Patients who meet eligibility criteria and consent to participate in the study will be randomly assigned to one of two arms, either the Concussion Coach group, which will receive an iPod touch® with the Concussion Coach "Explorer" version, or into the no mobile app control group. Study personnel will explain the purpose of the study, complete the informed consent process, obtain the random treatment assignment from a randomization sheet, and introduce the participant to his/her baseline evaluator. The random assignment to intervention will be accomplished in blocks within each site. While small block sizes allow intervention group sizes to be very similar it may make the allocation process predictable. Therefore to reduce selection bias and achieve balance across the intervention arms sequence list of individual assignments by random block sizes will be generated.

Both groups will be assessed in a pre/post intervention design and will be compensated for their time completing study surveys. During the 3 months that they are involved in the study, the intervention group will be sent (via Concussion Coach) reminders to engage with the app on a weekly basis. Their use (e.g., total time spent on each component of the app) will be collected electronically. Both groups will receive care as usual (meaning their regularly scheduled VA appointments and medications). At the completion of the study, both groups will be encouraged to download the App for their own use, with assistance from the study team if needed.

Description of Intervention \& Training The Concussion Coach is designed to provide psychoeducation, self-assessment, and treatment of PCS symptoms following a mild TBI. The PI and three of the co-investigators were co-developers of Concussion Coach. The public-facing Concussion Coach will be available for free download from a public marketplace and available for use with most mobile devices. The application has the advantage of privacy and anonymity, thus addressing the stigma often expressed as a barrier to seeking treatment. A mirror version of the public version, called Concussion Coach "Explorer Version", will be developed within three months and used for this study. Unlike the public version, it will have the capacity to collect usage information, such as length of time spent on each part of the app, self-report ratings of symptoms and distress, and identification of "favorites" among the self-help tools. These data can be uploaded in a de-identified form to a HIPAA compliant server. Other than the ability to collect data, it will be exactly like the "real" Concussion Coach. The Explorer version will be developed by our collaborators, Vertical Product Development, which developed Concussion Coach, PTSD Coach, and PTSD Explorer version. Explorer versions are especially useful as they allow for unobtrusive, highly detailed, real-time data collection without relying on patient self-report. In addition, the Concussion Coach will be an 'opportunistic' exporter of data. It will upload data to the server whenever it has new data and is in a WiFi zone; participants do not have to have a home wireless network. If they never enter a WiFi area, the investigators will collect their data at study termination when the investigators collect the iPod touch®. The investigators will utilize ohmage, an existing open source technology stack, to port the app to the server.