A Kinematic Description of a Static Balance Task by Deaf Children

Abstract

Delayed balance development by deaf children has been well documented. Studies indicate that the poor balance experienced by some deaf children may be associated with vestibular injury. Other investigations have examined deaf children's balance in relation to age, sex, hearing loss, and visual deprivation. The purpose of this study was to compare static (one leg) balance responses of deaf children who balance effectively and those who do not. Eleven boys and eight girls enrolled at the American School for the Deaf in Hartford, CT were individually administered Item 2 of the Bruininks-Oseretsky Test of Motor Proficiency. Time on balance (TOB) was used to rank order the subjects from 1 (best) to 19 (worst). From this list, two groups of four children each were selected for further analysis. Group (A) included three boys and one girl (mean age = 121.5 mo., 10.1 years; mean hearing loss = 85.25dB, range = 75-110dB) who had the longest TOB (mean * SD: 8.7, k 2.6 seconds). Group (B) consisted of two boys and two girls (mean age = 100 mo., 8.3 years; mean hearing loss = 90.75dB, range = 75-131dB) who had the shortest TOB (mean + SD: 1.9, k 1.2 seconds). A three segment (head, trunk, and support leg) spatial model was used to analyze angular displacement of the head (ADH) and trunk (ADT) segments, and resultant linear velocities of the head (VHD), hip (VHP), and trunk center of mass (VCOM) in the frontal plane (Peak Technologies, Inc.). Means (k SD) for angular displacements (degrees) and linear velocities (m/s) are presented below:--- Overall, the good balancers (Group A) demonstrated smaller displacements (trunk & head) and smaller resultant linear velocities than Group B. Head position relative to the gravity line is largely influenced by vestibular (utricle & saccule) input. Consequently, lack of effective vestibular function would no-doubt adversely impact performance on one foot (static) balance. Although available medical information did not indicate the presence (or absence) of vestibular dysfunction, these results seem to point in that direction.