Clinical Research Directory

Resonance Breathing and Postural Resonance: Acute Modulation of Autonomic and Hemodynamic Responses Via Arterial Baroreflex Mechanisms

This randomized crossover study compared the acute autonomic and hemodynamic responses to three experimental conditions: control, resonance breathing (RB), and postural resonance (PR), in healthy young adults. Each participant completed all three sessions in randomized order, separated by a 5-day washout period. Each session included a 15-minute baseline and a 15-minute assigned condition, followed by a post-condition stress protocol consisting of a 2-minute mental arithmetic task (MAT), 5 minutes of seated rest, a 2-minute cold pressor test (CPT), and a final 5-minute recovery period. Skin sympathetic nerve activity (SKNA) and heart rate variability (HRV) were recorded continuously throughout each session, including the stress tasks and recovery periods. Blood pressure (BP) was measured intermittently at the protocol-specified time points, and pulse wave velocity (PWV) was measured at the time points specified in the study protocol.

Randomized Controlled Trial of Treatment to Optimize Heart Rate Variability for Persistent Post-Concussion Symptoms

Many combat veterans (c-Vs), service members (SMs) and civilians with mild traumatic brain injury (mTBI, also termed concussion) suffer from persistent post-concussion symptoms (PPCS) that degrade physical and cognitive well-being and have been linked with early neurodegeneration. PPCS include somatosensory (e.g., headache, disturbed vision), vestibular (e.g., dizzy, clumsy), cognitive (e.g., executive function, memory) and affective symptoms (e.g., sleep disturbance, irritability, depression). A key pathological process that provokes and perpetuates PPCS is autonomic nervous system (ANS) dysfunction such as unremitting sympathetic nervous system activation that also exacerbates other pathology such as inflammation. ANS activity can be readily quantified by measuring heart rate variability (HRV), or the variation in heart rate over time, which serves as a valid index of both physiological and psychological health

Auricular Vagal Nerve Stimulation for Hypermobile Ehlers-Danlos Syndrome

Hypermobile Ehlers-Danlos Syndrome (hEDS) is a connective tissue disorder characterized by hyperextensible skin, joint hypermobility and additional connective tissue manifestations. For unclear reasons, hEDS is associated with many gastrointestinal (GI) and autonomic nervous system (ANS) complaints such as postural orthostatic tachycardia syndrome (POTS). This study will address the clinical relationship between hEDS/Hypermobile Spectrum Disorders and autonomic regulation and see if there is a benefit of two forms of non-invasive vagal nerve stimulation therapies to reduce GI symptoms in hEDS and POTS. The study will also investigate plausible effects of these nerve stimulation therapies on gastric function and autonomic signaling.