Numerous studies in high-risk populations established that variations in infant neuromotor development predict poor cognitive function. It is unclear whether this association is found in the general population. Moreover, previous population-based studies mostly focused on motor milestone achievement.
This study was embedded in the Generation R Study, a population-based cohort in Rotterdam, the Netherlands. Neuromotor development was assessed with an adapted version of Touwen's Neurodevelopmental Examination when infants (1205 males, 1278 females) were on average 12 weeks old (standard deviation 1, range, 9–15 weeks). To measure language function at age 1.5 years, the MacArthur Short Form Vocabulary Checklist was used. At 2.5 years, mothers completed the Language Development Survey and the Parent Report of Children's Abilities measuring language and nonverbal cognitive functioning, respectively.
After adjustment for confounders, less optimal neuromotor development, that is, more low tone symptoms, was associated with a delay in receptive language at 1.5 years (odds ratio [OR], 1.18; 95% confidence interval [CI], 1.05–1.34) and in expressive language at multiple time points (OR, 1.11; 95% CI, 1.02–1.21). Higher scores on overall neuromotor development, indicating a less optimal neuromotor development, was associated with an increased risk of a delay in nonverbal cognitive function at 2.5 years (OR, 1.19; 95% CI, 1.05–1.35).
The results of this study suggest that infants with more low tone symptoms, indicating minor deviances from normal neuromotor development, are somewhat more vulnerable to language delays than those infants who do not have these symptoms.