Table 1.
Characteristic | Session | Healthy controls | AD | Group comparison | |
---|---|---|---|---|---|
Statistic | P‐value | ||||
General | |||||
Gender (M:F) | NA | 11:6 | 9:8 | χ 2 = 0.49 | 0.486 |
Age (years) | NA | 66.6 (7.3) | 71.8 (8.2) | t = 1.93 | 0.062 |
Handedness (R:L) | NA | 16:1 | 17:0 | NA | NA |
Education (years) | NA | 16.5 (1.8) | 15.6 (2.6) | t = −1.13 | 0.267 |
MMSE (/30) | NA | 29.9 (0.2) | 23.9 (3.3) | z = −4.99 | <0.001 |
Symptom duration (years) | NA | NA | 4.5 (2.7) | NA | NA |
Donepezil duration (months) | NA | NA | 20.8 (13.1) | NA | NA |
Antidepressant therapy (no.)a | NA | 2 | 2 | NA | NA |
Behavioral tests | |||||
General cognitive | |||||
RMT Faces (/25): | baseline | 24.4 (0.9) | 19.7 (3.6)b | z = −3.61 | <0.001 |
change | 0.3 (1.0) | 0.0 (3.3) | z = 0.89 | 0.375 | |
RMT Words (/25) | baseline | 24.4 (1.5) | 18.0 (3.4)b | z = −4.55 | <0.001 |
change | −0.1 (0.8) | 0.4 (3.1) | z = 0.77 | 0.443 | |
GNT (/30) | baseline | 25.5 (3.6) | 14.1 (8.3) | z = −4.18 | <0.001 |
change | 0.8 (1.5) | −0.6 (2.5) | z = −1.81 | 0.071 | |
WASI matrices (/32) | baseline | 25.5 (4.0) | 11.6 (6.8) | z = −4.42 | <0.001 |
change | 1.2 (2.7) | −0.6 (3.4) | z = −1.40 | 0.163 | |
BPVS (/51) | baseline | 49.1 (1.7) | 40.4 (10.1)b | z = −4.00 | <0.001 |
change | −0.5 (1.2) | 0.6 (2.3) | z = 2.09 | 0.038 | |
Sinewave speech experiment | |||||
Sinewave speech (/20) | baseline | 15.4 (2.5) | 10.3 (5.1) | z = −3.40 | <0.001 |
repeat | 16.3 (2.7) | 13.9 (3.7) | z = −1.82 | 0.069 | |
change | 0.9 (3.1) | 3.6 (3.7)c | t = −2.36 | 0.025 | |
Session change scored | baseline | 2.0 (1.5) | 2.7 (2.8) | t = −0.91 | 0.369 |
repeat | 2.4 (2.1) | 2.5 (1.4) | t = −0.19 | 0.849 | |
change | 0.4 (2.2) | −0.2 (3.3) | t = 0.61 | 0.544 | |
Clear speech control (/10) | baseline | 10.0 (0.0) | 9.9 (0.2) | NA | NA |
repeat | 10.0 (0.0) | 10.0 (0.0) | NA | NA |
The Table shows mean (standard deviation) general demographic, clinical, and behavioral test data in the healthy control group and Alzheimer's disease (AD) patient group; comparisons between groups are also indicated. All AD patients were established on a standard daily 10 mg dose of donepezil at the time of participation; the baseline session was conducted prior to their next, intersession dose of donepezil. The interval between test sessions was similar for each group (healthy controls, 4.8 ± 0.4 h; AD, 4.9 ± 0.4 h; t 32 = −0.85, P = 0.400). The right‐hand columns show the effect of statistical comparisons between participant groups for each test. Maximum scores for standard tests of neuropsychological functions and for tests in the speech experiment (spoken numbers presented in sinewave form and in clear) are indicated in parentheses (see text and Fig. 1 for details). AD, Alzheimer's disease; BPVS, British Picture Vocabulary Scale (Dunn & Whetton, 1982); F, female; GNT, Graded Naming Test (McKenna & Warrington, 1980); L, left; M, male; MMSE, Mini‐Mental State Examination score; NA, not applicable; R, right; RMT, Recognition Memory Test (Warrington, 1984); WASI, Wechsler Abbreviated Scale of Intelligence (Wechsler, 1999).
no participant was taking memantine or other psychoactive agents;
one AD patient did not complete the test due to lack of time;
significant between‐session performance difference within group (P < 0.001);
index of intrinsic perceptual learning of sinewave speech (score on second 10 trials minus score on first 10 trials, within that session; see text and Figure 2).