Table 3.

Pearson and Spearman correlations between peripheral oxygen saturation changes and cerebral hemodynamic changes occurring in different types of respiratory events and various disease severities

	Hypopnea		Obstructive apnea		Snorers		Mild SDB		Severe OSAS
	Pearson	Spearman	Pearson	Spearman	Pearson	Spearman	Pearson	Spearman	Pearson	Spearman
StO2	0.23	−0.01	0.79b	0.59b	0.01	−0.09	−0.29	−0.27	0.78b	0.74b
tHb	−0.13	−0.20	−0.62b	−0.61b	0.03	−0.01	0.30	−0.04	−0.51a	−0.41a
O2Hb	−0.03	0.08	0.79b	0.44b	−0.10	−0.01	0.25	−0.11	0.75b	0.63b
HHb	−0.19	−0.13	−0.89b	−0.68b	−0.08	0.04	0.35	0.25	−0.86b	−0.75b

Results are shown as correlation coefficients. SDB refers to sleep disordered breathing; OSAS, obstructive sleep apnea syndrome; StO₂, cerebral oxygen saturation; tHb, total hemoglobin concentration; O₂Hb, oxygenated hemoglobin concentration; HHb deoxygenated hemoglobin concentration.

^ap ≤ 0.05

^bp ≤ 0.001