Effect of Bimodal Hearing in Speech Perception Under Noisy Environment According to Residual Hearing

Lim, Eun Jung; Lee, Kyu Yup; Kim, Yee Hyuk; Sin, Chang Min; Youn, Sung Jae; Park, Ji Hyun; Lee, Sang Heun

Abstract

BACKGROUND AND OBJECTIVES
In this study, we evaluated the effect of bimodal hearing in the speech perception test and the increasing level of bimodal hearing over cochlear implantation in speech perception score regarding residual hearing.
SUBJECTS AND METHOD
Nineteen prelingually deaf patients, who had used bimodal hearing over a period of 8 months, were divided in two groups in accordance to their low frequency residual hearing. The children were tested in open-set speech perception under +10 SNR and +20 SNR. The scores of bimodal hearing and unilateral cochlear implantation were compared by the Wilcoxon signed-rank test. Also, the increased level of speech perception scores of bimodal hearing over cochlear implantation alone were calculated using the formula, [bimodal score (%)-unilateral cochlear implantation (%)], and was compared between groups.
RESULTS
In pure tone audiometry under silent condition, the result of bimodal hearing was similar to unilateral cochlear implantation in magnitude in both groups. Under the noisy condition, both groups had better result in bimodal hearing in terms of speech perception. Also, the increased level was higher in bimodal hearing over unilateral cochlear implantation in the better residual hearing group. However, since the sample size was small enough, it is considered that there was no statistical significance.
CONCLUSION
Cochlear implanted patients with residual hearing are expected to get better speech perception in noisy environment with bimodal hearing regardless of the level of residual hearing.