A new study suggests that Alzheimer’s disease can be detected decades before onset, using a virtual reality test.

People aged 18 to 30 were asked to navigate through a virtual maze to test the function of certain brain cells.

According to German neuroscientists, those with a high genetic risk of Alzheimer’s could be identified by their performance.

The findings could help future research, diagnosis and treatment, researchers report in the journal Science.

The scientists, led by Lukas Kunz of the German Centre for Neurodegenerative Diseases in Bonn, say the high risk group navigated the maze differently and had reduced functioning of a type of brain cell involved in spatial navigation.

The findings could give an insight into why people with dementia can find navigating the world around them challenging, they say.

“Our results could provide a new basic framework for preclinical research on Alzheimer’s disease and may provide a neurocognitive explanation of spatial disorientation in Alzheimer’s disease,” Science report says.

Although genes play a role in dementia, their effects are complex with many unknowns.