Spanish Study Group on Cochlear Implants for Persons with Marginal Benefit from Acoustic Amplification

Abstract

Recently the U.S. Food and Drug Administration approved the use of cochlear implants (CI) in patients with severe-to-profound sensorineural hearing loss with marginal benefit (< 30% speech discrimination) from hearing aids (HA). A multicentre trial was developed to determine whether this approval could be applied to the Spanish population. Nine postlingual adults from 3 centres were selected for the study. The mean preoperative unaided PTA threshold (0.25 to 4 KHz) was 108.6 dB HL for the poorer ear and 99.8 dB HL for the better. In all subjects the poorer ear was implanted with a Mini Nucleus 22 device. A single subject design study was used to compare performance with HA preoperatively and with CI postoperatively, or CI with contralateral HA. PTA measures and Spanish open set speech recognition tests were used. Comparing pre-implant levels with results after 6 months of CI use, all subjects improved significantly on all test measures: i) Mean aided soundfield threshold: 73.6 dB vs 39.8 dB ii) Mean bisyllabic recognition: 20% vs 57% iii) Mean consonant discrimination: 20% vs 49% iv) Mean CID sentences: 22% vs 73%. Five subjects discontinued use of the contralateral HA after implantation, three continued occasionally to use the HA, and one continued to use both on a full-time basis. Patients performed significantly better post-implant on speech recognition compared with their best pre-implant HA scores. Therefore the CI appears an appropriate treatment for Spanish speakers with a severe-to-profound hearing loss and marginal benefits with HA.