[Effects of mild and moderate hypoxia on event-related potentials and the comparison of different stimulus paradigms].

Objective To investigate the effects of mild and moderate hypoxia on event related potentials (ERP), and to compare the sensitivity of different stimulus paradigms to hypoxia. Methods Twelve subjects performed visual Oddball and memory set size (MSET) 1 and MSET 3 of Sternberg tasks on the ground and at the simulated altitudes of 2500m and 4300m by breathing low oxygen mixtures. P 3 latency and amplitude of ERP, reaction time (RT) and response error rate (ER) were recorded. Results During hypoxia at the altitude of 4300m, P 3 latency significantly delayed, and ER was high when the difficulty of task increased (Sternberg paradigm with MSET 3). In contrast, at the altitude of 2500m no changes were observed. Sternberg paradigm with MSET 1, in comparison with others, could elicit clearer ERP waves, and P 3 latency was slower during hypoxia. Conclusion Hypoxia at the altitude of 4300m has strong influence on ERP.P 3 latency can be used as a sensitive index in evaluating the decrement of brain cognitive capacity during hypoxia. ERP elicited by Sternberg paradigm with MSET 1 was more sensitive to hypoxia.