The effect of core stabilization exercises on the respiratory muscle strength, respiratory functions and postural control in children with hearing impairment

Studies in hearing impaired children; mention about a number of problems such as delays in motor development, decreased coordination of movements, hypotonia, lower cardiorespiratory level and lower muscular endurance compared to their peers. When the literature is searched, we encounter studies evaluating respiratory functions and postural control in hearing-impaired children. However, no study evaluating respiratory muscle strength in these children was found. In addition, the effects of core stabilization exercises performed in these children on respiratory muscle strength, respiratory functions and postural control have not been investigated. Therefore, we planned this study to investigate the effects of core stabilization training on respiratory muscle strength, respiratory functions and postural control in children with hearing impairment. Within the scope of the study, 30 children with hearing impairment who were diagnosed with prelingual sensorineural hearing loss between the ages of 9-15 were randomly divided into study and control groups. Pulmonary function test, respiratory muscle strength measurement, postural stability, limits of stability and sensory integration tests with "Biodex Balance System® (BBS)" and Balance Error Scoring System (BESS) were performed for all cases. While no training was performed to the control group, core stabilization training protocol was performed to the study group consisting of static contraction training on a stable surface at the first level; dynamic training on a stable surface at the second level; dynamic and resistant training on an unstable surface at the third level. All assessments were repeated at the end of the eighth week. SPSS v.20 program was used for data analysis. Categorical variables were analyzed with the χ2-test. Paired Sample T-test or Wilcoxon test was used for in-group comparisons and Independent Samples T-test or Mann Whitney U test was used for between-groups comparisons depending on the distribution properties of the data. The significance level for all statistical tests was set at p<0.05. After eight weeks of training, significant improvements were achieved in forced vital capacity (FVC) and peak expiratory flow rate (PEF), maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP) and all parameters of BBS in the study group (p<0.05). Significant improvements were achieved 'double leg', 'single leg' and 'tandem' stances on firm surface and 'double leg' and 'tandem' stances on foam surface parameters of BESS (p<0.05). In the control group, no significant difference was found between the first measurement and the last measurement in pulmonary functions, respiratory muscle strength, BBS and BESS (p>0.05). In the comparison of the tests between the groups, there was no significant difference regarding the parameters of pulmonary functions, whereas MEP measurement in respiratory muscle strength was found significant in favor of the study group (p<0.01). In the comparison of BBS between groups; there was a significant increase in 'overall' and 'anterior/posterior' parameters of postural stability; 'overall', 'left', 'backwardleft' and 'backwardright' parameters of limits of stability; 'eyes open/closed firm surface', 'eyes closed foam surface' and 'composite score' parameters in clinical test of sensory integration and balance in favor of the study group (p<0.05). In the comparison of BESS between groups, a significant difference was observed in favor of the study group in the 'overall total score' (p<0.05). It is reported in the literature that core stabilization training in healthy and patient populations has a positive effect on respiratory muscle strength, pulmonary functions and postural control. According to the results of our study, similar positive effects were observed for children with hearing impairment and core stabilization exercises were observed to improve respiratory muscle strength, pulmonary functions and postural control in children with severe to profound hearing loss. In the light of the results we obtained from our study, it would be useful to include a training that includes core stabilization exercises in these children's rehabilitation programs.