Relationship between Lower Limb Muscle Structure and Function in Cerebral Palsy

[Purpose] The purpose of the study was to provide information for intervention by comparing lower limb muscle thickness, gross motor function and functional level of activity daily living between cerebral palsy (CP) and mental retardation (MR). [Subjects] Sixty subjects participated: 38 CP and 9 MR subjects and 13 normally developing infants. [Methods] Ultrasonography and a manual muscle tester were used for measuring the thickness and strength of knee extensor and ankle plantar flexor muscles. The Gross Motor Function Measure (GMFM) and Wee Functional Independence Measure (WeeFIM) were used to evaluate level of gross motor and independence level. [Results] Knee extensor thicknesses of CP and MR subjects were thinner than those of normally developing infants. Strengths of knee extensor and ankle plantar flexor showed differences being strongest in normally developing infants, followed by MR, and CP. Subjects in the examination of GMFM, there were no significant differences between CP and MR. A decline in social cognition of MR subjects was found in the examination of WeeFIM. [Conclusion] CP and MR subjects had smaller muscle thicknesses and strengths than those of normally developing infants, and lower gross motor function and functional independent level.