SOS1 and attention deficit-hyperactivity disorder: Given that a sizeable proportion of the PTPN11 (20%) and SOS1 (50%) groups were taking stimulant medications and that stimulants have been shown to improve performance on attentional measures in children with ADHD [30], it is possible that differences between NS and TD groups on Auditory Attention and Inhibition scores may be even larger without the effect of stimulants.