Signs of dementia ‘might be visible up to a DECADE before patients are even diagnosed’

Possible signs of dementia may be visible up to a decade before people are typically diagnosed, a study suggests.

People who performed badly on problem solving and memory tests nine years earlier were more likely to get diseases including Alzheimer’s, Cambridge scientists found.

Experts said the finding could lead to routine screening for those most at risk, who might benefit from early treatment and clinical trials.

The team analysed data on half a million UK participants aged 40-69 from the UK Biobank.

As well as collecting information on participants’ health and disease diagnoses, they also underwent a series of tests including problem solving, memory, reaction times and grip strength.

Information was also collected on weight loss and gain and on the number of falls.

This was then compared to information collected between five and nine years earlier.

People who went on to develop Alzheimer’s scored more poorly than healthy individuals when it came to problem solving tasks, reaction times, remembering lists of numbers, prospective memory (our 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, the researchers found.

Those who went on to develop Alzheimer’s were more likely than healthy adults to have had a fall in the previous 12 months, according to the findings published in the journal Alzheimer’s & Dementia.

Scientists found that for every condition studied — including Parkinson’s disease and dementia — patients reported poorer overall health at the beginning.

Dr Nol Swaddiwudhipong, of the University of Cambridge, said: ‘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.

‘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.’

Currently there are very few effective treatments for dementia or other neurodegenerative diseases such as Parkinson’s disease.

Experts suggest this is partly because these conditions are often only diagnosed once symptoms appear, whereas the underlying issue may have begun years – even decades – earlier.

This means that by the time patients take part in clinical trials, it could already be too late in the disease process to alter its course.

Until now, it has been unclear whether it could be possible to detect changes in brain function before the onset of symptoms.

Experts said that people should not be unduly worried if they had problems recalling certain things like numbers, suggesting there was variation among healthy adults too.

But they encouraged anyone with concerns to speak to their GP.

David Thomas, head of policy at Alzheimer’s Research UK, said: ‘It is increasingly clear that the best chance to affect the course of the diseases which cause dementia lies in intervening at their earliest stages.

‘Health services don’t routinely offer the tests needed to detect changes in brain function that happen before symptoms are noticeable, like those alluded to in this study.

‘In fact, the NHS is currently unable to guarantee early and accurate diagnosis for people living with dementia – more than a third of people over 65 living with dementia go undiagnosed.

He added: ‘It’s now more important than ever that NHS services reflect our growing understanding of the importance of detection and early diagnosis.

‘We must ensure that people with dementia don’t fall through the cracks at a time when treatment or risk-reduction interventions are most likely to be effective.’