Table 5. Meta-regression analyses.
| Anatomical label | Peak MNI coordinate (x, y, z) | No. of voxels | SDM-Z value | p value |
|---|---|---|---|---|
| Effect of age: GM changes in studies with older patients compared to younger patients | ||||
| a. Right/Left thalamus/midbrain | 2, -14, 6 | 655 | -4.98 | ∼0 |
| b. Left insula/inferior frontal gyrus | -44, 12, 4 | 641 | -4.15 | 0.0000026 |
| Effect of gender: GM changes in studies with a higher male ratio of patients | ||||
| c. Left caudate nucleus/thalamus | -6, -4, 14 | 155 | -3.71 | 0.000014 |
| Effect of motor severity: GM changes in studies of patients with higher average UPDRS-III score | ||||
| d. Left insula | -32, 12, 10 | 15 | -3.38 | 0.00015 |
| Effect of cognitive impairment: GM changes in studies of patients with lower average MMSE score | ||||
| e. Left insula | -32, 22, 0 | 41 | -3.66 | 0.00015 |
| Effect of illness duration: GM changes in studies of patients with longer average illness duration | ||||
| f. Left caudate nucleus/thalamus/Right thalamus | 0, -8, 12 | 1447 | -6.00 | ∼0 |
| Effect of scanner field-strength: GM changes in studies of patients with higher scanner field-strength | ||||
| g. Right inferior frontal gyrus | 54, 12, 16 | 127 | -4.02 | 0.000037 |
| h. Left supplementary motor area | -2, 24, 56 | 11 | -3.49 | 0.00032 |
Key: GM, Gray Matter; MNI, Montreal Neurological Institute; No., Number; SDM, Seed-based d Mapping; BA, Brodmann Area; UPDRS-III, Unified Parkinson's Disease Rating Scale-motor examination; MMSE, Mini-Mental State Examination.