Health Story

02 December 2008 15:21 BST

Mental skills decline with age

A new study has found that older people's mental skills decline with age, even if they do not have dementia.

In a report published in the journal Neurology today, scientists claim that people's mental skills start declining years before death.

"These changes are different and separate from the changes in thinking skills that occur as people get older," the report's author Valgeir Thorvaldsson, of Göteberg University in Sweden, said.

"We found accelerated changes in people's mental skills that indicated a terminal decline phase years before death."

The study examined 288 people who did not suffer from dementia, from the age of 70 to death.

The participant's mental skills were measured up to 12 times over a period of 30 years and evaluated to make sure they were not suffering from dementia.

The decline of an individual's mental skills was shown to differ for various cognitive abilities.

Perceptual speed, which measures how quickly people can compare figures, begins declining nearly 15 years before death, spatial ability begins declining eight years before and verbal ability starts declining six-and-a-half years before death.

A number of factors may explain the decline in mental skills with age, Mr Thorvaldsson said.

"Cardiovascular conditions such as heart disease or dementia that is too early to be detected could be factors," he said.

"Increased health problems and frailty in old age often lead to inactivity, and this lack of exercise and mental stimulation could accelerate mental decline."

Also, verbal abilities appear to only decline sharply as an individual approaches death.

"This indicates that people remain stable in their verbal abilities unless they are experiencing disease processes that also increase their mortality risk," Mr Thorvaldsson added.

"A change in verbal ability might therefore be considered a critical marker for degeneration in health in older people."