A digital map of the ageing brain could help the diagnosis of Alzheimer's and other neurodegenerative conditions in older people, a study has suggested.

Researchers at the University of Edinburgh constructed a detailed atlas of the human brain using MRI scans from more than 130 healthy people aged 60 or over.

The team said most existing MRI atlases are based on the brains of young and middle-aged people which do not reflect the normal changes that take place over time.

The atlas created using images from MRI scans of older people could aid diagnosis by comparing the patients' scans with a detailed map of the healthy ageing brain, they said.

It was used to study brain scans taken of normal older subjects and those who had been diagnosed with Alzheimer's disease, and researchers said the atlas was able to pinpoint changes in patients' brain structure that can be an underlying sign of the condition.

The scientists said a key early sign is the loss of brain tissue in a region of the brain known as the medial temporal lobe, but these changes are often subtle and can be difficult to spot. An MRI atlas could make it easier to detect them, according to the team.

They are now continuing to develop atlases of the healthy brain over different stages of life as part of a project aiming to detect brain damage in other diseases.

Dr David Alexander Dickie, who was first author of the study, said: "We're absolutely delighted with these preliminary results and that our brain MRI atlases may be used to support earlier diagnoses of diseases such as Alzheimer's.

"Earlier diagnoses are currently our strongest defence against these devastating diseases and, while our work is preliminary and ongoing, digital brain atlases are likely to be at the core of this defence."

Researchers said brain imaging centres need to continue to collect scans from many healthy older people and work together to make large image banks in order for the atlases to be useful and reliable.

The ultimate aim is to use the information to support earlier diagnoses of Alzheimer's and other neurological diseases that develop at different stages of life.

Dr Doug Brown, director of research and development at Alzheimer's Society, said: "As we age, the structure of our brain changes and this will vary from person to person.

"This can be a challenge for diagnosing dementia with an MRI scan as it can be difficult to separate changes which are down to ageing from the early signs of dementia.

"By developing a refined digital brain atlas, the researchers have been able to get a clearer picture of what happens to a brain with Alzheimer's disease. This could one day help doctors make earlier, accurate diagnoses of dementia, and in turn support people with the condition to access vital treatments, information and support as soon as possible."