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Gross Motor Function Measure (GMFM)

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Purpose
The Gross Motor Function Measure (GMFM) is an observational clinical tool designed to evaluate change in gross motor function in children with cerebral palsy. There are two versions of the GMFM - the original 88-item measure (GMFM-88) and the more recent 66-item GMFM (GMFM-66).

Assesment Type

Objective

Patient Group

Cerebral Palsy | Other

Age Group

Infants (0-2 years) | Children (3-12 years) | Adolescents (13-17 years)

ICF domain

Activity & Participation

Area of assessment

None

Key description

ADMINISTRATION

Each item consists of the observations of the performance of standardised tests.

The GMFM-88 is the original 88-item measure.  The GMFM-66 is a 66-items subsetof the original 88 items.

Item span the spectrum of gross motor activities in five dimensions:

A: Lying and Rolling

B: Sitting

C: Crawling and Kneeling

D: Standing

E: Walking, Running and Jumping

 

Item scoring is the same for the GMFM-88 and the GMFM-66:

0 - does not initiate

1 -  initiates

2 - partially completes

3 - completes

 

It is important to use the specific starting positions and detailed scoring guidelines outlined in the Gross Motor Function Measure (GMFM-66 & GMFM-88) User’s Manual 3nd Edition (2021) for accurate and reliable testing.

Items that a child refuses to attempt despite reason they may be able to perform at least partially or items not administered are scored as ‘not tested’.

GMFM score sheets for all versions can be downloaded from the Canchild website.

 

SCORING

GMFM-88 scores are summed to calcuate raw and percent scores for each of the five GMFM-88 dimensions.  Dimension percent scores are averaged to obtain an overall totla score.  Not tested items in the GMFM-88 are scored as '0'.

Scoring the GMFM-66 requires the use of a computer program called the Gross Motor Ability Estimator (GMAE). Individual item scores are entered and a mathematical algorithm calculates an interval level total score. The total score is an estimate of the child’s gross motor function.  The GMAE can be downloaded from the Canchild website.

Cost

£80.00 (Gross Motor Function Measure (GMFM-66 & GMFM-88) User’s Manual 3rd Edition

Equipment required

The required equipment is available in most physiotherapy facilities e.g. mats, benches, toys. Details are included in the GMFM Manual. Access to stairs with at least five steps is required if testing stair items.

Training required

The GMFM was designed for use by paediatric therapists who are familiar with assessing motor skills in children and children with cerebral palsy. Users should familiarise themselves with the Gross Motor Function Measure (GMFM-66 & GMFM-88) User’s Manual 3nd Edition (2021) and the score sheets prior to assessing children. A GMFM Training Video is available from the CanChild website.

Considerations & references

Use of the GMFM in other populations

  • The GMFM has been validated for use with children with cerebral palsy aged between 5 months to 16 years whose motor skills are delayed compated to those of the same age.
  • The GMFM-88 has also been validated for other populations, such as children with Down Syndrome and acquired brain damage.
  • The GMFM-66 is currently only validated for children with CP.
  • There are no published references of the use of the GMFM in adult populations, however research is currently underway.

Abbreviated versions of the GMFM

  • Two abbreviated versions of the GMFM-66 have bene developed to faciliate the best chocie of test items.
  • The Item Set version uses an algorithm with three decision items to detrmine which one of the four item sets is most appropaite for a child's level of functioning.
  • The Basal and Ceiling version uses guidelies based on Gross Motor Function Classification System levels and age to determine suggested points at which to begin testing.
  • Both versions are reliable and valid, however, the Item Set version is preferable for children with inilateral cerebrla palsy.
Time to administer
  • Administering thr GMFM-88 takes approximately 45 to 60 minutes for someone familiar with the measure.  Time will vary depending on the ability level of the child and the child's level of co-operation and understanding.
  • The GMFM-66 should take less time to administer as there are fewer items and allows for not-tested items.
  • The abbreviated versions, the Item Set and the Basal and Ceiling versions, take approximately 20 to 30 minutes to administer.
Choosing between the GMFM-88 and the GMFM-66
  • The choice of which GMFM version to use depends on the purpose ofthe assessment.
  • The GMFM-88 provides more descriptive information about motor function for very young children or children with  more complex motor disability such as those functioning at GMFCS level V, as it has more items that descibe early motor skills.
  • The choice of which GMFM version to use depends on the purpose of the assessment. 
  • The GMFM-88 should be used if the evaluation of children using ambulatory aids and/or orthoses or shoes is of interest as the GMFM-66 scores are based on barefoot testing.
  • The GMFM-88 also allows testing of one or more specific dimensions.
  • The GMFM-66 takes less time to administer compared to the GMFM-88 and it does not require all items to be assessed to get an accurate esitmate of the child's score.  To document within-child change over time or to compare patterns of change among children, the GMFM-66 provides a more meaningful assessment of change because the items are ordered by level of difficulty. 
References
 

If you spot any errors or wish to suggest any amendments to this summary, please contact paediatricmeasures@apcp.org.uk