Purpose/Objective:   To describe the psychometrics and utility of the Neurobehavioral Symptom Inventory (NSI) and provide suggestions for clinical usage and future research. Research Method/Design:   Thirty studies examining aspects of the NSI, published between 1995 and 2020, were reviewed. Results:   The NSI is a 22-item self-report questionnaire of neurobehavioral symptoms. The NSI was first published in 1995 and has since been adopted by the Department of Defense and Department of Veterans affairs for traumatic brain injury (TBI) research and clinical evaluation. Most research on the NSI has been conducted in veteran and military samples with predominantly mild TBI. Cronbach’s alpha ranged from .81 to .96 for the total score and exceeded .80 for most scales. Test–retest values ranged from .78 to .94 for the total score and ranged from .52 to .91 for subscales. Item content overlaps with psychiatric disorders and is expectedly correlated with psychiatric measures and emotional distress. Although consensus about its factor structure is lacking, the 3- and 4-factor solutions have been replicated and have the strongest support. Subsequent researchers have published reliable change indices, embedded validity indices, and normative data using civilian and military samples. Conclusions/Implications:   The NSI has acceptable reliability and some evidence supporting its validity in measuring neurobehavioral symptoms. Although not intended to diagnose TBI, the NSI has value for clinicians and researchers in characterizing the presence and severity of symptom complaints and tracking symptomatic change in persons with TBI.

This review of the Neurobehavioral Symptom Inventory (NSI) is the first to synthesize evidence regarding its three time frame versions, internal consistency and structure, external correlates, embedded validity scales, and sensitivity to change in a concise report. Evidence supports the NSI as a reliable measure with reliable change indices and normative data available to guide clinicians in score interpretation and evaluating intraindividual change. The three- and four-factor structure models have the largest evidence base and may assist traumatic brain injury (TBI) clinicians and researchers with developing and...