Via PhysOrg.com: researchers have found "elderly people with super-sharp memory - so-called 'super-aged' individuals - who somehow escaped formation of brain 'tangles.' The tangles consist of an abnormal form of a protein called 'tau' that damages and eventually kills nerve cells. Named for their snarled, knotted appearance under a microscope, tangles increase with advancing age and peak in people with Alzheimer's disease. ... its implications are vast. We always assumed that the accumulation of tangles is a progressive phenomenon throughout the normal aging process. Healthy people develop moderate numbers of tangles, with the most severe cases linked to Alzheimer's disease. But now we have evidence that some individuals are immune to tangle formation. The evidence also supports the notion that the presence of tangles may influence cognitive performance. Individuals with the fewest tangles perform at superior levels. Those with more appear to be normal for their age. ... One group of super-aged seems to dodge tangle formation. Their brains are virtually clean, which doesn't happen in normal-aged individuals. The other group seems to get tangles but it's less than or equal to the amount in the normal elderly. But for some reason, they seem to be protected against its effects."