VEMP stands for Vestibular Evoked Myogenic Potential. It's a type of diagnostic test used to evaluate the function of the otolith organs within the inner ear, specifically the saccule and utricle, which are responsible for detecting linear acceleration and head position relative to gravity.
During a VEMP test, surface electrodes are typically placed on the skin overlying certain muscles, such as the sternocleidomastoid muscle in the neck or the orbicularis oculi muscle around the eyes. The patient is then instructed to perform specific actions, such as turning the head to one side or looking upward, which activates the otolith organs.
The VEMP test measures the electrical responses generated by the otolith organs in response to these stimuli. Specifically, it assesses the myogenic (muscle-generated) response of the muscles being monitored. The test helps evaluate the integrity and function of the vestibular system, particularly the saccule and utricle, and can aid in the diagnosis of certain vestibular disorders, such as
superior semicircular canal dehiscence (SSCD),
Meniere's disease, and
vestibular neuritis.
VEMP testing is often performed alongside other vestibular function tests, such as videonystagmography (VNG) or electronystagmography (ENG) and can provide valuable information to clinicians in diagnosing and managing vestibular disorders.
How to prepare
Medication: do not stop any long-term daily medications. Do not take vestibular suppressants such as antihistamines (Benadryl, Meclizine, Bonine), benzodiazepines (Valium, Xanax, Ativan), or other sedating medications such as sleep aids 24-48 hours prior to testing.
Avoid caffeine and nicotine: It's often recommended to avoid caffeine and nicotine for a certain period before the test, as they can affect vestibular function and eye movements.
Eat a light meal: Having a light meal before the test is generally recommended. The test can occasionally cause nausea.
Wear comfortable clothing: Dress comfortably for the test, as you may be lying down or sitting for an extended period during the procedure.
Remove eye makeup and contact lenses: If you wear eye makeup or contact lenses, you may be asked to remove them before the test.
Plan for transportation: Since the test may induce dizziness or vertigo, it's a good idea to arrange for someone to drive you home afterward, especially if you anticipate feeling unwell or dizzy.