UCLA researchers have used a brain-imaging tool and stroke risk assessment to identify signs of cognitive decline early on in individuals who don't yet show symptoms of dementia.
The connection between stroke risk and cognitive decline has been well established by previous research. Individuals with higher stroke risk, as measured by factors like high blood pressure, have traditionally performed worse on tests of memory, attention and abstract reasoning.
The current small study demonstrated that not only stroke risk, but also the burden of plaques and tangles, as measured by a UCLA brain scan, may influence cognitive decline. Plaques and tangles are clusters of proteins forming around nerve cells.
The imaging tool used in the study was developed at UCLA and reveals early evidence of amyloid beta plaques and neurofibrillary tau tangles in the brain — the hallmarks of Alzheimer's disease.
The study, published in the April issue of the Journal of Alzheimer's Disease, demonstrates that taking both stroke risk and the burden of plaques and tangles into account may offer a more powerful assessment of factors determining how people are doing now and will do in the future.
For the study, the team assessed 75 people who were healthy or had mild cognitive impairment, a risk factor for the future development of Alzheimer's. Each participant was injected with a chemical marker called FDDNP, which binds to deposits of amyloid beta plaques and neurofibrillary tau tangles in the brain. The researchers then used positron emission tomography (PET) to image the brains of the subjects — a method that enabled them to pinpoint where these abnormal proteins accumulate.
The study found that greater stroke risk was significantly related to lower performance in several cognitive areas, including language, attention, information-processing speed, memory, visual-spatial functioning (e.g. ability to read a map), problem-solving, and verbal reasoning.
The researchers also observed that FDDNP binding levels in the brain correlated with participants' cognitive performance. For example, volunteers who had greater difficulties with problem-solving and language displayed higher levels of the FDDNP marker in areas of their brain that control those cognitive activities.
‘The findings reinforce the importance of managing stroke risk factors to prevent cognitive decline even before clinical symptoms of dementia appear,’ said first author Dr David Merrill, an assistant clinical professor of psychiatry and biobehavioural sciences at the Semel Institute for Neuroscience and Human Behavior at UCLA.
According to the researchers, the UCLA brain-imaging tool could prove useful in tracking cognitive decline over time and offer additional insight when used with other assessment tools.
