Objective. The purpose of this study was to evaluate the relationship between cerebral palsy (CP) diagnoses as measured by the topographic distribution of the tone abnormality with level of function on the Gross Motor Function Classification System (GMFCS) and developmental performance on the Bayley Scales of Infant Development II (BSID-II). It was hypothesized that (1) the greater the number of limbs involved, the higher the GMFCS and the lower the BSID-II Motor Scores and (2) there would be a spectrum of function and skill achievement on the GMFCS and BSID-II Motor Scores for children in each of the CP categories.
Methods. A multicenter, longitudinal cohort study was conducted of 1860 extremely low birth weight (ELBW) infants who were born between August 1, 1995 and February 1, 1998, and evaluated at 18 to 22 months' corrected age. Children were categorized into impairment groups on the basis of the typography of neurologic findings: spastic quadriplegia, triplegia, diplegia, hemiplegia, monoplegia, hypotonic and/or athetotic CP, other abnormal neurologic findings, and normal. The neurologic category then was compared with GMFCS level and BSID-II Motor Scores.
Results. A total of 282 (15.2%) of the 1860 children evaluated had CP. Children with more limbs involved had more abnormal GMFCS levels and lower BSID-II scores, reflecting more severe functional limitations. However, for each CP diagnostic category, there was a spectrum of gross motor functional levels and BSID-II scores. Although more than 1 (26.6%) in 4 of the children with CP had moderate to severe gross motor functional impairment, 1 (27.6%) in 4 had motor functional skills that allowed for ambulation.
Conclusions. Given the range of gross motor skill outcomes for specific types of CP, the GMFCS is a better indicator of gross motor functional impairment than the traditional categorization of CP that specifies the number of limbs with neurologic impairment. The neurodevelopmental assessment of young children is optimized by combining a standard neurologic examination with measures of gross and fine motor function (GMFCS and Bayley Psychomotor Developmental Index). Additional studies to examine longer term functional motor and adaptive-functional developmental skills are required to devise strategies that delineate therapies to optimize functional performance.