Temperature & Vibration Threshold tests
 

Last year, my neuro decided (after seeing me for 10 yrs) that I should be tested to see if my "thresholds of perception" for temperature and vibration are normal.

Not sure if people here have had this done. It involves putting a transducer on your foot, that can be heated, cooled to varying degrees (...oops, pun not intended). Then you push a button if you feel anything. Similarly for vibration.

The outcome was that "thermal thresholds are elevated from both feet, but vibration thesholds were normal. These data are consistent with small fibre neuropathy"

Is this kind of testing definitive? How have others been diagnosed for small fibre neuropathy? What tests?

Oh ...here are the test results:
44bx.com/misc/thresholds.jpg

Best Wishes,
Steve

What you had--
 

--is called "quantitative sensory testing".

It can certainly be used to detect suspected small-fiber neuropathy. The small fibers subsume the sensations of pain and temperature, and abnormal results on this test point to a dysfunction of those fiber types.

The problem has been that the test had always relied both on the self-reporting of the testee and the interpretation of the tester, and these are not always reliable--there is great individual variation on both sides.

The current gold standard for detecting small-fiber damage is skin biopsy to detect reduced intraepidermal nerve fiber density and damaged/swollen fibers.

Glenn is it quantitative or qualitative. IM not being picky but i have seen it referred to as qualitative and when i discuss these tests at my soon to be visit i want to ask for the right name for obvious reasons. Thanks.

I've actually seen it both ways--
 

--but in most of the clinical application papers I've read that describe the procedure, it's referred to as quantitative, inasmuch as what is being looked at are thresholds for noticing pain as temperatures are increased/decreased, and also the JND--the just noticable difference at which one can discern that the temperature has actually changed.

A fairly consistent finding in this testing (probably the most consistent finding) is that people with small-fiber damage have to have the temperature increased/decreased by a greater amount than do "normals" to say they've noticed an actual change.

Hi Glentaj

Thanks for your comments -- yes, it is indeed called quantitative sensory testing, as this is the title at the top of my test results.

I was un-aware that a skin biopsy can also be used to verify smalll fibre neuropathy - next time I see the neuro I'll raise this with him. Thanks!

I agree with your comments about variability in test results from patient perception. I tried pretty hard to be consistent, but it was always difficult. I know that the computer controlling the test would re-test, and re-test until I was consistent in my responses.

Best wishes,
Steve

K
 

Did your Neuro tell you why it took 10 yrs. to decide to do this..I
would ask if he would update,but check your insurance..Are you sure he's
up to date on PN??? If you really like him just ignore me..What more has
he told you about your PN,and do your meds help?? Hugs to all Sue :)

Ok that answers that and Steve so right.
Glenn or anybody was the resulths of Steve's test normal,or good be better
can you tell from what he has written down or Steve have you seen
the Dr. yet,and please keep all your paper work and continue to do that,
there yours. Look up LJ sheets if you haven't done that yet..Sue

Hi Steve, Thermal threshold testing did show up my small fibre damage, & an EMG showed some damage to the large nerves as well, but thermal threshold testing doesn't always show the small fibre damage as Glentaj said, if i remember right it didn't work for him, but a skin punch biopsy did, the only trouble is finding a lab in Melbourne that does it, i do not know of any myself, but if you have the symptoms of small fibre damage and that thermal test showed abnormal reactions why bother, the important thing is to find the cause, which isn't always easy.
good luck
Brian :)

Brian is quite accurate--
 

--I did have this testing and it came up "normal", but the skin biopsy did show rather definite small-fiber de-enervation and damage.

Part of the reason skin biopsy has replaced quantitative sensory testing, at least at facilities at which the former is available, is that the former is far less subject to individual reporting variation. (It's far more objective to count nerve fibers.)

I think the Neuromuscular Lab at Johns Hopkins will send a test kit and spend about 5 minutes on the phone giving instructions to whoever is to do the punch.

I know they will do this for people out of their area in the U.S., so I assume that the punch could also be done in Australia, then sent to JH for their evaluation...

Cathie