Residual Speech Perception and Cochlear Implant Performance in Postlingually Deafened Adults

In Brief Objective This study aimed at testing the post-hoc validity of the previously reported predictive index for postoperative cochlear implant performance, based on preoperative duration of deafness, and speech reception. Study Design Adult patients with postlingual severe to profound hearing loss, who were implanted with Cochlear Corporation CI-22 and CI-24 devices were included in this study. We studied the relationship between their postoperative word rec-ognition scores and preoperative factors, namely, duration of deafness, and sentence recognition. We used the same predictive index reported in the previous study to predict their postoperative scores and test the model’s agreement with the actual performance. Results We found that postoperative performance as measured by CNC word scores had an inverse relationship with the duration of deafness, and a direct correlation with the preoperative performance on CID sentence recognition tests. A nonlinear term Duration / (1+CID) was shown to improve the correlation coefficient of our predictive index. Conclusion Some predictability of cochlear implant outcome is possible depending on the preoperative duration of deafness and speech recognition abilities. Preoperative residual speech recognition acts as a “trophic factor” that protects the spiral ganglion and/ or the central auditory pathways from degeneration. In other words, it improves the expected postoperative word scores. In a previous study, we demonstrated that both duration of deafness and residual speech perception were predictors of speech perception outcome with cochlear implants. We now have tested the previous predictive index on a subsequent cohort of patients and found it to be valid a priori. Postoperative speech perception scores of this subsequent cohort reliably fell within the range predicted by the preoperative index. The lower 95% confidence interval for the index appears to be a valid basis for implantation of ears with short durations of deafness and higher levels of residual speech perception.