STAR2 VALIDATION WORKING GROUP: TESTING COCHLEAR IMPLANT USERS IN REAL-LIFE LISTENING CONDITIONS

Arnold L, Joffo LM, Boyle P.

Advanced Bionics, Clinical Research Department

The STAR2 (Sentence Test with Adaptive Randomised Roving levels) aims to assess speech perception that more closely relates to real life listening situations than the fixed level tests traditionally conducted. Sentences are each delivered by either a male or a female speaker, at one of three different presentation levels, with adaptively varying background noise. The presentation order is randomized, for both the level and the speaker, such that subjects cannot optimize their processor controls as for fixed level tests. This aspect of the STAR2 design better mimics group conversations and more fully challenges sound processor functionality, such as the Automatic Gain Control (AGC) system which is not usually exercised in conventional tests.

The objective is to conduct a validation process for STAR2 by gathering data from a number of European centres using STAR2 in their clinical routine.

STAR2 data are collected from adult CI users. Lists of 30 sentences are delivered from a loudspeaker placed one metre in front of the participant. Global analysis will investigate: normative data, list equivalence, learning effects, test-retest variation. STAR2 scores will also be compared with other routine clinical tests as well as with other measures of everyday-life performance.

Pilot data on 18 normal hearing individuals found low inter-subject variability with mean Speech Reception Thresholds (SRTs) of -7.9 dB and -9.24 dB for the male and female speakers respectively (Nunn, 2008). Preliminary results obtained in the same study from hearing impaired subjects and CI users showed a reverse pattern with better SRTs for the male speaker, most likely due to the faster delivery rate of the female voice.

These observations as well as those from other studies using STAR2 to investigate front end processing are very encouraging on the usefulness of the methodology behind STAR2 for experimental designs as well as for clinical application.

E-mail: lumingj@abionics.fr