Reaffirmed Limitations of Meta-Analytic Methods in the Study of Mild Traumatic Brain Injury: A Response to Rohling et al.

Abstract

In 2009 Pertab, James, and Bigler published a critique of two prior meta-analyses by Binder, Rohling, and Larrabee (1997) and Frencham, Fox, and Maybery (2005) that showed small effect size difference at least 3 months post-injury in individuals who had sustained a mild traumatic brain injury (mTBI). The Binder et al. and Frencham et al. meta-analyses have been widely cited as showing no lasting effect of mTBI. In their critique Pertab et al. (2009) point out many limitations of these two prior meta-analyses, demonstrating that depending on how inclusion/exclusion criteria were defined different meta-analytic findings occur, some supporting the persistence of neuropsychological impairments beyond 3 months. Rohling et al. (2011) have now critiqued Pertab et al. (2009). Herein we respond to the Rolling et al. (2011) critique reaffirming the original findings of Pertab et al. (2009), providing additional details concerning the flaws in prior meta-analytic mTBI studies and the effects on neuropsychological performance.

Keywords:

• Mild traumatic brain injury
• Meta-analysis limitations
• Neuropsychological outcomes

Acknowledgments

Dr. Bigler provides forensic consultation related to traumatic brain injury. No other conflict of interest is present for any other author.

Notes

¹As of this writing, according to the Institute for Scientific Information (ISI; see Thomson Reuters, 2012) and Google Scholar (i.e., http://www/googlescholar.com retrieved May 7, 2012).

²mTBI classification is fraught with problems of nomenclature. For the purposes of this paper the terms mTBI and concussion will be used interchangeably.

³As with Rohling et al. (2011), for the sake of consistency in this paper a negative effect size indicates better performance by the control group than the TBI group.