I had bad carpal tunnel. I still do, but it was worse.
They do a test where they use some crazy BDSM shit and shock your arms to measure the response in your nerves (which indicates compression) and then they do a needle thing to measure the movement of your muscles.
The sick fucks said that second one would be "unpleasant" but it was like my hand was on fire the whole time.
If your fingers get tingly, get wrist splints for sleeping. That's it