Patients (n=39) had a mean age of 81, and 36 (92%) had a diagnosis of dementia. Forty-nine (94%) of the 52 total participants were White race; patients and caregivers reported similar years of education, with means of 13 and 15 years, respectively. With a mean age of 81, patients were older than caregivers (mean age 62). Except for the test of verbal fluency, patients also demonstrated lower performance on cognitive tasks relative to the caregivers based on their average raw scores.
Reliability of the ACED
Among a subset of participants (n=15), two trained interviewers showed good inter-scorer reliability for each decision-making ability, with intraclass correlation coefficients of 0.72, 0.69, and 0.65, respectively, for understanding, appreciation, and reasoning. Percentage agreement for choice was 93%. For patients and caregivers combined (n=52), the internal consistency of the ACED abilities was also good, with Cronbach alpha values of 0.92, 0.88, and 0.84, respectively, for understanding, appreciation, and reasoning.
Distribution of ACED Ability Scores
juxtaposes patients’ and caregivers’ ACED scores for each of the four decision-making abilities. Both groups were equally capable of articulating a choice. They differed in their abilities to understand, appreciate, and reason. Only 15 patients (38%) achieved an understanding score above the lowest score observed in the caregiver group. Six patients (15%) scored in the highest category (7
) for appreciation, whereas, all caregivers scored within the highest category. The majority of patients, 29 of 39, scored between one and four. Contributing to the lower scores was notably poor performance on the appreciation item asking patients whether they thought they had the functional problem: 22/39 patients (56%) demonstrated inadequate (score=0) recognition of proxy reported functional problems. Performance on reasoning ability was similar to appreciation, with only six patients (15%) achieving scores in the highest range (9 or 10). We observed total scores above five points in this ability for 30 patients (77%), reflecting the higher scores found from questions testing comparative reasoning and logical consistency.
Performance of patients and caregivers on measures of everyday decision-making performance
Correlates of Everyday Decision-making Performance
Among the 39 patients, we observed no significant correlation between ACED performance in understanding, appreciation or reasoning ability, and the variables of age, gender, or education level (spearman correlations (rs) ranged from −0.18 to 0.22, all p>0.16). In contrast, MMSE scores had a moderate to strong correlation with all three decision-making abilities (0.48≤ rs ≤0.60, all p<0.002). Among the three measures of executive function, the Trails B and COFL showed a moderate association with ACED understanding and reasoning performance (0.33≤ rs ≤0.59, all p<0.04). All three tests demonstrated no correlation with ACED appreciation scores (0.06≤ rs ≤0.25 p>0.08). Each ACED ability measure was associated with its corresponding measure on the MacCAT-T: appreciation rs=0.38 (p=0.02), reasoning rs=0.50 (p=0.001), understanding rs=0.63 (p<0.001), and expressing a choice rs=0.71 (p<0.001).