Can we predict lower extremity motor control problems from single leg standing test for children with cerebral palsy?

Selective voluntary motor control (SVMC) is a major contributor to motor function, balance, and gait performance in spastic cerebral palsy (SCP)(1). Single-leg standing (SLS) is a simple test to measure static balance which is highly correlated(2) and affected by impaired voluntary control in SCP(3). Therefore, a rapid and effective clinical evaluation of SVMC is of great importance. The aim of the study is to test whether SVMC assessment can be performed during SLS. May lower extremity SVMC be predicted during SLS in children with SCP? A total of 42 limbs of 11 children with SCP (6 females, 6 bilateral, 5 unilateral, 17 affected limbs; 11.33 ± 3.13 y.o, 39.14 ± 12.42 kg, 141.86 ± 14.46 cm) and 10 typically developed (TD) controls (4 females; 12.04 ± 3.16 y.o, 44.42 ± 16.12 kg, 151.88 ± 16.56 cm) were assessed in the study. The Selective Control Assessment of the Lower Extremity (SCALE) tool was used to measure SVMC(4). Hip, knee, and ankle movements were evaluated with a 3-point likert scale (2: normal, 1: impaired, 0: unable) at the monarthric level. In order to predict SVMC during SLS, the participants were videotaped while standing on a flat surface on one limb for as long as they could without any support by a smartphone (Xiaomi Redmi 10,50 MP) with a tripod placed at knee-level height (anterolaterally 45°). The longest SLS (max 10 sec.) of the three separate video recordings was evaluated. Similar to the SCALE, a 0-1-2 scoring system was developed to assess each joint’s SVMC during SLS: (2: the expected movements to maintain balance, 1: partial movements to maintain stability, 0: no compensated movement). 4 pediatric physical therapists with 7+ years of experience scored the videos 2 times in total, 1 week apart. The intra-rater and inter-rater reliability were statistically analyzed with intraclass correlation coefficients (ICC) and corresponding 95% confidence intervals (CI)(p<0.05)(5). Intra-rater reliability ICC correlation was excellent level at the subtalar-joint, good level at the ankle and toes, moderate level at the knee, and poor level at the hip were found between SVMC and SLS (Table-1). Also, significantly good to excellent inter-rater reliability (from 0.619 to 0.911) was found between SLS and SVMC (p<0.001). Download : Download high-res image (195KB)Download : Download full-size image The video-based SLS novel assessment methodology in this study succeeded to have a good to excellent correlation on SVMC on foot (ankle-subtalar-toe) joint level which was moderately correlated with appropriate ankle dorsiflexion at late swing(6). Movement assessment during SLS may give so much information about the quality of SVMC at the ankle-foot level which is the most related item with the gait abnormality. The research team is currently continuing to increase the sample size by including more participants and train more raters with a simple form and/or videos.