Electronystagmogram

Alternative names

Electronystagmography, videonystagmography.

Definition

Diagnostic test used in the field of Otorhinolaryngology that consists of obtaining a record of the voluntary and involuntary movements (or nystagmus) of both eyes. When the recording is done with the help of electrodes we speak of electronistagmography, when the recording is done with the help of a video camera we speak of videonystagmography.

The registration of eye movements allows us to indirectly know the state of the vestibular system (structures responsible for maintaining balance) and of the nerves that participate in the movement of both eyes.

How is the study done?

The study is carried out in the Otorhinolaryngology units, in conditioned rooms.

The patient remains seated or lying down during the study in front of his examiner. Electronistagmography requires the placement of small electrodes around both eyes in charge of collecting the different eye movements. Videonystagmography does not require the placement of electrodes since the movements will be recorded on a video camera.

In the first part of the study, a record is made of the voluntary (spontaneous) movements of both eyes, for which the patient is asked to fix his gaze on an object or a light source and follow their movements.

In the second part of the study, a record is made of the involuntary (provoked) movements of both eyes, for which different stimuli will be used (provocation tests) that will give rise to eye movements over which the patient has no control. The most commonly used stimuli for this part of the study are:

• Caloric stimulus: a small amount of water or air is instilled, first cold and then warm, into the external canal of each ear (alternately) and the eye movements caused by this stimulus are recorded.
• Rotating stimulus: the patient is subjected to rotary movements on a rotating chair and the eye movements caused by this stimulus are recorded.
• Oculomotor stimulus: moving objects are used and the eye movements caused by this stimulus are recorded.

The study usually lasts 60-90 minutes.

Preparation for the study

The study does not require prior preparation by the patient.

Alcohol consumption and taking certain drugs should be avoided.

The study should be postponed in the case of presenting some type of ear condition that may alter the results of the study.

What does it feel like before and after the study?

The study is painless for the patient.

Slight discomfort may appear during provocation tests in the form of a feeling of vertigo that will disappear at the end of the test.

The sensation of cold water in the ear may be unpleasant for some patients but not painful.

Study risks

The study does not present risks to the patient.

In electronystagmography, a small irritation (contact dermatitis) may develop in the area of ​​the skin where the electrodes are applied in patients sensitive to their composition, which generally will disappear after a short time.

Study contraindications

You should consult with your doctor before enhancing the study in case of:

• Take some kind of medication
• Present or have recently presented an ear condition (otitis, perforation of the eardrum, etc.)

Reasons why the study is carried out

Electronistagmogram is a widely used diagnostic test in the medical field as it is a safe and relatively simple test.

It makes it possible to detect alterations in the balance system in people with gait instability or vertigo and to identify whether these alterations originate in the ear or if, on the contrary, they originate in the central nervous system.

It is a screaning test that must be complemented with subsequent studies in order to establish a definitive diagnosis.