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Thank you for all this great content. This is truly a blessing of a site.

I had a couple quick questions I was hoping that somebody could assist on. I have been diagnosed with bilateral carpal tunnel based off clinical findings while at a visit with the neurosurgeon. My EMG/NCV came up negative on 2 separate occasions (both performed by neurologists), however, when I wear night wrist splints I can sleep through the night and my hands are not painful in the morning. When I don't wear the splints, I wake up continuously throughout the night with painful hands.

Question 1) I read about the effects of CTS on sleep and how wrist splints can be highly effective. This is definitely my case. My sleep is greatly improved with the splints but is still not great. What is the next step, when splints are not getting a patient to a good point? Is it common that some patients react well to splints and others do not? I'm considering surgery and am not sure if my situation is unique.

Question 2) I did receive a 2nd opinion from an orthopedic surgeon. He said that he would not be able to diagnose me since I am taking Gabapentin. I did read that patients taking Gabapentin showed reduction of symptoms and patients improved with significance on Phalens and Tinels test. Have you found that a CTS diagnosis could be clouded by this drug?

Thanks in advance for any insights.

All the best,


I just saw I missed the page title. If you would like to add an appropriate title, please feel free. Possible, "Splints not working"


First of all there have been two good quality randomised contrlolled trials of gabapentin in CTS both of which came to the conclusion that it had no significant effect. I cannot see any reason why it would interfere with diagnosis.

Our usual tactic when nerve conduction studies are negative but the problem still sounds like CTS is to try the effect of local corticosteroid injection. You can also carry out ultrasound imaging of the median nerve which shows an abnormality in about 50% of these NCS-negative cases if you need further confirmation of the diagnosis. My own interpretation of something which sounds clinically like classical CTS but has normal NCS is that there is not enough nerve damage to require immediate surgery so you can afford to experiment with other, less aggressive treatments first.

If the symptoms are not 'classical CTS' then it's always worth remembering that other hand problems might also respond to splints.

If you have access to your NCS results I can take a look at them for you. Not all are done to the same standards so it's sometimes worth checking. JB


Hi JB-

Thanks for the informative reply. I tried my best to retype the NCS results below. Hopefully, when I press submit, it will format correctly. :)

I did have a cortisone shot and it made a slight difference but I still couldn't remove my splints at night. Is that common? When I tried a night without the splints, after the shot, I woke up repeatedly throughout the night and with sore hands. The splints are pretty effective, as without them I'm a tired, pain-filled wreck in the morning. I remember, before using them, after 2-3 days I developed a trigger finger. It seems like I bend my wrists, when I sleep, to such a large degree that it blocks off circulation to my hand? The one doctor I saw called it “Dynamic CTS.”

I've had a full battery of tests for my thyroid, RA factor and other related diagnoses but all are negative. One interesting thing to note is that when this all begin, I had just moved into a house that we later found out had a severe black mold problem. We all had to move out. One of my physicians after hearing this took several blood tests including my VEGF which was very low and my Transforming Growth Factor Beta 1 which was very very high. I see those are mentioned in your the biochemistry section, although, their meaning and correlation with what you mention is beyond my current understanding.

In any event, one of the other interesting things I've read is the below study where both positive & negative EMG/NCV tests still had successful outcomes. That's made me contemplate the usefulness of the EMG/NCV.

Do you have any advice on a next step or a specialist / U.S. hospital/physican that I might visit? Does the idea of "Dynamic CTS" make sense, in your opinion? Could there be a legitimacy to exposure to a toxic agent, like mold, or other differential diagnosis causing some of these neurological items? I'm really suffering and confused so my sincerest appreciation for your opinion.

Motor NCS
Nerve / Sites Rec. Site Lat Amp Area Segments Dist Vel Temp

ms mV mVms mm m/s C
L Hand Median Wrist APB 2.86 8.5 27.7 Median Wrist-APB 32.8
Elbow APB 6.82 8.1 27.9 Elbow - Median Wrist 245 61.9 32.7
Ulnar Wrist ADM 2.29 12.6 33.6 Ulnar Wrist - ADM 33.1
B. Elbow ADM 5.94 12.5 34.3 B.Elbow-Ulnar Wrist 240 65.8 33.1
A. Elbow ADM 7.50 12.5 34.0 A. Elbow-B. Elbow 95 60.8 32.2

ms mV mVms mm m/s C
R Hand Median Wrist APB 2.66 9.3 42.1 Wrist-APB 80 32.5
Elbow APB 6.67 8.5 39.7 Elbow - Wrist 240 59.8 32.4
Ulnar Wrist ADM 2.29 11.5 34.5 Ulnar Wrist - ADM 32
B. Elbow ADM 6.25 11.4 33.6 B.Elbow-Ulnar Wrist 235 59.4 32.6
A. Elbow ADM 7.60 10.5 31.9 A. Elbow-B. Elbow 85 62.8 30.7

