Hi Marcia-
I've had that test a couple of times. I used to do computer drafting and spent many, many hours on the computer.
It is not my favorite test, that's for sure. I did not have any permanent damage. I wore a splint at night and still do if it's giving me problems. I also purchased some elastic fingerless gloves to use when I was on the computer. The splint would have been impossible to use while drafting on the computer. The gloves helped in that case.
So the splint at night, and the gloves during drafting gave my hands the needed support and kept the numb feeling under control.
I'm retired now, but can still get that feeling from time to time. I just go back to the old splint at night and the gloves during the day, and in a couple of days, it disappears.
I also have a mousepad with a gelpad wrist rest. That works great.
One more thing, I found some simple hand stretching exercises which gave me some relief. I simply pull back on each finger very gently until I can feel the stretch and hold for a few seconds. Also stretch by pulling all of the fingers back while my arm is extended. Nothing to drastic, just gently.
And you probably already know this, if you hang your arm down and let your muscles relax, you can shake your hand around and the numb feeling will go away.
Hope everything works as well for you as it did for me.