Early gross motor development: Agreement between the AIMS and the BSID-III.

BACKGROUND

Early gross motor development is a crucial indicator of overall neurodevelopment. In low- and middle-income countries, lack of accessible assessment tools poses challenges for healthcare professionals evaluating infant neurodevelopment.

OBJECTIVES

To determine the agreement between the Alberta Infant Motor Scale (AIMS) and Bayley Scales of Infant Development-III (BSID-III) gross motor domain at 6 months and to evaluate the predictive validity of the AIMS at 6 months for identifying severe gross motor delays at 18 months.

METHOD: This nested subgroup study assessed 112 full-term infants using both AIMS and BSID-III at 6 months and BSID-III at 18 months. Agreement between measures was determined using Bland-Altman plots, while predictive validity was evaluated using receiver operating characteristic (ROC) curves with various cut-off scores.

RESULTS

Bland-Altman analysis showed strong agreement between AIMS and BSID-III in the lower-performance range, with bias only in scores above 33. The traditional 10th percentile AIMS cut-off had low sensitivity (27.3%) but high specificity (98%) for predicting delays at 18 months. A modified 23rd percentile cut-off improved sensitivity to 63.6% while maintaining acceptable specificity (81.6%), with a 95.2% negative predictive value (NPV).

CONCLUSION

The AIMS demonstrates strong agreement with BSID-III when identifying potential developmental delays. The proposed 23rd percentile cut-off offers a more balanced screening threshold for this population.

CLINICAL IMPLICATIONS: The AIMS presents a viable alternative to the BSID-III for initial screening in resource-limited settings. The high NPV at the 23rd percentile cut-off makes it useful for ruling out developmental delays.