Abstract
Introduction: Type 2 diabetes mellitus (T2DM) and major depressive disorder (MDD) together occur frequently among the elderly population. However, the inconsistency in assessments and limited medical resources in the community make it challenging to identify depression in patients with T2DM. This cross-sectional study aimed to investigate the activation pattern and network connectivity of prefrontal cortex (PFC) during a verbal fluency task (VFT) in patients with T2DM and MDD using functional near-infrared spectroscopy (fNIRS). Methods: Three parallel groups (T2DM with MDD group, T2DM group, and healthy group) with 100 participants in each group were included in the study. Recruitment took place from August 1, 2020, to December 31, 2023. Due to the close association between the PFC and depressive emotions, fNIRS was used to monitor brain activation and network connectivity of PFC in all participants during a task of Chinese-language phonological VFT. Network-based statistic prediction was adopted as data analysis method. Results: Patients in the T2DM with MDD group showed characteristic activation pattern and network connectivity in contrast with patients with T2DM and healthy controls, including decreased activation in PFC, and decreased network connectivity of right dorsolateral prefrontal cortex (DLPFC). Furthermore, the network connectivity of the right DLPFC in patients with T2DM and MDD was negatively correlated with scores of Hamilton Depression Scale-24 (HAMD-24). Conclusions: There was a distinctive activation pattern and network connectivity of the PFC in patients with T2DM and MDD. The right DLPFC could serve as a potential target for the diagnosis and intervention of MDD in patients with T2DM.
Plain Language Summary
As we all know, type 2 diabetes mellitus (T2DM) and major depressive disorder (MDD) are highly prevalent and frequently coexist in older adults. The prevalence of MDD among individuals with T2DM has been reported to be as much as 28%. Practice guidelines from the American Diabetes Association and the World Health Organization recommend physicians should pay attention to depressive disorder in patients with T2DM. According to previous studies, functional near-infrared spectroscopy (fNIRS) may be a promising technique to objectively evaluate the functional changes of prefrontal cortex (PFC) in patients with T2DM and MDD. The preliminary study for this research “Characteristic changes of prefrontal and motor areas in patients with type 2 diabetes and major depressive disorder during a motor task of tai chi chuan: A functional near-infrared spectroscopy study” has already been published on Brain and Behavior. In this study, we utilized fNIRS system and planned to investigate the differences of activation, network connectivity and receiver-operating characteristic curve in the PFC among patients with T2DM and MDD, patients with T2DM, and healthy subjects during a verbal fluency task (VFT), aiming to confirm the characteristic activation pattern of PFC during VFT in patients with T2DM and MDD and identify the potential brain targets for intervention of depression in patients with T2DM.
