Have you ever noticed whether your fingers go numb when you are not riding? Like when you are cold or under stress? I have Raynaud's Phenomenon, which is a condition in which something triggers the blood vessels in the extremities (fingers, toes, hands, feet) to constrict, causing numbness (among other things). Although my RP is a hereditary rheumatic form, RP can also be acquired as a result of trauma and it is common to see in bikers who experience a lot of road vibration. Vibration triggers mine all the time. Good gloves help - I also have the Trek "buzzkill" ends in my handlebars and that seems to help as well. There isn't really a "test" for RP - just symptomology - but you might want to check with your doc if it is becoming a big problem. There are test for the various rheumatic conditions that can cause it. RP isn't necessarily dangerous in and of itself - but the one thing my doctor is adamant about is that I must never ever smoke (not that I would anyway, but apparently that can create havoc with RP because of tobacco's constricting effect)