Repetitive linear head trauma can cause cummulative subclinical effects on visual and vestibular (balance) function
Linear repetitive impact without concussion symptoms have been shown to have some impact on visual memory and vestibular (balance) function. Interestingly, although these researchers didn't find clinical neurolgical deficits, others, using MRI imaging, have reported anomalies. Speculation remains, that cortical cognitive reserve means that these deficits are not immediately apparent, Judicious use of ball heading is recommended and potentially should be completely avoided in the young. (Caccesse et al 2019. MedScSpEx, 51, 7, 1355-1361). https://www.back-in-business-physiotherapy.com/we-treat/concussion.html