There are special tests that can be done to measure the nerve's ability to send messages. These are called nerve conduction velocity (NCV) tests.

The tests aren't usually advised when symptoms first come on. They are expensive and can be somewhat uncomfortable. Other tests can be done by a physician, physical, or occupational therapist to gain information about nerve function.

It's likely that pressure on the nerves as they pass through the wrist is causing these symptoms. You can help by avoiding prolonged gripping on the bike handlebars.

If you are leaning forward over the bars, sit up and take periodic breaks. Roll your shoulders back and down. Take a deep breath and exhale to release tension. Shake your hands out every so often.

You can also wear biker's gloves to help absorb some of the pressure. Don't wait to see a doctor if the symptoms persist. Pressure on the nerve for too long can cause permanent damage. Early intervention is best for a good result.