LAUSR

With this prospective population-based study, we showed that infant neuromotor development, including muscle tone and senses, predicted internalizing problems but not externalizing problems through age 10 years. BACKGROUND: Research of adults and school-aged children suggest a neurodevelopmental basis for psychiatric disorders. We examined whether infant neuromotor development predicted internalizing and externalizing problems in young children. METHODS: In Generation R, a population-based cohort in the Netherlands (2002–2006), trained research assistants evaluated the neuromotor development of 4006 infants aged 2 to 5 months by using an adapted version of Touwen’s Neurodevelopmental Examination (tone, responses, and senses and other observations). We defined nonoptimal neuromotor development as scores in the highest tertile. Mothers and fathers rated their children’s behavior at ages 1.5, 3, 6, and 10 years with the Child Behavior Checklist (n = 3474, response: 86.7%). The associations were tested with generalized linear mixed models. RESULTS: Overall, neuromotor development predicted internalizing scores, but no association was observed with externalizing scores. Nonoptimal muscle tone was associated with higher internalizing scores (mothers’ report: β = .07; 95% confidence interval [CI]: 0.01 to 0.13; fathers’ report: β = .09, 95% CI: 0.00 to 0.16). In particular, nonoptimal low muscle tone was associated with higher internalizing scores (mothers’ report: β = .11; 95% CI: 0.05 to 0.18; fathers’ report: β = .13; 95% CI: 0.04 to 0.22). We also observed an association between senses and other observations with internalizing scores. There was no relationship between high muscle tone or reflexes and internalizing scores. CONCLUSIONS: Common emotional problems in childhood have a neurodevelopmental basis in infancy. Neuromotor assessment in infancy may help identify vulnerability to early internalizing symptoms and offer the opportunity for targeted interventions.