Linear and Non-Linear Changes of Center of Pressure due to Vestibular System Disorders: Comparison of Balance and Gait in Hearing and Sensorineural Deaf Children

Balance weakness and changes in the walking pattern of deaf children due to vestibular disorders have been clarified by past studies. This study aimed to investigate static balance and walking in sensorineural deaf children with two methods of linear and non-linear assessment of posture control.

This descriptive study was conducted on 20 hearing and healthy boys (10.80±1.46 years old) and 20 boys with deafness greater than 75 dB (11.30±1.89 years old). Static balance was evaluated during tandem stance and with feet together on an unstable surface using a force plate. Kinetic and kinematic variables of gait were also investigated. The independent and dependent t-tests were used to assess the inter-group and between-group differences in SPSS21 software with p < 0.05.

The results of static balance showed a significant difference between groups in linear variables. The amount of sway, path, area, and speed of the center of pressure movement in the deaf was significantly higher than that in the control group (P<0.05). However, entropy (non-linear evaluation) was only significant in the medial-lateral direction of tandem test (P<0.05). Lower gait speed and an increase in the medial-lateral component of the ground reaction force were observed in the deaf (P<0.05).

According to the results, the evaluated linear variables were more sensitive to deafness and vestibular system disorder than the nonlinear variable. Entropy is a sign of variability and irregularity in a person's performance; therefore, deaf people may be more likely to be vulnerable in the medial-lateral direction due to more irregularity in this direction.