Next week I'm scheduled for a couple of diagnostic tests: Electronystagmography (ENG) and Vestibular Evoked Myogenic Potentials (VEMPs). The
Vestibular Disorders Association describes ENG as "a battery (group) of eye-movement tests that look for signs of vestibular dysfunction or neurological problems by measuring nystagmus (a type of involuntary side-to-side eye movement)." The site goes on to explain what occurs during ENG.
During ENG, eye movements are recorded and analyzed via small electrodes placed on the skin around the eyes. The electrodes attach to the skin with an adhesive, much like a small bandage. Alternatively, eye movements may be recorded by videonystagmography (VNG) using an infrared video camera mounted inside goggles that the patient wears instead of sticky-patch electrodes.
One ENG test evaluates the movement of the eyes as they follow a moving target. Another observes eye movements as the head is positioned in different directions. During the caloric test warm or cold water or air is circulated in the ear canal. The temperature change stimulates the inner ear in order to test the nystagmus response.
The
Mayo Clinic's website offers some information on what I can expect during the VEMPs test.
This test measures tiny variations in neck muscle contractions that occur when a sudden burst of sound is introduced to the ear. The linear sensing parts of the inner ear cause a brief relaxation of the muscles in the neck which function to keep the head erect. To record VEMPs, a skin electrode patch is placed over the larger neck muscles and on the forehead. The patient lifts their head from the table while listening to a clicking sound. The electrodes then detect tiny changes in muscle contractions, which are analyzed by a computer.
I'll post my results as soon as I receive them. This is another one of those situations where you hope something is found almost as much as you hope nothing is found. Migraineurs always want - correction, we need - validation, and the thought that we may hear "you're normal," when we feel 100 miles from normal, can cause a little anxiety.
