Bimodal Benefits on Objective and Subjective Outcomes for Adult Cochlear Implant Users

BACKGROUND AND OBJECTIVES: Given that only a few studies have focused on the bimodal benefits on objective and subjective outcomes and emphasized the importance of individual data, the present study aimed to measure the bimodal benefits on the objective and subjective outcomes for adults with cochlear implant. SUBJECTS AND METHODS: Fourteen listeners with bimodal devices were tested on the localization and recognition abilities using environmental sounds, 1-talker, and 2-talker speech materials. The localization ability was measured through an 8-loudspeaker array. For the recognition measures, listeners were asked to repeat the sentences or say the environmental sounds the listeners heard. As a subjective questionnaire, three domains of Korean-version of Speech, Spatial, Qualities of Hearing scale (K-SSQ) were used to explore any relationships between objective and subjective outcomes. RESULTS: Based on the group-mean data, the bimodal hearing enhanced both localization and recognition regardless of test material. However, the inter- and intra-subject variability appeared to be large across test materials for both localization and recognition abilities. Correlation analyses revealed that the relationships were not always consistent between the objective outcomes and the subjective self-reports with bimodal devices. CONCLUSIONS: Overall, this study supports significant bimodal advantages on localization and recognition measures, yet the large individual variability in bimodal benefits should be considered carefully for the clinical assessment as well as counseling. The discrepant relations between objective and subjective results suggest that the bimodal benefits in traditional localization or recognition measures might not necessarily correspond to the self-reported subjective advantages in everyday listening environments.

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

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.