Multilevel Upper Body Movement Control during Gait in Children with Cerebral Palsy

Abstract

Upper body movements during walking provide information about balance control and gait stability. Typically developing (TD) children normally present a progressive decrease of accelerations from the pelvis to the head, whereas children with cerebral palsy (CP) exhibit a general increase of upper body accelerations. However, the literature describing how they are transmitted from the pelvis to the head is lacking. This study proposes a multilevel motion sensor approach to characterize upper body accelerations and how they propagate from pelvis to head in children with CP, comparing with their TD peers. Two age- and gender-matched groups of 20 children performed a 10m walking test at self-selected speed while wearing three magneto-inertial sensors located at pelvis, sternum, and head levels. The root mean square value of the accelerations at each level was computed in a local anatomical frame and its variation from lower to upper levels was described using attenuation coefficients. Between-group differences were assessed performing an ANCOVA, while the mutual dependence between acceleration components and the relationship between biomechanical parameters and typical clinical scores were investigated using Regression Analysis and Spearman's Correlation, respectively (α = 0.05). New insights were obtained on how the CP group managed the transmission of accelerations through the upper body. Despite a significant reduction of the acceleration from pelvis to sternum, children with CP do not compensate for large accelerations, which are greater than in TD children. Furthermore, those with CP showed negative sternum-to-head attenuations, in agreement with the documented rigidity of the head-trunk system observed in this population. In addition, the estimated parameters proved to correlate with the scores used in daily clinical practice. The proposed multilevel approach was fruitful in highlighting CP-TD gait differences, supported the in-field quantitative gait assessment in children with CP and might prove beneficial to designing innovative intervention protocols based on pelvis stabilization.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1. Sensor location and axes orientation of the Magneto-Inertial Measurement Units (MIMUs) attached on the children’s body segments.

H: head level; S: sternum level; P: pelvis.

Fig 2. On the left, RMS of the acceleration components at the three levels.

On the right, attenuation coefficients from pelvis to head (CPH), from pelvis to sternum (CPS), and from sternum to head (CSH) along the three anatomical axes. Parameters computed for the TD and CP groups are represented with empty and filled box-plots, respectively. Significant between-groups differences (p < 0.05 or p < 0.01) are reported with the symbol § or §§, respectively.

Fig 3. RMSa inter-component relationships for the two groups (TD in light grey and CP in black).

The inter-component comparison graphs characterized by significant different regression lines between the TD and CP groups are reported in figure: RMSaAP vs RMSaML for head (p = 0.007), RMSaML vs RMSaCC for sternum (p = 0.048), and RMSaAP vs RMSaCC for pelvis (p = 0.043).