Search

Aim: Multiple impairments contribute to motor deficits in spastic cerebral palsy (CP). Selective voluntary motor control (SVMC), namely isolation of joint movement upon request, is important, but frequently overlooked. This study evaluated the proximal to distal distribution of SVMC impairment among lower extremity joints., Method: Using a recently developed tool, the Selective Control Assessment of the Lower Extremity (SCALE), we evaluated the SVMC of the hip, knee, ankle, subtalar joint, and toes in a cross-sectional, observational study of 47 participants with spastic, diplegic, hemiplegic, and quadriplegic CP (22 males, 25 females; mean age 11 y 9 mo, SD 4 y 8 mo; Gross Motor Function Classification System levels I-IV)., Results: Statistically significant decreases in SCALE scores from hip to toes were found using the Page statistical test for trend (p<0.001). Statistically significant differences (p<0.05) were found between all joint pairs, except toes versus subtalar, toes versus ankle, and right ankle versus subtalar joints. Cross-tabulation of score frequencies for all pairs revealed that proximal joint scores were higher or equal to distal ones 81 to 100% of the time. Excluding toes versus subtalar joints, proximal scores exceeded distal ones 94 to 100% of the time., Interpretation: We confirmed increasing proximal to distal SVMC impairment, which may have implications for treatment and research.

Normal selective voluntary motor control (SVMC) can be defined as the ability to perform isolated joint movement without using mass flexor/extensor patterns or undesired movement at other joints, such as mirroring. SVMC is an important determinant of function, yet a valid, reliable assessment tool is lacking. The Selective Control Assessment of the Lower Extremity (SCALE) is a clinical tool developed to quantify SVMC in patients with cerebral palsy (CP). This paper describes the development, utility, validation, and interrater reliability of SCALE. Content validity was based on review by 14 experienced clinicians. Mean agreement was 91.9% (range 71.4-100%) for statements about content, administration, and grading. SCALE scores were compared with Gross Motor Function Classification System Expanded and Revised (GMFCS-ER) levels for 51 participants with spastic diplegic, hemiplegic, and quadriplegic CP (GMFCS levels I - IV, 21 males, 30 females; mean age 11y 11mo [SD 4y 9mo]; range 5-23y). Construct validity was supported by significant inverse correlation (Spearman's r=-0.83, p<0.001) between SCALE scores and GMFCS levels. Six clinicians rated 20 participants with spastic CP (seven males, 13 females, mean age 12y 3mo [SD 5y 5mo], range 7-23y) using SCALE. A high level of interrater reliability was demonstrated by intraclass correlation coefficients ranging from 0.88 to 0.91 (p<0.001).