Insurance companies’ hired courtroom doctors often cite to mild traumatic brain injury meta-analyses studies to support their claims that an individual plaintiff has fully recovered from the effects of a mild traumatic brain injury. Use of the these meta-analyses by these courtroom doctors have been previously criticized by Ronald Ruff, Ph.D., Erin Bigler, Ph.D., and others.
In the most recent issue of Brain Injury, the official research journal of the International Brain Injury Associations, Grant L. Iverson, Ph.D. demonstrates that the use of mild traumatic brain injury meta-analyses can obscure individual differences. Dr. Iverson writes:
It is important to appreciate that meta-analyses represent an aggregation of effect sizes derived from multiple groups across multiple studies. As such, as illustrated with real and hypothetical data in this paper, group data can obscure small sub-group or individual effects. A sub-group of patients with residual cognitive deficits could exist and yet be obscured by group inferential statistical analyses. Therefore, clinicians should not use the results of meta-analysis to state unequivocally, that “MTBI” cannot cause residual cognitive difficulties in individual patients. It is simply an over-generalization and is invariably inaccurate at some point or other.