A Year in Review: Clarifying the State of Chronic Traumatic Encephalopathy Research in 2016
Introduction: Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative disease associated with repeated mild traumatic brain injury. In the past decade, CTE has raised concern regarding safety in athletics and has been subject to intense media coverage. The medical and lay community continue to debate its impact as it pertains to athletics, military trauma, and domestic abuse. Despite newfound focus in recent years, fundamental knowledge gaps persist in understanding CTE. Purpose: To better understand the state of current CTE research, we performed a systematized review of publications from 2016. The study clarifies the manner in which CTE research has evolved over time, distinguishes the various areas of research as of 2016, and identifies knowledge gaps requiring further investigation. Methods: We completed a PubMed search with MeSH terms Chronic Traumatic Encephalopathy and CTE on publications released after January 1st, 2016. The search places priority on articles considered to have had the most impact in the past year based on their number of times cited and impact factor. The various papers are organized into categories based on their primary focus: Cellular and Molecular Mechanisms, Pathology and Pathophysiology, Antemortem Diagnosis, Suicide, Risk and Protective Factors, Review articles, and Controversy and Challenges in the diagnosis of CTE. Results: After applying inclusion criteria, 136 articles were identified and categorized. Efforts to identify impact articles from the overall search cohort are ongoing as of abstract submission in order to avoid study exclusion. Search results demonstrate the breadth of ongoing research and the areas in which researchers made particularly notable achievements in 2016. Of greatest note, a NINDS/NIBIB consensus panel (McKee et al. 2016) published a series of studies to standardize neuropathological criteria for post-mortem diagnosis of CTE and to distinguish CTE from other neurodegenerative tauopathies. Furthermore, significant research was published in the above categories including the development of biomarkers for antemortem diagnosis of CTE and the impact of cognitive reserve on the progression of symptomatic disease. Discussion: Despite increased awareness of CTE in the medical community, debate continues over the underlying pathogenic mechanism and its status as its own entity rather than as a subset of another neurodegenerative disease. A knowledge gap exists in the ability to make a definitive antemortem diagnosis of CTE and requires further research. Overall, this review accomplishes its primary aims of clarifying the state of current CTE research and identifying areas for future direction.