VANCOUVER—Internet-based assessments have the potential to aid the diagnosis of cognitive disorders and the conduct of preclinical dementia trials, according to two studies presented at the 2012 Alzheimer’s Association International Conference.
Dementia Risk Assessment
Jason Brandt, PhD, Director of the Division of Medical Psychology at the Johns Hopkins University School of Medicine in Baltimore, and colleagues conducted two studies to evaluate the Dementia Risk Assessment (DRA), an Internet-based instrument. The DRA collects responders’ risk factors, administers the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), and tests responders’ associative memory.
In the first study, the researchers solicited 3,168 participants ages 50 and older to respond to the DRA between April 2009 and December 2011. The investigators defined possible impairment as a score lower than 0.25 on the recognition memory test. In the second study, the researchers recruited 52 patients who wanted to be evaluated for possible cognitive disorder from two private memory clinics. Patients completed the DRA and subsequently underwent a comprehensive dementia diagnostic evaluation that did not consider DRA results.
The mean age of participants in the first study was 64, and approximately 38% were male. Dr. Brandt’s team performed a forward stepwise regression on memory test score and found that the resulting seven-variable linear model was statistically significant. The model, which included age, severe memory problems, sex, education, memory delay interval, stroke, and Parkinson’s disease, accounted for 14.5% of the total variance in recognition memory score.
In the second study, all participants completed the DRA and comprehensive clinical evaluations. Patients’ mean age was 76, and their mean Mini Mental State Examination score was 23.22. The researchers found that the predictive value of a positive test was 67% and that the predictive value of a negative test was 68%. Patients’ IQCODEs were significantly correlated with their memory test scores.
The study results “suggest that the DRA holds promise in the identification of cognitive disorders diagnosed by … formal evaluation by a geriatric neuropsychiatrist,” said Dr. Brandt.
An Online Test of Cognitive Function
Keith Wesnes, PhD, practice leader at Bracket in Goring, United Kingdom, assessed an Internet-based version of the Cognitive Drug Research (CDR) System, which is a battery of computerized tests of cognitive function. Participants logged on to a website, reported their age and gender, and took tests of simple reaction time, choice reaction time, digit vigilance, and delayed picture recognition. Dr. Wesnes assessed the data by age and compared the results to normative data from the standard administration of the CDR System.
The mean age of participants who took the Internet version of the tests was 41.6. A total of 54,623 participants took the tests, including 22,204 males. Of the total, 47,731 participants completed all parts of the CDR. Dr. Wesnes compared the data with those of a control group of 5,324 healthy volunteers who took the standard version of the CDR. The mean age of the control group was 39.6, and 3,900 controls were male.
The overall patterns of the data from the Internet and standard versions of the CDR System were comparable, according to Dr. Wesnes. Power of attention declined at a similar rate during the adult lifespan in both groups. The likelihood of false positive responses in the picture-recognition task also was similar for both groups.
Of the group that took the Internet version of the tests, 2,386 participants were between the ages of 5 and 17. Data from this subpopulation confirmed previous observations of a large increase in cognitive ability between the ages of 5 and 14. Accuracy did not differ according to gender, but males consistently responded slightly faster on the power of attention measure throughout the age span.
“This study has demonstrated that cognitive testing can be performed over the Internet and that the pattern of changes seen over the lifespan is comparable to data gathered from one-on-one cognitive testing,” said Dr. Wesnes. “Such a technique will be suitable for large-scale patient registries and preclinical dementia trials,” he added.
—Erik Greb