Noise has a bad reputation, says Boston University bioengineer James Collins. "We typically view noise as being detrimental to signal detection and information transmission," he explains. But Collins believes noise could actually help elderly people, diabetics, and stroke patients whose sense of touch has been dulled by age, injury, or ailment. His work builds on a discovery made two decades ago by physicists who found that in certain circumstances, adding noise aids the detection of weak signals. Researchers dubbed this odd phenomenon, in which noise essentially pushes a weak signal above a detection threshold, "stochastic resonance." Eight years ago, Collins began investigating the effect of stochastic resonance on people. "I recognized that all sensory neurons in humans are threshold-based," he says, and "these thresholds get elevated as a result of disease, age, and injury." This reduced ability to sense the world can have profound consequences. For the elderly, for instance, numbness in the feet is often a factor in falling-the leading cause of injury-related death in people over 65. So Collins and his team began to investigate whether noise, delivered via mechanical vibration or electrical stimulation, could restore lost sensation. In October, Collins showed Technology Review senior editor Rebecca Zacks an early prototype of a system-in the form of a vibrating pair of gel insoles-that might help take noise-based therapy to the streets.