Effects of chronic high-altitude exposure on memory function in indigenous highland junior high school students: behavioral and electroencephalographic evidence

Background This study investigated the effects of chronic high-altitude exposure on memory function and neural processing in indigenous highland junior high school students. Methods Three altitude groups were established–low (1,400 m), mid (2,800 m), and high (4,200 m). A delayed recognition task dissociated memory encoding, maintenance, and retrieval stages. Physiological (blood oxygen saturation, heart rate, vital capacity), behavioral, and electroencephalographic measures were employed. Results Physiological: Blood oxygen saturation, heart rate, and maximal vital capacity decreased with increasing altitude. Behavioral: The high-altitude group showed lower recognition discriminability and more conservative decision-making vs. lower-altitude groups. Electrophysiological: High-altitude subjects exhibited reduced encoding-related attention, altered maintenance activity, and attenuated early retrieval attention. Correlation analyses linked blood oxygen saturation to behavioral discriminability and event-related potential components across memory stages. Conclusion Chronic hypoxic exposure associates with stage-specific alterations in memory-related neural and behavioral performance in adolescent highlanders. While more pronounced impairments occurred at 4,200 m, these findings are preliminary; finer-grained altitude sampling and larger samples are needed to identify critical altitude thresholds.