Vestibular system in performance of standing balance of children and youngadults under altered sensory conditions

Inputs from the visual, somatosensory and vestibular systems must be integr ated efficiently to activate appropriate motor responses in maintaining opt imal balance. This study examined the standing balance of 17 children (7 to 10 years old) and 17 young adults (19 to 23 years old) as a function of se nsory organization, sensory system efficiency, and postural strategy adopte d. Tests of standing balance were administered under six sensory conditions created by simultaneous alteration of the visual (full, occluded, or sway- referenced) and the somatosensory inputs (fixed-foot or compliant-foot supp ort). The sway area and the sway amplitude of the center of pressure were m easured and analyzed. Three findings are notable. The function of sensory o rganization for balance control was poorer for the children than the young adults. The functional efficiency of the somatosensory and the visual syste ms of children have developed to the young adult level, but that of the ves tibular system has not. There was no difference between children and young adults in hip control, but there was in ankle control when the vestibular i nput was the only reliable source of sensory input. These results suggest t hat the functional efficiency of the vestibular system in children 7 to 10 years of age may still be developing. This may account for their poorer fun ction of sensory organization and lower performance of standing balance.