PROJECT SUMMARY/ABSTRACT Adult traumatic brachial plexus injuries (BPI) have a devastating impact on patients, affecting multiple domains (physical, social, and emotional) of their lives. Prior studies have focused on neurologic and biologic predictors of severity of injury (such as extent of plexus injury), but little attention has been paid to other predictors of recovery. A better understanding of how other factors (such as emotional trauma, mental health, pain, and social support) influence recovery after BPI will provide new insight into ways to optimize outcomes for BPI patients. The long-term goal of our research program is to develop a national multicenter prospective cohort study of patients with BPI, assessing outcomes at standardized intervals using a patient-reported, disease-specific outcome measure that captures the physical and emotional domains of recovery. The objectives of this application are (1) to determine the outcome measures that best capture the experience of recovering from BPI and (2) to establish a framework of prospective multicenter data collection that can be expanded in the near future. We will use a prospective observational cohort study design, enrolling patients from five centers prior to surgical reconstruction for adult traumatic BPI. We will examine the criterion validity, responsiveness, and appropriateness of the DASH, SF-36, and a BPI-specific, patient-reported outcomes instrument that our group recently developed (“Impact of BPI” questionnaire). After we have completed the expected research, we will have a well-validated outcome measure for the BPI population along with the ability to define which surgical treatments provide meaningful improvement to patients.