Construct validity and reliability of the Selective Control Assessment of the Lower Extremity in children with cerebral palsy.

Aim: Assessing impaired selective voluntary movement control in children with cerebral palsy (CP) has gained increasing interest. We investigated construct validity and intra- and interrater reliability of the Selective Control Assessment of the Lower Extremity (SCALE).

Method: Thirty-nine children (21 males, 18 females) with spastic CP, mean age 12 years 6 months [range 6y 11mo-19y 9mo], Gross Motor Function Classification System (GMFCS) levels I to IV, participated. Differences in SCALE scores were determined on joint levels and between patients categorized according to their limb distribution and GMFCS levels. SCALE scores were correlated with the Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale. To determine reliability, the SCALE was applied once and recorded on video.

Results: SCALE scores differed significantly between the less and more affected leg (p<0.001) and between most leg joints. Total SCALE scores differed significantly between GMFCS levels I and II. Correlations with Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale were 0.88, 0.88, and -0.55 respectively. Intraclass correlation coefficients were all above 0.9, with the minimal detectable change below 2 points.

Interpretation: The SCALE appears to be a valid and reliable tool to assess selective voluntary movement control of the legs in children with spastic CP.