Famous mugs do more than prompt us into buying magazines, according to new Université de Montréal research. In the December issue of the Canadian Journal on Aging, a team of scientists explain how the ability to name famous faces or access biographical knowledge about celebrities holds clues that could help in early Alzheimer's detection.
"Semantic memory for people - triggered through name, voice or face - is knowledge we have gathered over the course of our lifetime on a person which enables us to recognize this person," says senior author Sven Joubert, a professor at the Université de Montréal Department of Psychology and a researcher at the Centre de recherche de l'Institut universitaire de gériatrie de Montréal.
The goal of semantic study was to determine whether the ability to recall names of famous people decreases with age, since the condition named anomia ranks among the most common complaints from the elderly. To investigate, Dr. Joubert collaborated with first author Roxane Langlois to divide 117 healthy elderly, aged 60 to 91 years old, into three groups who were submitted to two semantic memory tests.
In a first test, subjects were shown the faces of 30 famous people such as Albert Einstein, Céline Dion, Catherine Deneuve, Pierre Elliott Trudeau, Wayne Gretzky. They were first asked to name these famous faces, and then questioned on their professions, nationality and specific life events. In a second test a few weeks later, subjects were shown the names of the same 30 celebrities and were questioned again on biographical knowledge.
The result? Our ability to recall the name of someone we know upon seeing their face declines steadily in normal aging. Semantic memory for people however seems unaffected by age. For instance, even if a subject couldn't name George W. Bush they still knew he was a politician or president of the United States. Another finding is that healthy elderly are better at accessing biographical knowledge about famous people from their names than from their faces. A person's name provides direct access to semantic memory because it is invariant, contrarily to visual stimuli.
These findings motived Dr. Joubert to conduct a second study, in press in Neuropsychologia, on elderly people suffering from mild cognitive impairment and another group in the initial phase of Alzheimer's.
"Our hypothesis was that contrary to the healthy subjects, both these groups should show difficulties finding the names of people, but that they should also show signs of a depleting semantic memory," says Dr. Joubert, adding that since 50 to 80 percent of people with mild cognitive problems develop Alzheimer's over the course of several years.
This semantic memory test could become an essential clinical tool to identify people at risk of developing the disease. Results show that the ability to remember names is even more pronounced in mild cognitive impairment and in early Alzheimer's disease than in normal aging. Contrary to normal aging, however, a decline in semantic memory for famous people was also observed.
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