A simple number naming test can identify those with cognitive impairment among elderly individuals, clearly differentiating patients with dementia and people with mild cognitive impairment from cognitively healthy people.
The study, “Screening Utility of the King-Devick Test in Mild Cognitive Impairment and Alzheimer Disease Dementia,” published in the journal Alzheimer’s Disease and Associated Disorders, provides clinicians with a tool for selection of individuals who might benefit from more extensive testing.
Diagnosing Alzheimer’s disease is far from a straightforward process, and with the current knowledge available, a definitive diagnosis can only be set when examining the brain after a patient dies.
Nevertheless, recent research advances have produced tests allowing more accurate diagnoses, but such tests are often both invasive — measuring levels of molecules in liquid collected by a spinal tap — and expensive. Therefore, a better way to select patients who should undergo these tests would benefit both patients and doctors.
Researchers from the Boston University Alzheimer’s Disease Center, Harvard Medical School, and the New York University School of Medicine worked together to assess whether a test commonly used to detect concussion might also be used to differentiate cognitive decline.
The test, called King-Devick (K-D), usually takes one to two minutes to complete, and has also been used to quantify the level of impairment in other neurological diseases, such as Parkinson’s disease and multiple sclerosis.
In addition to the speed of completion, the test has the beneficial feature that it can be administered by non-trained office staff, and exists as both a paper version and as an electronic form adapted to tablet computers.
Researchers put 206 individuals through the test, of which 135 were cognitively healthy, 39 had mild cognitive impairment, and 32 suffered Alzheimer’s dementia. The study shows that the number test placed participants in the correct category 90 percent of the time, and was as accurate in detecting milder impairment as it was in identifying Alzheimer’s patients. Results of the number test also correlated well with more comprehensive neuropsychological tests.
Senior study author Robert Stern, director of the Clinical Core of the Alzheimer’s Disease Center and a professor of neurology, suggested that the number test could become a good screening tool in a primary care setting, allowing physicians to detect early changes needing a more thorough dementia investigation.
“Alarmingly, Alzheimer’s disease is underdiagnosed in nearly half of the American population, and the brain changes of Alzheimer’s disease may begin up to 20 years before clinical symptoms. There is a need, therefore, for sensitive and readily available screening tools that can detect Alzheimer’s disease in its early stages, particularly as potential disease-modifying therapies become available,” Stern said in a news release.