Related Experiment Video
Updated: Jul 19, 2026
Quantified Assessment of Infant's Gross Motor Abilities Using a Multisensor Wearable
Published on: May 17, 2024
Examination of the item structure of the Alberta infant motor scale
Pai-Jun M Liao1, Suzann K Campbell
1Department of Physical Therapy, University of Illinois at Chicago, Chicago, IL, USA. pliao1@uic.edu
Insights
The Alberta Infant Motor Scale (AIMS) effectively screens motor development up to nine months. However, a ceiling effect limits its precision for older infants, suggesting cautious interpretation of results past this age.
Area of Science:
- Developmental Pediatrics
- Psychometrics
- Infant Motor Development
Background:
- The Alberta Infant Motor Scale (AIMS) is a widely used screening tool for assessing motor development in infants from birth to 18 months.
- Understanding the psychometric properties of the AIMS is crucial for accurate identification of developmental delays.
Purpose of the Study:
- To examine the psychometric structure of the AIMS.
- To evaluate the hierarchical arrangement of items within the AIMS.
- To assess the precision of the AIMS in measuring infant ability across different age points.
Main Methods:
- Ninety-seven at-risk infants were recruited from the Chicago metropolitan area.
- Infants were assessed using the AIMS at 3, 6, 9, and 12 months of age.
- Rasch psychometric analysis was employed to analyze item hierarchy and difficulty.
Main Results:
- Rasch analysis confirmed item ordering by difficulty for supine, prone, sitting, and standing positions.
- A significant ceiling effect was identified in the AIMS.
- Gaps in ability levels indicate reduced measurement precision for infants older than approximately nine months.
Conclusions:
- The AIMS demonstrates a ceiling effect, with optimal measurement precision between three and nine months of age.
- The scale has limited items for discriminating abilities in infants beyond the 'controlled lowering through standing' item.
- Clinical interpretations of AIMS scores for infants older than nine months should be made with caution due to decreased measurement precision.
Purpose:
The Alberta Infant Motor Scale (AIMS) is a screening tool for identifying delayed motor development from birth to 18 months of age. The purpose of this study was to examine the psychometric structure of the AIMS, including the hierarchical scale of items and the precision for measuring infant ability at different ages.
Methods:
Ninety-seven infants with varying degrees of risk of developmental disability were recruited from three hospitals or from the community in the Chicago metropolitan area. Infants were tested on the AIMS at three, six, nine, and 12 months of age. The hierarchical structure and the range and distribution of item difficulty on the AIMS were analyzed using Rasch psychometric analysis.
Results:
The Rasch analysis confirmed that items for each of the four testing positions (supine, prone, sitting, and standing) were arranged in increasing order of difficulty, but a ceiling effect was present. Gaps exist at six ability levels, indicating low precision of measurement for differentiating among infants after about nine months of age.
Conclusions:
The AIMS shows a ceiling effect, measures infant ability best from three to nine months of age, and has few items available for discriminating among infants after they pass the controlled lowering through standing item. Clinical impressions should be drawn with caution at ages when the precision of measurement is low.
