July 08, 2016
For the first time, researchers have determined that a brief but simple number-naming test can differentiate between cognitively healthy elderly individuals and cognitively impaired people with Alzheimer’s disease (AD), including those with mild cognitive impairment (MCI) as well as those with AD dementia (published online ahead of print in Alzheimer Disease & Associated Disorders).
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 or in a paper version.
“Alarmingly, AD is underdiagnosed in nearly half of the American population, and the brain changes of AD may begin up to 20 years before clinical symptoms. There is a need, therefore, for sensitive and readily available screening tools that can detect AD in its early stages (such as MCI), particularly as potential disease-modifying therapies become available,” explained corresponding author Robert Stern, PhD, director of the Clinical Core of the Boston University Alzheimer’s Disease Center, Boston, MA.
In this study, Dr Stern and colleagues administered the K-D test to 206 study participants, including 135 cognitively healthy individuals, 39 people with MCI, and 32 AD dementia patients and found the test could accurately distinguish the controls from the cognitively impaired individuals more than 90% of the time.
The K-D performed equally well in detecting participants with MCI from controls as it did detecting the more advanced AD dementia patients from controls, providing evidence for its utility in screening for more subtle cognitive impairment. It also correlated strongly with lengthier, standardized neuropsychological tests.
Dr Stern concluded: “If replicated in larger samples, our findings suggest that the K-D may be an appropriate screening test in fast-paced 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.” —Amanda Del Signore