Insomniacs show greater prefrontal activation during verbal fluency task compared to non-insomniacs: A functional near-infrared spectroscopy investigation of depression in patients

Abstract

Abstract Background: Previous studies have shown that insomnia affects human prefrontal function and that there are specific patterns of brain activation to counteract sleep and improve cognition; however, the effects of insomnia on the prefrontal cortex of MMD patients and the patterns of activation to counteract sleep in MMD patients remain unclear. The aim of this study was to examine it using functional near infrared spectroscopy. Methods: Eighty depressed patients and 44 healthy controls were recruited in this study.fNIRS was used to assess the changes in the concentration of oxygenated hemoglobin([oxy-Hb])in the prefrontal cortex of all Participants during a verbal fluency task(VFT) and record the number of words created to assess cognitive ability. The Pittsburgh sleep quality index assessed the sleeping quality. Hamilton Rating Scale for Depression 24 item and Hamilton Rating Scale for Anxiety 14 item were used to assess the Severity of depression and anxiety. Results: Comparing patients, the healthy control group had significantly higher [oxy-Hb] values in the bilateral prefrontal cortex during VFT than the MMD group. In the MMD group, the [oxy-Hb] values in all brain regions except the right DLPFC were significantly lower in the group without insomnia than in the group with insomnia， their VFT performance was significantly lower than in the group without insomnia and the healthy group. PSQI scores were positively correlated with [oxy-Hb] values in some left-brain regions, whereas HAMD and HAMA scores were not correlated with [oxy-Hb] values. Conslusion: The PFC brain region was significantly less active during VFT in those with MDD than in healthy controls. All brain regions, except the right DLPFC, were significantly more active in MMD patients with insomnia than in those without insomnia, suggesting that sleep quality needs to be an important indicator in fNIRS screening. In addition, there was a positive correlation between the severity of insomnia in the left VLPFC and the level of activation, suggesting a role for the left brain region in the neurophysiology of overcoming sleepiness in MMD patients; these findings may provide new ideas for the treatment of MMD patients in the future. Trial registration: Our experiment was registered in the China Clinical Trial Registry (registration number ChiCTR2200065622) on November 10.( The first patient was recruited in 10/11/2022.)