Vertigo, dizziness, balance and loss of equilibrium are common and often frustrating complaints. Many patients go from one physician to another seeking answers. Yet, with the best will in the world, many physicians do not have the time or perhaps the expertise or the facilities to evaluate these complaints. Internet searches by the patient can lead to a lot of complex information and can be frustrating.
How do we diagnose vertigo or dizziness? Is it likely to be inner ear in origin? Or is it light headedness due to circulation disorders (an episode of low blood-pressure for example), or drug side-effects, hyperventilation or other metabolic disorders?
There are four basic steps in the initial evaluation of the chronically "dizzy" patient that may be inner ear in origin (rather than a circulatory or neurological disorder):
- Medical history
- Physical examination
- Audiology
- Balance tests
Other studies such as imaging or blood tests may follow. All these items are important but the medical history of the patient remains the keystone of the evaluation and it is critically important that adequate time be devoted to this aspect of the evaluation. Clues as to the ultimate diagnosis are often to be found in the history of the complaint.
Audiology:
A series of tests to evaluate the hearing functions of the ear. Some conditions that affect balance may affect the hearing. The tests are done in the office by an Audiologist. There is no discomfort and the tests take about 30-40 minutes. Loss of hearing (which may be subtle and unnoticed by the patient) in one ear, for example, might suggest Meniere's disorder or a benign tumor of the balance nerve or other disorders.
Balance:
Tests of the balance functions of the inner ear (vestibular tests) must be done indirectly. The inner ears play a vital role in adjusting the muscles that move our eyes, thus stabilizing our gaze despite head movements. The eyes therefore become our “window” into the inner ears. Some ear disorders may cause rhythmic movements of the eyes called nystagmus. The basic battery of tests often utilized to record these and other eye movements is called video-nystagmography (VNG).
Videonystagmography (VNG):
VNG records eye movements by using infra-red cameras inside goggles worn by the patient. The eyes are seen on the computer screen alongside graphical tracings, even when the eyes are covered by shades, (with eyes open, fixation of vision on an object tends to suppress the abnormal eye movements or nystagmus). Video recordings allow replay of the nystagmus; this is of great value and a huge advance on older techniques.
Fig. 1. Goggles with infra-red cameras. Fig. 2. Graphical tracings of eye movements and video recordings.
Our page "Investigations" gives more information on the VNG test.
The VNG test is done in the office and take about one and a half hours. The patient watches a spot moving on a screen in various ways and is then placed in certain positions (lying back, on one side and so on). “Caloric” tests are performed in which each ear is gently irrigated for 30 seconds one after the other, with cool and then warm water. This can make the patient slightly dizzy and maybe a little nauseated, but this usually passes off in a few minutes. These irrigations stimulate (or depress) each ear in turn and the resultant nystagmus is recorded and analyzed by the computer and the reporting physician or audiologist.
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