Buying time: experts could diagnose Alzheimer’s five years earlier

Researchers at the Australian National University can now let patients with mild cognitive impairment (MCI) know five years in advance whether they are at risk of developing Alzheimer’s disease – the most common form of dementia.

“The ANU team’s research is the first to examine data of patients with MCI and accurately predict whether they are at risk of developing Alzheimer’s up to five years prior to a potential diagnosis,” the university said.

This is a coup for individuals with MCI and their families as, up until now, experts did not have a way of “linking a patient’s deteriorating brain health and the likelihood of them getting Alzheimer’s disease”. 

The study is also significant as increased life expectancy across the world is leading to an increased prevalence of Alzheimer’s and dementia, the researchers write in the introduction to their study. Not only does dementia come at an “enormous personal, social, and socioeconomic cost”, it is expected to affect over 115 million people by 2050. 

“We have the ability to see into the future and estimate whether they are at low, moderate or high risk,” head of the ANU centre for ageing, health and wellbeing, Professor Nicolas Cherbuin, said.

“Knowing whether someone is at risk of developing Alzheimer’s five years in the future is really positive in terms of being able to improve health outcomes for patients by giving them the best advice as early as possible.”

Dementia advocate Cathy Ryan said knowing her father was at high risk of developing Alzheimer’s disease years in advance would have been beneficial for both him and their family in “processing what was to come” and putting plans in place.

“After putting my dad through some rigorous tests and an MRI of his brain, the diagnosis was that he had MCI but had recently crossed the line over to Alzheimer's disease,” she said.

“We were fortunate to get a fairly early diagnosis from a specialist, but I often wonder what might have played out if that diagnosis had happened earlier.

“I believe this research is vital to improving our understanding of what MCI is because there is a real lack of awareness and knowledge about this condition and how it can potentially lead to Alzheimer's.”

The team of researchers are hopeful the findings will help medical experts provide more specific, timely advice to patients based on their particular risk level of developing Alzheimer’s disease. 

"This gives patients more time to plan for their future, get their affairs in order and talk to family members about how best to move forward," Cherbuin said.

How the test works

The team used blood biomarkers called plasma neurofilament light chain (pNFL) to measure the fragments of dying brain neurons that have “trickled into the bloodstream” of a patient. These measurements were then combined with patients’ Mini-Mental State Examination (MMSE) scores to predict the likelihood of a person’s condition progressing from MCI to Alzheimer’s. 

A benefit of the test is that it is less invasive and more accessible than other diagnostic procedures such as Positron Emission Tomography (PET) scans, given all that is required is a blood sample taken by needle. 

It’s Cherbuin’s wish that pNFL measurements become more commonly used in the healthcare sector, providing “a more comfortable experience for patients throughout the diagnostic stage”, ANU says.  

"We hope, through this research, we’re able to provide more choices to patients and their families by giving them plenty of time to introduce positive lifestyle changes and hopefully delay the onset of this terrible disease for as long as possible,” Cherbuin concluded.

To undertake the study, the ANU research team used data from the Alzheimer's Disease Neuroimaging Initiative and assessed the brain health of 440 patients living with MCI.

Cherbuin collaborated with ANU medical student Nicolas Darmanthe and Dr Hossein Tabatabaei-Jafari for the study, which is published in the Journal of Alzheimer’s Disease.