Is Losing It Part of Old Age? : Researcher Decides That Years Alone Don’t Explain Senility
Lissy Jarvik disliked the notion that she was doomed to get senile when she grew old, so as a young psychologist in 1946 she began to study how age influences the brain.
“I didn’t want to believe our intelligence would go down from then on. It didn’t seem like a good thing to face for the rest of your life,” said Jarvik, now a psychiatrist, pediatrician and geriatrician.
By giving intelligence tests to 134 pairs of elderly twins over four decades, she concluded that old age alone doesn’t rob people of their mental abilities and that when people do get senile, it’s due to disease.
A Lot of Clues
So it’s possible “we’ll die with all our marbles, and that’s all I care about,” said Jarvik, a psychiatry professor and chief of neuropsychogeriatrics at UCLA. Her research may help explain why some elderly people become senile, while others remain sharp until death.
“I don’t think mental decline is necessary in old age. We don’t know yet how to prevent it, but we have a lot of clues,” including the possibility that a healthy life style--including good nutrition and exercise and avoiding drugs, alcohol, cigarettes and pollution--may help prevent or delay senility.
Jarvik’s research also led her to speculate that people, through life-style improvements, might someday live to 120 or even 150 years, and that intelligence test scores might be used to identify people who face senility and need treatment.
Dementia, the preferred medical term, is the loss of the ability to think clearly, express oneself intelligently and do complex intellectual tasks.
Valuable Work
“Her work certainly has contributed to change in the general idea about what happens in normal aging,” said psychologist David Arenberg of the National Institute on Aging’s Gerontology Research Center in Baltimore.
The once-controversial idea that old age doesn’t necessarily doom people to senility now is “almost universally accepted,” said Arenberg, who studies how the elderly remember, learn, solve problems and process information.
But there still is disagreement over whether subtle loss of people’s mental faculties is due to disease.
Jarvik said the elderly do tend to slow down mentally and physically, and that some memory loss may be due to aging, not disease.
But even if mental deterioration often--rather than always--results from some underlying disease, there is hope that science can learn to help people postpone any loss of their intellectual abilities.
Project Began in 1946
Jarvik started her lifelong research project in 1946 when she went to work for Columbia University psychiatrist Franz Kallmann.
Kallmann had just started studying the 134 pairs of twins in their 50s and 60s to learn what environmental factors, like life style, might be responsible for intellectual differences between members of each pair.
Because identical twins are genetically identical and fraternal twins share inherited traits, scientists assume somewhat simplistically that differences between them tend to be due to differences in their environment.
Jarvik took over the study a couple years later, administering intelligence tests to the twins about every five years. Many findings were published in the 1960s, but the study continued until 1986, after the last twins died.
Better With Age
The twins didn’t necessarily decline intellectually after 60. Indeed, as their average age rose from 64 to 73, they did better on all intelligence tests except those related to speed. Only as they reached their 80s did scores fall.
Jarvik’s conclusion that disease, not age, was responsible, was based on two other major findings of the study:
* In every pair, the twin who first showed a decline on certain intelligence test scores also was the first to die.
* Those who initially scored low on the tests were roughly four times more likely than high-scorers to become senile 20 years later.
The findings “indicate we’re dealing with some sort of a disease process that affects the brain,” she said. Such ailments may include those that attack the brain directly, such as Alzheimer’s disease, and “some process taking place elsewhere in the body that affects the blood supply to the brain.”
Clue in IQ Tests
That suggests that declining intelligence tests might be a way to detect the subtle beginnings of Alzheimer’s attack on the brain or of brain impairment caused indirectly by other diseases, Jarvik said. Older people who believe they are losing their mental abilities might want to “check with their doctor to see if they’re physically ill,” she said.
Arenberg disagreed: “Just because a person believes his or her mental capacity is diminishing doesn’t mean that is accurate.”
Jarvik said her study also suggests that if science ever finds a way to prevent or treat Alzheimer’s, intelligence tests could be administered to aging people every three to five years to identify those likely to develop dementia.
