Physiological Correlates of Stress in Individuals about to Undergo Eye Laser Surgery

We examined to what extent we can distinguish between ´real-life´ stressed and relaxed participants on the basis of heart rate (HR), heart rate variability (HRV) and skin conductance level (SCL) as measured during rest. Physiological and subjective measures were compared between individuals that were to undergo eye laser surgery and a control group. We found significantly higher HR and lower HRV in surgery clients, but no effect on SCL. Moreover, physiological indicators (HR) were found to correlate with subjective ones. Despite the inter-subject variations we were able to discriminate (using an SVM classifier) between surgery clients and controls with an accuracy of 70%. An alternative method of measuring HR using a Vital Signs camera showed good correspondence (error of 0.50 bpm in mean HR) with HR determined from ECG, opening up a range of practical applications that require contact less measurement methods.