Table 2.
Comparisons with Significant Findings: Number of Participants, Direction of Change, Lowest Adjusted p Value, and the Number and Percentage of Significant Voxels
| Comparison | n | Direction < / > | Lowest p value | Number of significant voxels | % of total voxels |
|---|---|---|---|---|---|
| PPCS+ vs. PPCS- | |||||
| Total sample | |||||
| FA | 35/141 | PPCS+<PPCS- | 0.035 | 3695 | 2.7 |
| RD | 35/141 | PPCS+>PPCS- | 0.044 | 411 | 0.3 |
| KFA | 35/141 | PPCS+<PPCS- | 0.026 | 9544 | 6.9 |
| Uncomplicated sample | |||||
| FA | 27/131 | PPCS+<PPCS- | 0.028 | 6950 | 5.0 |
| PPCS+ vs. Controls | |||||
| Total sample | |||||
| FA | 35/78 | PPCS+<Controls | 0.002 | 12818 | 9.3 |
| MD | 35/78 | PPCS+>Controls | 0.019 | 25329 | 18.4 |
| AD | 35/78 | PPCS+>Controls | 0.015 | 2245 | 1.6 |
| RD | 35/78 | PPCS+>Controls | 0.005 | 24590 | 17.8 |
| KFA | 35/78 | PPCS+<Controls | 0.006 | 25387 | 18.4 |
| Kmean | 35/78 | PPCS+<Controls | 0.032 | 7600 | 5.5 |
| Kax | 35/78 | PPCS+<Controls | 0.028 | 5244 | 3.8 |
| Krad | 35/78 | PPCS+<Controls | 0.026 | 9780 | 7.1 |
| Uncomplicated sample | |||||
| FA | 27/78 | PPCS+<Controls | 0.003 | 22422 | 16.3 |
| MD | 27/78 | PPCS+>Controls | 0.028 | 15915 | 11.5 |
| RD | 27/78 | PPCS+>Controls | 0.010 | 26144 | 19.0 |
| KFA | 27/78 | PPCS+<Controls | 0.018 | 20456 | 14.8 |
| Kmean | 27/78 | PPCS+<Controls | 0.027 | 16713 | 12.1 |
| Kax | 27/78 | PPCS+<Controls | 0.050 | 3 | < 0.1 |
| Krad | 27/78 | PPCS+<Controls | 0.027 | 19553 | 14.2 |
| Adjusted for vocabulary | |||||
| MD, Total sample | 25/74 | PPCS+>Controls | 0.038 | 6743 | 4.9 |
| AD, Total sample | 25/74 | PPCS+>Controls | 0.029 | 1059 | 0.8 |
| RD, Total sample | 25/74 | PPCS+>Controls | 0.047 | 292 | 0.2 |
| RD, Uncomplicated | 19/74 | PPCS+>Controls | 0.049 | 212 | 0.2 |
| PPCS- vs. Controls | |||||
| Total sample | |||||
| Kmean | 141/78 | PPCS-<Controls | 0.029 | 7092 | 5.1 |
| Kax | 141/78 | PPCS-<Controls | 0.035 | 333 | 0.2 |
| Krad | 141/78 | PPCS-<Controls | 0.036 | 4970 | 3.6 |
| Uncomplicated sample | |||||
| Kmean | 131/78 | PPCS-<Controls | 0.040 | 3978 | 2.9 |
| Krad | 131/78 | PPCS-<Controls | 0.030 | 6533 | 4.7 |
| Adjusted for vocabulary | |||||
| Kmean, Total sample | 132/74 | PPCS-<Controls | 0.023 | 11258 | 8.2 |
| Kax, Total sample | 132/74 | PPCS-<Controls | 0.025 | 825 | 0.6 |
| Krad, Total sample | 132/74 | PPCS-<Controls | 0.036 | 4838 | 3.5 |
| Kmean, Uncomplicated | 123/74 | PPCS-<Controls | 0.026 | 10318 | 7.5 |
| Krad, Uncomplicated | 123/74 | PPCS-<Controls | 0.030 | 9455 | 6.9 |
The table shows the p value for the voxel with the lowest p value, the direction, and the number of significant voxels. For example, for FA, when comparing patients with PPCS (n = 35) to patients without PPCS (n = 141) in the total sample, patients with PPCS had significantly lower FA in 3695 voxels, which equals 2.7% of the total number of voxels (137,832). The lowest adjusted p value among these voxels was 0.035.
PPCS+/-, patients with and without persistent post-concussion symptoms; FA, fractional anisotropy; RD, radial diffusivity; KFA, kurtosis fractional anisotropy; Kmean, kurtosis mean; Kax, axial kurtosis; Krad, radial kurtosis; MD, mean diffusivity; AD, axial diffusivity.