Video Nystagmography (VNG) reveals the underlying cause of dizziness and balance problems by measuring how your eyes respond to specific stimuli — giving neurologists an objective window into the health of your vestibular system. If you have been struggling with unexplained dizziness, vertigo, or unsteadiness, a Video Nystagmography (VNG) evaluation can pinpoint whether the problem originates in your inner ear, your brainstem, or elsewhere in the central nervous system.
Understanding Nystagmus and Why It Matters
Nystagmus is an involuntary, rhythmic movement of the eyes. Under normal conditions you are barely aware of it, but when the vestibular system — the sensory network that tracks head position and movement — is disrupted, nystagmus becomes abnormal in speed, direction, or duration.
Because the eyes and the vestibular system are tightly connected through a reflex called the vestibulo-ocular reflex (VOR), recording eye movements provides reliable, measurable data about how well that reflex is working. VNG does exactly that, using lightweight infrared goggles fitted with small cameras that capture every eye movement in real time.
How a VNG Test Works
The test is non-invasive and typically completed in under an hour. It consists of three main phases, each targeting a different part of the balance pathway.
1. Ocular Motility Testing
You track a moving light or dot on a screen. This phase checks whether your eyes can follow a target smoothly (pursuit tracking) and make rapid, accurate jumps between targets (saccades). Abnormalities here suggest central nervous system involvement rather than a pure inner-ear problem.
2. Positional and Positioning Tests
The clinician moves your head and body into a series of specific positions while the goggles record any nystagmus that is triggered. This is one of the most informative phases for diagnosing Benign Paroxysmal Positional Vertigo (BPPV) — a condition caused by displaced calcium crystals in the inner ear canals — as well as other positional disorders.
When BPPV is confirmed, treatment can follow directly. Canalith repositioning is a highly effective in-office maneuver that guides those displaced crystals back to where they belong, often resolving spinning sensations within one or two sessions.
3. Caloric Irrigation
Warm and cool air (or water) are introduced into each ear canal one at a time. The temperature change creates a gentle convection current in the inner ear fluid, which normally triggers a predictable nystagmus response. By comparing the strength of that response between the two ears, the neurologist can determine whether one vestibular nerve or inner ear is weaker than the other — a finding called a canal paresis.
What VNG Can Diagnose
VNG results help distinguish between peripheral vestibular disorders (originating in the inner ear or vestibular nerve) and central vestibular disorders (originating in the brainstem or cerebellum). This distinction is critical because the two categories have very different treatments.
- Benign Paroxysmal Positional Vertigo (BPPV): Triggered by position changes; identified by brief, direction-specific nystagmus in the positional phase.
- Vestibular neuritis or labyrinthitis: Inflammation of the vestibular nerve or inner ear; shows as a significant canal paresis on one side during caloric testing.
- Ménière’s disease: Associated with fluctuating low-frequency hearing loss and episodic vertigo; caloric testing may reveal reduced function on the affected side.
- Central vestibular disorders: Abnormal pursuit tracking, direction-changing nystagmus, or gaze-evoked nystagmus point toward brainstem or cerebellar pathology rather than the inner ear.
- Bilateral vestibular hypofunction: Reduced caloric responses in both ears, often presenting as chronic unsteadiness rather than true spinning vertigo.
VNG vs. ENG: A Quick Comparison
| Feature | VNG (Video Nystagmography) | ENG (Electronystagmography) |
|---|---|---|
| Recording method | Infrared video cameras in goggles | Skin electrodes around the eyes |
| Accuracy | Higher — captures vertical eye movements | Lower — misses vertical nystagmus |
| Patient comfort | Comfortable, no gel or adhesives | Less comfortable due to electrodes |
| Data detail | Comprehensive waveform and video record | Electrical signal only |
| Current standard? | Yes — preferred in modern clinics | Being phased out in favor of VNG |
When VNG Is Combined with Other Neurological Tests
VNG rarely stands alone in a thorough neurological workup. When central involvement is suspected — for example, when nystagmus patterns suggest a brainstem or cerebellar problem rather than the inner ear — additional testing adds important clarity.
A Transcranial Doppler (TCD) study, for instance, evaluates blood flow velocity through the cerebral arteries and can detect vascular causes of dizziness, such as vertebrobasilar insufficiency. Combining VNG with TCD gives a much more complete picture of whether balance problems stem from a structural, vascular, or purely vestibular source.
For patients whose dizziness accompanies neurological symptoms like numbness, cognitive changes, or seizures, EEG testing may be ordered alongside VNG to rule out epileptiform activity as a contributing factor.
Who Should Consider VNG Testing?
VNG is appropriate for anyone experiencing persistent or recurring dizziness, vertigo, or balance difficulties — particularly when the cause has not been identified through a standard examination. It is especially useful if you notice any of the following:
- Spinning sensations (vertigo) triggered by lying down, rolling over, or looking up
- A feeling of swaying or rocking even when standing still
- Dizziness that follows a head injury, infection, or ear surgery
- Unsteadiness that worsens in dim lighting or on uneven ground
- Recurrent falls without a clear musculoskeletal cause
- Dizziness accompanied by hearing changes or ringing in the ears (tinnitus)
Many patients in Manhattan and the surrounding area live with these symptoms for months before learning that a single, objective test could identify the source. Dizziness is not something you simply have to tolerate — it has causes, and most of those causes are treatable once properly identified.
Preparing for Your VNG Appointment
Preparation is straightforward but important for accurate results. Most clinicians advise the following in the 24–48 hours before the test:
- Avoid alcohol, sedatives, and anti-vertigo medications (such as meclizine) unless your neurologist instructs otherwise — they can suppress nystagmus and alter findings.
- Do not eat a heavy meal immediately before testing; caloric irrigation can occasionally cause mild nausea.
- Bring a list of all current medications, including supplements.
- Arrange a driver if you are prone to severe dizziness, though most patients feel fine after the test.
What Happens After a VNG?
Results are interpreted by a neurologist who considers the full clinical picture — your symptoms, history, and any additional test findings. A clearly peripheral finding like BPPV leads swiftly to a targeted treatment such as canalith repositioning. A central finding triggers further imaging or vascular testing. Bilateral hypofunction may lead to a structured vestibular rehabilitation plan.
The goal is never to hand you a report and send you home — it is to translate those objective findings into a clear, actionable path toward feeling better.
Getting Answers to Your Dizziness
Persistent dizziness and balance problems deserve more than a wait-and-see approach. VNG is one of the most informative tools available for cutting through the guesswork and identifying where — and why — your vestibular system is misfiring.
If you are ready to find out what is really behind your dizziness, the team at Apex Neurology is experienced in the full spectrum of vestibular and neurological evaluation. You can explore our dizziness treatment options or reach out to schedule an evaluation when you feel the time is right. You can also find us and read patient reviews on our Google Business Profile.
