US scientists have found brain scans measuring the thickness of certain regions of the brain may help identify people who have a higher risk of developing Alzheimer’s disease.

 

Researchers at Massachusetts General Hospital, in Boston, and the University of Pennsylvania, in Philadelphia, studied MRI scans from 159 cognitively normal older people. The scientists looked at measurements of the brain’s cortex in nine regions that, in earlier studies, have been shown to shrink in Alzheimer’s disease. They theorised that those with a thinner than average cortex would have a higher risk of Alzheimer’s, and those with a thicker than average cortex would have lower risk.

 

The scientists analysed cognitive test results for 125 participants, and found that 21% of those with a thinner cortex showed signs of cognitive decline over three years. In comparison, just 7% of those with a cortex of average thickness showed decline, and among participants with a thicker cortex, none showed a decline.

 

The researchers also looked at cerebrospinal fluid (CSF) samples taken from 84 of the participants after three years, checking for levels of amyloid – a hallmark protein found in the brains of Alzheimer’s patients. They found 60% of those with a thinner cortex had abnormal amyloid levels in their CSF, similar to those seen in Alzheimer’s, compared to 36% of those with a cortex of average thickness and 19% of those with a thicker cortex.

 

The findings, which are published online today (21 December) in the journal Neurology, add to previous evidence suggesting that brain shrinkage may start years before the symptoms of Alzheimer’s, such as memory loss, begin to show. The researchers believe that MRI scans measuring cortical thickness may be useful for helping to identify people at greater risk of developing the disease. However, they stress that studies with a longer follow-up period are now needed.

 

Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:

“The ability to predict who will develop Alzheimer’s disease is a key target for dementia research, as it would allow new treatments to be trialled early, when they are more likely to be effective. These findings add weight to existing evidence that Alzheimer’s begins long before symptoms appear, although it’s important to note that the study did not assess who went on to develop the disease. This research provides a potential new avenue to follow, but we need to see larger and longer-term studies before we can know whether this type of brain scan could accurately predict Alzheimer’s.

 

“There are currently 820,000 people in the UK affected by dementia, yet research into the condition is desperately underfunded compared to other serious diseases. We urgently need to invest in research if we are to find new ways to diagnose, treat and prevent dementia.”