A landmark £6.9 million trial that could mark a turning point in tackling Alzheimer's disease has been launched in the UK.
The Deep and Frequent Phenotyping study, backed by the Medical Research Council (MRC), aims to identify biomarkers that allow Alzheimer's to be diagnosed at an early stage, when there are no obvious symptoms.
Success could herald a revolution in the treatment of Alzheimer's, with drugs being used to halt progress of the disease before irreparable damage to the brain has occurred.
Between 2002 and 2012, 99% of clinical trials testing new therapies for Alzheimer's disease ended in failure.
A likely reason for the disappointing trend is that drugs are being tested on people whose brains are already badly damaged.
Clear symptoms of Alzheimer's, such as severe memory loss, confusion and mood changes, only appear after the disease has progressed for many years, experts believe.
Experimental treatments may be far more effective if administered at earlier stages - but first some way has to be found of identifying patients with early Alzheimer's.
A total of 250 study participants will undergo up to 50 tests designed to detect early signs of dementia.
The procedures will include detailed measurements of movement and gait using wearable devices and retinal imaging to spot subtle changes affecting vision. Blood, urine and cerebrospinal fluid samples will also be analysed.
The potential new biomarkers will be used both alone and alongside established tests such as brain imaging and assessments of memory and thinking ability
Lead scientist Professor Simon Lovestone, from Oxford University, said: "We know that Alzheimer's disease starts long before it is noticed by those with the disease or their doctor. Previous studies have shown changes to the brain as early as 10 to 20 years before symptoms arise.
"If we can identify the biomarkers present in this very early stage, we have the chance of treating the disease earlier, which is vital if we are to prevent damage to people's memory and thinking. We're indebted to those volunteers taking part in the study whose time and effort will make a real difference to our ability to diagnose and treat this disease."
Some of the volunteers will be considered at risk of developing Alzheimer's due to their age, genes, and performance in memory tests. Others will not be at-risk individuals.
Around 850,000 people in the UK are believed to suffer from some form of dementia, the majority having Alzheimer's.
In less than 10 years the number of dementia patients in Britain is predicted to reach a million, soaring to two million by 2051. Dementia already costs the UK economy more than £26 billion per year - the equivalent of more than £30,000 per person with the condition.
Matt Murray, from the charity Alzheimer's Society, which helped researchers conduct a pilot study in preparation for the trial, said: "This exciting research will help transform our understanding of the earliest signs and symptoms of dementia, supporting researchers to ensure that they recruit the most appropriate people for their trials.
"With help from Alzheimer's Society, people in the early stages of dementia tried out the procedures that are involved in the study and shared their experiences to ensure the trial wouldn't be daunting for others. While people were nervous about some of the tests, this try-out stage successfully made them feel more comfortable recommending the study to other people."
The trial was made possible by Dementias Platform UK, a £60 million public-private partnership set up in 2014 and led by the MRC to accelerate progress in dementia research. The body, a collaboration between universities and drug companies, brings together world leading experts and cutting edge technology.
Dr Rob Buckle, director of science programmes at the MRC, said: "This is the first major clinical study based on Dementias Platform UK and the results could be game changing for dementia research.
"Our goal is to find treatments that can slow down or even stop the progression of Alzheimer's disease. Finding biomarkers for clinical trials is crucial for fast-tracking decisions as to whether a trial should stop or continue, and the faster we can find out which drugs work and which ones don't, the faster we can benefit patients. An ability to deliver more cost-effective clinical trials would also encourage investment and increase the number of such studies in the future."
Health Secretary Jeremy Hunt said: "Dementia can be a heart-breaking condition, but it is my mission as health secretary to make this country the best place in the world to get a dementia diagnosis and support, as well as being a global leader in the effort to find a cure. This extra investment is a vital step forwards towards that goal."