Speech perception after Cochlear Implantation in patients with preoperative residual hearing and Monosyllabic word recognition

Since the beginning of cochlear implant (CI) treatment, the indication has steadily increased towards more residual hearing. According to current guidelines, an indication for Cl fitting is fulfilled when monosyllabic word recognition score with hearing aid is 60% or less. The aim of this study was to compare the hearing performance in people with residual hearing before and after Cl fitting. Data from 100 patients with Cl treatment (mean age: 57.5 years) were retrospectively analyzed. The average maximum monosyllabic word score before surgery was 34.1±23.6%, and the average pure-tone hearing loss (test frequencies: 0.5/1/2/4 kHz) was 75.0±7.9 dB HL. Monosyllabic word recognition score at 65 dB SPL in the free field before surgery with hearing aid was compared with the time point 1 year after Cl implantation. Furthermore, speech reception threshold in noise (Oldenburg sentence test) was evaluated one year after implantation. Compared with hearing aid fitting before surgery, monosyllabic word recognition improved on average by 46.6±27.7% with Cl fitting. In less than 10% of cases, no significant improvement in speech recognition was achieved by Cl-fitting compared to hearing aid fitting. The average speech reception threshold in noise one year after Cl fitting was -0.7±2.4 dB SNR. The results show that the vast majority of patients benefit significantly from Cl fitting, even with preoperative residual hearing and existing monosyllabic word understanding. While no adaptive measurement of speech reception thresholds in noise was possible before Cl surgery due to poor speech understanding in quiet, the average threshold after Cl fitting was better than 0 dB SNR.