A comprehensive approach for assessing the effectiveness of frequency-lowering hearing aids and electric acoustic stimulation (EAS) cochlear implant for treating people with a severe-to-profound high-frequency hearing loss.

Introduction: The effectiveness of hearing aids (HA) for treating people with severe-to-profound sensorineural high-frequency hearing losses (HFHL) is known to be limited. Technological alternatives have been developed to meet the needs of these individuals, such as frequency-lowering (FL) HAs or electric acoustic stimulation (EAS) implants. To date, no study has shown which of these alternatives is the most effective to improve hearing abilities for this population. Objective: To compare the effectiveness of frequency-compression and frequency-transposition HA, and of EAS cochlear implant on speech perception for people with a severe-to-profound sensorineural HFHL.  Methods: Ten adults tested frequency-compression and frequency-transposition HAs following an ABAC single-subject design; four week baselines were completed with own HA, followed by 8 week trials with each device. One participant also received an EAS implant. Speech recognition was measured each week. Questionnaires and semi-structured interviews were used to collect participants’ perspectives on the benefits of each technology.  Results: FL HAs improved speech recognition up to 10% compared to conventional HAs in 5/10 subjects. Others experienced either no gain or some degradation (from -9 to -15%) when using FL. The participant who received an EAS implant obtained a gain from +17 to +43% compared to conventional or FL HA. Significant benefits on questionnaires and interviews were reported by 8 participants. Learning and ceiling effects were encountered during speech recognition assessments with most subjects. This will be discussed further at the conference. Conclusion: The EAS implant appears as the first indication for treating people with a HFHL. However, FL HAs can provide significant benefits for some individuals. In this context, and considering the potential risks and high costs related to EAS, trials with FL should be considered on an individual basis prior to implantation. Results support the use of a global approach when assessing the benefits of hearing technologies.