Table 2.
Generalized Estimating Equation (GEE) analysis results for cognitive measures with significant effects.
| Measure | Variable | Factor | B | SE | p |
|---|---|---|---|---|---|
| Flicker Fusion | Threshold frequency | Session | −2.629 | 0.718 | 0.000 |
| Simple RT | Median RT (ms) | Session | 18.255 | 8.671 | 0.035 |
| Median RT (ms) | Session × Duration | 0.459 | 0.143 | 0.001 | |
| RT Range (ms) | Session | 815.687 | 318.525 | 0.010 | |
| Circular Lights | # correct | Session × Duration | −0.027 | 0.013 | 0.037 |
| oTrail Making Test | Trails A time (s) | Session × Order | 11.950 | 5.856 | 0.041 |
| Trails B-A time (s) | Dose | −45.667 | 19.698 | 0.020 | |
| oDSST | # trials attempted | Session | 1.842 | 0.741 | 0.013 |
| # trials attempted | Session × Order | −3.967 | 1.100 | <0.001 | |
| Divided Attention | # tracking moves | Dose | −992.858 | 399.392 | 0.013 |
| Tracking deviation (pixels) | Session | 2.276 | 1.152 | 0.048 | |
| Tracking overlap (accuracy) | Session | −2.433 | 1.112 | 0.029 | |
| RT (monitoring) (ms) | Dose | 0.237 | 0.096 | 0.013 | |
| RT (monitoring) (ms) | Session × Dose | −0.201 | 0.092 | 0.028 | |
| n-Back | Hit rate | Dose | −0.045 | 0.020 | 0.023 |
| C (response bias) | Session × Duration | −0.001 | 0.000 | 0.018 | |
| Median RT (ms) | Session | 37.756 | 16.333 | 0.021 | |
| Sternberg | Proportion correct | Duration | 0.037 | 0.013 | 0.004 |
| oFree Recall | # correct responses | Session | 0.984 | 0.468 | 0.036 |
| # correct responses | Session × Dose | −4.624 | 0.931 | <0.001 | |
| # correct responses | Order × Dose | −5.906 | 2.622 | 0.024 | |
| # correct responses | Session × Order × Dose | 8.631 | 1.969 | <0.001 | |
| # correct responses | Duration | 0.018 | 0.008 | 0.022 | |
| Recognition | Hit rate | Session × Dose | −0.078 | 0.037 | 0.032 |
| Memory | False alarm rate | Duration | −0.001 | 0.000 | 0.023 |
| d′ (sensitivity) | Duration | 0.003 | 0.001 | 0.012 | |
| d′ (sensitivity) | Session × Duration | −0.002 | 0.001 | 0.001 | |
| Metamemory | Gamma | Duration | 0.002 | 0.001 | 0.036 |
Note. RT = Reaction time. Session = peak vs. trough session. Dose = participant's daily methadone maintenance dose (in mg). Duration = months in methadone maintenance treatment, Order = peak session first vs. trough session first. Order was included as a factor in the model only when it had a significant effect, and was only included in the table when there was a significant interaction between Order and another factor.
o
model included Order as a factor. Positive beta values reflect a higher value on the performance variable for: the peak vs. trough session, higher vs. lower dose, and longer vs. shorter treatment duration.