Reliability of the Empatica E4 wristband to measure electrodermal activity to emotional stimuli

The electrodermal activity has been used in research as a physiological measure of the activity of the autonomic nervous system when patients face emotional stimuli. Laboratory-grade systems that register the galvanic skin response include sensors that are wired to expensive amplifiers, which can limit its portability and accessibility for non-research centers. In the last years, different devices, mostly wireless wristbands, have come into the market at lower prices. While their portability and lower cost are interesting features for virtual reality applications, their reliability still remains unclear. The objective of this study was to determine the reliability of a wireless wristband, the Empatica E4, to register changes in the galvanic skin response when facing emotionally-valenced images in comparison to a laboratory-grade system. Our data showed that correlation between both systems were low to moderate for negative and positive-valenced images, and non-existent for neutral images. These results suggest that the E4 should be used with caution when assessing changes in emotionally-valenced images and should be avoided for neutral images.