Analysis of autonomic response to stressful and calming visual and auditory stimuli

Abstract

Stress is a recognizable physical sensation that results from a stimulus associated with anxiety or fear in which the body has regulatory mechanisms for control in order to alter the stimulation of sympathetic innervation and therefore alter the body’s behavior during a stress-inducing incident. The human body’s method of monitoring acute stress is through the hypothalamic-pituitary adrenal axis (HPA-axis), which assists in regulation of the autonomic responses that result from acute stress including, but not limited to, immediate changes in blood pressure (BP), heart rate (HR), and skin conductance response (SCR). The purpose of this study was to determine how stressful and calming auditory and visual stimuli affect the body’s acute autonomic response. It was hypothesized that calming stimuli would result in decreased BP, HR, and SCR, while stressful stimuli would result in an increase in these variable measurements. It was also hypothesized that visual exposure to stimuli would result in a larger autonomic response than auditory exposure for both calming and stressful stimuli. After analyzing HR, BP, and SCR in 11 subjects exposed to calming visual and auditory stimuli and 9 additional subjects exposed to stressful visual and auditory stimuli, it was determined that some, but not all, measures of autonomic response resulted in a statistically significant difference in baseline measurements and measurements gathered during exposure to stimuli. Measures of systolic blood pressure (sBP) and diastolic blood pressure (dBP) were found to have a significant change in calming visual stimuli and calming auditory stimuli respectively. SCR was found to have a significant change in baseline and autonomic response to stimuli in both calming auditory and visual stimuli. In addition, it was determined that some, but not all, measures of autonomic response resulted in a significant statistical difference in visual and auditory exposure to stimuli. A significant change in dBP and SCR appeared to demonstrate a more prominent autonomic response to visually presented stimuli and further investigation would determine if this observed trend could be established and reproduced.