Memory may decline three years before dementia onset

People who are at risk of dementia could develop memory problems up two or three years before the onset of the disease, a new study published in the medical journal of the American Academy of Neurology has revealed.

Researchers found several brain changes or pathologies, relating to dementia, were present in the decline of memory awareness.

Author of the study, Professor Robert Wilson of Rush University Medical Centre in Chicago said: “Our findings suggest that unawareness of one’s memory problems is an inevitable feature of late-life dementia, driven by a build-up of dementia-related changes in the brain.”

“Lack of awareness of memory loss is common in dementia, but we haven’t known much about how common it is, when it develops or why some people seem more affected than others.

“Most studies of memory unawareness in dementia have focused on people who have already been diagnosed. In contrast, this new study began following older adults before they showed signs of dementia.”

The study was supported by the National Institute of Ageing and the Illinois Departments of Public Health.

Researchers analysed more than 2,000 participants from three on-going studies, following older people over more than 10 years. When the study began, participants had an average age of 76 years old and showed no signs of memory problems or cognitive impairments. Participants were given yearly memory and thinking ability tests to monitor how much they could remember and to rate their memories in comparison to how they scored 10 years earlier.

During the course of the study, 239 people were diagnosed with dementia and of those, the study revealed their memory awareness was stable until it began to sharply decline 2.6 years before the onset of dementia, followed by years of severe decline in cognitive ability.

Professor Wilson said: “Although there were individual differences in when the unawareness started and how fast it progressed, virtually everyone had a lack of awareness of their memory problems at some point in the disease.”

The study revealed that memory unawareness began earlier in young people than older people, this is most likely because older people anticipated some memory loss as part of the natural ageing process.

Research manager at Alzheimer’s Society, Dr Clare Walton, said: “Memory loss can be an important first sign of dementia however this study shows that people are not always aware of changes to their memory in the early stages of the condition. Often, friends and family are the first to recognise the warning signs. People who are concerned about the memory of someone close to them should encourage that person to visit their GP. A diagnosis can help people with dementia plan for the future and get access to vital care and support.”

“We need more research to improve our understanding of how memory is affected as people get older and how this differs in people with dementia. This will allow us to develop better ways to diagnose and support people with the condition as early as possible.”

Researchers studied the brains of 385 study participants who died during the course of the study, looking for seven types of brain changes, commonly found in people with dementia. The analysis revealed three dementia-related pathologies, associated with rapid decline in memory awareness, these pathologies were: tau proteins or tangles; infarcts, or areas of brain damage; and changes in the protein TDP-43. As the brain changes build up, those affected lose awareness that their memory is failing.

Professor Wilson added: “This study underscores the importance of family members looking for help from doctors and doctors getting information from friends or family when making decisions about whether a person has dementia, since people may be unable to give reliable reports about the history of their own memory and thinking abilities.”