Head Acceleration In Para Swimming And Its Consequences On Behavioral And Brain Functions

PURPOSE: Para swimmers with dysmelia face the particular situation that due to the malformation of their limbs they must use their head to finish each competition by a hit to the wall. Repetitive head impacts with high acceleration may result in impaired behavioral and brain functions. We therefore investigated motor, cognitive, and neuronal functions before and after repeated head impacts of a para swimmer with dysmelia. METHODS: We investigated a para swimmer with dysmelia at two time points (/intervention): T1: swimming with repeated (4) head collision against the wall; T2: swimming without head collisions. Head acceleration was recorded at T1 and T2. Before (pre) and immediately after the intervention (post) we assessed post-concussion symptoms (PCS), working memory (WM) functions, nonverbal hand movement behavior, and brain functions (by applying functional Near InfraRed Spectroscopy (fNIRS) for functional brain activation as well as brain connectivity). RESULTS: The average peak head impact was 13.6 g at T1 (versus 3.0 g at T2). Mean impact force at T1 constituted 6689.9 Newton. Post-concussion symptoms increased from zero (pre) to 54 (post) at T1 (T2: pre: 0; post: 0). WM scores decreased from 92% to 71% at T1 (T2: pre: 77; post: 85). The frequency of nonverbal hand movements decreased at T1 with a simultaneous increase of their duration (but not at T2). Functional brain oxygenation during the WM task as well as brain connectivity during rest reduced from pre to post at T1 (but not at T2). CONCLUSIONS: The present data showed reduced cognitive, motoric, and neuronal functions after repetitive head accelerations in para swimming with dysmelia. This study reveals that para swimmers with dysmelia may be affected by an increased risk of impaired behavioral and brain functions similar to the consequences of repeated sport-related concussions. This research was supported by the Federal Institute for Sports Science (ZMI4-070401/21-23).