Probably stating the obvious, but just an observation that's worth mentioning. I'm surprised at the number of riders (MTB) that ride with brake levers set straight out from the bars, causing the wrist to be bent at quite an angle. Presumably you have tried setting the brake levers so that your wrists are not bent. Over time I have rotated the levers more and more - they markedly point down towards the road now.
Rob
Rob