Abstract
STUDY DESIGN: Single-subject case design OBJECTIVE: To evaluate the Autogenic Feedback Training Exercise (AFTE) on autonomic nervous system responses. INTRODUCTION: AFTE combines specific autogenic exercises with biofeedback of multiple physiological responses. Originally developed by the National Aeronautics and Space Administration (NASA), AFTE is used to improve post-flight orthostatic intolerance and motion sickness in astronauts. Individuals with cervical or upper thoracic spinal cord injury (SCI) often present symptoms of autonomic dysfunction similar to astronauts. We hypothesize that AFTE challenges nervous system baroreflex, gastric and vascular responses often impaired after SCI. METHODS: Using a modified AFTE protocol, we trained a hypotensive female participant with cervical motor complete (C5/6-AIS A) SCI, and a male non-injured control participant (NI) and measured blood pressure (BP), heart rate (HR), gastric electrical activity, and microvascular blood volume before, during and after AFTE. The participants were instructed to complete breathing and imagery exercises to help facilitate relaxation. Subsequently, they were instructed to use stressful imagery and breathing exercises during arousal trials. RESULTS: Both participants completed 8 sessions of approximately 45 min each. Microvascular blood volume decreased 23% (SCI) and 54% (NI) from the beginning to the end of the stimulation cycles. The participant with SCI became progressively more normotensive and improved levels of gastric electrical activity, while the NI participant's changes in HR, gastric electrical activity, and BP were negligible. CONCLUSIONS: AFTE may offer a novel non-pharmacologic intervention to minimize symptoms of dysautonomia in people with SCI.