Greco Alberto, Lanata Antonio, Valenza Gaetano, Scilingo Enzo Pasquale, Citi Luca
Annu Int Conf IEEE Eng Med Biol Soc. 2014;2014:2290-3. doi: 10.1109/EMBC.2014.6944077.
This paper reports on a novel model based on convex optimization methods for the analysis of the skin conductance (SC) as response of the electrodermal activity (EDA) to affective stimuli. Starting from previous assessed methodological approaches, this new model proposes a decomposition of SC into tonic and phasic components through the solution of a convex optimization problem. Previous knowledge about the physiology of the EDA is accounted for by means of an appropriate choice of constraints and regularizers. In order to test the effectiveness of the new approach, an experimental session in which 9 healthy subjects were stimulated using affective pictures gathered from the IAPS database was designed and carried out. The experimental session included series of negative-valence high-arousal images and series of neutral images, with an inter-stimulus interval of about 2 seconds for both neutral and high arousal pictures. Next, a statistical analysis was performed on a set of features extracted from the phasic driver and the tonic signal estimated by the model. Results showed that the phasic driver extracted from the model was able to strongly distinguish arousal sessions from neutral ones. Conversely, no significant difference was found for the tonic components. This experimental findings are consistent with the literature and confirm that the phasic component is strictly related to changes in the sympathetic activity of the autonomic nervous system. Although preliminary, these results are very encouraging and future work will progress to further validate the model through specific and controlled experiments.
本文报道了一种基于凸优化方法的新型模型，用于分析皮肤电导（SC），作为皮肤电活动（EDA）对情感刺激的反应。从先前评估的方法学方法出发，这个新模型通过解决一个凸优化问题，提出将SC分解为紧张性和相位性成分。通过适当选择约束和正则化器，考虑了先前关于EDA生理学的知识。为了测试新方法的有效性，设计并进行了一项实验，其中使用从国际情感图片系统（IAPS）数据库收集的情感图片对9名健康受试者进行刺激。实验包括一系列负价高唤醒图像和一系列中性图像，中性和高唤醒图片的刺激间隔均约为2秒。接下来，对从相位驱动因素和模型估计的紧张性信号中提取的一组特征进行了统计分析。结果表明，从模型中提取的相位驱动因素能够强烈区分唤醒阶段和中性阶段。相反，紧张性成分没有发现显著差异。这些实验结果与文献一致，并证实相位成分与自主神经系统交感神经活动的变化密切相关。尽管是初步的，但这些结果非常令人鼓舞，未来的工作将通过具体的对照实验进一步验证该模型。
