Table 4

Correlations between clinical or polysomnographic data and diffusion measures connecting the left thalamus and the left pars triangularis in patients with insomnia

	Fractional anisotropy		Radial diffusivity		Axial diffusivity

Variables	r	p	r	p	r	p
Insomnia duration, yr	−0.218	0.33	0.142	0.53	−0.217	0.33
Epworth Sleepiness Scale score	−0.318	0.15	0.437	0.042	0.017	0.94
Insomnia Severity Index score	0.254	0.25	−0.183	0.41	0.210	0.35
Dysfunctional Beliefs and Attitudes About Sleep score	0.186	0.41	−0.238	0.29	−0.067	0.77
Pittsburgh Sleep Quality Index score	0.279	0.21	−0.261	0.24	0.167	0.46
Beck Depression Inventory (non-sleep score)^*	0.018	0.94	−0.037	0.87	−0.028	0.90
Neuropsychological test data
SOC, problems solved in minimal moves	0.451	0.034	−0.348	0.11	0.355	0.11
Polysomnographic data
Total sleep time, min	−0.046	0.84	−0.056	0.80	−0.115	0.61
Sleep efficiency, %	−0.237	0.29	0.280	0.21	−0.006	0.98

SOC = Stockings of Cambridge from the Cambridge Neuropsychological Test Automated Battery.
Statistical analyses were performed using Pearson’s r correlation.
↵* Beck Depression Inventory (non-sleep score): excluding the sleep item (16) from the total Beck Depression Inventory 21-item score.