When a balance disorder is suspected, balance testing is used to evaluate a person’s vestibular function. The vestibular system includes parts of the inner ear and brain that process the sensory information involved with controlling balance and eye movements.
Because the inner ears’ vestibular organs and the associated nerves and brain centers form a complex system, their many functions can be affected by a number of outside systems. As a result, a thorough evaluation of the inner ear is necessary and may require several different kinds of tests.
Your doctor will review your medical history and perform a physical examination to determine which diagnostic tests are needed to assess your vestibular system function and rule out any alternative causes of symptoms. Testing can sometimes be fatiguing and result in temporary unsteadiness, but most people tolerate it well.
Most Diagnosed Vestibular Disorders
The most commonly diagnosed vestibular disorders include
- Benign Paroxysmal Positional Vertigo (BPPV)
- Vestibular Neuritis/Labyrinthitis
- Meniere’s Disease
- Acoustic Neuroma
- Perilymph Fistula
- Superior Canal Dehiscence
- Vascular Dizziness
- Natural Aging Process
There are also other problems related to vestibular dysfunction, including a vestibular migraine and complications from autoimmune disorders and allergies.
Ideal Candidate for Balance Testing
You may be an appropriate candidate for balance testing if you are having issues with balance, hearing, or vision. These tests may help your doctor determine the cause of your symptoms and subsequently formulate an appropriate treatment plan.
Many vestibular tests use equipment to monitor the eyes for normal and abnormal movements when the vestibular system is stimulated. Testing is done to evaluate proper function–such as good balance, and good eye muscle movements (vestibulo-ocular reflex or VOR).
The following is a brief summary of tests that your doctor may order for you.
Electronystagmography (ENG) & Videonystagmography (VNG)
Electronystagmography (ENG) testing uses small electrodes placed over the skin around the eyes. Videonystagmography (VNG) testing uses goggles with video cameras to monitor the eyes. Both the video cameras and the electrodes can measure eye movements to evaluate signs of vestibular dysfunction or neurological problems. Generally, these tests are performed in a room that is dark or with low lighting. The examiner asks random questions that are meant to occupy the person being tested and keep them alert. ENG/VNG tests are the most common set of tests administered to people with dizziness, vertigo, and/or imbalance.
Dix-Hallpike and Canalith Repositioning
There are two main techniques used in the assessment and management of benign paroxysmal positional vertigo (BPPV). The Dix-Hallpike test is used for the diagnosis of BPPV, and the Epley Maneuver can be used for its treatment once diagnosed. The Dix-Hallpike is performed by rapidly moving the patient from a sitting position to the supine position (lying face upward) with the head turned 45 degrees to one side and extended about 20 degrees backward. Once supine, the eyes are typically observed for 30 seconds. If no nystagmus is observed, the person is brought back to a sitting position. After 20-30 seconds, the other side is tested.
The Epley maneuver involves a series of specially patterned head and trunk movements to move tiny displaced otoliths to a place in the inner ear where they can’t cause symptoms.
Rotation tests evaluate how well the eyes and inner ear work together. These tests use video goggles or electrodes to monitor eye movements. The head is rotated side to side at moderate or slow speeds, and associated eye movements are analyzed. Like the ENG/VNG, rotation tests are performed in a room that is dark with the examiner asking random questions during testing. Rotation tests provide information beyond the ENG/ VNG about how well the balance organs are functioning.
Vestibular Evoked Myogenic Potential (VEMP)
VEMP testing is used to evaluate whether certain vestibular organs and associated nerves are intact and functioning normally. Responses in this test are measured from different muscles in the neck and around the eyes. VEMP testing uses adhesive, skin surface electrodes (like ENG testing or some rotational tests) and earphones (like those used during a hearing test). Sound is played for a few seconds through the earphones, the vestibular organs are stimulated and activate muscle responses, and electrodes record the results.
Audiometry (Hearing Tests)
Audiometry measures hearing function. Hearing evaluations are an important part of vestibular diagnostics because the inner ear contains both hearing and balance organs. More than one hearing test may be required when a person has a vestibular disorder, especially when there is evidence of hearing loss, a sensation of fullness in the ears, or tinnitus (ringing or noise in the ears).
Another part of a standard hearing test is tympanometry, which can help detect problems between the eardrum and the inner ear. Tympanometry uses a small earpiece that creates pressure and plays sound in the ear canal to gather information. The same equipment can also be used for acoustic-reflex testing, which measures the reflex of muscles in the middle ear in response to pressure and loud sound.
Otoacoustic Emissions (OAE)
OAE testing provides information about how the hair cells of the cochlea are working. It measures the responsiveness of hair cells to a series of clicks produced from a tiny speaker inserted into the ear canal. Most often this test is used to evaluate hearing for people who are unable to respond to a traditional hearing test (such as infants).
Auditory Brainstem Response Test (ABR)
The ABR measures how the nervous system responds to sound. The test setup and procedure are similar to an electrocochleography (EcochG is a test that measures electrical potentials derived from the cochlea in response to audio stimulation). Most often ABR is used to test hearing for people who are unable to respond for audiometry (such as infants). Occasionally this test is used when someone cannot have imaging performed (such as people with a metal plate in the body/brain).
Under certain circumstances, this test can indicate the presence of an acoustic neuroma (a rare, benign tumor of the vestibulocochlear nerve). It may also help identify conditions such as multiple sclerosis if they have affected the auditory pathway to the brain.
Depending on your circumstances, other tests may be necessary to discover the cause of a balance disorder. Blood work, allergy tests, vision tests, and other exams may help rule out causes of imbalance that are unrelated to the vestibular system.
Treatment Options for Balance Disorders
There are several treatment options available for vertigo, imbalance, and dizziness due to vestibular dysfunction. Your prescribed treatment will depend on your symptoms, medical history and general health, your diagnostic test results, and your physical exam. Your doctor will prescribe the best treatment option for you that addresses your specific condition and any other underlying disease that may be contributing to your balance disorder.