The human body uses three sensory inputs to maintain proper balance. They are: Touch (feet, ankles, joints), Sight (eyes), and Vestibular (inner ear system). These sensory inputs interact with the brain, which then drive and control our motor functions. Because of the complexity of the balance system, diagnosing a dizziness or balance problem and its specific cause can be difficult. The good news is that there are a number of diagnostic tests that can be performed to more accurately determine the source of your dizziness or balance problem.
These are the common diagnostic tests performed for dizziness and balance disorders:
This is the most common test administered to patients with dizziness and/or balance disorders. It is a battery of tests that records quantitative measurements of nystagmus using infrared goggles and provides objective documentation of vestibular function. This is also currently the one of the only tests available to decipher between a bilateral (both ears) and unilateral (one ear) weakness, the other being Rotational Chair below.
Rotational Chair Testing
The purpose of rotational chair testing is to determine whether or not dizziness may be due to a disorder of inner ear or brain. This tests measures the dizziness (nystagmus) while slowly being turned in a chair that rotates back and forth. Rotary chair tests are usually ordered in addition to ENG/VNG (caloric) testing to confirm a diagnosis and increase accuracy.
Computerized Dynamic Posturography (CDP)
This tests the relationships among all the parts of a patient’s balance system–eyes, somatosensory system, and vestibular system. The patient stands on a platform surrounded on three sides by a colored screen. His or her stability is first measured using all three inputs. Then, the patient is tested with one or more of the three inputs either reduced or eliminated. For example, the patient stands with eyes closed to eliminate the visual input. The platform and/or the screen may also move slightly during the testing.
Evoked Potentials Testing
Auditory Evoked Potential (AEP) testing is used to determine if specific parts of the vestibular system are functioning properly. Evoked potentials, sometimes called evoked responses, record the amount of time the nerves take to respond to electrical and sound stimulations.