Table 2.

Region of Interest-Based Fractional Anisotropy Measures of Parkinson's Disease Patients and Healthy Controls

	PD patients (mean ± standard deviation)	Healthy controls (mean ± standard deviation)	Two-sided p-value	Effect size
Olfactory tract: 4188 voxels	0.118 ± 0.012	0.129 ± 0.017	0.0054**	0.75
Substantia nigra: 192 voxels	0.385 ± 0.027	0.395 ± 0.027	0.134	0.38
Anterior thalamic radiation: 16,720 voxels	0.319 ± 0.026	0.317 ± 0.018	0.789	0.07
Corticospinal tract: 10,739 voxels	0.498 ± 0.026	0.475 ± 0.033	0.0041**	0.77
Cingulum (cingulate gyrus): 2877 voxels	0.430 ± 0.040	0.419 ± 0.040	0.240	0.30
Cingulum (hippocampus): 1355 voxels	0.353 ± 0.025	0.334 ± 0.024	0.0030*	0.80
Forceps major: 6458 voxels	0.478 ± 0.029	0.476 ± 0.020	0.700	0.09
Forceps minor: 19,407 voxels	0.346 ± 0.022	0.342 ± 0.018	0.353	0.24
Inferior fronto-occipital fasciculus: 12,751 voxels	0.376 ± 0.022	0.370 ± 0.020	0.220	0.32
Inferior longitudinal fasciculus: 9551 voxels	0.383 ± 0.023	0.371 ± 0.019	0.034	0.56
Superior longitudinal fasciculus: 17,657 voxels	0.326 ± 0.026	0.321 ± 0.018	0.376	0.23
Uncinate fasciculus: 1985 voxels	0.330 ± 0.020	0.320 ± 0.017	0.041	0.54
Superior longitudinal fasciculus (temporal part): 374 voxels	0.451 ± 0.028	0.424 ± 0.038	0.0033*	0.79

Effect size >0.75 in bold.

^*Statistically significant after multiple comparison correction (p < 0.0038: two tailed).

^**The corrected p-value is slightly larger than our threshold (0.0038: two tailed).