The DCTclock demonstrated a 37% increase in discrimination over the traditional cognitive assessments.
Dorene M. Rentz, PsyD
A digital version of the clock drawing test showed very good discrimination between cognitively normal adults and those with mild cognitive impairment (MCI), as good as or better than traditional cognitive tests, according to study results presented at the 2019 Alzheimer’s Association International Conference, July 14-18, in Los Angeles, California.
Given the increased focus on early diagnosis and intervention in Alzheimer disease dementia, there is a need for more easily administered yet increasingly reliable cognitive assessments to distinguish subtle changes in cognition.
In the current study, led by Dorene M. Rentz, PsyD, of Massachusetts General Hospital in Boston, investigators assessed whether a digitized version of the clock drawing test was more sensitive than traditional pen and paper tests at distinguishing cognitive impairments between diagnostic groups, and whether performance was correlated with amyloid and tau deposition.
The study included 183 older adults from the Harvard Aging Brain Study, of whom 159 were cognitively normal and 24 met criteria for MCI. All study participants completed the DCTclock, traditional cognitive assessments, as well as PET imaging and flortaucipir to measure amyloid and tau accumulation in the inferior temporal and entorhinal regions.
Overall, the DCTclick was found to be a significant predictor of processing speed and worse executive function, and was highly correlated with the Preclinical Alzheimer’s Cognitive Composite (PACC5), which assesses amyloid burden in the preclinical stage.
In addition, the DCTclock displayed very good discrimination between participants who were cognitively normal and those with MCI (AUC 0.89; 95% CI, 0.83-0.95), with a 37% increase in discrimination over the traditional cognitive assessments (AUC 0.65; 95% CI, 0.53-0.77). The level of discrimination was also comparable to the PACC5 (AUC 0.91; 95% CI, 0.82- 0.99).
In participants who were cognitively normal, the DCTclock total score was significantly correlated with PET markers of entorhinal tau (r =-0.197); the spatial reasoning sub-score was also significantly correlated with amyloid-beta (r =-0.3217), entorhinal tau (r =-0.343), and inferior temporal tau (r =-0.235).
Overall, the results validate the feasibility of a digital version of traditional cognitive assessments in their ability to discriminate, as well as or better than, traditional tests, with an added degree of convenience for both the clinician and patient.
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Rentz DM, Papp KV, Sperling RA, et al. Capturing cognitive impairment at the preclinical stage of Alzheimer’s disease using digital technology. Presented at: 2019 Alzheimer’s Association International Conference. July 14-18, 2019; Los Angeles, CA. Abstract 31529.