Are electroacoustic output measures of cochlear implant (CI) speech processors and dynamic modulation (DM) receivers necessary?

Abstract

Background: the UK Assistive Listening Technology Working Group and the National Deaf Children’s Society have published standards for amplification systems for ensuring similar output from the CI speech processor and the CI with the DM system for the same inputs. (ALTWG 2024; NDCS 2017).

Do these standards remain necessary with the new technology? If so, which frequencies should be included when seeking transparency?

Methods: electroacoustic responses of CI speech processors and DM radio aid receivers taken according to UKALTWG and NDCS standards were analysed for transparency using two methods with the default receiver setting of EasyGain 0:

· Method 1: Averages of 750, 1000, and 2000 Hz frequencies, as per Schafer et al. (2013), reported transparency at ±3dB.

· Method 2: Averages of six frequencies (750, 1000, 1500, 2000, 3000, and 4000 Hz), as proposed by ALTWG (2024), also achieved transparency at ±3dB.

A total of 41 CI processors and 41 DM receivers were analysed, including 13 N7, 16 N8 with Roger 20 receivers, 9 Sky CI M with Roger Direct, and 3 SONNET 2 with Roger 21 receivers.

Results:

· 73% of processors achieved transparency at EasyGain 0, with method 1 (Schafer et al.).

· 78% of processors achieved transparency at EasyGain 0, with method 2 (ALTWG).

Conclusion: there is no significant difference between methods. Electroacoustic measures remain essential for identifying processor and receiver combinations that do not achieve transparency at default settings.

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Identifiers

ORCID for Stuart Whyte: orcid.org/0000-0003-3464-8510

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