Correlates of decline in gross motor capacity in adolescents with cerebral palsy in Gross Motor Function Classification System levels III to V: an exploratory study

AIM: To explore associations between clinical variables and decline in motor capacity in adolescents with cerebral palsy (CP). METHOD: Participants included 76 males and 59 females, whose mean age at the beginning of the study was 14 years 6 months (SD 2.4, range 11.6-17.9); 51 at Gross Motor Function Classification System (GMFCS) level III, 47 at level IV, and 37 at level V. Ninety-six participants had tetraplegia, 32 had diplegia, and one had hemiplegia. Types of motor disorder were spastic n=98; mixed, n=11; dystonic, n=9; hypotonic, n=7; and ataxic n=3 (seven participants were not classified). Reliable raters collected data annually for 4 years on anthropometric characteristics, the Spinal Alignment and Range of Motion Measure, as well as the Gross Motor Function Measure, 66 items (GMFM-66); participants or their parents reported on health status (using the Health Utilities Questionnaire), pain, and exercise participation (using measures developed for this study). The predicted drop in GMFM-66 scores after childhood was calculated using data on the same children from an earlier study. Correlations were calculated between the drop in GMFM-66 scores and the average and change scores of the clinical variables (the alpha level for statistical significance of this exploratory study was 0.10). RESULTS: The drop in GMFM-66 score was significantly correlated with limitations in range of motion (r=0.42) and spinal alignment (r=0.28), and pain (r=0.16). Increases in triceps skinfold (r=-0.19), mid-arm circumference (r=-0.23), and the ratio of mid-arm circumference to knee height (r=-0.23) were associated with less decline. INTERPRETATION: Preventing range-of-motion limitations and pain experiences and optimizing nutrition might contribute to less decline in the gross motor capacity of adolescents with CP. Further investigation is required to clarify the role other factors that contribute to maintained function over time.