“…Studies on cognition examine a variety of neurocognitive functions, including: verbal learning, verbal recognition, spatial recognition, visual working memory, visual-motor speed, impulse inhibition, visual attention, and concentration. Using athletes from a variety of sports but primarily soccer, some studies find an effect on cognition ( Downs and Abwender, 2002 ; Ellemberg et al, 2007 ; Killam et al, 2005 ; Matser et al, 1999 , Matser et al, 2001 , Matser et al, 1998 ; McAllister et al, 2012a ; Miyashita et al, 2017 ; Straume-Naesheim et al, 2009 ; Talavage et al, 2014 ; Tsushima et al, 2016 ; Tysvaer and Løchen, 1991 ; Witol and Webbe, 2003 ; Zhang et al, 2013 ), while others find no effect ( Abreau et al, 1990 ; Guskiewicz et al, 2002 ; Janda et al, 2002 ; Kaminski et al, 2008 ; Kemp et al, 2016 ; Miller et al, 2007 ; Putukian et al, 2000 ; Rutherford et al, 2009 ; Salinas et al, 2009 ; Stephens et al, 2010 ; Straume-Naesheim, 2005 ; Vann Jones et al, 2014 ). The subconcussive effect of hits on balance is also inconclusive with some reporting a positive effect ( Haran et al, 2013 ; Miyashita et al, 2017 ), and others reporting no effect ( Broglio et al, 2004 ; Gysland et al, 2012 ; Mangus et al, 2004 ; Schmitt et al, 2004 ).…”