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

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.

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 2500 m and 4300 m by breathing low oxygen mixtures. P3 latency and amplitude of ERP, reaction time (RT) and response error rate (ER) were recorded.

During hypoxia at the altitude of 4300 m, P3 latency significantly delayed, and ER was high when the difficulty of task increased (Sternberg paradigm with MSET 3). In contrast, at the altitude of 2500 m no changes were observed. Sternberg paradigm with MSET 1, in comparison with others, could elicit clearer ERP waves, and P3 latency was slower during hypoxia.

Hypoxia at the altitude of 4300 m has strong influence on ERP. P3 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.