Wondering if it is Possible to Have BPPV Even if VNG Test Results are Normal?
Many doctors rely on VNG test results to diagnose vestibular disorders such as BPPV.
Can a patient have BPPV even if the VNG test results are negative or normal? I will answer this important question in this blog.
What is a VNG test?
VNG stands for videonystagmography. In other words, the test produces video recordings of nystagmus.
Nystagmus is involuntary eye movement.
The VNG is a battery of oculomotor and vestibular tests. Some of the tests are a standard part of the VNG testing protocol. Other tests are optional, specific to the preferences of the doctor ordering the VNG or the clinic performing the VNG test.
I’ve encountered some patients who have BPPV despite normal VNG test results. How is that possible? There are two possibilities.
Type 2 BPPV
Type 2 BPPV does not produce nystagmus!
This type of BPPV still causes motion activated dizziness or vertigo. Type 2 BPPV also respond favorably to proper treatment.
However, if a doctor or clinician is solely relying on the VNG test results to diagnose a patient, then they might miss Type 2 BPPV.
Learn more about Type 2 BPPV here.
I also refer to Type 2 BPPV as Symptomatic BPPV in this blog.
BPPV Started After VNG Test was Completed
Most cases of BPPV are idiopathic. This means that most BPPV occurs spontaneously with no known cause.
Anyone who has ever woken up with BPPV randomly knows it can happen anytime without warning!
Since a new onset of BPPV can occur anytime, there is always a possibility that BPPV started after a VNG test was already completed.
A Hands On Exam is Key
For these reasons, I always evaluate my patients for BPPV as part of a comprehensive hands on exam regardless of VNG test results.
I certainly review any available VNG test results as part of a comprehensive root cause analysis, but I do not solely rely on the VNG test results for answers.
In many cases of dizziness or vertigo, a hands on exam by a skilled and experienced clinician is superior to diagnostic testing. Diagnostic testing is valuable as a means of confirming the physical exam findings and correct diagnosis.
Disclaimer
This blog is provided for informational and educational purposes only. The content and any comments by Dr. Kim Bell, DPT are not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. The details of any case mentioned in this post represent a typical patient that Dr. Bell might see and do not describe the circumstances of a specific individual.
