Combining blood markers with cognitive test could aid early detection of Alzheimer’s
By Jan Jarvis
Combining blood biomarkers with only one cognitive test could add up to simpler, effective and less costly way to detect early-stage Alzheimer’s disease in Mexican Americans.
The study, conducted by researchers at The University of North Texas Health Science Center at Fort Worth, builds on previous work that uses protein biomarkers in blood to detect Alzheimer’s disease in Mexican Americans with 96 percent accuracy.
By combining fewer blood biomarkers with just one cognitive test, it is possible to detect earlier stages of cognitive impairment that often precede Alzheimer’s disease in this underserved population, said Melissa Petersen, PhD, Assistant Professor in the Institute for Translational Research and Department of Family Medicine.
“Detection rates are high with this method even for this very early stage of Alzheimer’s disease, which is exciting,” Dr. Petersen said. “When blood biomarkers and a single cognitive test are combined with demographic variables, it could help predict 96 percent of people with the disease.”
The study, which appears in the Journal of Alzheimer’s Disease, further validates HSC research showing that a blood test performed as part of a routine physical in a doctor’s office could be used to detect very early stages of Alzheimer’s – allowing treatment to begin as early as possible.
The research used data from the university’s Health & Aging Brain among Latino Elders (HABLE) study. One thousand older Mexican-American residents from the Fort Worth area have participated in this study, which seeks to understand aging in this underserved population.
In previous research, 21 blood biomarkers were used to predict early Alzheimer’s disease with approximately 90 percent accuracy.
When the number of blood biomarkers was reduced from 21 to five, the accuracy dropped to 82 percent, Dr. Petersen said. But when a cognitive test was added, the accuracy increased to 94 percent. When demographic variables were included, the accuracy was 96 percent.
Fewer cognitive tests and a simple blood test that can be done in the doctor’s office could make a big difference to patients.
“When an individual presents to their doctor with cognitive concerns, they are often referred for a cognitive evaluation, which includes undergoing a series of cognitive tests that are used to predict impairment that reflects Alzheimer’s disease,” Dr. Petersen said. “These cognitive tests put the brain to work doing a variety of tasks spanning problem-solving, multi-tasking and other skills.”
Dr. Petersen narrowed down the number of cognitive tests to one that focuses on executive skills, which require an individual to multi-task and engage in task-switching.
But performance on cognitive tests can be impacted by a variety of factors including education level, which can limit their accuracy at times to predict Alzheimer’s disease.
The goal is to identify the right combination of cognitive tests and blood biomarkers to be able to screen out those who do not have the disease, Dr. Petersen said.
“The use of just blood biomarkers to detect Alzheimer’s disease has shown considerable promise; however, there remains room to improve on detection accuracy,” she said. “That’s why we added a cognitive test and demographic factors such as age, gender and education.”
The hope is that the blood test will be transitioned to the primary care setting and be used to predict Alzheimer’s in a vulnerable population, and that the addition of a cognitive test and select demographics can help to improve the detection accuracy.
Overall, 13 percent of U.S. Latinos age 65 and older are thought to have Alzheimer’s or a related dementia, lower than for African Americans and higher than for non-Hispanic whites, the Centers for Disease Control and Prevention estimates.