London, Sep 1 (IANS): Decline in older adults' navigational skills could predict the onset of neurodegenerative diseases such as Alzheimer's, a study has found.

According to researchers, the changes in how people map their surroundings and construct and follow directions as they age have been neglected in studies on the brain condition compared to effects on memory and learning.

At present, Alzheimer's disease is diagnosed based on an individual's medical history, genetic risk factors and performance on tests that measure memory, language and reasoning impairments.

However, navigational impairments are among the earliest signs of the Alzheimer's progression and can help in early diagnosis as well as treatment.

"It can take up to 10 years after the onset of Alzheimer's for someone to show abnormal results on the standard cognitive tests that are available today and that's 10 years that you've lost for treating it should an effective therapy come along down the road," said Thomas Wolbers, a neuroscientist at the German Center for Neurodegenerative Diseases in Germany.

"This is where navigation-based diagnostics could contribute by reducing that window," Wolbers added in the paper published in the journal Neuron.

Navigational testing is held back because of lack of standard tests for navigational tasks and population norms with which to evaluate results.

"We need longitudinal human data to be able to definitively say whether a change in navigational function can be used to predict whether Alzheimer's or any other neurodegenerative disease will develop later on," Wolbers said.

People should use their navigational skills instead of relying on such things as in-car and handheld GPS technology.

"There is growing evidence that if you rely too much on that technology, it can have a detrimental effect on your navigational ability and in the long term may even be a risk to develop pathological conditions," Wolbers suggested.