Influencing Factors on the Vestibular Function of Deaf Children and Adolescents - Evaluation by Means of Dynamic Posturography

Objectives: Previous studies have shown that both motor exercises and vestibuloocular tests reveal a difference in the balance function of deaf and normal-hearing children and adolescents. The purpose is to evaluate the influence on balance function of the hearing status. Material and Methods: A total of 80 children and adolescents between the ages of 4 and 20 years were studied. Of these, 40 children were either deaf or severely hearing impaired. The remaining 40 were control subjects of equivalent age without hearing or balance impairment. The EquiTest, a device used in computerized dynamic posturography, was employed for the investigations. Mean equilibrium and latency scores from both groups were compared using t-tests for unrelated random samples. Results: The deaf children achieved significantly lower equilibrium scores and latency scores than the control group. A positive linear relationship exists between the age of the subjects and the equilibrium scores obtained. Gender, extent of hearing loss and cause of deafness have no significant effect on the balance function of the deaf children. Deaf subjects with normal caloric excitability achieved significantly higher equilibrium scores than those with vestibular deficits. Conclusions: The results support the hypothesis that damage to the cochlea, whatever its cause, may also detrimentally affect the vestibular organ. They do not, however, exclude the possibility that the poorer balance proficiency shown by deaf children may have other possible causes, such as CNS damage. The fact that equilibrium scores increase with increasing age can be seen as indicating the maturation of central nervous mechanisms involved in integrating the various sensory qualities in the sense of balance. An improvement in vestibular function through special training appears plausible, although this would necessitate diagnosis at a very early stage.