GMFM in infancy: age-specific limitations and adaptations.

Purpose: To evaluate longitudinal applicability of the gross motor function measure (GMFM) in infants younger than 2 years.
Methods: Twelve infants at very high risk for cerebral palsy were enrolled between 1 and 9 months corrected age. The children were assessed 4 times during 1 year with the GMFM-66, GMFM-88, and other neuromotor tests.
Results: Longitudinal use of the GMFM in infancy was hampered by age and function-specific limitations. The GMFM-66 differentiated less at lower-ability levels than at higher-ability levels. The GMFM-88 demonstrated flattening of the developmental curve when infants had developed more motor abilities. We formulated adaptations for the longitudinal use of GMFM in infancy.
Conclusions: To facilitate use of the GMFM in infancy, an adapted version may be an option. Further research is required to assess reliability and validity, and in particular, the sensitivity to change of the suggested adaptations.