Measuring grip strength in adolescents and adults with cerebral palsy in a clinic setting: Feasibility, reliability, and clinical associations.

Abstract

To determine the feasibility and reliability of measuring grip strength and its association with anthropometrics and diseases among adolescents and adults (≥16 years old) with cerebral palsy (CP). In this cross-sectional study, individuals with CP, classified in Gross Motor Function Classification System (GMFCS)/Manual Ability Classification System (MACS) levels I to V, were recruited to measure grip strength, anthropometrics, and self-reported current/history of disease during a routine clinical visit. Feasibility was determined as the proportion recruited/consented/completed testing. Test-retest reliability of three maximal effort trials per side was assessed. Linear regression determined associations of grip strength with anthropometrics after adjusting for age, sex, and GMFCS. The predictive ability of GMFCS alone, grip strength alone, GMFCS + grip strength, and GMFCS × grip strength for diseases was compared. Of 114 individuals approached, 112 participated and 111 successfully completed all tasks. There was good to excellent reliability of test-retest grip strength between trials for dominant and non-dominant sides for the entire cohort and when stratified by each GMFCS and MACS level (intraclass correlation coefficient range 0.83-0.97). Sex, GMFCS, MACS, body mass, and waist circumference were associated with grip strength (p < 0.05), but not hip circumference, waist:hip ratio, or triceps skinfold thickness. Modeling grip strength with GMFCS had a higher predictive value for relevant diseases than GMFCS alone. Grip strength is a feasible and reliable measurement for CP, and is associated with some demographics and anthropometric measures. Grip strength, in addition to the GMFCS, enhanced prediction of disease outcomes. Measurement of hand grip strength is clinically feasible for adolescents/adults with cerebral palsy. Grip strength has good to excellent test-retest reliability across Gross Motor Function Classification System (GMFCS) and Manual Ability Classification System (MACS) levels. Grip strength is associated with sex, weight, waist circumference, GMFCS, and especially MACS. Grip strength, in addition to GMFCS, shows promise for enhancing disease prediction in this cohort.