The vestibular system plays a crucial role in many bodily functions, and pinpointing the root cause of dizziness requires several specific tests. These assessments focus on eye and head movements, hearing and more, providing detailed insights into the functioning of the inner ear.
Vestibular evaluations are known for their comprehensive and precise nature, effectively identifying issues within the inner ear. They can also indicate if further tests, like an MRI or neurological assessment, might be necessary.
A set of standard tests typically includes:
- Videonystagmography/ Electronystagmography (VNG/ENG): VNG/ENG tests use an infrared camera mounted on goggles or electrodes around the eyes to track eye movements. This multi-part test includes assessing rapid eye movements, following a moving target, testing dizziness in various head positions and evaluating reactions to temperature changes in the ear canal through a caloric test. VNG/ENG is often the first step for those experiencing dizziness or vertigo. Before undergoing VNG/ENG, it’s important to be aware of specific medications to avoid.
- Caloric Test: This test stimulates the vestibular system by delivering cold or warm water or air into the ear canal to simulate the rotational movement of the head. Infrared video goggles are often used to track eye movements to assess the horizontal semicircular canal functions.
- Vestibular Evoked Myogenic Potential (VEMP): This test checks the functionality of the otolith organs (an inner ear component) and vestibular nerves by placing electrodes on the neck and sending sounds through headphones. The response from the neck’s sternocleidomastoid muscle is then measured.
- Video Head Impulse Test (vHIT): The vHIT test uses an infrared camera mounted on goggles to track eye movements. The tester then moves the head rapidly in horizontal and vertical directions to assess the functions of the semicircular canals in the inner ear.
- Rotary Chair: The Rotary Chair test uses a rotational computerized chair. A pair of infrared video goggles are used to track the eye movements. It is often used to assess and detect bilateral peripheral vestibular weaknesses in conjunction with the VNG/Caloric tests.