If you are riding flat bars, you may want to consider Ergon grips such as the Ergon gp3 or 4 that provide multiple hand positions. I ride the gp3s on my Brompton and love them. Be sure to set them up at the correct angle. Part of the problem with carpal tunnel is caused by a less than nuetral wrist position. Set up correctly they should align your hand, wrist and forearm to reduce some of the compression in the synovial sheath (where the median nerves travel).

Another alternative would be to shift to a more upright handlebar such as a Jones sg 2.5 H-bar (https://www.jonesbikes.com/jones-sg-...um-loop-h-bar/) or Nitto Albatross (https://www.rivbike.com/products/nit...mo-55cm-x-25-4). This will put your body in a position that will reduce pressure on your hands.

Good luck.
john