GSTM1 and obstructive sleep apnea syndrome: Inter‐group comparisons showed that the Oxy‐Hb change of Channel 25 (located in the dorsolateral prefrontal cortex [DLPFC]) in OSA group was less than that in HC group (p = .006), and the Oxy‐Hb change of Channel 43 (located in the right frontal polar region) in OSA group with depression was less than that in OSA group (p = .025).