Abstract: Objective  To investigate the relationship between phase lag index (PLI) and cognitive impairment (CI) in elderly maintenance hemodialysis (MHD) patients.  Methods  A total of 100 elderly patients undergoing regular hemodialysis in our hospital from August 2019 to June 2023 were selected and divided into CI group (n=61) and non-CI group (n=39) according to the Montreal Cognitive Assessment (MoCA) score. All patients underwent electroencephalogram (EEG) examination and PLI was calculated. The clinical data and PLI of various frequency bands were compared between the two groups. Pearson correlation was used to analyze the relationship between PLI and MoCA score. Multivariate logistic regression was used to analyze the risk factors for CI in elderly MHD patients. The receiver operating characteristic (ROC) curve was used to analyze the predictive value of PLI for CI in elderly MHD patients.  Results  The α band PLI was significantly lower in CI group than in non-CI group (t=7.585, P＜0.001). There were statistically significant differences in α band PLI from C3-P3, C4-P8, F3-C5, F4-P3, F8-P8, P4-CP3, CP3-O1 and CP5-O2 electrode pairs between the two groups (t=10.692, 6.485, 5.507, 7.505, 7.342, 14.720, 8.413 and 6.947 respectively; P＜0.001). Correlation analyses showed that there was a positive correlation between α-band PLI and MoCA score in CI group (R=0.486, P=0.013). Multivariate logistic regression showed that MoCA score (OR=11.512, 95% CI: 2.159～61.389, P=0.008) and α-band PLI (OR=5.669, 95% CI: 1.595～20.149, P=0.023) were the risk factors for CI in elderly MHD patients. ROC curve analyses showed that the area under the curve (AUC) of α-band PLI in predicting CI in elderly MHD patients was 0.818 (95% CI: 0.747～0.888), with the sensitivity and specificity of 78.46% and 64.62% respectively.  Conclusion  The decrease of α-band PLI is closely related to the decline of cognitive function in elderly MHD patients. α-band PLI has a better efficacy in predicting CI in elderly MHD patients and has the significance of guidance for clinical evaluation of CI.

Key words: Maintenance hemodialysis, Cognitive dysfunction, Phase lag index