A vestibular test is a series of diagnostic assessments that evaluate the function of the inner ear balance system and its connections to the brain. These tests help healthcare providers determine if symptoms like dizziness or imbalance stem from an issue within this complex system. The goal is to diagnose disorders affecting balance and spatial orientation.
Why They Are Performed
Healthcare providers order vestibular tests when individuals experience symptoms suggesting a balance disorder. These symptoms include dizziness, vertigo (a spinning sensation), imbalance, lightheadedness, nausea triggered by movement, and unexplained falls. The tests help pinpoint whether these issues originate from the inner ear or related neurological pathways.
Vestibular testing aids in diagnosing specific conditions such as Benign Paroxysmal Positional Vertigo (BPPV), a common cause of vertigo due to inner ear crystal displacement. Other conditions that may necessitate these tests include Meniere’s disease, which affects hearing and balance, labyrinthitis, an inner ear infection, vestibular neuritis, an inflammation of the vestibular nerve, and acoustic neuroma, a benign tumor on the nerve connecting the ear to the brain. The tests can also help rule out an inner ear problem, as vision, brain, heart issues, or certain medications can mimic balance disorder symptoms.
Common Vestibular Tests
A comprehensive vestibular assessment involves a combination of specialized tests, each evaluating a different aspect of the balance system. These tests rely on the vestibulo-ocular reflex (VOR), an involuntary eye movement that helps stabilize vision during head movements.
Videonystagmography (VNG) or Electronystagmography (ENG) track eye movements using goggles with infrared cameras (VNG) or electrodes (ENG). These tests assess how the brain controls eye movements and uses vestibular information, looking for involuntary eye movements called nystagmus. Caloric testing, often part of VNG/ENG, involves introducing warm or cool air or water into the ear canals to stimulate the inner ear and observe resulting eye movements, which helps evaluate each ear’s balance system separately.
The Rotary Chair Test measures bilateral vestibular function by rotating the patient in a computerized chair in a dark booth while tracking eye movements. This test assesses how the eyes and inner ear work together across different speeds of movement. Vestibular Evoked Myogenic Potential (VEMP) testing uses sound or vibration to stimulate specific inner ear organs (saccule and utricle), with electrodes placed on the neck or near the eyes to record muscle responses. This helps evaluate the function of these sound-sensitive balance organs.
Preparing for and During the Test
Preparation for a vestibular test involves specific instructions to ensure accurate results. Patients are advised to avoid eating solid foods for 2-4 hours before the test. Avoiding excessive fluids for three hours prior is also recommended.
It is advised to discontinue certain medications 24 to 48 hours before testing, including anti-dizziness medications like meclizine, antihistamines, sedatives, tranquilizers, and some pain relievers, as these can interfere with results. Patients should consult their doctor before stopping any prescription medication. On the day of the test, avoiding caffeine, alcohol, and tobacco is important. Patients should wear comfortable clothing and refrain from wearing facial or eye makeup, as it can interfere with eye-tracking equipment. Having someone available to drive home after the test is recommended, as temporary dizziness may occur.
During the test, patients will be in a quiet room. Equipment may include special goggles with infrared cameras or electrodes placed near the eyes to record eye movements. Patients will be guided through various tasks, such as tracking moving lights, changing body positions, or having warm and cool air or water introduced into their ear canals. Some parts of the test, particularly caloric testing, may induce a sensation of dizziness or mild nausea, but this is temporary and closely monitored by the audiologist or technician. The entire assessment can take between 1.5 to 2 hours to complete.
Understanding Your Results
After completing the vestibular tests, the results are interpreted by a specialist, such as an audiologist, otolaryngologist (ENT), or neurologist. The interpretation helps determine if there are signs of vestibular dysfunction and whether the problem originates from the inner ear or a related neurological issue. Results can indicate the specific type of vestibular dysfunction, identify which side of the balance system is affected, and assess the severity of the condition.
Normal results suggest no vestibular dysfunction was found to explain the reported symptoms, while abnormal results point to a vestibular or neurological problem. These findings are then used to guide the next steps in patient care. The treatment plan may include medications, specialized exercises known as vestibular rehabilitation therapy, or further diagnostic procedures like imaging tests to investigate underlying causes.