Chapter 32.Overview of Mild Brain Injury

Interest in the milder degrees of traumatic brain injury (TBI) severity has grown dramatically since the early 2000s, driven by a number of factors including the conflicts in Iraq and Afghanistan and concerns about potential long-term effects of concussion and repetitive head impacts associated with contact sports. A Medline search for literature on mild brain injury suggests that more than 60% of the papers written on this topic (some 7,000 articles) have been published since the second edition of this book appeared in 2011. In recognition of this phenomenon, this edition contains an expanded number of chapters addressing various aspects of mild TBI (mTBI). Although this explosion of interest and knowledge is welcome, a consequence is a noticeable drift toward increasing subspecialization of interest and knowledge along such fault lines as injury context (civilian trauma vs. military vs. sport) and age of injury (adults vs. children), associated with a tendency for clinicians and investigators within these interest groups to develop different professional organizations, varying outcome measures, and classification schemes. With these developments, clinicians and investigators may at times lose track of the larger context in which severity of brain injury exists along a broad continuum (see Chapter 3, “Pathophysiology”), and of the fact that “mild brain injury” is not a separate and distinct disease process from more severe injuries, but rather is best understood in the broader context of the entire spectrum of injury severity.