Abstract— Electrodermal activity (EDA) has been found to be a highly sensitive, accurate and non-invasive measure of the sympathetic nervous system’s activity and has been used to extract biomarkers of various pathophysiological conditions including stress, fatigue, epilepsy, and chronic pain. Recently, various robust signal processing techniques have been developed to obtain more reliable and accurate indices that capture the meaningful characteristics of the EDA using data collected from laboratory-scale devices. However, EDA also has the potential to monitor such physiological conditions in active ambulatory settings, for which the developed tools must be deployed in wearable devices. In this paper, we studied the feasibility of obtaining the highly-sensitive spectral indices of EDA using a wearable device. EDA signals were collected from left hand fingers using a wearable device and a laboratory-scale reference device, while N=18 subjects underwent the Head up Tilt test and the Stroop test to stimulate orthostatic and cognitive stress, respectively. We computed two time-domain indices, the skin conductance level (SCL) and nonspecific skin conductance responses (NS.SCRs), and two spectral indices, the normalized sympathetic components of the EDA (EDASympn), and the time-varying EDA index of sympathetic control (TVSymp). The results showed similar performances for EDASympn and TVSymp indices across both devices. While spectral indices obtained from both devices performed similarly in response to orthostatic and cognitive stress, time-domain exhibited large variation when obtained by the wearable device. Further research is required to develop and refine such devices, as well as the indices used to analyze EDA results. Clinical Relevance— This study proves the feasibility of obtaining spectral indices of EDA using a wearable device, which can be used to develop wearable tools to detect pain, stress, fatigue, between others. I. INTRODUCTION Electrodermal activity (EDA) has recently increased in popularity due to its sensitivity as a measure of sympathetic activity. In measuring changes in the conductance of skin, EDA acts as a method for evaluating the state of the autonomic nervous system in addition to the cognitive activity of a subject [1]–[5]. Obtained in a noninvasive and direct process, EDA has proven to be an accurate and useful metric in studies observing a range of conditions including emotional arousal R. McNaboe, H.F. Posada-Quintero, M-B. Hossain, Y. Kong, and K.H. Chon are with the Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269 USA (corresponding author to provide phone: 959-777-2623; e-mail: riley.mcnaboe@uconn.edu, h.posada@uconn.edu, [6], pain [7] and stress [8],[9]. However, the majority of research utilizing EDA signals is conducted with large, laboratory designed devices that limit the potential EDA has to be used as a measure in ambulatory settings. By incorporating EDA functionality into wearable devices, it is possible to provide sensitive, accurate, and real-time metrics similar to those currently produced in research laboratories in an unobtrusive and practical manner. High sensitivity measures of a subject’s sympathetic tone are needed, as they provide means of monitoring and treating various conditions related to the impairment of sympathetic control [10]. Traditionally, the analysis of EDA has been in the time domain [1], using two highly variable measures, skin conductance level (SCL) and nonspecific skin conductance responses (NS.SCRs) [11]. Recent studies have also used a normalized time-invariant frequency domain analysis of EDA (EDASympn) which has demonstrated lower variability compared to SCL and NS.SCRs, but still only marginally acceptable consistency in results [11]. Recently, we have created a technique to improve upon these metrics by accounting for the time-varying characteristic of the sympathetic tone using a time-varying analysis of EDA referred to as TVSymp [12]. This index was developed using a variable frequency complex demodulation, a time-frequency spectral analysis technique and a high time-frequency resolution to develop and index of sympathetic tone. TVSymp is the mean spectral amplitudes in the frequency band associated with the sympathetic tone of the EDA signals. When compared to the time-domain and time-invariant indices such as heat rate variability, SCL, NS.SCRs, and EDASympn, TVSymp proved to be the most sensitive to applied stimuli. TVSymp has proven to be a reproducible index of EDA activity in various applications [13] including dental pain [14], dehydration [15], stress [16]. In accurately quantifying various forms of sympathetic activity, its promising results not only demonstrates consistency but enables future applications and studies with EDA. An accurate understanding of the autonomic nervous system’s dynamics can lead to improved treatment and interventions related to the performance and health of patients with related conditions. Wearable devices are one of the most obvious implementations of such a sensitive and versatile measure like EDA. Several studies have looked into collecting EDA data from wearable devices, such md.b.hossain@uconn.edu, youngsun.kong@uconn.edu, ki.chon@uconn.edu). Validation of Spectral Indices of Electrodermal Activity with a Wearable Device* Riley Q. McNaboe, Member, IEEE, Md-Billal Hossain, Member, IEEE, Youngsun Kong, Member, IEEE, Ki H. Chon, Senior Member, IEEE, Hugo F. Posada-Quintero, 2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) Oct 31 - Nov 4, 2021. Virtual Conference 978-1-7281-1178-0/21/$31.00 ©2021 IEEE 6991