The Scope E-Newsletter June 2011 Dr. Terrell Receives Grant to Examine Nature Versus Nurture in Concussion

UTGSM Dr. Thomas Terrell Concussion is momentous topic in athletic fields, and rightfully so. Recent estimates are that concussion occurs in 1.6 to 3.6 million young athletes per year. Congress is even considering a bill, the Protecting Student Athletes from Concussions Act, which would establish standards for student athletes who sustain concussion, so research is critical.

The National Operating Committee on Standards for Athletic Equipment, a leading nongovernmental source for research funding in all sports medicine related to concussion, recently awarded Thomas Terrell, MD, Associate Professor, Family Medicine, a second-year grant of $90,000 to continue his research, "Genetic risk factors for concussion, concussion severity, and neurocognitive recovery in athletes."

Prior to Dr. Terrell's research, concussion risk factors including prior concussion, migraine headache and other conditions had not been studied in relationship to genetic factors. It is intuitive to suspect that environmental factors, such as the magnitude of force associated with head impacts, would directly influence concussion risk. However, studies have shown that athletes' response to impacts over 75 g, the magnitude previously established as the concussion threshold measured in G-force, can vary greatly and some athletes experienced no symptoms of concussion at 100 g or more. Dr. Terrell finds the variability in response by athletes exposed to the same traumatic G-force to be striking, which is why he believes an intrinsic factor, a predisposition to concussion, may account for some of the variability.

The long-term goal of Dr. Terrell's project is to further understand the association between genetic and environmental risk factors related to concussion onset and causes, recurrence and severity of concussion, and concussions with slower neurocognitive recovery. Dr. Terrell hypothesizes that genetic polymorphisms are associated with risk for sustaining a concussion, the severity of the concussion, and the short- and long-term outcome after a concussion.

In addition to answering questions on concussion, the molecular research of Dr. Terrell's study may contribute to new diagnostic approaches for traumatic brain injury (TBI) diseases such as Alzheimer's disease. Several lines of evidence suggest that certain genetic polymorphisms may play a role in TBI, specifically apolipoprotein (APOE) e4, which remains the main genetic risk factor for late onset Alzheimer's disease. APOE is responsible for maintaining neural structural integrity and recovery after neurological injury. Investigators have shown in bench research that a synthetic apolipoprotein-like peptide improved functional recovery after TBI. However, the role of APOE e4 as a risk factor for concussion in athletes is currently unclear.

Dr. Terrell began his research in 2003 and has steadily grown the project through grants. He hopes that by December he will be able to answer whether or not a genetic risk factor exists in determining concussion severity and possible recurrence in athletes.