It is well understood that traumatic brain injury is a continuum with mild at one extreme and severe at the other. What constitutes the mildest form of traumatic brain injury was the subject of much disagreement, ultimately leading to the American Congress of Rehabilitation to develop a definition of mild traumatic brain injury in 1993. This has led multiple researchers to advance various similar, but at times dissimilar, definitions of mild traumatic brain injury. See “In Search of a Unified Definition for Mild Traumatic Brain Injury,” Ruff RM and Jurica P. Brain Injury, 1999, Vol. 13 No. 12:943-952; International Classification of Diseases, 9th revision, clinical modification (ICD-9-CM) codes proposed by the Centers for Disease Control and Prevention (CDC) in a 2003 report to Congress and the VA/DOD “Management of Concussion/Mild Traumatic Brain Injury (2009). The various definitions have led to debate over the diagnostic criteria for mild traumatic brain injury. See “Mild Traumatic Brain Injury: Scope of the Problem,” Malec JF. in the Evaluation and Treatment of Mild Traumatic Brain Injury (ed. Varney NR and Roberts RJ). The question to be posed is, is it now time that we stop using the terms, mild, moderate, and severe as qualifiers in describing traumatic brain injury?
This question came to mind when I attended a recent brain injury claims seminar in Philadelphia last week. During a panel discussion on neuro imaging, one of the panelist, a defense attorney, attempted to make the case that neuro imaging in the context of mild traumatic brain injury litigation, failed to meet the Daubert standard, although she rightfully acknowledged that she could find no published case law to support her argument. However, in attempting to make her case, she noted that researchers could not even agree on a definition of mild traumatic brain injury, thus calling into question the ability of neuro imaging experts to conclude that neuro imaging is scientifically valid to detect mild traumatic brain injury. The following day, I participated in a workshop on the identification and handling of traumatic brain injury cases. During my presentation I spoke about the definition of mild traumatic brain injury developed by the American Congress of Rehabilitation Medicine (Kay 1993). At that time, I made the statement that I liked this definition over the definition more recently developed by Menon. See “Position Statement: Definition of Traumatic Brain Injury,” Menon DK, Schwab K, Wright DW, and Maas AI. Arch Phys Med Rehabil Vol 91, 1637-1638 (2010). I indicated that my preference was based on the ACRM list of symptoms broken down by the categories of physical, cognitive, and behavioral, as this definition serves as a check list in which to demonstrate to a jury that a particular individual has sustained a traumatic brain injury.
Over the weekend, I had an opportunity to reread “Limitations of Mild Traumatic Brain Injury Meta-Analyses,” Pertab JL, James KM, Bigler ED, Brain Injury, 23:6, 498-508 (2009), and “Reaffirmed Limitations of Med-Analytic Methods in the Study of Mild Traumatic Brain Injury: A Response to Rohling, et al., Bigler, ED, Farrer, TJ, Pertab, JL, James K, Petrie JA, and Hedges DW. Clinical Neuropsychologist (2013). In Bigler (2013) the authors state, “There is absolutely no consensus of cross studies as to how MTBI was defined the most fundamental of issues. Diagnostic heterogeneity should be a red flag for any meta-analysis”.
This whole attempt to develop a diagnostic criterion for mild traumatic brain injury seems to result in greater confusion rather than clarity. When did mild traumatic brain injury become a separate and distinct injury from moderate-severe traumatic brain injury?
I have now come to the position that we should just use the term traumatic brain injury, recognizing that in any individual case, one’s symptoms can fall anywhere on the mild to severe continuum. For this reason, I think we should use the Menon definition of traumatic brain injury, and not try to define places along the TBI continuum. This is highlighted by the recent American Academy of Neurology updated sports concussion guidelines in which the AAN recommended “concussion and return to play be assessed in each athlete individually. There is no set timeline for safe return to play.” Thus, this is an important recognition that traumatic brain injury is and individualized injury and that each individual responds and heals differently.