Table 2.
Comparison of decisionally capable and incapable subjects with Alzheimer’s disease.
| Capable AD (n=20) |
Incapable AD (n=44) |
Statistical test with df |
p | |
|---|---|---|---|---|
| Age (years) | 76.9 (6.2) | 80.6 (6.9) | t(62.0) = 2.09 | .041 |
| Education (years) | 15.6 (2.7) | 13.1 (3.1) | t(61.0) = 3.01 | .004 |
| Gender (% female) | 46.5% | 43.2% | χ2(1) = 0.09 | .767 |
| Ethnicity (% Caucasian) | 90.7% | 79.5% | χ2(1) = 1.06 | .304 |
| NPI-CGA total | 10.86 (12.39) | 16.28 (15.34) | t(44) = 1.16 | .250 |
| Delusions | 0.31 (1.01) | 0.74 (1.90) | t(44.0) = 1.16 | .250 |
| Hallucinations | 0.31 (1.01) | 0.13 (0.41) | t(53.0) = 0.97 | .337 |
| Agitation/Aggression | 1.44 (3.10) | 1.44 (2.36) | t(22.5) = 0.01 | .999 |
| Depression/Dysphoria | 1.13 (1.09) | 1.05 (2.37) | t(53) = 0.12 | .906 |
| Anxiety | 1.06 (2.14) | 0.90 (2.40) | t(53) = 0.24 | .813 |
| Elation/Euphoria | 0.50 (1.55) | 0.28 (1.02) | t(53) = 0.61 | .542 |
| Apathy/Indifference | 2.63 (3.72) | 3.65 (4.04) | t(48) = 0.85 | .397 |
| Disinhibition | 0.69 (1.66) | 0.95 (2.11) | t(53) = 0.44 | .661 |
| Irritability/Lability | 1.56 (2.48) | 1.26 (2.69) | t(53) = 0.39 | .697 |
| Motor | 1.60 (3.58) | 0.95 (1.93) | t(52) = 0.86 | .393 |
| Sleep/Nighttime | 1.07 (2.22) | 1.30 (3.26) | t(50) = 0.25 | .803 |
| Appetite/Eating | 1.63 (3.52) | 2.51 (3.99) | t(53) = 0.77 | .442 |
| MMSE total | 23.3 (3.4) | 21.0 (3.1) | t(62.0) = 2.64 | .010 |
| MoCA total | 17.5 (4.6) | 13.9 (4.6) | t(48.0) = 2.47 | .017 |
| DRS total | 120.8 (8.2) | 111.4 (14.1) | t(55.4) = 3.30 | .002 |
| 5-item total | 7.6 (2.1) | 4.7 (2.3) | t(62) = 4.85 | <.001 |
| MacCAT-CR | ||||
| Understanding | 23.4 (1.6) | 11.7 (5.6) | a | a |
| Appreciation | 5.1 (0.9) | 3.7 (1.4) | t(61) = 4.04 | <.001 |
| Reasoning | 7.1 (1.9) | 5.4 (2.5) | t(45.4) = 2.94 | .005 |
| Expression of Choice | 1.7 (0.7) | 1.6 (0.7) | t(61) = 0.75 | .454 |
| Protocol type (% higher risk) |
50.0% | 47.7% | χ2(1) = 0.03 | .866 |
a
t-test not calculated since grouping was based on MacCAT-CR Understanding cut-score, null hypothesis false by definition.
Note: Values represent group means (and SDs) or proportions; AD = Alzheimer’s disease; CGA-NPI = Caregiver Administered Neuropsychiatric Inventory; MMSE = Mini Mental State Examination; MoCA= Montreal Cognitive Assessment; DRS = Mattis Dementia Rating Scale; MacCAT-CR = MacArthur Competence Assessment Tool – Clinical Research.