Publications by authors named "Srirakshaa Sundararaj"

Stress is a major determinant of health and wellbeing. Conventional stress management approaches do not account for the daily-living acute changes in stress that affect quality of life. The combination of physiological monitoring and non-invasive Peripheral Nerve Stimulation (PNS) represents a promising technological approach to quantify stress-induced physiological manifestations and reduce stress during everyday life.

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Research has shown that transcutaneous cervical vagus nerve stimulation (tcVNS) yields downstream changes in peripheral physiology in individuals afflicted with posttraumatic stress disorder (PTSD). While the cardiovascular effects of tcVNS have been studied broadly in prior work, the specific effects of tcVNS on the reciprocal of the pulse transit time (1/PTT) remain unknown. By quantifying detectable effects, tcVNS can be further evaluated as a counterbalance to sympathetic hyperactivity during distress - specifically, we hypothesized that tcVNS would inhibit 1/PTT responses to traumatic stress.

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Objective: Variations in respiration patterns are a characteristic response to distress due to underlying neurorespiratory couplings. Yet, no work to date has quantified respiration pattern variability (RPV) in the context of traumatic stress and studied its functional neural correlates - this analysis aims to address this gap.

Methods: Fifty human subjects with prior traumatic experiences (24 with posttraumatic stress disorder (PTSD)) completed a ∼3-hr protocol involving personalized traumatic scripts and active/sham (double-blind) transcutaneous cervical vagus nerve stimulation (tcVNS).

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Transcutaneous electrical stimulation of the vagus nerve is believed to deliver afferent signaling to the brain that, in turn, yields downstream changes in peripheral physiology, including cardiovascular and respiratory parameters. While the effects of transcutaneous cervical vagus nerve stimulation (tcVNS) on these parameters have been studied broadly, little is known regarding the specific effects of tcVNS on exhalation time and the spontaneous respiration cycle. By understanding such effects, tcVNS could be used to counterbalance sympathetic hyperactivity following distress by enhancing vagal tone through parasympathetically favored modulation of inspiration and expiration - specifically, lengthened expiration relative to inspiration.

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