Abstract
Children with cerebral palsy (CP) often develop reduced passive range of motion with age. The determining factor underlying this process is believed to be progressive development of contracture in skeletal muscle that likely changes the biomechanics of the joints. Consequently, to identify the underlying mechanisms, we modeled the mechanical characteristics of the forearm flexors acting across the wrist joint. We investigated skeletal muscle strength (Grippit®) and passive stiffness and viscosity of the forearm flexors in 15 typically developing (TD) children (10 boys/5 girls, mean age 12 years, range 8–18 yrs) and nine children with CP Nine children (6 boys/3 girls, mean age 11 ± 3 years (yrs), range 7–15 yrs) using the NeuroFlexor® apparatus. The muscle stiffness we estimate and report is the instantaneous mechanical response of the tissue that is independent of reflex activity. Furthermore, we assessed cross-sectional area of the flexor carpi radialis (FCR) muscle using ultrasound. Age and body weight did not differ significantly between the two groups. Children with CP had a significantly weaker (−65%, p < 0.01) grip and had smaller cross-sectional area (−43%, p < 0.01) of the FCR muscle. Passive stiffness of the forearm muscles in children with CP was increased 2-fold (p < 0.05) whereas viscosity did not differ significantly between CP and TD children. FCR cross-sectional area correlated to age (R2 = 0.58, p < 0.01), body weight (R2 = 0.92, p < 0.0001) and grip strength (R2 = 0.82, p < 0.0001) in TD children but only to grip strength (R2 = 0.60, p < 0.05) in children with CP. We conclude that children with CP have weaker, thinner, and stiffer forearm flexors as compared to typically developing children.
Highlights
An insult to the immature, developing brain before the age of two results in a condition clinically referred to as cerebral palsy (CP), characterized by motor impairment (Rosenbaum et al, 2007)
Skeletal muscle size correlated to age (R2 = 0.58, p < 0.01), body weight (R2 = 0.92, p < 0.0001) and strength (R2 = 0.58, p < 0.01) in typically developing (TD) children
The same relationship between skeletal muscle size did not correlate to age and body weight in children with CP, still showing a significant correlation to strength (R2 = 0.60, p < 0.05)
Summary
An insult to the immature, developing brain before the age of two results in a condition clinically referred to as cerebral palsy (CP), characterized by motor impairment (Rosenbaum et al, 2007). Despite that the brain injury is non-progressive, motor function commonly deteriorates over time and a progressive contracture formation, i.e., a decrease in passive range of motion (pROM), is common (Hagglund and Wagner, 2011). Clinical experience suggests that contracture formation is Frontiers in Computational Neuroscience | www.frontiersin.org von Walden et al. Increased Stiffness of Forearm Flexors in CP due to shortening/stiffening of the musculotendinous complex, as the range of motion of the joint often is practically normal when tendons of contracted muscles are cut during surgery. What causes the increased stiffness and shortness of the muscle is not known, but clinically we know that it affects joint biomechanics
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
