Alzheimer’s disease is a brain condition affecting millions of people worldwide. The disease is characterised by symptoms including memory loss, confusion, problems with orientation and language, and eventually changes in behaviour. Alzheimer’s disease is also the most common cause of dementia. One of the earliest changes that take place in the patient’s brain is an accumulation of ‘amyloid plaques’. These are proteins that form between the brain’s nerve cells disrupting brain function in that area. ‘However, not everyone with these protein accumulations will necessarily develop Alzheimer’s Disease’, says Pieter Jelle Visser, clinical epidemiologist in Maastricht and Amsterdam. ‘It is a risk factor, but not everyone with these accumulations of protein will eventually suffer dementia.’
Predecessor to Alzheimer-type dementia
The Dutch scientists have taken the initiative to better identify the development of protein accumulations in the brain with a worldwide study. The scientists analysed data from over 10,000 people from 56 international research centres. One of the studies focussed on Alzheimer protein in people with no symptoms of dementia, and another examined the presence of this protein in people with various types of dementia. The results of the study on ‘healthy’ people showed, among other things, that plaque formation can be detected in one in ten 50-year-olds who have no signs of dementia whatsoever. This percentage increased to 44 per cent among 90-year-olds. The protein accumulation was shown to precede the development of Alzheimer-type dementia by twenty to thirty years, which offers good prospects for the prevention of dementia.
Higher education
Brain plaques also appear to be more common among highly-educated people. ‘One possible explanation for this is that the brains of more highly-educated people have a larger reserve capacity, so that they can withstand more damage by the protein accumulation before they experience symptoms’, says Willemijn Jansen, one of the researchers at Maastricht UMC+. The fact that the plaques are already present in people without dementia provides the potential for early treatment in the future. Visser: ‘Pharmaceuticals must first be developed for this. Research is already underway, but it will take 5 to 10 years before we know the results.’
More memory problems
The study on protein accumulation in the brains of people with various types of dementia showed that the build-up of amyloid is present in Alzheimer’s patients in particular. Protein accumulation was not evident, however, in twenty per cent of those diagnosed with Alzheimer’s. ‘Imaging of these plaques in the brain can therefore significantly improve the quality of diagnosis’, suggests Rik Ossenkoppele from the VUmc Alzheimer’s Centre. Amyloid plaques were also sometimes found in people with other types of dementia, and this appeared to increase significantly with age. ‘This study clearly shows that patients who do have an accumulation of amyloid protein in the brain have more problems with their memory and other cognitive tasks’, says Ossenkoppele.