Electronystagmography

As electronystagmography (ENG ) refers to into the ear, nose and throat, and ophthalmology Applied investigation procedures for registration and provision faster nystagmiformer eye movement using pasted electrodes.

Indications

The electronystagmography is inserted into the ear, nose and throat medicine for an objective evaluation of the oculomotor and vestibular system in patients with dizziness or balance disorders. It is the most common clinical test to check the balance function. In addition, it provides in ophthalmology, especially the neuro-ophthalmology, a portion of the electrooculography is serving for the diagnosis and determination of a pathological, not vestibular -induced nystagmus.

Principle

The human balance system continuously registers the spatial position and all movements of the body and body parts. The spatial information is needed, among other things, in order to coordinate the eye movements. So when changing the spatial position of the eyes are kept stable and undisturbed vision allows. For the balance and seeing a complex interplay of various processes in the vestibular and visual system, as well as afferents from the spinal cord and the brain stem reflexes (especially vestibulookulärer reflex) is necessary. Many of these functions can be tested in ENG.

For ENG - examination so include:

• Examination of the eye movements ( optokinetic nystagmus): The patient is monitored eg with his eyes moving objects, the movements are documented here. The correct function of the eye muscles and the nerves supplying it in itself is provided here.
• Examination of the response of vestibular system on location or storage
• Examination of the reaction of the vestibular system to caloric stimulation

Malfunctions manifest themselves as a pathological nystagmus. Modern ENG systems are computer controlled - by the stimulus generation, registering the response via electrodes to the automatic evaluation.

Preparation

It is that the patient has sufficient vision is a prerequisite for the implementation of an Eng. Before the study, a thorough history is collected and cleared and instructed the patient. Possible unwanted effects that may occur while ENG, are dizziness and nausea.

The ENG may provide important insights into the medical history and the symptoms described by the patient and allows so often a diagnosis. A comparison test of individual components (e.g., caloric and nystagmus ) can on the rough location of the impairment point (for example, peripheral imbalance Vs. Central imbalance ). An accurate localization of lesions in the vestibular system is not only possible with the ENG.

A normal ENG exclude the presence of a disorder of the vestibular system is not enough. Certain drugs, the test result can be affected.

Alternative

As an alternative to electronystagmography also the video nystagmography (VNG ), the registration of eye movements with a video camera, and the Infrarotokulographie ( IROG ) are increasingly popular.