Does chronic occupational demand alter EEG stress biomarkers during cognitive challenge? a study of emergency...

Acute cognitive challenge produces consistent changes in several EEG indices, including alpha-band desynchronization, frontocentral theta enhancement, beta-band activity, and the theta/beta ratio. These measures serve as common biomarkers of cognitive workload and stress. It is not yet clear whether chronic occupational exposure to high cognitive demand alters these responses. Emergency physicians offer a useful test case, since their work involves repeated cognitive control under time pressure and high-stakes decision-making. We recorded 19-channel electroencephalography from 17 board-certified emergency physicians and 18 non-healthcare comparison participants during eyes-open rest and a standardized composite challenge combining Stroop interference, serial subtraction, time pressure, and evaluative feedback. Spectral power was estimated with Welch's method, log-transformed, and analyzed using a hierarchical framework combining six a priori regional features with electrode-wise topographic mapping. Across groups, the challenge produced robust frontal and posterior alpha suppression and increased frontocentral theta, consistent with workload-related cortical engagement. No Group x Condition interaction survived false discovery rate correction for the regional features, and no exploratory electrode-wise interaction survived correction across the full feature set. A complementary Bayesian analysis yielded moderate evidence for the null for the alpha and theta features, but inconclusive evidence for the beta and theta/beta features. Sub-band decomposition showed the challenge-related beta increase was specific to high beta (20-30 Hz), while low and mid beta decreased in emergency physicians. These results indicate an absence of detectable large group differences in EEG stress biomarkers following prolonged occupational exposure to high cognitive demand, although the sample constrains this conclusion to large effects.