The Thomas More Lists: A Phonemically Balanced Dutch Monosyllabic Speech Audiometry Test.

Speech audiometry tests are a crucial tool in clinical care and research. In Dutch, the common practice is to use lists of monosyllabic words with a consonant-vowel-consonant (CVC) structure. However, there are relatively few lists, and they are short. Here, the goal is to develop an adult speech audiometry test for Dutch (Flemish) consisting of phonemically balanced lists of 25 CVC words. The ISO 8253-3:2012 norm was followed. From a pool of 689 well-known words, an initial set of 26 lists was recorded by a female speaker. The lists were optimized for perceptual balance by means of two studies with young normal hearing listeners (N1 = 24, N2 = 32). The final corpus contains 16 phonetically and perceptually balanced lists. In a last study (N3 = 25), the reference speech recognition curves in quiet and in speech-shaped noise were determined. Reference speech recognition threshold and slope values for phoneme scoring are respectively 20.3 dBSPL in quiet (slope 5.2%/dB) and -7.7 dBSNR (7.5%/dB) in noise, similar to existing materials. The lists may be a useful addition to the existing audiometric tests.

Feasibility of an implanted microphone for cochlear implant listening.

This study aimed at evaluating the feasibility of an implanted microphone for cochlear implants (CI) by comparison of hearing outcomes, sound quality and patient satisfaction of a subcutaneous microphone to a standard external microphone of a behind-the-ear sound processor. In this prospective feasibility study with a within-subject repeated measures design comparing the microphone modalities, ten experienced adult unilateral CI users received an implantable contralateral subcutaneous microphone attached to a percutaneous plug. The signal was pre-processed and fed into their CI sound processor. Subjects compared listening modes at home for a period of up to 4 months. At the end of the study the microphone was explanted. Aided audiometric thresholds, speech understanding in quiet, and sound quality questionnaires were assessed. On average thresholds (250, 500, 750, 1k, 2k, 3k, 4k and 6 kHz) with the subcutaneous microphone were 44.9 dB, compared to 36.4 dB for the external mode. Speech understanding on sentences in quiet was high, within approximately 90% of performance levels compared to hearing with an external microphone. Body sounds were audible but not annoying to almost all subjects. This feasibility study with a research device shows significantly better results than previous studies with implanted microphones. This is attributed to technology enhancements and careful fitting. Listening effort was somewhat increased with an implanted microphone. Under good sound conditions, speech performance is nearly similar to that of external microphones demonstrating that an implanted microphone is feasible in a range of normal listening conditions.

A multicentre clinical evaluation of paediatric cochlear implant users upgrading to the Nucleus(®) 6 system.

OBJECTIVES: The aim of this study was to investigate whether experienced paediatric cochlear implant users could show benefits to speech perception outcomes from the introduction of noise reduction and automated scene classification technologies as implemented in the Nucleus(®) 6 sound processor. Previous research with adult cochlear implant users had shown significant improvements in speech intelligibility for listening in noisy conditions and good user acceptance for upgrading to the Nucleus 6 processor. In adults, these improvements for listening in noise were primarily attributed to the use of a range of new input processing technologies including noise reduction, as well as introduction of automatic scene classification technology. METHODS: Experienced paediatric cochlear implant users (n=25) were recruited from four clinics located in three countries. Research participants were evaluated on three occasions, an initial session using their Nucleus 5 sound processor; a second session in which participants used the Nucleus 6 processor programmed with the same technologies as were used in their Nucleus 5 sound processor; and a final session in which participants used the Nucleus 6 processor programmed with the default technologies including automatic scene classification (SCAN) which automatically selects the microphone directionality, noise reduction (SNR-NR), and wind noise reduction (WNR) technologies. Prior to both the second and third evaluations, research participants had approximately two weeks take-home experience with the new system. Speech perception performances on monosyllabic word tests presented in quiet and in noise, and a sentence test presented in noise, were compared across the three processor conditions. Acceptance of the Nucleus 6 default settings was assessed in a final session. RESULTS: No group mean difference in performance was found for monosyllabic words in quiet. A significant improvement in speech perception was found for both monosyllabic words and sentences in noise with the default Nucleus 6 program condition as compared with the Nucleus 5 condition. No acceptance issues were noted for any of the children. CONCLUSIONS: Experienced paediatric cochlear implant users showed a significant improvement in speech perception in listening in noise when upgraded to the Nucleus 6 sound processor primarily due to the introduction of a noise reduction technology, and all children accepted the default program. These findings suggest that school-aged children may benefit from upgrading to the Nucleus 6 sound processor using the default program.