The touch-screen test, known as Cantab and is currently being piloted in GP surgeries, will be made available to people aged over 50.Developed by the Cambridge University scientists, it can distinguish between normal forgetfulness and the more dangerous memory lapses that signal dementia in its earliest stages.
The new test has been specifically developed to home in on memory lapses that occur very early in the onset of dementia.
These involve episodic memory, the type used to recall a shopping list or remember where a car is left in a large car park.
The software contains a series of tasks which include memorising the location of objects and then bringing them back to mind when asked a few seconds later.
"You want to detect Alzheimer's disease before the damage is done, before you can't work any longer and before you can't hold down your family responsibilities and relationships," Professor Barbara Sahakian, co-inventor of the Cantab test, said.