Validity Assessment of Wrist-Worn Electrodermal Activity Measurement During Relaxation and Acute Stressor Tasks: Comparing the EmbracePlus and Shimmer3 GSR+

Wearable electrodermal activity (EDA) monitoring enables assessment of stress-related physiological changes in daily life, but new devices require validation. This study evaluated the newly introduced EmbracePlus against the Shimmer3 GSR+, used as a research-grade wrist-based comparator. Healthy volunteers (n = 53; n = 41 valid paired recordings) completed breathing exercises, a Stroop task, and a virtual reality (VR) height stressor while wearing both devices simultaneously on the non-dominant wrist. Agreement was assessed at signal, parameter, and event levels for mean phasic activity, skin conductance level (SCL), summed skin conductance response (SCR) amplitude/min, and SCR count/min. Mean signal-level cross-correlation was r = 0.30. At the parameter level, only 44% of SCL, 24% of SCR amplitude/min, and 5% of SCR count/min differences fell within a priori acceptable boundaries, and regression analyses indicated proportional bias for mean phasic activity, summed SCR amplitude/min and SCR count/min. At the event level, Shimmer3 detected increases across all four EDA metrics during both stress tasks (all p < 0.001). EmbracePlus showed increases across all four metrics during VR (all p < 0.001), whereas during Stroop only mean phasic activity (p = 0.001) and SCL (p < 0.001) increased. EmbracePlus and Shimmer3 are therefore not interchangeable for absolute EDA assessment, and EmbracePlus validity depends on stressor intensity and metric selection.