Table 2.

Fiber density and cross section values of white matter tracts.

	HC		TD-PD		PIGD-PD		P-value				Cohen’s d
	Mean	SD	Mean	SD	Mean	SD	HC vs. TD-PD vs. PIGD-PD	HC vs. TD-PDa	HC vs. PIGD-PDa	TD-PD vs. PIGD-PDa	HC vs. TD-PD	HC vs. PIGD-PD	TD-PD vs. PIGD-PD
ATR	0.49	0.05	0.52	0.05	0.50	0.06	0.014	0.012	0.26	1.00	−0.61	−0.30	0.28
CST	0.74	0.06	0.81	0.07	0.79	0.10	0.000049	0.000036	0.017	0.97	−1.07	−0.65	0.25
Cingulum	0.61	0.06	0.65	0.08	0.63	0.08	0.089	0.084	0.89	1.00	−0.48	−0.21	0.24
Forceps major	0.69	0.08	0.70	0.08	0.70	0.10	0.84	1.00	1.00	1.00	−0.12	−0.06	0.06
Forceps minor	0.46	0.05	0.48	0.05	0.47	0.05	0.028	0.024	0.91	0.66	−0.55	−0.25	0.31
IFOF	0.58	0.06	0.61	0.06	0.59	0.05	0.31	0.096	1.00	0.77	−0.44	−0.14	0.30
ILF	0.54	0.05	0.57	0.06	0.54	0.05	0.051	0.072	1.00	0.26	−0.46	−0.04	0.42
SLF	0.64	0.06	0.68	0.07	0.66	0.08	0.013	0.012	1.00	0.31	−0.63	−0.23	0.36
UF	0.60	0.06	0.63	0.08	0.62	0.07	0.18	0.24	0.59	1.00	−0.37	−0.26	0.12
Genu of CC	0.65	0.09	0.69	0.08	0.67	0.08	0.10	0.10	0.99	1.00	−0.44	−0.22	0.23
Body of CC	0.74	0.08	0.78	0.08	0.75	0.10	0.13	0.14	1.00	0.70	−0.43	−0.11	0.30
Splenium of CC	0.79	0.11	0.81	0.09	0.78	0.11	0.52	1.00	1.00	0.84	−0.16	0.14	0.33

ATR anterior thalamic radiation, CST corticospinal tract, HC healthy controls, IFOF inferior fronto-occipital fasciculus, ILF inferior longitudinal fasciculus, PIGD-PD patients with postural instability and gait disorder Parkinson’s disease, SD standard deviation, SLF superior longitudinal fasciculus, TD-PD patients with tremor-dominant Parkinson’s disease.

^aAnalysis of covariance with Bonferroni-adjusted post hoc tests.