Table 4.
Example features.
| Eye-tracking | EEG | ECG | EDA | Actigraphy | FACET |
|---|---|---|---|---|---|
| Tobii X2-30 | Brain Vision ActiCHamp 32 | CamNtech Actiwave Cardio Single-Channel ECG | Empatica E4™ | AMI Motionlogger® Actigraph | iMotions® FACial Expression |
| General features • Fixations and saccades (using velocity based binocular algorithms) • % valid time on screen • % on ROIs (also normalized to % valid time) • Pupil size Specific features • Biological Motion preference (%), first saccade orienting (%) saccade latency, fixation orienting (%), fixation latency • VET exploration, preservation, detail orientation, RQA features |
Induced EEG activity (estimated for each electrode and different brain region) • Power spectra at different bands (delta, theta, alpha, beta, gamma) • Normalized power spectra at different bands • Brain asymmetry index for different bands • Coherence between at different bands ERP • Components' amplitudes with peak- and area-based methods • Components' latencies with peak- and area-based methods |
• HR • SDNN • SDSD • rMSSD • NN50 • pNN50 • ApEn • SpEn • LF HRV • Normalized LF HRV • HF HRV • Normalized HF HRV • LF/HF HRV |
Tonic activity • SCL Phasic activity: • SCRR |
• Sleep duration • Sleep start • Sleep end • # awakenings • Sleep efficiency |
For each emotion (joy, anger, surprise, fear, contempt, disgust, sadness, confusion, frustration) and action unit defined according to FACS • Average evidence • Variance of evidence • Area under evidence curve |
ApEn, approximate entropy; ECG, electrocardiography; EEG, electroencephalograpy; EDA, electrodermal activity; ERP, event-related potentials; FACET, iMotions® FACial Expression analysis; FACS, Facial Action Coding System; HF, high frequency; HR, heart rate; HRV, heart rate variability; LF, low frequency; NN50, number of pairs of successive NNs that differ by more than 50 ms; pNN50, proportion of NN50 divided by total number of NNs); rMSSD, root mean square of successive differences; ROI, Region of interest (such as eye region, mouth region, face region, and so on); RQA, recurrence quantification analysis; SCL, skin conductance level; SCRR, skin conductance response rate; SDNN, standard deviation of normal to normal R-R intervals; SDSD, standard deviation of successive differences; SpEn, sample entropy; VET, visual exploration task.