Abstract: 【Abstract】 Objective To assess the value of the Montreal cognitive assessment (MoCA) and the event-related brain potential P300 in screening mild cognitive impairment (MCI) in maintenance hemodialysis (MHD) patients.  Methods Twenty MHD patients and 20 healthy controls were examined for P300 and cognitive performance by the Chinese version of MoCA. Results MHD patients with MCI had significantly lower scores than the healthy subjects in all MoCA sub-items except for name (t= -1.18, P =0.246) and fixed orientation sub-items (t= -0.38, P=0.70). The latency of P300 was significantly longer, and the amplitude of P300 was significantly lower in MHD patients than in normal subjects (P＜0.01). The latency of P300 was negatively correlated to the sub-item scores of visual spatial and executive function, attention and delayed recall, and the total MoCA score (P＜0.01). The amplitude of P300 was positively correlated to the sub-item scores of visual spatial and executive function, attention and delayed recall, and the total MoCA score (P＜0.01).  Conclusion P300 and MoCA can comprehensively assess MCI in MHD patients, and can help identify sub-clinical cognition damage.

Key words: Maintenance hemodialysis, Mild cognitive impairment, The Montreal Cognitive Assessment (MoCA), Event-related brain potentials