An Electrodermal Activity-Based Approach for the Assessment of Cognitive Stress

Cognitive stress refers to the mental tension resulting from complex or demanding cognitive tasks. It is linked to physiological signals, such as variations in skin conductance and brain activity, as the human body responds to stress with measurable changes in these parameters. The purpose of this work was to measure cognitive stress using commercially available and low-cost wearable devices. To this end, an experimental protocol of 1200 seconds was implemented, consisting of both relaxation and stress phases, during which the electrodermal activity (EDA) signal was acquired. The stress-inducing stimulus was represented as a computerised version of the Stroop Colour-Word Test implemented in PsychoPy, in which participants were also required to name the ink colour of words that could denote incongruent colours, thereby engaging inhibitory control and cognitive flexibility. This task was administered together with an additional quiz task. Thirty-two subjects participated in the test, aged between 23 and 37 years. EDA features were extracted within a 90-second window. Statistical analysis showed significant variations in all EDA features, except latency. Analyses based on the Cognitive Interference Index (IG) calculated according to Golden's method and on perceived stress distinguished participants as stressed or non-stressed, showing significant differences in some EDA features. These results provide evidence supporting the effectiveness of the proposed protocol and wearable devices for assessing cognitive stress, and suggest promising directions for engineering applications in continuous health monitoring and m-health.