ECog scores tied to imaging biomarkers, neuropsychological test scores
Scores in the total and memory domain of the Everyday Cognition (ECog) scale are associated with neuroimaging biomarkers and neuropsychological tests, a new study shows. Moreover, the ECog can differentiate normally ageing adults from patients with early stage Alzheimer’s disease (AD).
In the study, 200 participants were made to accomplish the ECog. Of the 200, 160 were normally ageing while 40 were in the early stages of probably AD. All of the participants were at least 50 years of age and had no significant neurological or brain lesions.
Participants were subjected to a battery of neuropsychological tests including the mini mental state examination (MMSE), consortium to establish a registry for Alzheimer’s disease neuropsychological assessment battery (CERAD-NAB) and clinical dementia rating (CDR). Magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) scans were also performed on the patients.
Between the normally ageing group and probable AD patients, there were no significant differences in age (p=0.12), gender distribution (p=0.97) and educational years (p=0.72). On the other hand, the normally ageing group had significantly higher mean CERAD (75.5±9.0 vs 62.6±11.5; p<0.01) and MMSE (26.4±3.1 vs 22.9±4.2; p<0.01) scores and a lower median CBR (0 vs 0.5; p<001) scores. [Sci Rep 2017;7:1719]
CERAD-NAB scores were associated with years of education and age (p<0.01) but not with gender (p=0.58) in the normally ageing group.
Total (43.5±7 vs 76.9±24; p<0.01) and average (1.1±0.2 vs 2.1±0.7; p<0.01) ECog scores were significantly lower in the normally ageing participants compared with the early stage probable AD patients.
Similarly, the average ECog scores for the memory (1.3±0.4 vs 2.8±0.8; p<0.01), language (1.1±0.2 vs 1.7±0.7; p<0.01), visual-spatial and perceptual ability (1.1±0.2 vs 1.8±0.7; p<0.01), planning (1.0±0.2 vs 1.8±0.7; p<0.01), organization (1.0±0.1 vs 1.9±0.8; p<0.01) and divided attention (1.3±0.4 vs 2.4±1.0; p<0.01) domains were significantly lower in the normally ageing group.
While the ECog scores were not significantly associated with age (p=0.18), gender (p=0.89) or years of education (p=0.70), total scores were significantly correlated with total CERAD-NAB scores (p<0.01).
“The results revealed that the total and average ECog scores were significantly associated with the neuropsychological test scores. The total ECog scores and all average domain-specific scores were significantly correlated with the CERAD-NAB memory subtest and total CERAD-NAB scores,” the investigators said.
Nonparametric pairwise correlation analysis showed that the average total ECog score was not significantly associated with AD t-sum scores. On the other hand, CERAD-NAB scores (p<0.01) and the average score of the memory domain of ECog (p=0.02) were significantly correlated with AD t-sum scores.
The standard uptake value ratios (SUVr) from the angular gyrus and posterior cingulum gyrus were significantly correlated with CERAD-NAB memory domain scores and total CERAD-NAB scores (p<0.01 for all). The SUVr of the posterior cingulum gyrus was also associated with scores in the executive domain of CERAD-NAB (p<0.01), while the memory domain of ECog was significantly inversely correlated with angular gyrus and posterior cingulum gyrus SUVr (p<0.01 for both).
“[T]he memory domain of the ECog scale and CERAD-NAB score were both significantly associated with the regional SUVr in the angular gyrus and posterior cingulum gyrus, suggesting their diagnostic potential for the early stage of AD,” researchers said.
While the study corroborates the findings of previous reports, it has several limitations including the low number of probable AD patients, mode of AD diagnosis and the failure to administer self-rated ECog tests, all of which may have influenced the strength of the correlations obtained in the study.
Regardless, “the present study is the first to provide the results of applying the ECog scale to normally ageing adults and patients with the early stage of probable AD,” the investigators claimed. “The ECog scores exhibited significant correlations with standard neuropsychological tests and could also discriminate between both groups.”