Resting-State EEG Microstate Dynamics and their Associations with Acclimatization Index and Serum Albumin in Healthy Adults with Chronic High-Altitude Exposure.

High-altitude hypoxia has been examined with conventional electroencephalography (EEG), event-related potentials, and neuroimaging, but its association with millisecond-scale resting-state EEG microstate dynamics and peripheral physiology remains unclear. We studied healthy adults including 124 low-altitude (LA) participants (50 men, 74 women) and 174 high-altitude (HA) participants (42 men, 132 women; age 28.05 ± 8.59 years; age unavailable for LA). Coverage, duration, global explained variance (GEV), occurrence, and transition probabilities were extracted for four canonical microstates. LA-HA differences were tested using unadjusted linear models; within-HA associations among the high-altitude acclimatization index (AAI), serum albumin, and Microstate A-related indicators were examined using covariate-adjusted regressions and exploratory bootstrapped mediation analyses. Compared with LA participants, HA participants showed increased Microstate A duration and GEV, decreased occurrence, and unchanged coverage, together with reduced Microstate B-related indicators, enhanced Microstate C-related indicators, and increased A→B and A→C transitions. Within HA participants, AAI was negatively associated with serum albumin, and exploratory mediation analyses indicated indirect associations between AAI and Coverage A, Occurrence A, GEV A, and Microstate A-originating transitions through serum albumin. These findings suggest that chronic high-altitude exposure is associated with resting-state EEG microstate reorganization in healthy adults and that acclimatization-related individual differences may be linked to Microstate A dynamics through serum albumin-related peripheral status.