Table 5.
Studies of global white matter microstructure.
| Study | N | Mean age | % female | Design | PFA assessment | MRI assessment | Measure | Significant results |
|---|---|---|---|---|---|---|---|---|
| Cross-sectional MRI | ||||||||
| Gow et al. (2012) | 691 | 70 | 47.3 | T1: PA; T2: MRI; T1–T2: 3.2 y | Q — 6-point scale | Tractography (global — 12 tracts) | FA | ↑ global a |
| MD | No significant results b | |||||||
| AD | No significant results | |||||||
| RD | No significant results |
Abbreviations — AD: axial diffusivity; FA: fractional anisotropy; MD: mean diffusivity; Q: questionnaire; RD: radial diffusivity; T1: time-point 1; T2: time-point 2; T1–T2: interval between time-point 1 and time-point 2; y: years; ↑ indicates a significant positive relationship between PFA and MRI measures.
a
After co-varying for age and sex. Results were no longer significant following additional co-varying for IQ, social class and disease.
b
After co-varying for age and sex. Results did not change following additional co-varying for IQ, social class and disease.