VNG results

[joannela]

Hello:

I posted a couple of weeks ago called "Chronic Dizziness."  I mentioned I have weeks at a time of dizziness, not room spinning vertigo like I used to have when diagnosed with BPPV ten years ago. Your answer said I had a number of non-specific dizziness complaints but did not sound like BPPV.

I saw a neurologist who felt I had an inner ear problem and sent me for a VNG. The results of the VNG were "normal" I was told.  The audiologist did say that at one point I had some upbeating nystagmus, however she said it was very, very weak - too weak for her to even measure with the computer, and it stopped as soon as I fixed my gaze. She also said that b/c I am on an SSRI that it could be the cause, but in any event I shouldn't worry about it. (Of course I still am.)

Since the neuro felt it was an inner ear problem, the negative VNG is concerning me b/c I guess that means he was wrong?  Can you please tell me what a VNG is meant to rule out - does it rule out ALL inner ear disorders?  Does it rule out anything else?

So does that mean I am left with the possible diagnoses of migraines, anxiety, MS or brain tumor?
(I have an MRI scheduled for next week, "for reassurance" - mine, supposedly.

[Eric P Wilkinson, MD]

Xanax can certainly have affected the results of your VNG.  You should not take antihistamines or benzodiazepines before your VNG.  That being said, if your caloric testing was full and normal in both ears on the testing, it probably didn't affect it.

A negative VNG, as long as the caloric testing portion was performed with cool and warm water (bithermal water caloric testing), does rule out a significant difference in the function of the upper balance nerves.  VEMP testing can give some indication as to the function of the lower balance nerves.

Dizziness occurring for long periods of time, with only upbeating nystagmus on VNG and normal hearing, is less likely to be inner ear in origin.  An MRI should be obtained at some point to rule out a mass lesion or a microvascular compression of the balance nerve.

See an otologist (ear specialist) for a full evaluation and testing.  You may also want to see a neurologist.  Followup with your primary care physician is essential.

Hope this helps.  Good luck!

This answer is not intended as and does not substitute for medical
advice - the information presented is for patients education only.
Please see your personal physician for further evaluation of your
individual case.

[joannela]

Follow on question:

I have been prescribed Xanax prn for anxiety. I took two Xanax pills (.25 each - .5 mgs total) approximately 4-6 hours before my VNG b/c I was anxious about my neuro appt and didn't know they'd get me in for the VNG that same day.  I've recently read that Xanax is sometimes used as a "vestibular suppressant."  Is it likely that it would affect me VNG results? (I did tell the audiologist that I had taken it.)

Thanks

[joannela]

Can I get a doctor response please?

[Nancy T]

The doctor here will give you the expert answer, but what I have heard (from an expert balance-testing person) is that the VNG/ENG (same thing, basically) is a pretty rough test, and a negative one DOES NOT rule out inner-ear disorders. He compares it to "if you don't find your keys on the table, it doesn't mean they're not somewhere in the house."

In some cases (depending on the symptoms or history, I guess) the doctor may go on to rotary-chair testing or other vestibular or brain tests. I have undiagnosed dizziness/hearing loss for many years and never had testing further than the ENG and ABR (so I'm not saying that you should NECESSARILY have further testing--only that it might be something to ask your doctor about, whether it would be appropriate).

Did you see a neurologist who SPECIALIZES in dizziness? These are called oto-neurologists, and there aren't many of them around. Usually they seem to be connected to a university. There is a list at www.robbmd.com, although I'm not sure that it's a complete list nor that all the doctors on there would call themselves by that name. Best bet is to call around or ask for a referral to a neurologist SPECIALIZING in dizziness.

Yeah, doctors sometimes talk about tests as if they're doing them just to mollify the patient, and I'm sure that's sometimes the case, but anyone with ongoing undiagnosed dizziness ought to have an MRI. Just to be sure they're not missing something important. But most MRIs on dizzy people ARE normal. Hope yours is too.

It seems (from what I've read of other people's experiences) that dizzy people are often bounced from ENT to neurologist and back, the ENT saying there's no evidence of an inner ear problem and the neurologist saying there's no evidence of a neurological (brain) problem. Brain vs. ear can be difficult to sort out, and then when you've been dizzy awhile and developed anxiety, panic, etc. (as MANY dizzy people do--though I never did)--that just complicates things further.

What you want is to make sure that you have seen DIZZINESS specialists on both sides (ENT and neurology). But be aware that not everyone gets a diagnosis, or a correct one. Sometimes even the best doctors just can't say for sure. But there are usually a number of treatments (medicines and other) to try. So don't give up! Hang in there!

Nancy T.