can anyone interpret the results of my husband's VEP test?

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can anyone interpret the results of my husband's VEP test?

Postby ebrownkirkland » Wed Feb 08, 2017 6:32 am

My husband had his VEP test this morning. Anyone know how to read it? Here are the results:

Right eye:
76.5
113
149
7.46

Left eye:
83.5
111
153
7.15

Norm:
75
100
145

Thanks in advance for your help.
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Re: can anyone interpret the results of my husband's VEP tes

Postby NHE » Wed Feb 08, 2017 3:16 pm

Here's lots of info about the VEP test, but no simple answer to your question.

http://webvision.med.utah.edu/book/electrophysiology/visually-evoked-potentials/
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Re: can anyone interpret the results of my husband's VEP tes

Postby ebrownkirkland » Fri Feb 10, 2017 7:45 am

Yeah, I have seen that site--it was one of the first I went to--as well as a host of others. It's so frustrating because one site says one thing while another says something else. Here's what I've found:

From a paper from 2005: P100 latency >115 is considered abnormal. It also says that most labs consider responses less than 115mS to be normal. Given that my husband's numbers were 113 and 111, respectively, for right and left eye, that would mean his results would be normal.

But then a 2008 document from the American Clinical Neurophysiology Society states, "Most laboratories regard as abnormal P100 latencies and intraocular latency differences exceeding 2.5 or 3 standard deviations above the mean as an age-matched control sample from the normal population. So that would mean the results of my husband's test would be abnormal, right?

But, normative data will age with age and gender. Furthermore, I've read that each lab should collect its own normative data. And that they are not routinely interchangeable between laboratories. Something I read said, "Laboratories using the same stimulating and recording equipment may be able to interchange normative data if all recording and stimulating parameters are identical." Then it goes on to say that normative data varies with age and gender. I wonder what the normative data is for GW, where my husband had his test run... I would think they would follow pretty closely to the P100 value, and I have found one book that sited 87-104 as the normal range for VEP P100 latency (Clinical Neurology and Neurosurgery, Volume 85, Issue 4, 1983, Pages 267-272), but I could be wrong. I have also read that most labs consider responses less than 115mS to be in the normal range. But if that is the case, his result of 113 would be borderline. Would that therefore mean he could have had a mild case of optic neuritis? I have read somewhere else that "The highest positive peak (typically called P100) should happen in less than 115 mS for people less than 60 years old."

My husband did find some interesting information which sounds reasonable: VEP latency categories, according to a 2012 study, are as follows: normal <113mS, mild >=113 and <130.

Diagnosing him with having had "mild optic neuritis" seems to me to be the most reasonable, given his symptoms (a scotoma in his right eye that came and went over the course of two months).

Ugh. All of this information I've been reading over the last few days has been making me dizzy. I just wish the doctor would get back to us with results so that we know where we are going to have to go from here. My husband had the test Wednesday morning at 8 a.m. so it's been a full 48 hours since then. He went by the radiology department yesterday at lunch but the report still wasn't ready. He filled out all sorts of paperwork so he could get the report from the hospital as soon as it's ready, but he was told that it could be as much as 10 days before he got the results. TEN DAYS. That is ridiculous!

Sorry. Just venting. This is the last hoop my husband has to jump through before a diagnosis is made. His MRI showed "Dawson's Fingers," so the MS specialist highly suspects MS, given the ocular symptoms he had for two months prior to his VEP test.
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Re: can anyone interpret the results of my husband's VEP tes

Postby NHE » Fri Feb 10, 2017 10:59 pm

ebrownkirkland wrote:But then a 2008 document from the American Clinical Neurophysiology Society states, "Most laboratories regard as abnormal P100 latencies and intraocular latency differences exceeding 2.5 or 3 standard deviations above the mean as an age-matched control sample from the normal population. So that would mean the results of my husband's test would be abnormal, right?

That would depend on the variance in the population used for comparison.

To elaborate, low population variance produces a narrow bell curve while high population variance produces a broad bell curve.

Low variance would lead to a small standard deviation and a higher likelihood that your husband's data was abnormal. In contrast, a population with a large variance would lead to a greater standard deviation and a lower probability that your husband's data was abnormal.
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Re: can anyone interpret the results of my husband's VEP tes

Postby ebrownkirkland » Sun Apr 30, 2017 8:46 am

Well, the VEP was borderline, but we just received the diagnosis yesterday... Relapsing remitting MS. It was sort of expected but I am still in a kind of shock-like state... it is an almost out-of-body feeling. It's going to take awhile for the news to sink in, I think.
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