Heterogeneity Is a Hallmark of Traumatic Brain Injury, Not a Limitation: A New Perspective on Study Design in Rehabilitation Research.

Covington, Natalie V.; Duff, Melissa C.

Purpose: In both basic science and intervention research in traumatic brain injury (TBI), heterogeneity in the patient population is frequently cited as a limitation and is often interpreted as a factor reducing certainty in the generalizability of research findings and as a source of conflicting findings across studies. Historically, much of TBI research in rehabilitation and cognition has relied upon case-control studies, with small to modest sample sizes. In this context, heterogeneity is indeed a significant limitation. Here, however, we argue that heterogeneity in patient profiles is a hallmark characteristic of TBI and therefore cannot be avoided or ignored. We argue that this inherent heterogeneity must be acknowledged and accounted for prior to study design. Fortunately, advances in statistical methods and computing power allow researchers to leverage heterogeneity, rather than be constrained by it. Method: In this article, we review sources of heterogeneity that contribute to challenges in TBI research, highlight methodological advances in statistical analysis and in other fields with high degrees of heterogeneity (e.g., psychiatry) that may be fruitfully applied to decomposing heterogeneity in TBI, and offer an example from our research group incorporating this approach. Conclusion: Only by adopting new methodological approaches can we advance the science of rehabilitation following TBI in ways that will impact clinical practice and inform decision making, allowing us to understand and respond to the range of individual differences that are a hallmark in this population.

EXPERIMENTAL design; COGNITION; DECISION making; AUTISM; BRAIN injuries; REHABILITATION research

American Journal of Speech-Language Pathology, 2021, Vol 30, p974

1058-0360

Academic Journal

10.1044/2020_AJSLP-20-00081