For the first time, researchers have determined that a brief, simple number naming test can differentiate between cognitively healthy elderly individuals and cognitively impaired people with Alzheimer’s disease, including those with mild cognitive impairment, as well as those with Alzheimer’s dementia.
The study appears online in the journal Alzheimer’s Disease and Associated Disorders, and was conducted by researchers at Boston University Alzheimer’s Disease Center, with collaborators from Harvard Medical School and New York University School of Medicine.
Alzheimer’s disease can only be definitively diagnosed through postmortem examination of brain tissue. However, in recent years, the diagnosis of Alzheimer’s disease during life has become more accurate through the use of objective biological tests, including advanced brain scans and measures of proteins in cerebrospinal fluid and blood, in addition to lengthy formal cognitive evaluations.
Prior to ordering the tests, clinicians, such as primary care physicians, must determine a patient’s level of cognitive functioning to decide who may benefit from the relatively expensive and often invasive tests.
The King-Devick (K-D) test is a one- to two-minute rapid number naming test that has previously been found useful in the detection of concussion, as well as in detecting level of impairment in other neurological conditions such as Parkinson’s disease and multiple sclerosis. The K-D test can be quickly administered by non-professional office staff on either a tablet (iPad) or in a paper version.
In the study, researchers administered the K-D test to 206 study participants, including 135 cognitively healthy individuals, 39 people with mild cognitive impairment, and 32 Alzheimer’s disease dementia patients, and found the test could accurately distinguish the controls from the cognitively impaired individuals more than 90 percent of the time.
The K-D performed equally well in detecting participants with mild cognitive impairment from controls as it did detecting the more advanced Alzheimer’s dementia patients from controls, providing evidence for its utility in screening for more subtle cognitive impairment. It also correlated strongly with lengthier, standardize neuropsychological tests.
“If replicated in larger samples, our findings suggest that the K-D may be an appropriate screening test in fast-past clinical settings, such as primary care physician offices, to assist in the early detection of cognitive impairment and guide referral for more comprehensive evaluation to ultimately facilitate early intervention,” corresponding author Robert Stern, PhD, professor of neurology, neurosurgery and anatomy and neurobiology at Boston University School of Medicine, said.