Table 4.
Mediation models assessing the effect of grey-matter disintegration as measured by the SCNs on the relationship between age and cognitive performance and fine motor skills
| N | Total effect (c) | Direct effect (c′) | Indirect effect (ab) | Ratioa | Bootstrapped CI | |
|---|---|---|---|---|---|---|
| Total memory | ||||||
| Temporal network (e) | 206 | − 0.5196 | − 0.4237 | − 0.0959 | 0.1845 | − 0.1800, − 0.0279 |
| Secondary somatosensory network (h) | 206 | − 0.5196 | − 0.4753 | − 0.0443 | 0.0852 | − 0.1264, 0.0315 |
| Limbic network (d) | 206 | − 0.5196 | − 0.4813 | − 0.0383 | 0.0738 | − 0.0867, − 0.0056 |
| Cuneal network (a) | 206 | − 0.5196 | − 0.5461 | − 0.0265 | − 0.0509 | − 0.0032, 0.0751 |
| Figural memory | ||||||
| Secondary somatosensory network (h) | 206 | − 0.1612 | − 0.1234 | − 0.0378 | 0.2348 | − 0.0741, − 0.0103 |
| Temporal network (e) | 206 | − 0.1612 | − 0.1374 | − 0.0238 | 0.1477 | − 0.0513, 0.009 |
| Limbic network (d) | 206 | − 0.1612 | − 0.1459 | − 0.0153 | 0.1048 | − 0.0346, − 0.0020 |
| Fronto-occipital network (i) | 206 | − 0.1612 | − 0.1543 | − 0.0069 | 0.0426 | − 0.0281, 0.0134 |
| Cuneal network (a) | 206 | − 0.1612 | − 0.1693 | − 0.0081 | − 0.0505 | − 0.00046, 0.0307 |
| Verbal memory | ||||||
| Temporal network (e) | 206 | − 0.2474 | − 0.1953 | − 0.0521 | 0.2108 | − 0.0996, − 0.0103 |
| Fronto-parietal network (g) | 205 | − 0.2433 | − 0.2268 | − 0.0164 | 0.0675 | − 0.0409, 0.0010 |
| Cuneal network (a) | 206 | − 0.2474 | − 0.2680 | 0.0206 | na | 0.0018, 0.0532 |
| Executive functions | ||||||
| Fronto-parietal network (g) | 213 | − 0.0311 | − 0.0275 | − 0.0036 | 0.1144 | − 0.0074, − 0.0014 |
| Temporal network (e) | 214 | − 0.0319 | 0.0270 | − 0.0048 | 0.1520 | − 0.0111, 0.0005 |
| Sensorimotor network (j) | 214 | − 0.0319 | − 0.0297 | − 0.0022 | 0.0690 | − 0.0061, 0.0008 |
| Limbic network (d) | 214 | − 0.0319 | − 0.0288 | − 0.0030 | 0.0955 | − 0.0069, − 0.0001 |
| Secondary somatosensory network (h) | 214 | − 0.0319 | − 0.0300 | − 0.0019 | 0.0598 | − 0.0076, 0.0035 |
| Cerebellar network (v) | 214 | − 0.0319 | − 0.0295 | − 0.0024 | 0.0762 | − 0.0063, 0.0005 |
| Fine motor skills | ||||||
| Secondary somatosensory network (h) | 212 | − 0.3034 | − 0.2446 | − 0.0588 | 0.1938 | − 0.1172, − 0.0115 |
| Sensorimotor network (j) | 212 | − 0.3034 | − 0.2631 | − 0.0403 | 0.1328 | − 0.0763, − 0.0161 |
| Temporal network (e) | 212 | − 0.3034 | − 0.2450 | − 0.0583 | 0.1923 | − 0.1061, − 0.0151 |
| Limbic network (d) | 212 | − 0.3034 | − 0.2685 | − 0.0348 | 0.1148 | − 0.0684, − 0.0122 |
| Cerebellar network (v) | 212 | − 0.3034 | − 0.2745 | − 0.0289 | 0.0951 | − 0.0613, − 0.0056 |
| Fronto-occipital network (i) | 212 | − 0.3034 | − 0.2794 | − 0.0240 | 0.0790 | − 0.0580, 0.0004 |
| Fronto-parietal network (g) | 211 | − 0.2982 | − 0.2779 | − 0.0204 | 0.0683 | − 0.0576, 0.0028 |
Dependent variables: total memory, figural memory, verbal memory, executive functions, fine motor skills; independent variable: age; mediator: structural covariance networks. All models are adjusted for sex and education
Significant results are highlighted in bold
CI confidence interval, na not applicable
aRatio of indirect effect to total effect of independent variable on dependent variable, i.e., the amount the mediator can account for of the total effect. Because of missing data, effective sample size varied between 206 and 214