Selective Control Assessment of the Lower Extremity (SCALE): development, validation, and interrater reliability of a clinical tool for patients with cerebral palsy

Abstract

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).

Selective motor control correlates with gait abnormality in children with cerebral palsy

“…SCALE was assessed according to Fowler et al [3] by one of 3 assessors. SCALE assesses 5 sets of movements on both the left and right lower limbs: hip flexion/extension, knee flexion/extension, ankle dorsiflexion/plantarflexion, inversion/eversion of the subtalar joint and toe flexion/extension.…”

“…Development of the Selective Control Assessment of the Lower Extremity (SCALE) [3] has allowed reliable assessment of SMC with an easily implemented tool [4].…”

Case Reports: The Influence of Selective Voluntary Motor Control on Gait After Hamstring Lengthening Surgery

“…SVMC was assessed using SCALE [9]. Specific isolated movement patterns at the hip, knee, ankle, subtalar, and toe joints were observed bilaterally.…”

“…A National Institutes of Health Task Force, created for this purpose, defined selective motor control as the ''ability to isolate the activation of muscles in a selected pattern in response to demands of a voluntary movement or posture'' [17]. Selective voluntary motor control is the deliberate performance of isolated movement on request as opposed to habitual selective muscle activation during a functional task such as walking [9]. Recently, a clinical assessment tool was developed for SVMC called the Selective Control Assessment of the Lower Extremity (SCALE) [9].…”

“…Selective voluntary motor control is the deliberate performance of isolated movement on request as opposed to habitual selective muscle activation during a functional task such as walking [9]. Recently, a clinical assessment tool was developed for SVMC called the Selective Control Assessment of the Lower Extremity (SCALE) [9]. SCALE evaluates the ability of a patient to isolate joint movement without the use of flexor and extensor synergy patterns and without other undesired movements.…”