**5. Conclusions**

Our findings suggest that it is feasible to use IMUs to measure head and trunk movement and provide metrics that are clinically important. The system is portable, unobtrusive, and easy to use. These features make such systems well suited for use in the clinic to detect and characterize head and trunk movement during routine and standard vestibular rehabilitation. This study provides an initial step towards the implementation of IMUs to provide clinically meaningful information to physical therapists treating patients with imbalance after mTBI.

**Author Contributions:** Conceptualization: P.C.F., D.A.J., L.A.K.; data curation: P.C.F., D.A.J., L.P.; formal analysis: L.P., S.P., M.E.-G.; funding acquisition: P.C.F., L.A.K.; methodology: P.C.F., D.A.J., S.P., M.E.-G.; project administration: L.A.K.; software: S.P., M.E.-G.; writing—original draft, L.P.; writing—review and editing: L.P., P.C.F., D.A.J., S.P., M.E.-G., L.A.K.

**Funding:** This work was supported by the Assistant Secretary of Defense for Health Affairs under Award No. W81XWH-17-1-0424. Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the Department of Defense.

**Acknowledgments:** We would like to acknowledge the help of research assistants Nicholas Kreter, Alexa Beeson, Sharna Clark-Donovan and Brian Rios.

**Conflicts of Interest:** The authors affiliated with APDM have a financial interest in APDM, a company that may have a commercial interest in the results of this research and technology. The potential individual and institutional conflicts of interest have been reviewed and managed by OHSU and APDM.
