Udhayakumar Radhagayathri, Rahman Saifur, Buxi Dilpreet, Macefield Vaughan G, Dawood Tye, Mellor Nicholas, Karmakar Chandan
School of Information Technology Deakin University, Geelong 3225, Australia.
Philia Labs Pty Ltd, Melbourne, Australia.
R Soc Open Sci. 2023 Aug 30;10(8):221382. doi: 10.1098/rsos.221382. eCollection 2023 Aug.
The onset of stress triggers sympathetic arousal (SA), which causes detectable changes to physiological parameters such as heart rate, blood pressure, dilation of the pupils and sweat release. The objective quantification of SA has tremendous potential to prevent and manage psychological disorders. Photoplethysmography (PPG), a non-invasive method to measure skin blood flow changes, has been used to estimate SA indirectly. However, the impact of various wavelengths of the PPG signal has not been investigated for estimating SA. In this study, we explore the feasibility of using various statistical and nonlinear features derived from peak-to-peak (AC) values of PPG signals of different wavelengths (green, blue, infrared and red) to estimate stress-induced changes in SA and compare their performances. The impact of two physical stressors: and Hand Grip are studied on 32 healthy individuals. Linear (Mean, s.d.) and nonlinear (Katz, Petrosian, Higuchi, SampEn, TotalSampEn) features are extracted from the PPG signal's AC amplitudes to identify the onset, continuation and recovery phases of those stressors. The results show that the nonlinear features are the most promising in detecting stress-induced sympathetic activity. feature was capable of detecting stress-induced changes in SA for all wavelengths, whereas other features (Petrosian, AvgSampEn) are significant (AUC ≥ 0.8) only for IR and Red wavelengths. The outcomes of this study can be used to make device design decisions as well as develop stress detection algorithms.
压力的产生会引发交感神经兴奋（SA），这会导致心率、血压、瞳孔扩张和出汗等生理参数发生可检测到的变化。对SA进行客观量化在预防和管理心理障碍方面具有巨大潜力。光电容积脉搏波描记法（PPG）是一种测量皮肤血流变化的非侵入性方法，已被用于间接估计SA。然而，尚未研究PPG信号的各种波长对估计SA的影响。在本研究中，我们探讨了利用从不同波长（绿色、蓝色、红外和红色）的PPG信号的峰峰值（AC）值中提取的各种统计和非线性特征来估计压力引起的SA变化并比较其性能的可行性。研究了两种身体应激源——握力和手部运动对32名健康个体的影响。从PPG信号的AC幅度中提取线性（均值、标准差）和非线性（卡茨、彼得罗相、 Higuchi、样本熵、总样本熵）特征，以识别这些应激源的发作、持续和恢复阶段。结果表明，非线性特征在检测压力引起的交感神经活动方面最有前景。 特征能够检测所有波长下压力引起的SA变化，而其他特征（彼得罗相、平均样本熵）仅在红外和红色波长下具有显著性（AUC≥0.8）。本研究的结果可用于做出设备设计决策以及开发压力检测算法。
