Researchers have found that working with people and training the brain are two ways to slow the progression of Alzheimer's and other dementias.

TWO APPROACHES THAT SLOW ALZHEIMER'S:

• Cognitive reserve

Complex jobs that require working with people may help the brain build resilience against dementia, what's called "cognitive reserve", University of Wisconsin researchers report.

The team tested 284 adults in late middle-age whose brain scans showed changes that have been linked to an increased risk of Alzheimer's.

Comparing their cognitive ability and their careers, the researchers found those who worked primarily with people, rather than objects or data, functioned better even if brain scans showed more of that quiet damage.

• Brain training

Preliminary results from a study of "brain training" suggested one type might help delay cognitive impairment.

Researchers examined records from 2785 older adults who'd participated in a previous trial that compared three cognitive training strategies - to improve memory, reasoning or reaction times - with no intervention.

A decade later, that reaction-time training suggested benefit: 12 per cent of people who'd completed up to 10 hours had evidence of cognitive decline or dementia compared with 14 per cent in the control group, said Dr Jerri Edwards of the University of South Florida.

The figure was lower - 8 per cent - for people who got some extra booster training.

"It's the first hint for a cognitive training intervention like this," but more research is needed, said Dr Jonathan King of the National Institute on Aging in the US, who wasn't involved in the new study.