Comparison of speech recognition in cochlear implant patients with and without residual hearing: A review of indications

Abstract

Objective: This study evaluated existing guidelines for cochlear implantation (CI) according to the residual hearing of the patient. Speech recognition performance of adults implanted according to their degree of residual hearing was retrospectively evaluated.

Methods: Speech recognition results of 174 adult cochlear implant recipients were analyzed. All participants had pure tone thresholds of >75 dB at 2 and 4 kHz and were divided into three groups based on differing levels of low-frequency residual hearing.

Results: Findings indicate that CI was of benefit for all patients with bilateral severe hearing loss and patients with nonfunctional residual hearing both in quiet and noisy conditions. Patients with residual low-frequency hearing could benefit from combined electro-acoustic stimulation compared to CI alone or to hearing aids alone preoperatively. The speech recognition performance of all CI recipients with different levels of residual hearing in the low frequencies was similar except that superior performance was observed in the group using electro-acoustic stimulation compared to electrical stimulation alone.

Discussion and conclusions: Study results demonstrate the success of CI in accordance with current guidelines and also support expanding implantation guidelines to include patients who have severe-to-profound high-frequency sensorineural hearing loss and usable residual low frequency hearing.

Keywords: Cochlear implant; Electro-acoustic stimulation; Hearing aid; Indication for cochlear implantation; Residual hearing; Speech test.