Dizziness can be caused by numerous disturbances to any of many different parts of the body. Based upon your history and physical findings your physician 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, and ultrasound tests. A general physical exam and neurological tests may also be needed.
The most common test for dizziness is the videonystagmogram (VNG). In these tests, the strength of the inner ear is tested, as well as the coordination of eye movements. They involve watching the eye movements after placing warm or cool air into the ear canal. This usually causes a normal sensation of brief dizziness. 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 will impact the outcome of the tests.
Other tests that are done for dizziness are the electrocochleography (ECoG) and Vestibular evoked myogenic potentials (VEMP). These painless tests may be useful in determining the cause of dizziness in complex cases. The object of this evaluation is to be certain that there is no serious or life-threatening disease and to pinpoint the exact site of the problem. This lays the groundwork for effective medical or surgical treatment.
Diagnosis can often be difficult. Frequently, multiple tests must be conducted. Patience and understanding is necessary on the part of the doctor and patient alike. Prior to your appointment, we will give all patients detailed information so you can better prepare for this testing and prevent further delay in an accurate diagnosis.
Evaluating and Treating Equilibrium Disorders. Problems with the equilibrium system can result in dizziness, vertigo, and imbalance. The equilibrium system is very complex and cannot be directly observed. To truly understand a patient’s equilibrium, a number of sophisticated tests must be performed, correlated, and compared.
Balance disorders are often accompanied by changes in hearing and/or ear function. These changes can be acute and hardly noticeable by the patient. Vestibular testing will include comprehensive testing of your outer, middle, and inner ears. These tests include audiologic, tympanometry, immittance, and distortion product otoacoustic emission tests.
A number of complex pathways control our equilibrium. A comprehensive vestibular evaluation will include sophisticated measures of these pathways and your central nervous system.
These tests include:
- Sensory Organization Performance (SOP)
- Videonystagmography (VNG) with Air Calorics
- Rotary Chair
- Video Head Impulse Test (vHIT)
- Vestibular Evoked Myogenic Potential (C-VEMP & O-VEMP)
- Electrocochleography (ECoG)
- Posturography (CDP)
- Auditory Brainstem Response (ABR)
- Dynamic Visual Acuity
Tests used to evaluate dizziness and imbalance
Audiometry: Evaluates the hearing portion of a patient’s ear. This allows us to define cause, type and degree of hearing loss. This testing is important for dizzy and off-balance patients because small unnoticed hearing changes can indicate inner ear damage or other medical problems.
Distortion Product Otoacoustic Emissions: This test helps us evaluate the function of the inner ear. This test also helps us further differentiate where an individual’s hearing loss is coming from. This is important for patients who have equilibrium disorders, as it further defines the location of an inner ear problem.
Neurodiagnostic Auditory Brainstem Response (ABR): This test helps us evaluate the neural integrity of the nerve going to the hearing part of the inner ear. This test is often used to further explain why a person might have unilateral symptoms or test findings. This test helps us evaluate the nerve quality and function of the inner ear hearing nerve.
Dynamic Visual Acuity Test: This test is fairly similar to the VAT, but the test protocol is slightly modified. It may be easier for some patients to perform.
Electrocochleography (ECoG): This technique records electricity generated in the inner ear and auditory nerve. The test helps rule out an abnormal accumulation of fluid within the inner ear that may be causing acute attacks of true room spinning vertigo.
Electro-oculography: This testing evaluates very specific eye movements that are coordinated by the equilibrium centers of the brain. Damage to these brain areas can cause dizziness.
Rotary Chair: This advanced test utilizes a computer-controlled motorized chair to stimulate the ear at different speeds. A patient's eye movements are also recorded with video goggles. This test allows us to assess the overall health of the inner ears and how the brain is adapting to a vestibular disorder.
Sensory Organization Test: This test helps us identify balance problems. With careful evaluation, it allows your audiologist to determine the cause of your imbalance and identify a potential fall risk.
Tympanometry / Immittance testing: Helps us rule out fluid in the middle part of the ear, which can impact other vestibular test results. This test also allows us to evaluate nerve responses.
Vestibular Evoked Myogenic Potential (VEMP): This neurological test helps to evaluate a very specific portion of the nerve that goes to the equilibrium part of the inner ear. There are two portions of the equilibrium nerve, and this test evaluates the bottom part of the nerve.
Computerized Dynamic Posturography (CDP): Tests postural stability or the ability to maintain upright posture in different environmental conditions. Maintenance of postural stability depends on sensory information from the body’s muscles/joints, eyes, and inner ears. CDP investigates the relationship among these three sensory systems and records the balance and posture adjustments made when different challenges are presented.
Video/Electro-nystagmography (VNG/ENG): This test is composed of a number of subtests. For this testing, a patient wears video goggles or electrodes. These allow us to watch for small eye movement abnormalities, which can indicate an inner ear problem. There are also sub-tests that can help us identify positional vertigo and/or permanent ear damage. This testing also looks at the top portion of the nerve going to the equilibrium part of the inner ear.
Learn more about Balance Disorders here.