Brain Changes Seen Decades Before Alzheimer's Onset

New research suggests it may be possible to identify people at risk of Alzheimer's a decade before the disease would be diagnosed. Scientists from the Department of Applied Mathematics and Statistics at The Johns Hopkins University reviewed records of 290 people at risk for Alzheimer's disease, and have found an average level of biological and anatomical brain changes linked to Alzheimer's disease that occur three to 10 years before the disease's first recognizable symptoms appear.

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In some cases, the brain changes occurred 30 years before verified symptoms appeared. "Our study suggests it may be possible to use brain imaging and spinal fluid analysis to assess risk of Alzheimer's disease at least 10 years or more before the most common symptoms, such as mild cognitive impairment, occur," says Laurent Younes, Ph.D., professor and chair of the Department of Applied Mathematics and Statistics at The Johns Hopkins University.

Research marks first step

But Younes warns that brain changes are varied widely across people and that their results do not draw any precise conclusions brain changes in individual people. Treatment for Alzheimer's is difficult and currently, there are no known cures for the disease, though there are drugs that can slow down its progression.

This research, while not conclusive in its findings, does pave the way of further research into early diagnosis and treatment for the devastating disease. To complete the study, researchers examined the records of 290 people age 40 and older that took part in the BIOCARD project, an initiative that looks to develop predictors of cognitive decline.

Long-term study provides crucial data

The majority of the 290 people had at least one first-degree relative with dementia of the Alzheimer's disease type, which puts them in a higher risk category. These BIOCARD volunteers had their cerebrospinal fluid drawn and received MRI brain scans every two years between 1995 and 2005.

They also underwent five standard tests of memory, learning, reading, and attention annually from 1995 to 2013. All 290 participants began the BIOCARD project with a normal cognition evaluation. By the end of the project, 209 study participants remained cognitively normal, and 81 had been diagnosed with mild cognitive impairment or dementia due to Alzheimer's disease.

Tracking onset invaluable

Incredibly the study was able to track theses patients various biological and clinical features associated with Alzheimer's disease in the years leading up to the appearance of symptoms.

Among the 81 participants diagnosed with cognitive impairment, the Johns Hopkins team found subtle changes in cognitive test scores 11 to 15 years before the onset of clear cognitive impairment. Interestingly there were also increases in the rate of change of a protein called Tau. This protein has long been associated with the onset of Alzheimer's disease. A report of their findings was published online April 2 in Frontiers in Aging Neuroscience.