Lower-extremity selective voluntary motor control in patients with spastic cerebral palsy: increased distal motor impairment.

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.