Effects of Chronic High-Altitude Exposure on Memory Function in Indigenous Highland Junior High School Students: Behavioral and Electroencephalographic Evidence

Abstract

By establishing three altitude groups—low (1,400 m), mid (2,800 m), and high (4,200 m)—and employing a delayed recognition task to dissociate the encoding, maintenance, and retrieval stages of memory, this study investigated the effects of chronic high-altitude exposure on memory function and neural processing in indigenous highland junior high school students using physiological, behavioral, and electroencephalographic measures. At the physiological level, blood oxygen saturation, heart rate, and maximal vital capacity decreased with increasing altitude. At the behavioral level, compared with the low-and mid-altitude groups, the high-altitude group exhibited lower recognition discriminability and adopted more conservative decision-making strategies. At the electrophysiological level, the high-altitude group showed reduced encoding-related attentional allocation, altered maintenance-related neural activity, and attenuated early selective attention during retrieval. Correlation analyses further indicated that blood oxygen saturation was selectively associated with behavioral discriminability and stage-specific event-related potential components, suggesting that reduced oxygen availability may constrain neural processing efficiency across multiple memory stages. Together, these findings indicate that chronic hypoxic exposure is associated with stage-specific alterations in memory-related neural and behavioral performance in adolescent high-altitude residents. Although more pronounced impairments were observed at 4,200 m, the present results should be regarded as preliminary, and further studies with finer-grained altitude sampling and larger samples are required to determine whether a critical altitude threshold exists.