Toddler motor performance and intelligence at school age in preterm born children: A longitudinal cohort study

Background: Current knowledge regarding differences in verbal intelligence scores (VIQ) and performance intelligence scores (PIQ) in preterm born children is limited. As early motor performance may be essential for developing later visual-perceptual and visual-motor skills, early motor performance may be associated with PIQ. Aims: To evaluate whether in preterm born children motor performance at two years was associated with PIQ at eight years. Methods: Single-centre cohort study including 88 children born <30 weeks' gestation between 2007 and 2011, who completed the Bayley Scales of Infant and Toddler Development-III (BSID-III) at two years and the Wechsler Intelligence Scale for Children-III-NL (WISC-III-NL) at eight years. Outcome measurements (mean (SD)) were gross and fine motor performance based on the BSID-III, and PIQ and VIQ based on the WISC-III-NL. Linear regression analysis was performed to evaluate the association between motor performance at two years and PIQ at eight years. Results: At two years, mean BSID-III gross motor scaled score was 9.0 (SD 3.0) and fine motor score was 11.5 (SD 2.3). At eight years, mean PIQ was 94.9 (SD 13.5) and mean VIQ 101.8 (SD 13.7). A one-point increase in fine motor scaled score was associated with 1.7 points (95% CI 0.5-2.8) increase in PIQ. Gross motor scaled score was not associated with PIQ. Conclusions: Fine motor performance in toddlerhood was related to PIQ at school age, with lower scores indicating a lower PIQ. Early assessment of fine motor performance may be beneficial in identifying children at risk for lower performance intelligence.