Whether you push a broom or type on a keyboard, you're at risk for carpal tunnel syndrome (CTS). But, unless you're a neurological specialist, this damage to nerves in the wrist is tough to diagnose. "Lots of things look like CTS, including arthritis, wrist sprains and hypochondria," says bioengineer Shai Gozani.

Gozani's company, NeuroMetrix of Cambridge, Mass., has designed a flexible Mylar strip embedded with electrical sensors, circuits and a tiny processor that should enable the family physician to identify CTS. Positioned at the heel of the wrist, it shoots a current through the nerve, causing thumb muscles to contract and produce impulses of their own. The sensors pick these up, allowing the processor to calculate the speed of the nerve signals. Normal nerves carry signals at about 60 meters per second, but damage by CTS can slow that by half.