WHILE most old people tend to become forgetful, some have a rather different problem: they feel as if they are remembering something that happened to them in the past when they are actually having a new experience.
The condition might be more common than is usually realised, says Martin Conway of the University of Leeds in the UK, and could explain some unusual behaviour. His team has studied three sufferers. One 80-year-old man refused to watch TV or read newspapers because he had 鈥渟een it all before鈥�. A 70-year-old woman thought she could see the future. 鈥淪he saw the Bali bombing on the news and told her husband she already knew all about it,鈥� Conway says. The third, a 65-year-old woman, greeted strangers like long-lost friends.
The three are constantly convinced they are remembering past events rather than living in the present, an extreme form of the d茅j脿 vecu (feeling you having lived through something before) most people occasionally experience. 鈥淚t鈥檚 quite a catastrophic injury,鈥� says Conway, who described the case studies at an Australian Psychological Society meeting in Sydney earlier this month.
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Brain scans showed that all three had some temporal lobe damage. The Leeds team suggests that everyday life constantly triggers memories and associated feelings of remembering, which are usually suppressed. Damage to the temporal lobes, though, might allow the feelings but not the memories to enter consciousness. So seeing a new face, for instance, might produce the feelings associated with remembering other faces, convincing a person that they have seen the new face before.
Recent studies suggest a part of the temporal lobes called the entorhinal cortex 鈥� often the first area damaged in Alzheimer鈥檚 鈥� is the key to feelings of d茅j脿 vecu, says neuroscientist Eric Halgren of Harvard University.