Table 3.
Cognitive Measures in the Three Groups
| Test | Healthy Controls | L-T4 Euthyroid | L-T4 Suppressed | P Values for Comparing Groups |
|---|---|---|---|---|
| Declarative memory | ||||
| Paragraph recall | ||||
| Immediate | 13.5 ± 0.9 | 13.7 ± 0.6 | 13.9 ± 0.8 | .81 |
| 30-min delay | 11.8 ± 1.1 | 11.9 ± 0.7 | 12.2 ± 0.9 | .81 |
| Working memory | ||||
| N-Back number correct on target | ||||
| 1-Back* | 65% | 85%a | 58%b | .02 |
| 2-Back* | 35% | 59%a | 46%b | |
| 3-Back | 10.2 ± 0.4 | 10.7 ± 0.4 | 10.0 ± 0.6 | .29 |
| N-Back number incorrect nontarget | ||||
| 1-Back* | 20% | 21% | 25% | .50 |
| 2-Back* | 35% | 21% | 38% | |
| 3-Back | 3.0 ± 0.3 | 2.9 ± 0.3 | 3.9 ± 0.5 | .09 |
| SOP errors | ||||
| 6 | 0.7 ± 0.1 | 0.5 ± 0.1 | 0.5 ± 0.1 | .16 |
| 8 | 1.4 ± 0.2 | 0.9 ± 0.1 | 1.0 ± 0.1 | .16 |
| 10 | 1.3 ± 0.2 | 1.2 ± 0.1 | 1.2 ± 0.2 | .16 |
| 12 | 1.4 ± 0.2 | 1.6 ± 0.2 | 1.5 ± 0.2 | .16 |
| Motor learning | ||||
| Pursuit Rotor Trial | ||||
| Time on target, s | ||||
| 1 | 34.0 ± 2.5 | 33.2 ± 2.0 | 31.9 ± 2.2 | .87 |
| 2 | 38.1 ± 2.5 | 36.5 ± 2.0 | 37.8 ± 2.4 | .87 |
| 3 | 39.2 ± 2.6 | 38.5 ± 2.0 | 38.9 ± 2.6 | .87 |
| 4 | 39.6 ± 2.4 | 39.0 ± 1.7 | 40.7 ± 2.4 | .87 |
| Motor Sequence Learning Test | ||||
| Total movement time, s | 1069 ± 48 | 1001 ± 43 | 1000 ± 43 | .74 |
| Executive function | ||||
| Letter Cancellation Test | ||||
| Time, s | 96 ± 4 | 95 ± 3 | 100 ± 4 | .54 |
| Errors | 2.6 ± 0.7 | 2.9 ± 0.7 | 2.5 ± 0.6 | .95 |
| % with no errors | 20% | 23% | 21% | 1.00 |
| Trail Making Test | ||||
| Time, s | 25 ± 2 | 22 ± 1 | 21 ± 1 | |
| ABC time, s | 57 ± 4 | 53 ± 3 | 61 ± 4 | .30 |
| % with errors | 10% | 11% | 4% | |
| % with ABC errors | 25% | 23% | 17% | .63 |
| Iowa Gambling Test | ||||
| Net-1 | 1.3 ± 2.8 | −4.6 ± 1.5 | −3.9 ± 1.8 | .88 |
| Net-2 | 2.7 ± 2.3 | 6.5 ± 1.4 | 3.3 ± 1.8 | .88 |
| Net-3 | 7.9 ± 2.1 | 9.9 ± 1.4 | 8.8 ± 1.6 | .88 |
| Net-4 | 7.7 ± 2.1 | 10.1 ± 1.8 | 11.9 ± 1.7 | .88 |
| Net-5 | 9.7 ± 2.1 | 11.1 ± 1.8 | 9.3 ± 2.0 | .88 |
Data are expressed as mean ± SEM, unless otherwise specified. Individual tests are grouped by cognitive subdomains (first column). P values for continuous outcomes were adjusted for age, years of education, WAIS-R, BMI, and estrogen status. Boldface indicates measures that were statistically different among groups.
*
These values were calculated as proportion of subjects for which each measure was ≥ 15 (for Correct on Target) or > 0 (for Incorrect Off Target) because there were floor effects.
a
Significantly different than healthy control group at level 0.05 by post hoc tests.
b
Significantly different than L-T4 euthyroid group at level 0.05 by post hoc tests.