Mild head injury as a source of developmental disabilities.

The hospital-reported incidence of mild head injury among children indicates a prevalence of 2% to 3% in high-school-aged adolescents (14 to 18 years). Yet, our survey of 616 high school adolescents suggests that light and mild head injury (not necessarily leading to hospital admission) is almost 10 times this level. Despite the common notion that such injury is generally benign, we found significant relationships in our sample between reported head injury and hyperactivity, stuttering, mixed handedness, and dislike of mathematics.