Objectives: The question of whether any adverse cognitive or psychosocial outcomes occur after mild head injury in early childhood has evoked considerable controversy. This study examined mild head injury before age 10 and potential differences in late childhood/early adolescence as a function of severity of mild injury and age at injury.
Methods: A fully prospective longitudinal design tracked a large birth cohort of children. Confirmed cases of mild head injury before age 10 were divided on the basis of outpatient medical attention (n=64–84) or inpatient observation (hospital overnight; n=26–28 ) and compared with the non-injured remainder of the cohort (reference group; n=613–807). A range of pre-injury and post-injury child and family characteristics were used to control for any potential confounds. Outcome after injury before and after age 5 was also assessed.
Results: After accounting for several demographic, family, and pre-injury characteristics, the inpatient but not the outpatient group displayed increased hyperactivity/inattention and conduct disorder between ages 10 to 13, as rated by both mothers and teachers. Psychosocial deficits were more prevalent in the inpatient subgroup injured before age 5. No clear effects were evident for various cognitive/academic measures, irrespective of severity of mild injury or age at injury.
Conclusions: Most cases of mild head injury in young children do not produce any adverse effects, but long term problems in psychosocial function are possible in more severe cases, perhaps especially when this event occurs during the preschool years. The view that all mild head injuries in children are benign events requires revision and more objective measures are required to identify cases at risk.