The audiologist obtains a detailed history of the dizziness symptoms and performs a number of functional balance tests. Among the functional assessments are ability to stand eyes-open, eyes-closed, ability to walk, ability to maintain balance on cushions. Other tests include ability to read an eye chart with head movement, ability to keep the eyes focused during rapid head turns, and symptoms of dizziness during lying-to-sitting and sitting-to-lying action. Other general measures are evaluated, as well. If hearing loss is present, a detailed hearing test is completed.
Among the additional tests that may be ordered are:
Videonystagmography (VNG) attempts to determine if dizziness is due to inner ear or brain/other disease. The test checks how the eyes move as a reflex to balance system stimulation.Auditory Brainstem Responses (ABR) testing checks associated hearing pathways from the inner to the brain since, when the balance system is abnormal, the hearing may also be abnormal.Electrocochleography (EcoG) checks ratios of inner ear and hearing nerve output. The ratio is commonly too high in Ménière's disease, indicative of elevated inner ear fluid pressure.Other tests such as an MRI and a CT Scan may be ordered.
The brain's ability to maintain balance employs the inner ear, the eyes and a variety of muscle and joint sensors to inform the brain so that the body moves smoothly while in action. For it all to function well, circulation of blood to the brain must be sufficient and stable.
A person who has poor balance might have abnormalities in one or more of these systems. Balance, therefore, is supported by more than the inner ear. Several other organ systems, critical to good balance, might have to be assessed to properly diagnose a person's particular balance problems.
The following is a brief explanation showing how these systems work together and influence one another:
Inner Ear Semicircular Canals
Each inner ear has five sensory organs. Three canals that sense changes in any direction of rotation and two sensors that detect changes in up-down, side-to-side, and front-to-back motion. Each ear has a duplicate set of these organs that are oriented to present mirror images of the opposite side. The resulting balance system provides an incredibly rich set of information tat keeps a person precisely oriented in space.
The eye-brain relationship has two systems that affect balance. The first, the pursuit system, keeps objects precisely focused on the central visual receptors in the eyes. The second, the saccadic system, finds objects in peripheral vision and moves the eyes with exceptional speed and precision to bring the object into the central visual field. Eye problems such as cataracts, eye muscle imbalance and altered eye position can affect precise movement and positioning of the eyes.
Muscles and Joints
The muscles, tendons and joints detect position and tension with special position and pressure receptors.
The brain combines the information from the inner ears, eyes, muscles and joints in several ways. Decisions are made subconsciously that adjust eye position to keep the environment in stable focus. In other words, the environment does not normally jump or shift during running, walking or riding. Automatic brain signals adjust muscle activity to maintain balance. For common activities, the brain recognizes patterns of movement and anticipates the next actions. Muscles, eyes and thought patterns adjust automatically for expected additional sensory information.
The blood's circulatory system has several features that are critical to balance. When shifting body position from either lying or sitting to standing, the muscles in the walls of blood vessels in the legs and the abdomen contract to prevent pooling of blood in those lower areas of the body. A regular heart beat provides uninterrupted circulation of blood to the brain. In the neck and the base of the brain, blood vessel walls free of obstructions maintain low resistance to circulating blood. These multiple mechanisms insure that the head and brain receive an adequate supply of blood.
Your first visit to Upper Valley Hearing & Balance, Inc. as a patient having dizziness will involve an extensive interview and physical performance test evaluating your present use of the major balance systems.
Clinical examination of sensory integration involves several tests. These first tests assess the ability to stand on a floor with feet together, eyes open and closed, and the ability to maintain balance in a tandem position with eyes open and closed. The next tests are the similar as the first three but are performed on a thick cushion. The tests asses the patient's ability to use all parts of the balance system together.
Position Tests: Position tests take the patient through several maneuvers to determine whether they provoke dizziness or imbalance. Position testing looks more vigorously for responses to more rapid position changes. The use of special goggles helps the examiner evaluate responses.
Upper Valley Hearing & Balance, Inc provide the following treatments for certain balance conditions:
Canalith repositioning procedure (stones or "crystals" in the semicircular ear canal)Home exercise program (performed daily)Physical Therapy Referral Services for Adaptation therapy (motion sensitivity)Gait and safety training (reduces fall risk)