Maybe you have an 85-year-old grandfather who still whips through the newspaper crossword puzzle every morning or a 94-year-old aunt who never forgets a name or a face. They don't seem to suffer the ravages of memory that beset most people as they age. Researchers at Northwestern University's Feinberg School of Medicine wondered if the brains of the elderly with still laser sharp memory -- called "super aged" -- were somehow different than everyone else's. Now they have a preliminary answer. Scientists examined the brains of five deceased people considered super aged because of their high performance on memory tests when they were more than 80 years old and compared them to the brains of elderly, non-demented individuals. Researchers found the super aged brains had many fewer fiber-like tangles than the brains of those who had aged normally. The tangles consist of a protein called tau that accumulates inside brain cells and is thought to eventually kill the cells. Tangles are found in moderate numbers in the brains of elderly and increase substantially in the brains of Alzheimer's disease patients.