Neurophysiological evidence for cognitive and brain functional adaptation in adolescents living at high altitude

OBJECTIVE Neurophysiological methods were used to study the effects of high altitude living on brain functions in a subgroup of participants of the Bolivian Children Living at Altitude (BoCLA) project. METHODS Electroencephalogram (EEG), event-related potentials (ERP) and cerebral blood flow velocity (CBFV) were recorded in two groups of adolescents (aged 13-16 years), living either at sea-level or high altitude (~3700m). RESULTS Neuropsychological testing revealed no deficits in the high altitude group, despite significantly reduced blood oxygen saturation. In agreement, ERPs elicited by oddball target detection and choice reaction time tasks were not different between groups. In contrast, resting state EEG showed reductions in delta and beta frequency amplitudes in adolescents living at high altitude. The EEG attenuations were correlated with lower CBFV, and the EEG group differences diminished during task performance. CONCLUSIONS No indication was found for negative sequelae of chronic hypoxia in adolescents born and living at an altitude of ~3700m, rather evidence for successful neurophysiological adaptation was found under such conditions. SIGNIFICANCE Dynamic regulation of metabolic demand is one adaptive mechanism that preserves cognitive development at high altitude.