Alberta Infant Motor Scale (AIMS)

Original Editor - Padraig O Beaglaoich

Top Contributors - Padraig O Beaglaoich, Naomi O'Reilly, Robin Tacchetti and Jess Bell  

Objective

The Alberta Infant Motor Scale (AIMS) is a standardized observational examination tool used to assess the maturation of gross motor skills of infants in the first 18 months post-term. The AIMS was developed as a reference guide for normal development of infants based on the age and sex related norms of 2200 infants in Alberta, Canada.

It can be used as a screening tool to detect and track early developmental delays. The tool compares the level of motor development against the expected norms for their age and sex in four categories: prone, supine, sitting and standing.

Intended Population

The AIMS can be used with all infants younger than 18 months to identify delays in motor skill development. It can be used to monitor the change in development over time of infants younger than 18 months who:

• show typical development with no medical concerns
• exhibit suspect motor development delays
• are at higher risk of developmental delay due to adverse genetic, prenatal, perinatal, neonatal, postnatal, or environmental complications.
• have been given a specific diagnosis that presents with immature development of motor skills (e.g., Downs syndrome, bronchopulmonary dysplasia).

The AIMS should NOT be used for infants who use altered movement patterns to compensate for functional limitations (e.g., paralysis, spina bifida, hypotonia, muscle spasticity) as their unique motor development improvements may not be reflected in the AIMS.

Tool Description

The AIMS is a 58-item observational scoring tool. These 58 items are divided into four position-centric subscales:

1. Prone (21 items)
2. Supine (9 items)
3. Sitting (12 items)
4. Standing (16 items)

Equipment Required

• AIMS score sheet and graph
• Examining table or other raised surface for younger infants
• Firm mat or carpet for older infants
• Low bench or chair for some items on the scale
• Toys appropriate for infants younger than 18 months

Set-up

The AIMS can be conducted in the home or in clinic. The assessment for younger infants can be conducted on an examining table or raised surface. For older infants, the assessment should occur on a firm mat or carpeted area of the floor.

Method of Use

The assessor should familiarize themselves with the administration and scoring guidelines of the Alberta Infant Motor Scale prior to conducting the assessment. The assessment takes a maximum of 20-30 minutes to complete. The assessor observes the motor functional patterns of the patient and compares them to the scale sheet.

Scoring

It is advised that the assessor completes the scoring after the assessment has finished. The scoring sheet is comprised of a short description of and visual aid of the movement to be assessed. The movements begin with the most basic presentations of prone lying, supine lying, sitting, and standing and progress to more advanced movement, incrementally.

During the assessment, the evaluator observes the movements of the child and scores each movement component as either “observed” or “not observed”. There is no option to score the patient on ‘emerging’ movement patterns. The patient should not be accredited for items reported by the parent/guardian.

The least advanced and most advanced movements observed in a given position (prone, supine, sitting, standing) create the ‘motor window’ for the patient in that position. All movements within the motor window for each position must be recorded as "observed" or "not observed".

The assessor scores the patient one point for each movement that was “observed” within each motor window. The accumulative score of all four positions provides the 'total score'. The total score is recorded against the age of the patient on a graph of normative data for infant motor function. This graph contains the percentile (5^th, 10^th, 25^th, 50^th, 75^th, 90^th) norms of infant motor function. The assessor determines at which percentile of motor development the patient is for their age based on the graphed normative values and records it on the scoring sheet.

Figure 1: Alberta Infant Motor Scale (AIMS) centile ranks graph.

Evidence

Standardization

Between 1990 and 1992, 2202 infants younger than 18 months who were living in Alberta, Canada, were assessed to determine the normal development of infants at given ages. These data were used in the development of the AIMS.

In 2014, twenty years after the initial normative data was published, developmental norms were reassessed in 650 Albertan infants over a two year period. This was due to concerns of motor development delays resulting from the widespread implementation of the 'back to sleep' campaign and due to the changes in ethnic diversity present in in Alberta in the 20 years since initial norms were established. The researchers of this review reported a correlation coefficient of 0.99 between the two populations, concluding that the validity of the initial research remained unchanged.

Reliability

Interrater Reliability

Table 1: adapted from

	0-3 months	4-7 months	8-11 months	12+ months	Total
different assessors on a single occasion	0.9556	0.9699	0.9822	0.9588	0.9967
different assessors across occasions	-	-	-	-	0.9891
same assessor over time	0.9485	0.9230	0.9775	0.8585	0.9925
different assessor over time	0.8245	0.9267	0.9352	0.8634	0.9891

Validity

Concurrent Validity (Normal Infants) - Correlation Coefficients- Normal Infants

Table 2: adapted from

	0-4 months	4-8 months	8-13 months	Total
AIMS with Peabody	0.90	0.98	0.94	0.99
AIMS with Bayley	0.84	0.93	0.85	0.97
Peabody with Bayley	0.93	0.91	0.92	0.98