Autonomic Nervous System Disease

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.

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