Table 2.
Group-wise comparisons of median values of FA, MD and number of streamlines, by tract and disease. Group-wise comparisons from Analysis of Variance, followed by Tukey Honest Significant Differences. Data shown are median (range). Median FA, MD, and # of streamlines across subjects were weighted by the number of streamlines. The MD values were multiplied by 10^6 to convert from mm^2/s to um^2/s, which makes the numbers > 1. Asymmetry scores were calculated as left hemisphere minus right hemisphere. For FA, a negative asymmetry score denotes that the left hemisphere shows more degeneration than the right. For MD, a positive asymmetry score denotes that the left hemisphere shows more degeneration than the right. Asterisks denote significantly different relative to healthy controls at *p < 0.05; **p < 0.01; ***p < 0.001. † P value compares across all four groups corrected for multiple comparisons using the false discovery rate. No significant differences were identified when comparing the three disease groups (PPAOS, AOS-PAA and PAA).
| Tract | Hem | AOS-PAA | PPAOS | PAA | Control | P value† |
|---|---|---|---|---|---|---|
| FA | ||||||
| SMA-putamen | Left | 0.45 (0.41, 0.49) | 0.44 (0.43, 0.46) | 0.43 (0.42, 0.44) | 0.47 (0.46, 0.48) | NS |
| Right | 0.42 (0.41, 0.47) | 0.43 (0.42, 0.45) | 0.43 (0.42, 0.43) | 0.45 (0.44, 0.47) | NS | |
| L-R | 0.004 (-0.008, 0.022) | 0.009 (-0.005, 0.028) | 0.009 (-0.005, 0.024) | 0.017 (0.001, 0.026) | NS | |
| FAT | Left | 0.40 (0.38, 0.43)* | 0.41 (0.39, 0.42)* | 0.40 (0.39, 0.41)* | 0.45 (0.43, 0.46) | 0.007 |
| Right | 0.40 (0.37, 0.44)* | 0.41 (0.39, 0.43)* | 0.41 (0.38, 0.42) | 0.44 (0.43, 0.47) | 0.02 | |
| L-R | 0.010 (-0.017, 0.018) | 0.007 (-0.018, 0.023) | −0.015 (-0.030, −0.001) | 0.006 (-0.013, 0.017) | NS | |
| SMA-prefrontal | Left | 0.37 (0.34, 0.40)** | 0.37 (0.34, 0.39)* | 0.35 (0.31, 0.37)** | 0.40 (0.38, 0.43) | 0.001 |
| Right | 0.38 (0.36, 0.41)** | 0.38 (0.36, 0.41)* | 0.36 (0.34, 0.40)* | 0.42 (0.41, 0.47) | 0.002 | |
| L-R | −0.025 (-0.037, 0.002) | −0.013 (-0.037, 0.004) | −0.032 (-0.048, −0.012) | −0.014 (-0.033, 0.003) | NS | |
| SMA-motor | Left | 0.40 (0.37, 0.41)** | 0.39 (0.37, 0.41)** | 0.41 (0.38, 0.41) | 0.44 (0.41, 0.47) | 0.003 |
| Right | 0.41 (0.37, 0.45) | 0.40 (0.38, 0.42)* | 0.42 (0.39, 0.44) | 0.44 (0.41, 0.47) | 0.02 | |
| L-R | −0.018 (-0.033, 0.000) | −0.012 (-0.029, 0.020) | −0.021 (-0.027, 0.001) | −0.003 (-0.013, 0.014) | NS | |
| Commissural SMA | 0.46 (0.43, 0.51)* | 0.46 (0.43, 0.49) | 0.49 (0.47, 0.50) | 0.52 (0.50, 0.54) | 0.02 | |
| MD | ||||||
| SMA-putamen | Left | 805 (756, 837)** | 787 (757, 815) | 774 (756, 812) | 738 (699, 748) | 0.003 |
| Right | 781 (737, 823) | 776 (725, 807) | 746 (726, 775) | 715 (691, 749) | 0.046 | |
| L-R | 24.4 (4.0, 51.4) | 14.6 (-4.0, 33.5) | 29.4 (16.9, 53.0) | 7.3 (0.5, 18.4) | NS | |
| FAT | Left | 824 (784, 859)** | 811 (776, 835) | 832 (792, 851)* | 743 (705, 750) | <0.001 |
| Right | 801 (754, 826)* | 799 (748, 824) | 770 (752, 822) | 732 (692, 753) | 0.02 | |
| L-R | 29.1 (-3.8, 54.7) | 15.9 (-4.5, 32.9) | 42.8 (26.0, 59.7) | 1.2 (-7.7, 9.1) | NS | |
| SMA-prefrontal | Left | 820 (778, 859)** | 800 (760, 833) | 821 (763, 857)* | 739 (707, 751) | 0.002 |
| Right | 802 (750, 829)* | 788 (747, 823) | 767 (754, 820) | 725 (706, 744) | 0.03 | |
| L-R | 23.7 (-7.0, 52.9) | 10.9 (-17.8, 36.5) | 29.8 (19.1, 48.8) | −5.6 (-8.6, 14.3) | NS | |
| SMA-motor | Left | 807 (773, 842)*** | 789 (764, 820)* | 789 (764, 808) | 734 (691, 743) | <0.001 |
| Right | 775 (721, 822)* | 776 (733, 810) | 735 (722, 777) | 718 (682, 747) | 0.02 | |
| L-R | 34.5 (6.9, 74.3) | 10.7 (-6.6, 43.7) | 34.5 (30.1, 42.6) | 3.0 (-3.3, 28.6) | 0.04 | |
| Commissural SMA | 877 (805, 910)** | 853 (802, 895)* | 805 (777, 850) | 751 (712, 765) | <0.001 | |
| Number of streamlines | ||||||
| SMA-putamen | Left | 760 (460, 1274) | 701 (490, 825) | 1488 (700, 1866) | 714 (427, 1222) | 0.04 |
| Right | 745 (442, 1138) | 725 (503, 914) | 1192 (874, 1323) | 721 (543, 1135) | NS | |
| FAT | Left | 96 (58, 157) | 71 (46, 121) | 128 (85, 161) | 37 (23, 60) | NS |
| Right | 108 (45, 186) | 55 (23, 115) | 96 (78, 119) | 55 (32, 80) | NS | |
| SMA-prefrontal | Left | 208 (132, 307) | 216 (133, 308) | 240 (196, 282) | 92 (24, 130) | NS |
| Right | 228 (146, 384) | 192 (136, 289) | 228 (172, 355) | 76 (51, 188) | NS | |
| SMA-motor | Left | 204 (115, 272) | 154 (103, 262) | 364 (192, 488) | 114 (74, 146) | NS |
| Right | 160 (98, 198) | 117 (71, 176) | 248 (111, 344) | 143 (107, 204) | NS | |
| Commissural SMA | 64 (28, 110)* | 44 (26, 98) | 298 (132, 317) | 116 (64, 206) | 0.03 | |