Prediction of gross motor development and independent walking in infants born very preterm using the Test of Infant Motor Performance and the Alberta Infant Motor Scale.

BACKGROUND

One objective of a neonatal follow-up program is to examine and predict gross motor outcome of infants born preterm.

AIMS: To assess the concurrent validity of the Test of Infant Motor Performance (TIMP) and the Alberta Infant Motor Scale (AIMS), the ability to predict gross motor outcome around 15 months corrected age (CA), and to explore factors associated with the age of independent walking.

METHODS

95 infants, born at a gestational age <30 weeks, were assessed around 3, 6 and 15 months CA. At 3 months CA, correlations of raw-scores, Z-scores, and diagnostic agreement between TIMP and AIMS were determined. AIMS-score at 15 months CA and parental-reported walking age were outcome measures for regression analyses.

RESULTS

The correlation between TIMP and AIMS raw-scores was 0.82, and between Z-scores 0.71. A cut-off Z-score of -1.0 on the TIMP had 92% diagnostic agreement (κ = 0.67) with an AIMS-score < P10. Neither TIMP- nor AIMS-scores at 3 months CA were associated with the gross motor outcome at 15 months CA. The AIMS-scores at 6 months CA predicted the AIMS-scores at 15 months CA with an explained variance of 19%. Median walking age was 15.7 months CA, with which only the hazard ratio of the AIMS at 6 months CA and ethnicity were significantly associated.

CONCLUSIONS

Prediction of gross motor development at 15 months CA and independent walking was not possible prior to 6 months CA using the AIMS, with restricted predictive value. Cultural and infant factors seem to influence the onset of independent walking.