The Advantage of a Binocular VNG


It’s similar to buying a new car. For example, if you were shown a standard Toyota Corolla and were told that you could get better mpg, built-in navigation, and more responsive brakes for an extra $2,000, would you pay the for the improvements? As with anything, it depends on your needs. If you’re a frequent traveler who is always driving to new places and through all types of hazardous weather conditions, the upgrades may be worth it.

When it comes to choosing between video goggles that screen the vestibular function, the reasoning isn’t much different. At the end of the day, your decision needs to come down to what’s best for your practice, and more importantly, what’s best for your patients. If you’re not seeing many patients coming from neurologists and general practitioners, chances are you’ll be fine with a monocular system. However, if you are seeing many patients coming from these types of medical professionals, you may want to consider spending the extra money on a binocular system. Chances are they may be suffering from more serious conditions that can only be detected by screening both eyes.


Two Cameras Provide a Clearer View of Disconjugate Eye Movements

For instance, recording activity from both eyes during a Pursuit or a Saccadic test gives you the ability to more easily examine disconjugate eye movements (movements of the eyes in opposite directions). These abnormal eye movements generally indicate paralysis of the extraocular muscles in one eye or a lesion affecting the medical longitudinal fasciculus (MLF). Being able to record and observe this enables you to better determine whether a patient’s dizziness is being caused by a more serious central issue affected by the brain (head injury, multiple sclerosis, brain tumor, etc.).

Similarly, using two cameras to perform a video head impulse test (vHIT) has its major advantages. Having two high-speed video cameras to perform a head impulse test with video eye tracking makes it much easier to accurately measure VOR gain or Positional gain and record compensatory saccades when each canal is tested. As a result, the risk of misinformation is drastically reduced, allowing you to confidently determine whether a patient has a peripheral or central lesion.

Two Cameras Can Help you Confidently Diagnose and Treat Patients

In short, binocular evaluation makes it more likely for you to catch a significant diagnosis that would otherwise have been missed using monocular techniques. Using two cameras to record eye movements as opposed to one could be the difference between diagnosing BPPV and a more severe cerebral dysfunction.

This enhanced accuracy can confidently determine whether you’ll be able to help a patient with positioning techniques like the Epley maneuver, or whether more intensive therapies like gaze stabilization or visual dependence training will be necessary. Additionally, you’ll be able to set better expectations on how long it will take before therapy shows significant results.

Choose What Makes Sense for Your Practice and Patients

While using two cameras in testing the vestibular function has its clear advantages, it is important to note that an accurate diagnosis can still be reached using a one-camera system; it just involves a more manual approach from the therapist. The possibility of a missed diagnosis on a monocular screening can be drastically reduced by performing an ocular motility assessment beforehand. By having the patient follow smooth and rapidly moving objects, you’ll be able to determine whether eye movements are conjugate or not. In turn, you’ll be safe in using monocular eye movement recording techniques.

As stated, your decision between a two camera system and a one camera system should be contingent on whether you see a large amount of patients coming from neurologists or general practitioners. You also may want to consider a two camera system if you’re seeing a large amount of dizzy patients with no prior history of vertigo because they’ve probably never been screened for vestibular impairment. If neither apply for your practice, then a one camera system is sufficient.