Sensory NCS

Nerve/Sites Rec. Site Onset Lat Peak Lat NP Amp Segments Distance Temp.
ms ms V mm C
L Hand Median Dig II 1.93 2.81 29.8 Median Wrist-Dig II 130 32.5
Wrist Median Wrist 1.41 1.77 27.7 Median Palm-Wrist 80 33.5
Palm Ulnar Dig V 2.08 2.60 25.6 Ulnar Wrist - Dig V 110 32.9
Wrist Ulnar Palm Wrist 1.35 1.77 30.7 Ulnar Palm - Wrist 80 33.5
Palm R Hand Median Dig II 2.08 2.92 28.2 Median Wrist - Dig II 130 33.0
Wrist Median Wrist 1.35 1.88 27.1 Median Palm - Wrist 80 32.9
Palm Ulnar Dig V 1.77 2.55 23.7 Ulnar Wrist - Dig V 110 32.7
Wrist Ulnar Palm Wrist 1.41 1.93 41.3 Ulnar Palm - Wrist 80 32.4

F Wave

Nerve Fmin Temp
L Median-APB 27.92 32.2

Needle EMG
Spontaneous MUAP Recruitment
IA Fib/PSW Fasc Other Amp Dur. PPP Pattern Activati
R. Deltoid N 0 0 0 N N N N on
R. Biceps N 0 0 0 N N N N Full
R Triceps N 0 0 0 N N N N Full
R. Pron Teres N 0 0 0 N N N N Full
R. First D Inteross N 0 0 0 N N N N Full
L. Deltoid N 0 0 0 N N N N Full
L. Biceps N 0 0 0 N N N N Full
L. Triceps N 0 0 0 N N N N Full
L. Pron Teres N 0 0 0 N N N N Full
L. First D Inteross N 0 0 0 N N N N Full


I might have to put those numbers in a spreadsheet to get a proper grasp of them but on a superficial galance they do indeed look normal and fairly comprehensive. They have used one of the standard sensitive tests for CTS in the form of the short segment palm/wrist comparison of median and ulnar conduction times. 

The Glowacki article is an old one with some methodological issues. The patients who had surgery with normal NCS numbered only 27 so it is a small group and they were highly selected by an expert hand surgeon. NCS are not done primarily for diagnostic purposes (at least not in my clinic) but to give an objective evaluation of the physiological function of the median nerve. I think there is a little doubt that if you have a patient with a typical history of CTS, benefit from splinting and a good temporary response to steroid injection (which was used before surgery in almost all Glowacki et al's patients) then there is a good chance of excellent results from surgery, even if the NCS are normal. Whether that surgery is actually necessary is a slightly different question - some such patients will also respond remarkably well to steroids and splinting. In your case I wonder if you know what steroid and dose was used when it was tried? Some people do use rather feeble doses.

The biochemical studies I refer to here were done on tissue samples from within the carpal tunnel. I know of no work on systemic levels of things like VEGF in the context of CTS, nor am I aware of any known link to molds and external toxins.

Dynamic CTS is just a fancy name for a simple concept - if you press on a nerve hard for a while it will stop working and you will experience the symptoms of nerve dysfunction. That does not mean there is necessarily anything intrinsically wrong with the nerve - just that you are attacking it! If you ignore the symptoms and keep up the compression you can produce actual damage to the nerve but most of us pay attention to the warning symptoms before that occurs and do something to get the pressure off, be that uncrossing our legs, shifting our weight off the sciatic nerve, or waking up and shaking the hands in the case of CTS.

What should you do next? I would check up on the steroid dose used, and perhaps try a second time, especially if it was a low dose the first time. If anyone around you is knowledgable about nerve ultrasound then I would try to get it checked that way as well.... and if it remained seriously symptomatic after that I would find an expert hand surgeon, and provided he/she agreed that the story sounds like CTS and no other explanation is obvious,  have it operated (keeping my fingers crossed about the outcome)

I'm afraid I can't really recommend a unit - I see you are in the USA but I don't know where. Wake Forest in North Carolina and Duke University in South Carolina are good at nerve ultrasound, as are the Mayo, and Washington University Missouri. For surgeons the best guide is probably to ask how many they have done and whether they monitor their outcomes systematically.

I would love to hear how it turns out of course. JB

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