From injury to inference: Neuropsychological reasoning across divergent mild traumatic brain injury (mTBI) criteria

Neuropsychologists are frequently asked to evaluate individuals following presumed mild traumatic brain injury (mTBI) and to communicate findings across clinical and forensic settings that rely on divergent diagnostic systems. This article provides an analytic review of major mTBI frameworks (American Congress of Rehabilitation Medicine [ACRM], Department of Veterans Affairs/Department of Defense [VA/DoD], Diagnostic and Statistical Manual of Mental Disorders-5-Text Revision [DSM-5-TR], International Classification of Diseases 11th Revision [ICD-11], and Concussion in Sport Group [CISG]), emphasizing their differing evidentiary thresholds and intended uses. Particular attention is given to retrospective determinations, gaps in acute documentation, and medicolegal constraints. Evidence is reviewed regarding diagnostic uncertainty, emergency department under recognition, construct boundaries between injury and sequelae, and reliance on historical markers such as loss of consciousness, posttraumatic amnesia, and altered mental status. Intimate partner violence-related brain injury and non-fatal strangulation illustrate mechanistic complexity that strains current criteria. Emerging blood-based biomarkers (GFAP, UCH-L1, NfL, S100B) are evaluated as adjunctive tools when imaging is normal. The scope of neuropsychological opinion under Daubert, Joiner, and Kumho is clarified, distinguishing functional assessment from retrospective causal inference. Across systems, apparent disagreements between experts often reflect mismatches between framework demands and available data. Recommendations emphasize explicit declaration of framework use, transparent articulation of inferential limits, and cautious integration of adjunctive methods that are time-sensitive and mechanism-aware.