In the past few years, a spate of studies about music as medicine has brought a new measure of scientific rigor to a field that once garnered only marginal respect from the medical mainstream. As a result, music therapy for people with dementia or head injuries is becoming commonplace in clinics and nursing homes, and has gained the support of such seemingly disparate celebrities as Grateful Dead drummer Mickey Hart and neurologist Oliver Sacks, author of "Awakenings."

Something as simple as beating on small drums together can have remarkable effects. Within moments, even the most disoriented individuals typically start beating in time with others in the room and a surprising degree of alertness and cooperation emerges. "The rhythm helps organize them in time and space," [Louise Lynch] said. "Alzheimer's is socially isolating, but the rhythm makes people more aware of people around them and helps them unite as a group."

Sacks said nobody knows for sure how or why music often brings a measure of lucidity to Alzheimer's patients. Some propose that while brain areas dealing with cognition and language degenerate, the parts that respond to music are left intact, providing an alternate pathway into the mind. In Sacks's view, the key may be music's well-known power to stimulate memories. Memory, he said, is the key to a sense of self.