Altered spontaneous brain activity in maintenance hemodialysis patients with cognitive impairment

OBJECTIVE: To measure changes in spontaneous brain activity in maintenance hemodialysis patients (MHD) with cognitive impairment (CI) by combining resting-state functional magnetic resonance imaging (rs-fMRI) and exploring the relationship between spontaneous brain activity and clinical indicators. METHODS: We selected 50 patients undergoing maintenance hemodialysis at the Second People's Hospital of Changzhou City from September 2020 to December 2021; 37 healthy volunteers were recruited during the same period, and all subjects underwent neuropsychological testing and rs-fMRI. Data analysis was performed after image preprocessing to explore spontaneous brain activity changes in differential brain regions of MHD-CI patients and to analyze the correlation between spontaneous brain activity and clinical variables. RESULTS: Compared to healthy controls, patients with MHD-CI had lower mean ALFF (mALFF) values in the left postcentral gyrus, lower mean fALFF (mfALFF) values in the left medial superior frontal gyrus, and lower mean mReHo (mReHo) values in the left middle occipital gyrus; by contrast, there were greater mALFF values in the left fusiform, left parahippocampal gyrus, right hippocampus, left caudate nucleus, and right caudate nucleus (p < 0.05). Compared with the MHD-NCI group, patients with MHD-CI had lower mALFF values in the left postcentral gyrus, lower mfALFF values in the left inferior temporal gyrus, and greater mALFF values in the right caudate nucleus (p < 0.05). Correlation analysis showed that mALFF values in the left postcentral gyrus of MHD-CI patients were significantly positively correlated with hemoglobin levels (r = 0.671, p = 0.000) and negatively correlated with urea nitrogen (r = –0.457, p = 0.011); mfALFF values in the left inferior temporal gyrus were significantly negatively correlated with urea nitrogen levels (r = –0.583, p = 0.000). Receiver operating characteristic curves suggested that all differential brain regions were diagnostically effective (p < 0.05). CONCLUSION Patients with MHD-CI have abnormal spontaneous brain activity in several brain regions, among which the left postcentral gyrus and left inferior temporal gyrus might be critical for the neurophysiological mechanisms of cognitive dysfunction. Correction of anemia and adjustment of urea nitrogen levels might help prevent CI in MHD patients.