Investigating history of concussion and data from head impact telemetry (xPatch) in relation to neuropsychological outcomes in a sample of adult rugby players in Cape Town
While Rugby Union has worldwide popularity, with over 5 million registered and nonregistered players participating every year, the game lends itself to a high incidence of concussion among players. Rugby players, more so than that recorded for any other contact sport, including American Football, are also more frequently exposed to head collisions not resulting in concussion (i.e., subconcussive head injuries). Despite some evidence for a potential association between such injuries and acute neurological and neuropsychological difficulties, which may at times persist among some players, overt symptoms still guide the initial on-field response for further concussion management to be initiated. The aim of this study was threefold: 1) to investigate the relationship between rugby players' history of concussion and neuropsychological outcomes, 2) to explore the use of a head impact telemetry (HIT) device in describing high-impact head collisions (and potentially subconcussive injuries), and 3) to explore the relationship between that HIT data and neuropsychological outcomes. Study 1 investigated differences between non-contact sport participants (n = 23) and rugby players with (Rugby Concussed; n = 31), and without a history of concussion (Rugby Not Concussed; n = 26) in a baseline cognitive assessment. Results showed that at the beginning of the rugby season there were no differences in cognitive abilities at a group level; a more severe concussion history was largely not associated with a poorer performance on these cognitive outcomes. Study 2 was a pilot study utilising the xPatch to objectively capture a rugby player's exposure to head impacts in an amateur rugby team (UCT IRL team; n = 8). Although the majority of impacts captured were of a 'mild' severity, there were many acceleration forces, particularly rotational accelerations, recorded above an injury threshold potentially implicated with concussion. Following from this, Study 3 used a prospective and repeated-measures design with the same UCT IRL team, to evaluate a means for investigating a player's neuropsychological vulnerability to high-impact subconcussive head injuries. Using correlational analyses, the Reliable Change Index (RCI) and head collision data from Study 2, there was a lack of evidence to indicate that player's increased exposure to repeated high-impact head collisions results in a generally poorer neuropsychological performance. However, a number of test practice effects are noted. Combined, these findings suggest that (a) identifying possible enduring neuropsychological difficulties retrospectively is limited, and issues such as test-practice effects and test sensitivity should be considered in future, preferably prospective studies, (b) rugby players are vulnerable to sustaining multiple high-impact subconcussive head injuries and the data suggests utility in including HIT like the xPatch, and (c) that implementing a multi-faceted protocol for monitoring rugby players' that negates a reliance on concussion diagnosis is necessary to better understanding individual recovery trajectories.
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