The effect of altered sensory environments on balance was studied in 82 healthy children between 3 and 6 years of age. The purpose was to obtain normative measurements of postural stability during early stages of development for use in clinical posturography. Subjects were tested in three visual conditions (eyes open, blind-folded, and sway-referenced visual enclosure) during stance on either a fixed or sway-referenced force platform (EquiTest). During sway-referenced conditions, spontaneous changes in the subject's center of force (COF) drove rotational displacements of the platform and/or visual surround. The gain of platform/COF or surround/COF displacement was altered from 0.00 to 1.5. An equilibrium score (ES) was calculated based on the amount of postural sway compared to the maximum sway possible without falling. A higher ES reflected greater postural stability. An improvement in postural stability was observed between 4 and 5 years of development when the sensory environment was fixed (sway referenced gain = 0.0). In a dynamic sensory environment, however, age-related improvements in postural stability were not uniform and depended upon the specific sensory condition. For example, while 6 year olds generally showed the greatest postural stability of any age group, all ages showed statistically equivalent equilibrium scores during stance on a compliant surface with eyes closed, at all sway gains. The ability to ignore misleading sensory inputs to maintain balance was observed at 3 years of age; 76% of the 3 year olds (n = 16) were able to maintain stance in altered sensory environments at the 1.0 sway gain. In addition, postural stability was greater when visual inputs were sway-referenced compared to conditions that manipulated the support surface compliance. These data suggest that the predominance of visual-vestibular control of balance gives way to a somatosensory-vestibular dependence by age 3, but that the transition to adult-like balance responses is not complete for all sensory conditions even by age 6. The use of posturography to enhance the assessment of pediatric vestibular and sensory integration deficits is discussed.
|Number of pages
|International Journal of Pediatric Otorhinolaryngology
|Published - Oct 1993