Diagnosing Alzheimer’s dementia can be difficult and resource-intensive, in part because the condition cannot be confirmed in living patients by any single lab test, scan, or exam. Researchers at the School of Public Health (SPH) and the Minneapolis VA Healthcare System conducted a review of medical literature to determine if there are brief cognitive tests that can be delivered in primary care clinics to help detect Alzheimer’s cases. The researchers found that many brief tests are accurate for distinguishing Alzheimer’s dementia from normal cognition in older adults. However, these tests are less accurate in distinguishing more subtle differences, such as Alzheimer’s dementia from mild cognitive impairment or mild Alzheimer’s dementia from normal cognition.
The study, published in the Annals of Internal Medicine, was conducted by a team from SPH’s Evidence-Based Practice Center led by Assistant Professor Laura Hemmy and Professor Howard Fink from the Medical School.
The research team analyzed fifty-seven studies that examined the accuracy of brief cognitive tests in older adults. The study found that tests that performed well in distinguishing between Alzheimer’s dementia and normal cognition included:
Mini-Mental State Examination
Montreal Cognitive Assessment
Brief Alzheimer Screen
Delayed list recall (remembering words from a list after a delay)
Category fluency (spontaneous generation of words from a category, e.g., animals)
“There are not enough health care resources to send everyone with suspected Alzheimer’s to a geriatrician, neurologist or neuropsychologist,” says Fink. “We really wanted to know what tools are useful for a doctor in the typical primary care setting. In that sense, knowing that brief cognitive tests seem to accurately distinguish between those who have Alzheimer’s dementia and those with normal cognition may be useful.”
Fink added that while the lists of tests identified in the study can generally reveal Alzheimer’s dementia when compared to normal cognition, they’re not as good at detecting mild cases or other more subtle issues.
The researchers believe the findings may help families and clinicians make important decisions about the type and amount of testing that’s warranted in specific individuals. Such decisions are weighty because diagnostic mistakes can cause harm. For example, incorrectly missing a diagnosis of Alzheimer’s dementia can delay early intervention and increase the risk of condition-related injury to patients. In the same sense, incorrectly diagnosing a patient as having Alzheimer’s dementia can lead to unnecessary drug treatments and other psychological harms, such as stigma and premature restrictions on independence.
“This research suggests that for individuals with greater impairment and symptoms of cognitive and functional decline, brief cognitive tests may provide a less burdensome way than comprehensive neuropsychological testing to objectively document cognitive impairment,” says Fink. “And for patients with less impairment, brief tests may help providers identify those whose conditions warrant further diagnostic evaluation.”
The researchers note that one important limitation of the research is that studies were small and few directly compared tests or combinations of tests with each other. Also, no eligible studies examined any of the popular online tests people can take at home.