Effect of Preoperative Residual Hearing on Speech Perception After Cochlear Implantation

Objective: To assess the effect of substantial preoperative residual hearing on speech perception outcomes in adult cochlear implant recipients. Setting: Tertiary care academic referral center. Methods: Twenty-nine patients with substantial preoperative residual hearing underwent cochlear implantation. Twenty-one implant recipients matched for age and duration of hearing loss, but without preoperative residual hearing, served as controls. Postoperative speech perception was assessed using City University of New York sentence, consonant-nucleus-consonant, and hearing in noise test in quiet and in noise (+10 dB signal to noise ratio) tests at 1, 3, 6, and 12 months after fitting. Results: After implantation, there were no significant differences between groups for any of the tests administered. The mean change in speech perception abilities from baseline was significantly greater for the control patients than those with substantial preoperative residual hearing at a number of the test intervals across the various conditions. Moreover, at both 1 and 3 months, some patients in the residual hearing group had speech perception scores that were worse than their preoperative values. Ultimately, all of the patients with substantial residual hearing surpassed their preoperative performance. Discussion: Patients with substantial preoperative residual hearing can gain significant benefit from cochlear implantation. Although the degree of improvement in these individuals is somewhat more modest than for those patients without preoperative residual hearing, the outcomes are still excellent. That there were no significant differences between the patient groups suggests that having substantial residual hearing before implantation does not provide a measurable performance advantage for electrical stimulation. Patients with substantial residual hearing who are contemplating cochlear implantation should be counseled regarding a possible initial decline in speech perception performance.