A VEMP test (vestibular evoked myogenic potential) is a diagnostic test that measures how well specific parts of your inner ear’s balance system respond to sound. It works by playing loud clicks or tone bursts into your ear and recording the tiny muscle reflexes those sounds trigger. The test is unique because it evaluates two small organs in your inner ear, the saccule and utricle, that no other standard balance test can assess directly.
How the Test Works
Deep inside your inner ear, you have two otolith organs that detect gravity and linear motion: the saccule and the utricle. These organs contain hair cells that, as a quirk of evolution, still respond to loud sounds. When a strong sound stimulus reaches these hair cells, they fire nerve signals that travel through the vestibular nerve to your brain, which then triggers a brief, measurable muscle reflex.
During a VEMP test, a clinician delivers short bursts of sound through headphones (or sometimes vibration applied to the skull) and picks up these reflexes using small electrodes stuck to your skin. The response shows up as a characteristic electrical waveform, and your clinician analyzes the timing and size of those waves to assess whether your inner ear balance organs are working normally.
Two Types: Cervical and Ocular
There are two versions of the VEMP test, and each one evaluates a different part of your balance system.
Cervical VEMP (cVEMP) tests the saccule and the lower branch of the vestibular nerve. Electrodes are placed on the sternocleidomastoid muscle, the large muscle running down each side of your neck. When the saccule detects the sound stimulus, it sends an inhibitory signal that briefly relaxes the neck muscle on the same side. To get a clear reading, you need to tense that muscle during the test. You’ll typically either recline at about 30 degrees and lift your head against gravity, or sit upright and turn your head away from the ear being tested.
Ocular VEMP (oVEMP) tests the utricle and its nerve pathways. For this version, electrodes go on your cheeks just below your eyes, and you look upward as far as comfortably possible while the sound plays. The utricle sends an excitatory signal to the eye muscles on the opposite side, producing a small measurable response. Looking up maximizes the signal strength.
What Happens During the Test
The test is noninvasive and relatively straightforward. A technician cleans the skin where the electrodes will go, then places small adhesive electrodes on your neck (for cVEMP) or beneath your eyes (for oVEMP), with reference electrodes on your collarbones or upper chest. You’ll wear headphones, and the test delivers a series of loud clicks or tone bursts, typically at a high volume.
For the cervical version, the most physically demanding part is holding your head up to keep the neck muscle contracted. Some clinics test both sides sequentially. The ocular version simply requires you to hold a steady upward gaze. Each recording takes a few minutes per ear, and the entire session, including both types, generally wraps up in 30 to 45 minutes.
Unlike caloric testing or rotary chair testing, VEMP does not provoke dizziness, which makes it particularly well suited for children and people who find other balance tests uncomfortable. One thing to be aware of: because the sound stimulus is loud, a small number of people report temporary muffled hearing afterward. In one study, about 27% of adult subjects noticed this effect, though it resolved. Sudden hearing loss from VEMP testing has been reported in only a single case in the published literature.
Conditions VEMP Helps Diagnose
Superior Canal Dehiscence Syndrome
The strongest clinical evidence for VEMP testing is in diagnosing superior canal dehiscence syndrome (SCDS), a condition where a thin spot or opening in the bone covering one of the semicircular canals causes symptoms like dizziness triggered by loud sounds, hearing your own heartbeat, or feeling off-balance. The American Academy of Neurology has published guidelines specifically supporting VEMP use for this condition.
In SCDS, the inner ear becomes hypersensitive to sound stimulation. This shows up on VEMP testing as abnormally low thresholds, meaning the reflex kicks in at much quieter volumes than normal. Research from Johns Hopkins found that ears with dehiscence had an average VEMP threshold of about 72 decibels, compared to 96 decibels in healthy ears. That 24-decibel gap is large and consistent enough to be diagnostically useful. VEMP serves as a physiological confirmation alongside CT imaging of the temporal bone.
Ménière’s Disease
VEMP testing shows promise for monitoring Ménière’s disease, a condition involving episodes of vertigo, hearing loss, and ringing in the ear caused by excess fluid pressure in the inner ear. The test can detect changes in how the saccule responds to different sound frequencies. In people with active Ménière’s symptoms, the response pattern shifts: higher-frequency tones produce relatively stronger responses compared to lower-frequency tones. One study found this frequency ratio was significantly higher in active disease (1.22) compared to stable disease (1.00), with 81% specificity for distinguishing between the two states.
This makes VEMP potentially valuable for tracking whether the disease is flaring or in remission, and it outperformed traditional tests like caloric testing and electrocochleography for this purpose. However, current guidelines note that the overall evidence for using VEMP to diagnose Ménière’s disease (as opposed to monitoring it) is still limited.
Vestibular Migraine
Vestibular migraine, which causes dizziness episodes linked to the migraine pathway, is frequently misdiagnosed as Ménière’s disease or benign positional vertigo because the symptoms overlap. VEMP testing may help sort this out. People with vestibular migraine tend to show a distinct pattern: normal cVEMP responses but abnormal oVEMP responses on one side. This makes sense physiologically, since vestibular migraine is primarily a central nervous system condition where the utricle’s pathway to the eye muscles appears to be particularly affected, while the saccule may be less involved.
By contrast, Ménière’s disease, which directly damages inner ear structures, tends to produce prolonged response times and reduced amplitudes on both VEMP types. These different patterns can help clinicians distinguish between the two conditions when symptoms alone aren’t conclusive.
What the Results Mean
Your clinician looks at several features of the VEMP waveform. The two most important are latency (how quickly the response appears after the sound) and amplitude (how strong the response is). They also calculate an asymmetry ratio, comparing the response strength between your two ears. In healthy adults, this ratio averages around 0.13, meaning the two sides are nearly equal. A large difference between ears points to a problem on the weaker side.
An absent response on one side can indicate damage to the saccule, utricle, or vestibular nerve on that side. An unusually strong or low-threshold response, as seen in SCDS, suggests the inner ear is abnormally sensitive to sound. Delayed timing of the response can indicate a problem along the nerve pathway between the inner ear and the brain.
Who Should Have VEMP Testing
The American Academy of Otolaryngology recognizes VEMP as medically indicated for evaluating certain people with suspected balance or dizziness disorders. In practice, the strongest and most widely accepted use is for suspected superior canal dehiscence syndrome. For other conditions, VEMP is typically used alongside other vestibular tests rather than as a standalone diagnostic tool.
Before the test, your clinician will usually check your hearing and middle ear function. Ears with perforations in the eardrum, pressure equalization tubes, or abnormal middle ear pressure may not produce reliable results with air-conducted sound and are generally excluded from testing or tested with bone vibration instead. No special preparation is needed on your part beyond being able to hold your head up or look upward steadily for a few minutes at a time.