The calibration and tracking tests are intended to diagnose central nervous system disorders. These tests are generally insensitive compared to an examination by a neurologist or an MRI scan. ENG, however, is much less expensive than an MRI in most institutions. In the author's clinical practice, ENG equipment supplied by Micromedical Technologies, Inc. is used. There are several other vendors.
Infrared reflectance is little used in recent times because of nonlinearity.
The purpose of rotational testing is to determine whether or not dizziness may be due to a disorder of inner ear or brain. There are three parts to the test. Persons with inner ear disease become less dizzy than do normal persons. Optokinetic testing is sometimes useful in diagnosis of bilateral vestibular loss and central conditions. The fixation test measures nystagmus while the person is being rotated, while they are looking at a dot of light that is rotating with them.