If hearing loss can have a huge effect on people's lives, so, too, can a strange, unpleasant hearing "gain." Imagine constantly living with buzzes and hums that sound perfectly real and yet only you can hear. Imagine never being able to escape those sounds, no matter how far you travel into the wilderness or however silent the outside world. This odd condition, in medical lingo, is known as tinnitus.

Beethoven (though he's better known for going deaf) was afflicted by it. So was the composer Smetana, who incorporated the note he heard into one of his string quartets. Michelangelo had it too: "A spider's web is hidden in one ear, and in the other, a cricket sings throughout the night," he wrote of his affliction--and no wonder he resorted to metaphors. Tinnitus can be hard to explain to people.