Does cochlear implantation influence postural stability in patients with hearing loss?

Abstract

Background: Cochlear implantation (CI) procedure carries the potential risk for vestibular system insult or stimulation with resultant dysfunction due to its proximity to the cochlea. The vestibular system plays an essential role in crucial tasks such as postural control, gaze stabilization and spatial orientation.

Research question: How does standard cochlear implantation influence postural stability in patients with hearing loss?

Methods: The study included 21 individuals (age 51 ± 18 years) qualified to undergo CI due to severe or profound hearing loss. Participants were qualified for both groups by a physician based on an interview, an otoneurological examination and vestibular tests. The first group included patients without vestibular dysfunction, whereas the other group consisted of persons with vestibular dysfunction. The research methodology included medical examinations, anthropometric measurements and stabilometry on the Biodex Balance System SD (BBS) platform. The examinations were carried out twice, i.e. prior to and 3 months post implantation. The recorded data was compared between the first and the second examination using a non-parametric Wilcoxon test. The analysis of variance (ANOVA) and Tukey's post-hoc HSD unequal sample sizes were performed for patients with and without vestibular dysfunction.

Results and significance: Study showed that 52.4% of the participants obtained results within the norm, while 47.6% scored below it. The comparison of stability indices of the examined individuals, with and without vestibular dysfunction, did not reveal statistically significant differences. The only difference was the anterior-posterior stability index assessed in static conditions. Three months after the implantation, no changes in the majority of indices were noted, with the exception of anterior-posterior stability index, which improved following the implantation. CI does not affect postural stability changes in the study participants.

Keywords: Biodex balance system; Cochlear implantation; Fall risk test; Hearing loss.