Heading In Soccer Is Associated With Neuronal Damage And Impaired Memory

Heading the ball in soccer has been linked to accelerated brain aging and increased risk of neurodegeneration, though the underpinning mechanisms remain unclear. PURPOSE: To determine the chronic effects heading the ball has on biomarkers of molecular, cerebrovascular and cognitive function. METHODS: Fifteen male amateur soccer players (age: 28 + 7 yrs) with a playing history of 15 + 7 yrs and a self-reported heading frequency of 7 + 3 balls per game were compared at rest to 10 age-, sex- and physical activity-matched controls with no history of concussion. The Sport Concussion Assessment Tool 5 was used to assess symptoms of head injury and cognition. Transcranial Doppler ultrasound was used to measure middle cerebral artery velocity (MCAv). Neurofilament light-chain (NF-L), Tau, ubiquitin c-terminal hydrolase L1 (UCHL1), glial fibrillary acidic protein (GFAP) and S100B were assayed (Quanterix) using blood serum to assess neuronal-axonal, neuronal cell, astrocyte and blood-brain barrier (BBB) damage, respectively. Data were analyzed using independent sample t-tests. RESULTS: No differences in the number/severity of symptoms associated with head injury or MCAv were observed between groups. Players presented with elevated NF-L and UCHL1 compared to controls, which translated into impaired immediate memory recall (all Table 1). CONCLUSION: Chronic exposure to heading in soccer is associated with neuronal-axonal injury, neuronal cell damage and impaired cognition, which appears to be independent of symptoms associated with head injury and cerebral hypoperfusion. Table 1. - Chronic effects. Controls Players P Values Symptoms Total Symptoms (score) 1 + 1 2 + 2 0.280 Symptom severity (score) 1 + 2 2 + 4 0.449 Molecular NF-L (pg.mL) 5.44 + 2.19 8.50 + 2.07† 0.002 UCHL1 (pg.mL) 11.66 + 13.45 27.10 + 23.46† 0.026 S100B (pg.mL) 0.0341 + 0.0480 0.0315 + 0.0106 0.571 Tau (pg.mL) 0.40 + 0.49 0.98 + 0.62 0.072 GFAP (pg.mL) 63.43 + 12.60 76.04 + 24.47 0.105 Cerebrovascular MCAv (cm.s-1) 64 + 10 60 + 10 0.335 Cognition Immediate memory (score) 24 + 4 21 + 5† 0.050 Concentration (score) 4 + 1 5 + 6 0.480 Delayed memory (score) 7 + 2 8 + 2 0.491 Values are mean + SD. NF-L represents Neuronal filament-light; UCHL1, ubiquitin c-terminal L1; GFAP, glial fibrillary acidic protein; MCAv, middle cerebral artery velocity. † = P < 0.050 University of South Wales Strategic Research and Impact Fund Grant