Lack of proprioceptive feedback is one cause for the high upper-limb prosthesis abandonment rate. The lack of environmental interaction normalcy from unreliable proprioception creates dissatisfaction among prosthesis users. The purpose of this experiment is to investigate the effects of square breathing on learning to navigate without reliable proprioception. Square breathing is thought to influence the vagus nerve which is linked to increased learning rates. In this experiment, participants were instructed to reach toward targets in a semi-immersive virtual reality environment. Directional error, peak velocity, and peak acceleration of the reaching hand were investigated before and after participants underwent square breathing training. As the results of<br/>this experiment are inconclusive, further investigation needs to be done with larger sample sizes and examining unperturbed data to fully understand the effects of square breathing on learning new motor strategies in unreliable proprioceptive conditions.

Neuromodulation is an emerging field of research that has a proven therapeutic benefit on a number of neurological disorders, including epilepsy and stroke. It is characterized by using exogenous stimulation to modify neural activity. Prior studies have shown the positive effect of non-invasive trigeminal nerve stimulation (TNS) on motor learning. However, few studies have explored the effect of this specific neuromodulatory method on the underlying physiological processes, including heart rate variability (HRV), facial skin temperatures, skin conductance level, and respiratory rate. Here we present preliminary results of the effects of 3kHz supraorbital TNS on HRV using non-linear (Poincaré plot descriptors) and time-domain (SDNN) measures of analysis. Twenty-one (21) healthy adult subjects were randomly assigned to 2 groups: 3kHz Active stimulation (n=11) and Sham (n=10). Participants’ physiological markers were monitored continuously across three blocks: one ten-minute baseline block, one twenty-minute treatment block, and one ten-minute recovery block. TNS targeting the ophthalmic branches of the trigeminal nerve was delivered during the treatment block for twenty minutes in 30 sec. ON/OFF cycles. The active stimulation group exhibited larger values of all Poincaré descriptors and SDNN during blocks two and three, signifying increased HRV and autonomic nervous system activity.