Posada-Quintero Hugo F, Florian John P, Orjuela-Cañón Alvaro D, Chon Ki H
Department of Biomedical Engineering, University of Connecticut, Storrs, CT, United States.
Navy Experimental Diving Unit, Panama City, FL, United States.
Front Physiol. 2018 Jan 17;8:1128. doi: 10.3389/fphys.2017.01128. eCollection 2017.
When divers are at depth in water, the high pressure and low temperature alone can cause severe stress, challenging the human physiological control systems. The addition of cognitive stress, for example during a military mission, exacerbates the challenge. In these conditions, humans are more susceptible to autonomic imbalance. Reliable tools for the assessment of the autonomic nervous system (ANS) could be used as indicators of the relative degree of stress a diver is experiencing, which could reveal heightened risk during a mission. Electrodermal activity (EDA), a measure of the changes in conductance at the skin surface due to sweat production, is considered a promising alternative for the non-invasive assessment of sympathetic control of the ANS. EDA is sensitive to stress of many kinds. Therefore, as a first step, we tested the sensitivity of EDA, in the time and frequency domains, specifically to stress during water immersion of the subject (albeit with their measurement finger dry for safety). The data from 14 volunteer subjects were used from the experiment. After a 4-min adjustment and baseline period after being immersed in water, subjects underwent the Stroop task, which is known to induce cognitive stress. The time-domain indices of EDA, skin conductance level (SCL) and non-specific skin conductance responses (NS.SCRs), did not change during cognitive stress, compared to baseline measurements. Frequency-domain indices of EDA, EDASymp (based on power spectral analysis) and TVSymp (based on time-frequency analysis), did significantly change during cognitive stress. This leads to the conclusion that EDA, assessed by spectral analysis, is sensitive to cognitive stress in water-immersed subjects, and can potentially be used to detect cognitive stress in divers.
当潜水员处于水下深处时，仅高压和低温就会造成严重压力，对人体生理控制系统构成挑战。再加上认知压力，例如在军事任务期间，这种挑战会加剧。在这些情况下，人类更容易出现自主神经失衡。用于评估自主神经系统（ANS）的可靠工具可作为潜水员所经历压力相对程度的指标，这可能揭示任务期间风险的增加。皮肤电活动（EDA），即由于出汗导致皮肤表面电导变化的一种测量方法，被认为是无创评估ANS交感神经控制的一种有前景的替代方法。EDA对多种压力敏感。因此，作为第一步，我们在时域和频域测试了EDA对受试者水浸期间压力的敏感性（尽管为安全起见，测量手指是干燥的）。实验使用了14名志愿者受试者的数据。在浸入水中4分钟的调整和基线期后，受试者进行了已知会诱发认知压力的Stroop任务。与基线测量相比，EDA的时域指标，皮肤电导水平（SCL）和非特异性皮肤电导反应（NS.SCRs）在认知压力期间没有变化。EDA的频域指标，EDASymp（基于功率谱分析）和TVSymp（基于时频分析）在认知压力期间确实发生了显著变化。这得出结论，通过频谱分析评估的EDA对水浸受试者的认知压力敏感，并有可能用于检测潜水员的认知压力。
