Football is a high impact game enjoyed by adult football players as well as young football players. When young brains develop normally there are no signs of psychological or neurological problems. However, young football players may experience a disruption in brain development after a single football season, according to a new study from UT Southwestern Medical Center in Dallas, Texas.
The human brain is a highly complex organ with many neural connections. New connections are formed constantly while unused connections fall away. This is known as synaptic pruning and is an important part of brain development between early childhood and adulthood. By pruning away synapses that are no longer required, the brain becomes more efficient with ageing. For this study, the researchers wanted to investigate whether exposure to repetitive head impacts affects pruning of the brain in young football players.
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Sixty youth and high school football players with no history of developmental, neurological or psychiatric abnormalities and no history of a concussion prior to or during the football season were outfitted with Head Impact Telemetry System (HITS) helmets. These helmets are lined with accelerometers or sensors that measure the magnitude, location and direction of impacts to the head. The data collected from the helmets was used to calculate the risk of concussion exposure for each player. The players were then split into two groups — high impact (24 players) and low impact (36 players) based on each player’s risk of cumulative head impact exposure as determined by HITS. The researchers performed pre- and post-season resting state functional (fMRI) scans on all players and analysed changes in power within five components of the default mode network (DMN) of the brain. The DMN network is deep within the grey matter area of the brain which includes structures that get activated when a person is awake or engaged in introspection or is processing emotions.
The study found significant increases in power and grey matter volume in the frontal DMN in the high impact group. The researchers also found a significant decrease in grey matter pruning in the frontal DMN, which is involved in higher cognitive functions such as the planning and controlling of social behaviours. Previous studies have shown that disruptions to normal pruning are related to weaker connections between different parts of the brain. Data from the same group of participants was also investigated by researchers at Wake Forest University in Winston-Salem showing that most head impacts occurred during training and that reducing high impact training for low/or no impact training can reduce the overall head-impact exposure of young players.
Playing a season of high impact contact sports is enough to affect normal grey matter pruning and thus impact brain development in high school and youth football players, as demonstrated by this study.
Source: Radiological Society of North America
