophysiological examination of auditory sensory pathways present in the cochlea. This exam will primarily assess the functioning of the cochlea.

The principle of the test is the same as for the study of PEA.

The review is to introduce a very fine needle into the eardrum to be closer to the cochlea.

The ear is then subjected to a repeated sound stimulation, but very brief. The electrical activity is recorded by the electrodes in the form of drawing.

The electronystagmography or ENG

The ENG is an electrophysiological examination of the vestibular system in the inner ear content with électronystagmographe. The vestibular system is involved in regulating the balance. If abnormalities in the control of balance, the eyes have jerky involuntary movements called nystagmus.

The ENG records and mainly studies the characteristics of nystagmus. The review will then search the causes of dizziness and allows to assess the origin of the disorder. During the examination, nystagmus may be spontaneous or induced.

The examination is performed with the patient sitting. Electrodes fixed around each eye then record the electrical activity produced by the movements of the eyeball.

The ENG is performed with different conditions and events in order to better appreciate each parameter:

In the dark and in a lighted room

Then still in a swivel chair

Eyes on an object and the moving eyes

The result is displayed on a computer in the form of trail called électronystagmogramme screen.