Diagnosing the Cause of Dizziness
Dizziness can be caused by numerous disturbances to one or more of the balance centres. Based upon your history and physical findings, your physician or rehabilitation specialist may require further tests to complete a full evaluation.
The tests necessary are determined at the time of examination, and may include:
- hearing and balance tests
- imaging (CT or MRI scans)
- blood tests
- ultrasound tests
- general physical exam
- neurological tests
- clinical tests of vestibular function.
The object of these evaluations is to be certain that there are no serious or life-threatening diseases, and to pinpoint the exact site of the problem. This lays the groundwork for effective medical, rehabilitative, or surgical treatment.
Diagnosis of vestibular disorders can often be difficult. Frequently, multiple tests must be conducted and not all vestibular disorders can be identified on these tests. Patience and understanding is necessary on the part of the doctor and patient alike.
Common tests of vestibular function include:
- ENG (electronystagmography) or VNG (videonystagmography) – in these tests, the strength of the inner ear is tested, as well as the coordination of eye movements. While ENG is still in use, VNGs are now done routinely as assessment. The difference is that ENG records eye movement using electrodes placed on the external eye muscles and VNG is the video recording of the actual eye movement. VNG is much more accurate than ENG.
- caloric testing – involves watching eye movements after flushing warm or cool water into the ear canal. This usually causes a normal sensation of brief vertigo. It is important not to be taking any medications which can affect the test, such as Valium, Antivert, alcohol, and others. When scheduling this test, make sure to ask if your medications are okay.
- a battery of balance testing, which can be conducted in the clinic by your physician or physiotherapist or in the laboratory with a balance machine (Computerized Dynamic Posturography).
Read more: How Audiologists Assess Balance Function.