With such a wide range of hearing and balance disorders, many of which have similar symptoms, it’s important for an audiologist to make an accurate diagnosis in order to come up with a successful treatment plan. Diagnostic testing plays an important role in determining the condition responsible for a patient’s suffering.
Types of Diagnostic Balance Tests
There are a number of diagnostic tests available, ranging from X-rays and CT scans to more in-depth tests. Here are some of the most common:
- Acoustic Immittance Measures. These tests evaluate the eardrum and middle ear and are used to determine which part of the ear is affected by hearing loss.
- Audiometry. This hearing exam measures your ability to hear different sounds, pitches and frequencies. It can determine the nature and extent of your hearing loss and whether you will benefit from hearing aids or surgery.
- Auditory Brainstem Response (ABR). This neurologic test provides information about the electrical activity in the auditory pathway between the inner ear and the brain, and measures a person’s hearing sensitivity.
- Electrocochleography. This test is used to determine whether there is excess fluid in the inner ear by measuring the electrical currents generated by sound stimulation, and can help with the diagnosis of Meniere’s disease and other balance and hearing disorders.
- Otoacoustic Emissions (OAE). This test measures the response of hair cells in the inner ear when stimulated, and can indicate the presence of a conductive or cochlear hearing loss.
- Posturography. This balance test measures the effectiveness of the somatosensory system, vestibular system, and vision to determine which area(s) to focus on when treating a balance disorder.
These diagnostic tests are quick, painless, and can help us diagnose and evaluate a variety of hearing and balance disorders.
Diagnostic Tests for the Vestibular System
The vestibular system is complex and responsible for many of the body’s functions. In order to narrow down the exact cause of dizziness, it is necessary to administer a variety of tests. These measure eye movements, head movements, hearing and more.
Studies indicate vestibular testing is extremely thorough and accurate in identifying inner ear disorders. Vestibular testing is also helpful in determining whether additional diagnostic testing, such as an MRI, is needed. A battery of tests is administered in most cases. The most common ones include:
- Electronystagmography (ENG). This series of tests measures eye movements via electrodes placed around the eyes. ENG tests usually consist of four parts: evaluation of rapid eye movements, tracking tests to measure eye movements as they follow a visual target, positional test for measuring dizziness in response to different head positions and a caloric test that measures responses to warm and cold water circulating through a tube in the ear canal. Most people reporting dizziness or vertigo will be given ENG tests initially.
- Videonystagmography (VNG). This is similar to ENG testing, but an infrared video camera attached to a pair of goggles is used in place of electrodes. The same four-part testing process is utilized.
- Rotary Chair Tests. The rotary chair test measures eye movements in response to corresponding head movements; it is used to determine whether symptoms are related to an inner ear disorder or a brain disorder. Like the ENG and VNG tests, either electrodes or a goggle-mounted video camera is used to record eye movements. You are seated in a computerized chair that moves. This test provides more detailed information about the function of the balance system than an ENG or VNG test.
- Computerized Dynamic Posturography (CDP). CDP tests measure how well the visual, vestibular and sensory systems work together to maintain balance. With this test, you stand on a platform and follow a visual target while platform movements record the degree to which your body sways. It includes an Adaptation Test in which the platform moves up and down and a Motor Control Test where the platform moves forward and backward. These are used to measure reflexive responses to unexpected movement. CDP is frequently used for those undergoing vestibular rehabilitation.
- Vestibular Evoked Myogenic Potential (VEMP). VEMP testing is used to determine whether the saccule (an inner ear organ) and vestibular nerves are functioning properly. Electrodes are attached to the neck and sounds are transmitted through a pair of headphones. The electrical response of the sternocleidomastoid muscle in the neck is recorded.
These tests may be combined with additional hearing or diagnostic tests depending on the results.
Call David R Brown MD Ear, Nose and Throat at (505) 820-9945 for more information or to schedule an appointment.