Evidence for Acute Electrophysiological and Cognitive Changes Following Routine Soccer Heading

Introduction There is growing concern around the effects of concussion and sub-concussive impacts in sport. Routine game-play in soccer involves intentional and repeated head impacts through ball heading. Although heading is frequently cited as a risk to brain health, little data exist regarding the consequences of this activity. This study aims to assess the immediate outcomes of routine football heading using direct and sensitive measures of brain function. Methods Nineteen amateur football players (5 females; age 22 ± 3 y) headed machine-projected soccer balls at standardized speeds, modelling routine soccer practice. The primary outcome measure of corticomotor inhibition measured using transcranial magnetic stimulation, was assessed prior to heading and repeated immediately, 24 h, 48 h and 2 weeks post-heading. Secondary outcome measures were cortical excitability, postural control, and cognitive function. Results Immediately following heading an increase in corticomotor inhibition was detected; further to these electrophysiological alterations, measurable reduction memory function were also found. These acute changes appear transient, with values normalizing 24 h post-heading. Discussion Sub-concussive head impacts routine in soccer heading are associated with immediate, measurable electrophysiological and cognitive impairments. Although these changes in brain function were transient, these effects may signal direct consequences of routine soccer heading on (long-term) brain health which requires further study.
Highlights • Standard soccer heading results in immediate and measurable alterations in brain function. • Changes in short and long term memory function and corticomotor inhibition are detectable immediately after soccer heading. • These changes in brain function after just a single session of heading appear transient. • These data provide direct evidence of immediate brain functional impairment associated with soccer heading. Questions have been raised over whether soccer heading might have an effect on a player's brain, with particular worry over the proposed link between brain injury and increased risk of dementia. However, until now there have been no studies of the immediate effects of heading in soccer directly on brain function. This study found that just a single session of heading practice resulted in temporary impairment of short and long term memory function and in electrophysiological function of the brain. Whether these effects remain temporary after repeated soccer heading exposure and their long-term consequences on brain health must now be investigated.