Non-invasive Nerve Stimulation and Sleep

People often have difficulty sleeping. Reasons are many. But, difficulty falling and staying asleep are common issues. Sleep difficulties are common in disorders such as Post Traumatic Stress Disorder. Current treatments for sleep difficulties are not effective for everyone. Better treatments are needed. In this study, the investigators are testing two nerve stimulation locations that may impact brain function in such a way that sleep is improved. Prior to the cross-over study described here, a dosing study will be completed. Twenty Veterans with PTSD with or without history of mTBI, assessed for inclusion and exclusion per protocol, will be evaluated over three polysomnography nights with at least a one week washout period. Pseudo-randomly distributed across the three nights, each participant will be tested on three of the 10 parameters, creating a total of 60 testing sessions (6 for each parameter setting with each represented twice in each night slot). primary sleep architecture variables (slow wave sleep time, REM sleep time) and autonomic responses will be used as outcomes. The optimal dose will be selected and the study will proceed to the cross-over design phase.