Publications

The autonomic nervous system (ANS) maintains physiological homeostasis in various organ systems via parasympathetic and sympathetic branches. Reliable, sensitive, and quantitative biomarkers of ANS function, first defined in healthy participants, could discriminate among clinically useful changes. This framework combines controlled autonomic testing with feature extraction during physiological responses. Twenty-one individuals were assessed in two morning and two afternoon sessions over two weeks. Each session included five standard clinical tests probing autonomic function: squat test, cold pressor test, diving reflex test, deep breathing, and Valsalva maneuver. Noninvasive sensors captured continuous electrocardiography, blood pressure, breathing, electrodermal activity, and pupil diameter. The battery of autonomic tests can be completed within 30 minutes and all sensors are non-invasively placed.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a noninvasive method of applying current at the cymba conchae of the outer ear to target the auricular branch of the vagus nerve. Recent efforts have shown therapeutic effects of taVNS on clinical populations, but the mechanism and autonomic nervous system (ANS) responses are not well understood. Twenty-one individuals were tested in four sessions over two weeks; taVNS was applied at the left ear while noninvasive sensors captured electrocardiography, blood pressure, breathing, electrodermal activity (EDA), and pupil diameter (PD). Physiological markers derived from these biosignals allowed for assessment of how taVNS affects the autonomic nervous system.