RecruitingClinical trialThe Effects of Stellate Ganglion Block Sleep in U.S. Active Duty Service Members and Veterans Receiving Prolonged Exposure Therapy for PTSDParticipants in this study will have already been enrolled in another research study: Combining Stellate Ganglion Block with Prolonged Exposure for PTSD, NCT05889741. The investigators are using a Sleep Profiler, EEG headband to monitor a participants brainwaves while they sleep to see what effects the Stellate Ganglion Block injection has on their sleep. Participants will wear the headband for 3 nights before the injection and then 3 nights after the injection. Participants will also complete self-report questionnaires regarding their sleep prior to the injection and following the injection. Approximately 40 participants will be included in this study. This study is a nested observational study whereby participants in the parent study who elect to participate will have their sleep assessed using the EEG headband device and self-reported sleep measures performed.