Development of a quantitative assessment system for correlation analysis of footprint parameters to postural control in children

It is known that neurological impairments impact postural stability, but few studies have observed the biomechanical influence of foot structure on balance. The aim of this study was to develop an integrated device for investigating the relationship between static balance and the foot structure, derived from a footprint image, under clinical tests of sensory interactions. Quantitative analysis of the footprint image acquired during balanced standing was developed as an indirect measure of the longitudinal arch, an important structural component of the foot. A data pool was collected from 64 children, 32 children from each of two age groups (4-5 years old versus 8-10 years old). Six common footprint parameters derived from the footprint angle or contact area were used to investigate the relationship between footprint parameters and postural stability. Postural balance ability was evaluated by analyzing sway area in posturography under visual or somatosensory confliction conditions. The footprint parameters, derived from the footprint image, inter-correlated well with each other (p < 0.01). The relationships between footprint parameters and sway area were correlated only for younger children under visually deprived (eye close) and cutaneous unreliable (standing on compliant foam) conditions. This implies that the correlations between footprint parameters and sway area are very subtle which can only be observed in unreliable visual and somatosensory conditions of younger children. In addition, younger children with a lower arch height would have a smaller sway area and better posture control which might result from more cutaneous somatosensation or a flexible biomechanical structure in low arch feet during conditioned static standing.