Alberta Infant Motor Scale (AIMS)

The Alberta Infant Motor Scale (AIMS) is a standardized observational tool designed to assess gross motor development in infants from birth (40 weeks gestational age) to 18 months post-term. Developed in Alberta, Canada, based on a normative sample of 2,200 infants, AIMS is now widely used both as a screening tool for early motor delays and as a method to monitor developmental progress over time.

Purpose and Application

The primary purpose of AIMS is to identify and track gross motor development in infants, allowing healthcare professionals to evaluate a child’s performance against age-appropriate norms. It is particularly valuable in detecting delayed motor milestones early, enabling timely intervention.

AIMS is frequently used in:

• Primary care and pediatric clinics

• Specialist services for children at risk of developmental disorders

• Follow-up programs for premature infants and those with genetic or neurological conditions

Target Population

AIMS can be used for all infants under 18 months, including:

• Healthy infants with expected development

• Infants with suspected motor delays

• Infants at increased risk due to prenatal, perinatal, or postnatal complications

• Children with known diagnoses such as Down syndrome or bronchopulmonary dysplasia

⚠️ AIMS is not recommended for infants who rely on alternative movement patterns due to severe neurological impairments (e.g., paralysis, spina bifida, pronounced hypotonia, or spasticity), as it may underestimate their abilities.

Structure of the AIMS

AIMS consists of 58 items across four postural categories:

• Prone (tummy lying): 21 items

• Supine (back lying): 9 items

• Sitting: 12 items

• Standing: 16 items

Each item represents a specific movement or posture, arranged from simple to complex (e.g., “lifting the head in prone” to “sitting independently”). This allows clinicians to clearly track progression.

Equipment Needed

Minimal equipment is required:

• AIMS manual and score sheet with normative chart

• Flat surface or examination table (depending on infant’s age)

• Small bench or chair for selected items

• Age-appropriate toys to stimulate movement

Test Setup and Administration

• Infants are assessed either on a firm mat on the floor (older infants) or on an examination table (younger infants).

• The child should be allowed to move freely, without being forced into positions.

• Observations must be made directly by the examiner – parental reports of abilities are not scored.

• Typical administration time: 20–30 minutes.

Scoring and Interpretation

Motor Window

For each posture category, the examiner identifies the “motor window” – the range between the least and most advanced observed skills.

• Items within this window are scored as observed (1) or not observed (0).

• No partial scoring is permitted.

Total Score

• The sum of all observed items provides a raw score.

• The score is plotted against the infant’s corrected age on the normative percentile chart (5th, 10th, 25th, 50th, 75th, 90th percentiles).

• This shows whether the infant is developing below, at, or above average for age.

Standardization and Validity

• Developed from a normative sample of 2,200 infants in Alberta, Canada (1990–1992).

• Percentile norms were calculated month by month.

• High inter-rater and test-retest reliability.

• Strong agreement with established developmental tools like the Bayley Scales of Infant Development and Peabody Developmental Motor Scales.

• Re-evaluated in 2014 with 650 additional infants, confirming its validity and reliability.

International Use

AIMS has been validated and adapted in multiple countries, including:

• Netherlands

• Brazil

• Serbia

• Korea

• Greece

• Poland

• Spain

• Thailand

• Taiwan

This allows for culture-specific norms where developmental patterns may differ.

Clinical Benefits

• Quick and easy to administer (20–30 minutes)

• Requires minimal equipment

• Provides clear percentile-based results for developmental monitoring

• Useful for:

  • Early detection of motor delays

  • Monitoring progress during physiotherapy or intervention programs

  • Guiding treatment planning

Limitations

• Does not explain why motor delay is present – only identifies whether it exists.

• May underestimate abilities in children with compensatory movement strategies.

• Should always be used alongside clinical assessment and other developmental tools.

Summary

The Alberta Infant Motor Scale (AIMS) is a validated, reliable, and widely used tool for assessing gross motor development in infants up to 18 months. It is simple, cost-effective, and clinically valuable for detecting motor delays, monitoring progress, and guiding interventions. While AIMS does not diagnose underlying causes, it remains an essential part of early developmental screening and pediatric physiotherapy.

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