The study on effects of acute exposure to high altitude hypoxia on cognitive function in lowlander.

The investigation of cognitive functions in response to high-altitude exposure has garnered increasing scientific interest. However, it remains unclear whether cognitive abilities are selectively impaired or what are the trends of the function. In this study, we examined the effects of acute exposure to 3800 m on cognition among 20 lowlanders (27.9 ± 3.08 years; 18 males) for 1 week. Cognitive functions, physiological parameters, various questionnaires, and electroencephalogram (EEG) data were assessed at 400 m (D0) and during the acute phase at 3800 m (D1, D2, D3, D5, D7). A control group consisting of 23 subjects (26.5 ± 3.17 years; 21 males) underwent identical assessments at 400 m. Our findings indicate that within two days following ascent to 3800 m, nearly all cognitive indicators exhibited impairment, but gradually improved from the 3rd day and largely recovered to the plain level on the 5th to 7th day. EEG frequency analysis also revealed significant alterations, relative power in the delta band decreased markedly by D7 compared with D0, while theta and alpha bands showed the opposite trends. Correlational analyses between EEG features and cognitive functions revealed that relative power in the delta band exhibited a negative correlation with most cognitive measures, while relative power in the theta and beta bands predominantly demonstrated positive correlations. We conclude that most cognitive functions exhibit a pattern characterized by initial decline followed by recovery at 3800 m-an observation closely linked to observed EEG changes. These findings provide valuable insights into cognitive function and EEG performance at high altitudes.