I have a carpal tunnel problem in my left wrist, and holding a cellphone just a few minutes causes numbness. However, I used my Leki poles almost constantly for 10 km yesterday without a problem. I don't clench my fingers around the pole. Instead, I place the handle in the V between my thumb and forefinger, then simply use my other fingers to guide the pole while placing it. Once the tip is planted, the edge (heel) of my hand begins pushing down against the strap. The result is a rather relaxed, cupped hand position. Make sure you pick up the pole by inserting your hand up through the strap, not down into it, so the loop passes around the back of your hand with the ends coming up across the palm between your hand and the pole. You may have to adjust the size of the loop. Whichever pole you use, buen camino.
Bob