In a guest post, Chloé Sharrocks looks at new research from Imperial College that shows shows distinctive brain activity in young adults carrying a gene associated with Alzheimer’s disease.

New research carried out in a joint venture between Imperial College, London and the University of Oxford and published in Proc Natl Acad Sci USA reports that scientists have come a step closer to developing a simple diagnostic test for Alzheimer’s.

The new study involved measuring the activity of the hippocampus, a region of the brain associated with memory, using fMRI scans. Thirty-six volunteers, aged 20-35, had their brains being studied while resting and performing memory tasks. Eighteen of the participants carried APOE4, a genetic variant found in a quarter of the population and implicated in Alzheimer’s susceptibility, while the remaining 18 did not. The scans revealed visible differences in hippocampus activity between carriers and non-carriers, at both rest and during memory tasks.

Alzheimer’s is the most common cause of dementia in the UK, affecting around 417,000 people and changing the lives of sufferer’s families and friends. If scientists could readily identify people who are at risk from developing the disease (and possibly treat it) years before the first symptoms, is it necessarily the right course?

Not all carriers of the APOE4 will go on to develop Alzheimer’s, so a screen that identifies potential sufferers early in life might needlessly distress up to a quarter of the population. Furthermore, Alzheimer’s is not the only disease for which diagnostic tests are currently being developed. Should we screen everyone for everything; and how do scientists and doctors communicate such statistical assessments without alarming patients?