Speech audiometry and data logging in CI patients : Implications for adequate test levels.

BACKGROUND: As part of postoperative cochlear implant (CI) diagnostics, speech comprehension tests are performed to monitor audiological outcome. In recent years, a trend toward improved suprathreshold speech intelligibility in quiet and an extension of intelligibility to softer sounds has been observed. Parallel to audiometric data, analysis of the patients' acoustic environment can take place by means of data logging in modern CI systems.

OBJECTIVES: Which speech test levels reflect the individual listening environment in a relevant manner and how can these be reflected in a clinical audiometric setting?

PATIENTS AND METHODS: In a retrospective analysis, data logs of 263 adult CI patients were evaluated for sound level and the listening situation (quiet, speech in quiet, noise, speech in noise, music, and wind). Additionally, monosyllabic word comprehension in quiet was analyzed in experienced CI users at presentation levels of 40-80 dB.

RESULTS: For the sound level in the acoustic environment of postlingually deafened adult CI users, data logging shows a maximum occurrence of speech signals in the range of 50-59 dB. This demonstrates the relevance of everyday speech comprehension at levels below 60 dB.

CONCLUSION: Individual optimization of speech intelligibility with a CI speech processor should not be performed in the range of 65-70 dB only, but also at lower levels. Measurements at 50 dB currently seem to be a useful addition.