November 1, 2017
It’s practically impossible today to predict if older adults with memory problems will go on to develop full-blown Alzheimer’s disease. But a study of more than 500 older men and women with memory problems suggests that certain biological features may help to accurately predict who will progress to Alzheimer’s.
For the study, Danish researchers studied 525 men and women, most in their late 60s, who had mild cognitive impairment, a clinical stage characterized by clear cognitive deficits not yet fully typical of Alzheimer’s disease but that often progresses to Alzheimer’s disease.In general, about half of those with mild cognitive impairment will go on to develop Alzheimer’s over the next three years.
For the study, volunteers completed the Mini-Mental State Examination, a 30-point questionnaire that takes five to 10 minutes to complete. Test takers are asked to answer a series of questions, including the time and place of the test, repeating a list of words, completing a math series and drawing various shapes. Any score from 24 to 30 generally indicates normal memory and thinking skills, while lower scores indicate impaired cognitive function.
Study participants also received an MRI scan of the brain. A shrinking brain is often a sign of Alzheimer’s disease, other studies have shown.
Finally, study participants had spinal fluid samples taken. The samples measured levels of various components, including the protein tau and the peptide beta-amyloid, that can signal the onset of Alzheimer’s disease.
During a follow-up period of two to three years, 38 percent of those in the study went on to develop Alzheimer’s disease.
The researchers came up with a fairly accurate assessment of who would go on to develop Alzheimer’s disease. They found, for example, that after three years, only 4 percent of patients with MMSE scores of 29 who had normal biological test results on spinal fluid proteins and brain size went on to develop Alzheimer’s. In contrast, as many as 89 percent of those with MMSE scores of 24 or less and abnormal spinal fluid markers progressed to Alzheimer’s disease.
After one year, less than 1 percent of those with normal biomarkers and high MMSE scores went on to develop Alzheimer’s. That compared to 26 percent of those with abnormal biomarkers and low MMSE scores.
The authors say their predictive models “could be easily implemented in daily practice”and enable doctors “to start treatment or provide more accurate patient management.” Determining who will likely not progress to full-blown Alzheimer’s can also be valuable for families, patients and clinicians. They intend to follow up with additional research and develop a web-based application for doctors.
By www.ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Ingrid S. van Maurik, MSc; Marissa D. Swan, PhD; Betty M. Tijms, PhD; et al: “Interpreting Biomarker Results in Individual Patients With Mild Cognitive Impairment in the Alzheimer’s Biomarkers in Daily Practice (ABIDE) Project.” JAMA Neurology, Oct. 16, 2017