Concussion Pathophysiology and Injury Biomechanics

Abstract

Purpose of review: The concussion public health burden has increased alongside our knowledge of the pathophysiology of mild traumatic brain injury (mTBI). The purpose of this review is to summarize our current understanding of mTBI pathophysiology and biomechanics and how these underlying principles correlate with clinical manifestations of mTBI.

Recent findings: Changes in post-mTBI glutamate and GABA concentrations seem to be region-specific and time-dependent. Genetic variability may predict recovery and symptom severity while gender differences appear to be associated with the neuroinflammatory response and neuroplasticity. Ongoing biomechanical research has shown a growing body of evidence in support of an "individual-specific threshold" for mTBI that varies based on individual intrinsic factors. The literature demonstrates a well-characterized timeframe for mTBI pathophysiologic changes in animal models while work in this area continues to grow in humans. Current human research shows that these underlying post-mTBI effects are multifactorial and may correlate with symptomatology and recovery. While wearable sensor technology has advanced biomechanical impact research, a definitive concussion threshold remains elusive.

Keywords: Biomechanical impact; Concussion pathophysiology; Concussion threshold; Linear-rotational acceleration; Mild traumatic brain injury; Neurometabolic cascade.

Conflict of interest statement

Rafael Romeu-Mejia and Joshua T. Goldman each declare no potential conflicts of interest.

Christopher C. Giza reports grants from NINDS, NCAA, US Department of Defense, UCLA Steve Tisch BrainSPORT Program, Easton Clinic for Brain Health, UCLA Brain Injury Research Center, and Avanir (2017–2018). Dr. Giza reports personal fees from Highmark Interactive (2018), Neural Analytics (2015–2016), and Medicolegal cases: 0–2 annually. Dr. Giza also reports book royalties from Blackwell Publishing.

Figures

Fig. 1

Examples of head-impact sensor technologies; a helmet sensor system, b mastoid process neck sensor, c skullcap-based sensor, d embedded mouth guard sensor