Table 3.

Eight significant clusters found in four statistical parametric mapping (SPM) regressions against clinical scores for the four MR image types, GM volume, WM volume, T₁w and T₂w

Item	MR	Clinical score	Design	Figure		Cluster		Location	Peak x,y,z
	image				Voxels	ccP1	ccP2		(mm)
1	T1w	seated PP	-2 s	3	2939	4.7e-6	2.5e-6	brainstem, cerebellum	12, -28, -22
2	rWMv	asleep HR (2)	-2 s	5A	3215	8.0e-6	5.7e-6	*L & R deep prefrontal WM	±21, 4, 39
3	rWMv	fatigue duration	-1 s	2a	2228	2.9e-5	6.1e-5	*midbrain	-12, -16, -18
4	T2w	fatigue duration	-1 s		133	*0.0027	0.015	R anterior middle frontal gyrus	36, 60, 2
5	rWMv	seated diastolic BP	+2 s	5B	975	0.0028	0.0016	R caudal basal pons	8, -25, -44
6	T2w	fatigue duration	-1 s		356	†0.0032	0.031	R middle temporal	52, -6, -16
7	rWMv	asleep HR	+2 s	5A	702	†0.0066	0.011	cerebellar vermis WM	0, -51, -23
8	rWMv	asleep HR	+2 s	5A	97	‡0.014	‡0.017	hypothalamus	-5, -4, -12

ccP₁ is adjusted for age and global value. ccP₂ is also adjusted for hospital anxiety and depression scale (HADS) anxiety and depression. Clusters are ordered by ascending ccP₁. Under ‘design’, 1 s indicates a one sample (CFS group versus CFS score) and 2 s a group (both CFS and NC) × haemodynamic score interaction design with the sign of the regression tested in the CFS group. Clusters of items 1 to 3 remained significant after Bonferroni's correction for multiple regressions. Clusters of items 1 to 7 were significant with false discovery rate (FDR) controlled at 0.05, although after adjustment for HADS anxiety and depression, items 4, 6 and 7 lost significance. Voxel volumes were 4.87 mm³ for grey and white, and 8 mm³ for T₁w and T₂w.

^†Not FDR significant after adjustment for HADS anxiety and depression.

^‡Cluster p not corrected for multiple comparisons (an a priori hypothesis existed for the hypothalamus).

^*peak voxel has corrected voxel p < 0.05 (see Results).

L, left; R, right; rWMv, relative white matter volume, WM, white matter; HR, heart rate; PP, pulse pressure; BP, blood pressure.