Research Paper: Assessment of Balance Recovery Strategies During Manipulation of Somatosensory, Vision, and Vestibular Systems in Deaf Persons

Purpose: Sensory systems play an essential role in motor control. The lack of information about each of these systems can affect postural sway. This study aimed to assess balance recovery during the manipulation of somatosensory, visual, and vestibular systems in deaf persons. Methods: Thirty healthy and deaf subjects were selected as samples. Balance recovery strategies in various situations were recorded by 6 high-speed cameras after a sudden movement of the treadmill. The Independent t-test was used for data analysis (P≤0.05). Results: The results of this study showed that the mean of hip and ankle swings in different conditions was significantly higher in the deaf group than the healthy group except for the reference position, both in the anterior-posterior and posterior-anterior perturbations. However, there was no significant difference between the ratios of hip-to-ankle swings in all situations except for the third position. Conclusion: The findings of this study showed that the effectiveness of all sensory systems involved in balance recovery in healthy people was significantly better than the deaf persons. The dominant sensory system for restoring balance in healthy people is the visual, somatosensory, and vestibular systems, respectively. While deaf people have a greater reliance on somatosensory information and, then, the visual system. The negative effect of the weakness of visual information in the process of staring can be useful in reducing the effectiveness of the visual system in balance control of the deaf persons.