Two decades of advances in understanding of mild traumatic brain injury.

The aim of this article is to highlight advances achieved over the past 2 decades in understanding mild traumatic brain injury (MTBI). The first section provides a historical background, which establishes that research during the 1980s was focused on more severe TBI. During the 1990s MTBI received substantially more recognition. The second section explains why the diagnostic frameworks have evolved. The third section examines why 80% to 90% of all MTBI patients have favorable outcomes whereas 10% to 20% do not. This latter subgroup, also known as the Miserable Minority, presents with a plethora of persistent physical, emotional, and cognitive symptoms. A dichotomy has emerged in the literature interpreting these postconcussional symptoms as being psychogenic or neurogenic. This article offers an alternate and more patient-based framework. Instead of the various disciplines focusing on select symptoms, the patient-based approach is aimed at phenomenologically understanding how the MTBI patient's life has changed. The fourth section provides practical steps for treatments. This historical review offers the conclusion that we have focused for too long on diagnostic challenges, without similarly focusing on treatment. It is time that we advance efficacious treatments for the Miserable Minority.