Psychophysiology of disgust: ECG noise entropy as a biomarker

The identification or classification of emotions allows the description of the person's state and, therefore, the inference of their preferences. The basic emotion of disgust, in particular, allows the organism to protect itself against diseases. Usually, the decrease in heart rate is associated with this emotion. As an avoidance behavior, when facing with disgust stimuli, the body reacts with movements, such as muscle contraction, etc. These reactions are evidenced in the electrocardiogram (ECG) as noise responses. In this paper, we propose the amount of ECG noise measured by the noise entropy as a new biomarker in emotion identification, which has been neglected in the literature. Our results showed that the noise entropy was able to discriminate between disgust, fear and neutral conditions in 88% (p<;0.05). It was also evidenced in this dataset that the median noise entropy in disgust was higher than in neutral and in fear conditions.