Some 20 million people in the United States have tinnitus, a chronic ringing or whooshing in the ears, and about 4 million of them experience such severe symptoms that "they wonder if they're going insane," says Martin Lenhardt, a biomedical engineer at Virginia Commonwealth University. The cause of the ailment is, in essence, a biological computer error. So Lenhardt has found a way to reprogram the brain and make the maddening sounds go away, temporarily at least. When people lose the ability to hear very high frequencies— whether due to aging, disease, or exposure to loud noise— the neurons...
