Alzheimer’s patients tend to get lost and disoriented easily, but new research indicates that this may not be caused by memory loss alone.

Charles Duffy, M.D., Ph.D., of the University of Rochester, studied the ability of six healthy young people, 12 healthy elderly people and 11 Alzheimer’s patients to see and interpret visual patterns. Participants were asked to view a panoramic computer display with radiating patterns of visual motion simulating what people see as they move through their surroundings. They were then asked whether it looked as though they were moving to the left or the right.

The Alzheimer’s patients had more than twice as much difficulty interpreting what they saw as the other subjects did. The Alzheimer’s patients also had more difficulty describing their route when tested for spatial navigation while walking from the hospital lobby to the lab.

"Alzheimer’s patients get lost not because they don’t remember where they’ve been, but because they can’t see where they’re going," said Dr. Duffy. He believes this condition, called "motion blindness," may result from damage in specific, limited areas of the brain and that the tests he used in the study could be applied to identify patients at particular risk for getting lost.