Dementia detectable 9 years before onset of symptoms or diagnosis, scientists say

CAMBRIDGE, United Kingdom — It may be possible to spot signs of dementia up to nine years before doctors make an official diagnosis, according to new research.

The study has shown that impairment in areas such as problem solving, reaction times, and number recall are more common among people who go on to develop dementia-related diseases such as Alzheimer’s. These findings raise the possibility that in the future, at-risk patients could be identified for clinical trials or new treatments before they begin to show symptoms.

One of the reasons why there are so few effective treatments for neurodegenerative diseases such as Alzheimer’s or Parkinson’s is because these conditions are only identified once symptoms appear, but neurodegeneration may have begun years or decades previously. This means that it may already be too late to affect the course of the disease once they become eligible to participate in clinical trials.

Worse overall health and falls increase dementia risk

In the current study, published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, researchers from the University of Cambridge analyzed data from the UK Biobank to see if it was possible to detect changes in brain function before the onset of dementia symptoms.

The UK Biobank is a biomedical database and research resource containing anonymized genetic, lifestyle, and health information from half a million U.K. participants between 40 and 69 years-old. As well as collecting information on participants’ health and disease diagnoses, UK Biobank collected data from a series of tests including problem solving, memory, reaction times, and grip strength, as well as data on weight changes and on the number of falls a person suffered.

This allowed the researchers to look back and see whether any signs were present at the baseline – that is, when measurements were first collected from participants between five and nine years prior to diagnosis.

People who went on to develop Alzheimer’s disease scored worse than healthy individuals when it came to problem solving tasks, reaction times, remembering lists of numbers, prospective memory (the ability to remember to do something later on), and pair matching. This was also the case for people who developed a rarer form of dementia known as frontotemporal dementia.

Also, people who went on to develop Alzheimer’s were more likely than healthy adults to have suffered a fall in the previous 12 months. Those patients who went on to develop a rare neurological condition known as progressive supranuclear palsy (PSP), which affects balance, were more than twice as likely as healthy individuals to have had a fall.

For every condition studied – including Parkinson’s disease and dementia with Lewy bodies – patients reported poorer overall health at the baseline.

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“When we looked back at patients’ histories, it became clear that they were showing some cognitive impairment several years before their symptoms became obvious enough to prompt a diagnosis. The impairments were often subtle, but across a number of aspects of cognition,” says first author Nol Swaddiwudhipong, a junior doctor at the University of Cambridge, in a media release.

“This is a step towards us being able to screen people who are at greatest risk – for example, people over 50 or those who have high blood pressure or do not do enough exercise – and intervene at an earlier stage to help them reduce their risk.”

“People should not be unduly worried if, for example, they are not good at recalling numbers. Even some healthy individuals will naturally score better or worse than their peers. But we would encourage anyone who has any concerns or notices that their memory or recall is getting worse to speak to their GP,” adds senior author Dr. Tim Rittman from the Department of Clinical Neurosciences at the University of Cambridge.

Dr. Rittman adds that the findings could also help identify people who can participate in clinical trials for potential new treatments.

“The problem with clinical trials is that by necessity they often recruit patients with a diagnosis, but we know that by this point they are already some way down the road and their condition cannot be stopped. If we can find these individuals early enough, we’ll have a better chance of seeing if the drugs are effective.”

South West News Service writer Danny Halpin contributed to this report.

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