A memory and logic test could help spot dementia nearly a decade before doctors notice symptoms.

People who went onto to develop conditions such as Alzheimer’s were found to perform less well at tasks that measured problem-solving, reaction times and the ability to recall a sequence of numbers.

Dementia Australia's Professor Henry Brodaty, from the Centre for Healthy Brain Ageing at the University of NSW, says a specialised 30-minute test could identify people with a high risk of developing Alzheimer’s, which currently affects 400,000 Australians.

"The tests are not routinely done, they don't take long to do, you need a bit of training in how to do them," he told Bartlett about the tests.

"One of the tests is how many digits can you remember.

"Another test is your reaction time, how quickly you react to various stimuli ... you might have to press a button for example, when two things are the same, or different."

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