Age-related changes of single-limb standing balance in children with and without deafness

Objective: The purposes of the present study were to elucidate the age-related changes in single-limb standing balance and sensory compensation for maintaining single-limb standing in profoundly deaf (PD) children, and to compare them with age-matched normal-hearing (NH) children. Methods: This study involved 57 PD children, aged 4-14 years and 57 age-matched NH children. Each group was subdivided into the following age groups: 4-6 years, 7-9 years, and 12-14 years. Postural stability was assessed using a single-limb standing test under four different sensory conditions: standing on a firm surface with eyes open (condition 1), standing on a firm surface with eyes closed and covered (condition 2), standing on a foam surface with eyes open (condition 3), and standing on a foam surface with eyes closed and covered (condition 4). Results: The age-related changes in single-limb standing balance of the PD children were notably affected by sensory conditions, in contrast with those of the NH children, which were not influenced by sensory conditions. In conditions 1 and 3, where visual information was enabled, the mean time of maintaining single-limb standing for the PD children significantly increased with age, and even reached levels similar to those of the NH children. However, in condition 2, where visual input was removed, the deficit of single-limb standing balance in the PD children persisted. Condition 4 revealed no significant age-related changes in the PD children. Conclusion: These results suggest that the postural stability of PD children improves as a result of adaptive sensory compensation, both visual and somatosensory. In addition, it appears that postural control is more highly dependent upon visual input than on somatosensory input.