Table 1.
A summary of demographics, neuropsychological scores, and task performance per group
| Young | Aged (AU) | Aged (AI) | |
|---|---|---|---|
| Unimpaired | Impaired | ||
| Years of age | 19.9 (2.4) | 69.1 (5.2) | 72.9 (4.1) |
| Years of education | 14.1 (1.7)a | 16.7 (1.8) | 15.5 (2.9) |
| Gender (male/female) | 3M/17F | 6M/14F | 5M/5F |
| RAVLT total performance | 53.5 (6.7) | 56.2 (6.4) | 43.4 (6.1)b |
| RAVLT immediate performance | 12.1 (1.9) | 12.2 (1.5) | 8.3 (1.9)b |
| RAVLT delay performance | 11.8 (1.4) | 11.8 (1.6) | 6.5 (1.7)b |
| Estimated IQ | – | 120.8 (5.5) | 115 (6.7)b |
| Digit span performance | – | 18.9 (4.5) | 17 (3.8) |
| Mini-Mental State examination | – | 28.6 (0.9) | 28.3 (0.9) |
All data are reported as mean (SD).
aAn unpaired t-test revealed higher years of education for the aged adults (16.3, SD 2.3) than the young adults (14.1, SD 1.7), t(48) = 3.7, P < 0.001.
bIn addition, unpaired t-tests showed a poorer performance for the AI group relative to the AU group for RAVLT Total t(28) = 5.2, P < 0.0001, RAVLT Immediate t(28) = 6.3, P < 0.0001, and RAVLT Delay t(28) = 8.6, P < 0.0001. Although there is a group difference in IQ t(26) = 2.5, P < 0.05, these are largely overlapping distributions, and the AI group's IQ scores are certainly within normal limits. In addition, there was no relationship between IQ scores and performance on any of the tasks or other measures we used.