Altered neural recruitment despite dual task performance recovery in athletes with repeat concussion

Sports-related concussions (SRCs) pose significant challenges to college-aged athletes, eliciting both immediate symptoms and subacute cognitive and motor function impairment. While most symptoms and impairments resolve within weeks, athletes with repeat SRCs may experience heightened risk for prolonged recovery trajectories, future musculoskeletal injuries, and long-term neurocognitive deficits. This includes impaired dual task performance and altered neurophysiology that could persist across the lifespan and elicit future pathophysiology and neurodegeneration. Thus, it is imperative to improve our understanding of neurophysiology after SRC. This study aimed to investigate the impact of repeat SRCs on dual task performance and associated neural recruitment using functional near-infrared spectroscopy (fNIRS). A total of 37 college-aged athletes (ages 18-24) participated in this cross-sectional observational study. Among these athletes, 20 had a history of two or more SRCs, while 17 had never sustained a SRC and served as controls. Participants completed the Neuroimaging-Compatible Dual Task Screen (NC-DTS) while fNIRS measured neural recruitment in the frontoparietal attention network and the primary motor and sensory cortices. Behavioral analysis revealed that athletes with repeat SRCs exhibited comparable single task and dual task performance to control athletes. Additionally, dual task effects (DTE), which capture performance declines in dual tasks versus single tasks, did not significantly differ between groups. Notably, the cohort of athletes with repeat SRC in this study had a longer time since their last SRC (mean = 1.75 years) than majority of previous SRC studies. Neuroimaging results indicated altered neural recruitment patterns in athletes with multiple repeat SRCs during both single and dual tasks. Specifically, athletes with repeat SRCs demonstrated increased prefrontal cortex (PFC) activation during single motor tasks compared to controls (P < 0.001, d = 0.47). Conversely, during dual tasks, these same athletes exhibited reduced PFC activation (P < 0.001, d = 0.29) and primary motor cortex (M1) activation (P = 0.038, d = 0.16) compared to their single task activation. These findings emphasize the complex relationship between SRC history, dual task performance, and changes in neurophysiology. While athletes with repeat SRCs demonstrate recovery in behavioral dual task performance, persistent alterations in neural recruitment patterns suggest ongoing neurophysiological changes, possibly indicating compensatory neural strategies and inefficient neural resource allocation, even beyond symptom resolution and medical clearance. Understanding the compensatory neural recruitment strategies that support behavioral performance following repeat SRCs can inform return-to-play decisions, future musculoskeletal injury risk, and the long-term impact of SRCs on neurocognitive function.