Internet-Based Test May Improve Early Detection of Cognitive Impairment

From Medscape Medical News
Caroline Cassels

March 25, 2010 — An interactive, Internet-based cognitive screening tool is superior to standard tests used to detect cognitive impairment and may provide clinicians with a simple, accurate, early screening tool that can be used in the primary care setting, new research suggests.

Developed by investigators at the University of Tennessee Medical Center, Knoxville, the computer self test (CST) was substantially more accurate than the Mini Mental Status Examination (MMSE) and the Mini-Cog in classifying cognitively impaired individuals vs control participants, with an accuracy rate of 96% vs 71% and 69%, respectively.

"Not only [was the CST] able to distinguish people who did and did not have cognitive impairment, but it was able to distinguish between the various stages of [Alzheimer's disease (AD)] with superior accuracy," study investigator Rex L. Cannon, PhD, CPA, BCN, told Medscape Psychiatry.

Led by John H. Dougherty, MD, the study was published online March 11 and will appear in the April issue of the Journal of Alzheimer's Disease.

Most AD Patients Not Diagnosed by General Practitioners

The investigators note that up to 60% of patients with AD are not diagnosed in the primary care setting — a situation that suggests there are a significant number of missed opportunities to slow disease progression with early intervention, using agents approved by the US Food and Drug Administration for mild AD including donepezil (Aricept, Eisai Co, Ltd), galantamine (Razadyne, Ortho-McNeil Neurologics), and rivastigmine (Exelon, Novartis).

Tacrine (Cognex), the first approved cholinesterase inhibitor for mild AD, is another treatment option but is rarely prescribed because of possible hepatotoxic effects.

"By the time patients reach a specialist clinic where the majority of cognitive testing is done, their overall cognitive function has dropped significantly. It is our hope that the development of a simple, accurate, user-friendly test that can be administered relatively quickly in the primary care setting will facilitate earlier diagnosis of cognitive impairment so that we can direct treatment more efficiently," said Dr. Cannon.

The CST, he added, assesses 6 cognitive domains including memory, verbal fluency, orientation, visuospatial organization, executive function, and attention, as well as processing speed, in approximately 15 minutes and is designed to detect early deficits in 1 or more specific cognitive domains.

The investigators hypothesized that CST would accurately identify patients who were cognitively normal or who had mild cognitive impairment, early AD, mild to moderate AD, moderate to severe AD, or severe AD.

Extending Quality of Life

The study included 215 participants with a mean age of 75.24 years. Of these individuals, 84 had a diagnosis of AD and 27 had mild cognitive impairment. The remainder of the study participants were cognitively intact age-matched controls.

The CST was administered to all participants before routine neurocognitive testing in a memory disorders clinic. Using laptop computers, participants completed the test. If subjects had little or no computer experience, a caregiver or technician could help administer the test by assisting with manipulation of the mouse or arrows or facilitating typing and entering subjects' responses.

Study participants then underwent traditional neurocognitive testing including the MMSE and Mini-Cog.

Using discriminant analysis, the investigators compared the accuracy of the CST, MMSE, and Mini-Cog in classifying cognitively impaired and control groups and in distinguishing between the different types of cognitive impairment.

The results showed that the CST correctly classified 91% of the 6 potential diagnostic groups and 96% of cognitively impaired individuals and control participants.

In comparison, the authors report, the MMSE correctly classified 54% of the 6 groups and 71% of cognitively impaired subjects and control participants. Similarly, the Mini-Cog correctly classified 48% of the 6 groups and 69% of cognitively impaired patients and control participants.

"We need further validation of these results, but we are open to using the CST in all areas, in the primary care as well as the specialist settings. This test...offers promise in a novel direction for testing, and we just need to optimize the primary care setting, particularly for the geriatric population, so that we can flag people with early [AD] or [mild cognitive impairment] and try to extend their quality of life," said Dr. Cannon.

Clinicians interested in the CST for clinical or research purposes can contact the investigators by visiting www.medinteract.com

Dr. Cannon reports he has received consulting or advisory board fees from Medical Interactive Education. Dr. Dougherty has received lecture fees from, and is a member of, the Speakers Bureau for Eisai, Forest, Novartis, and Pfizer. He also reports he has equity ownership/stock options in Medical Interactive Education.

J Alzheimers Dis. Published online March 11, 2010.