An Assessment of Frontal Lobe Activity and BDNF Levels Following Concussion in Collegiate Athletes: A Near-Infrared Spectroscopy Study

Impacts to the head that are associated with sports related injuries, can result in a mild traumatic brain injury (mTBI), known as a concussion. Previous research has assessed how mTBIs affect the brain, but these assessments are limited in their ability to directly measure the consequences of mTBI. Along with concussion assessments, only a few studies have used neuroimaging techniques to evaluate brain injury. This study utilized a neuroimaging technique that is inexpensive, non-invasive, and portable, to measure brain activity post-concussion. In particular, near-infrared spectroscopy (NIRS) was used to measure prefrontal cortex (PFC) activity during the dot-probe task of affective attentional bias. Brain-derived neurotrophic factor (BDNF) levels are related to frontal lobe activity, recovery from brain injury, attention, and affective processing. Therefore, BDNF levels were collected to assess their relationship to mTBI and PFC activity in the dot-probe task. Behaviorally, reaction times (RT) were overall significantly slower in individuals with mTBI over control. Although, RT did not vary in either group to indicate an attentional bias between trial types. The mTBI group’s deoxygenated hemoglobin (HbR) levels did not deviate greatly from baseline like the control did. The mPFC correlated with less responsive HbR levels with higher serum BDNF levels. For oxygenated hemoglobin (HbO), less deviation from baseline in the right PFC correlated with higher levels of serum BDNF levels. There were overall greater serum BDNF levels in mTBI than the control, but these levels did not react significance. These findings potentially assist in improving and developing more efficient diagnostic assessments