By Michael KahnWed Aug 27, 4:04 PM ET
The rapid deterioration of our mental abilities as we age begins far earlier
than scientists had suspected, Swedish researchers said on Wednesday.
Simple tests of perceptual speed, spatial ability and verbal function showed
that some cognitive skills begin rapidly fading nearly 15 years before death,
said Valgeir Thorvaldsson, who worked on the study.
"Previous studies have showed that the steep decline begins around five years
before death," said Thorvaldsson, a psychologist at Gothenburg University in
Sweden. "What we could see in our data is that these changes occur much earlier
than thought."
Most people reach their mental peak between the ages of 35 and 40, then begin a
steady decline that speeds up in the years before death, he said. The Swedish
team wanted to test when that acceleration starts, in order to better
understand the loss of mental ability.
In a 30-year study, the researchers tracked 288 men and women from age 70 until
death, measuring their mental skills at regular intervals.
They found perceptual speed, a measure of how quickly people can compare
figures, deteriorated rapidly from about 15 years before death. Spatial ability
began to decline fast about eight years pre-death, and verbal skills nearly
seven years before.
"There is substantial acceleration in cognitive decline many years prior to
death among individuals without dementia," Thorvaldsson and colleagues wrote in
the journal Neurology.
Lack of exercise and mental stimulation in old age, and increasing health
problems, may help explain what triggers that final decline, Thorvaldsson added
in a telephone interview.
Tracking when the rapid change begins could help doctors identify people likely
to encounter severe health problems in the near future, he said.
"A change in verbal ability might therefore be considered a critical marker for
degeneration in health in older people," Thorvaldsson said.
(Reporting by Michael Kahn; Editing by Catherine Evans)