Repetitive Head Impacts: Definitional Challenges, Clinical Implications, and Research Directions

Abstract Purpose of Review Repetitive head impacts (RHI)—repeated head trauma that may or may not result in clinically identified injury—are a growing public health concern due to links with neurodegenerative disease and long-term dysfunction. This review aimed to synthesize current knowledge of RHI and evaluate methodological challenges that limit conclusions about its clinical consequences. Recent Findings Emerging studies highlight associations between RHI and cognitive, emotional, and functional outcomes across vulnerable populations including athletes, military personnel, and survivors of intimate partner violence. However, definitional ambiguity, difficulties in measuring exposure, and population-specific confounds continue to hinder progress. Clinical approaches emphasize individualized assessment and management of symptoms in those with suspected RHI exposure. Summary Evidence supports concern about the long-term risks of RHI, but causal links remain uncertain. Advancing the field requires standardized definitions, longitudinal designs, and multimodal assessments. In the interim, patient-centered care focusing on symptom management and brain health optimization remains best practice.