How are vestibular disorders diagnosed?
The inner ear’s vestibular organs and the associated nerves and brain centers form a complex system that serves many functions and can be affected by a number of outside systems. A thorough evaluation of the inner ear may therefore
How are vestibular disorders diagnosed?
The inner ear’s vestibular organs and the associated nerves and brain centers form a complex system that serves many functions and can be affected by a number of outside systems. A thorough evaluation of the inner ear may therefore require several different kinds of tests.
Doctors use information from a person’s medical history and findings from a physical examination as a basis for ordering diagnostic tests to assess the vestibular system function and to rule out alternative causes of symptoms. Most people tolerate these tests well. However, sometimes the tests are fatiguing and can result in temporary unsteadiness.
Sometimes tests are fatiguing and can result in temporary unsteadiness.
TESTING VESTIBULAR DYSFUNCTION
The vestibular and visual systems are connected to each other and to the muscles in the eyes and neck that help maintain good balance. Head movements or other stimulation of the inner ear sends signals through the nervous system to control eye muscle movements. This forms a reflex pathway called the vestibulo-ocular reflex, or VOR. This system is designed to generate eye movements that maintain clear vision when the head is in motion. Many vestibular tests use equipment to monitor the eyes for normal and abnormal movements when the vestibular system is stimulated.
ELECTRO/VIDEO-NYSTAGMOGRAPHY (ENG OR VNG)
Electronystagmography (ENG) refers to a group of tests or test battery, and uses small electrodes placed over the skin around the eyes during testing. Videonystagmography (VNG) refers to the same test battery run using 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.
Parts of the ENG/VNG test battery evaluate the movement of the eyes as they follow different visual targets. Other parts of the ENG/VNG observe eye movements as the head is placed in different positions. A third component of the ENG/VNG is called the caloric test, which uses changes in temperature within th