Talker Adaptation and Lexical Difficulty Impact Word Recognition in Adults with Cochlear Implants

Introduction: Talker-specific adaptation facilitates speech recognition in normal-hearing listeners. This study examined talker adaptation in adult cochlear implant (CI) users. Three hypotheses were tested: (1) high-performing adult CI users show improved word recognition following exposure to a talker ("talker adaptation"), particularly for lexically hard words, (2) individual performance is determined by auditory sensitivity and neurocognitive skills, and (3) individual performance relates to real-world functioning. Methods: Fifteen high-performing, post-lingually deaf adult CI users completed a word recognition task consisting of 6 single-talker blocks (3 female/3 male native English speakers); words were lexically "easy" and "hard." Recognition accuracy was assessed "early" and "late" (first vs. last 10 trials); adaptation was assessed as the difference between late and early accuracy. Participants also completed measures of spectral-temporal processing and neurocognitive skills, as well as real-world measures of multiple-talker sentence recognition and quality of life (QoL). Results: CI users showed limited talker adaptation overall, but performance improved for lexically hard words. Stronger spectral-temporal processing and neurocognitive skills were weakly to moderately associated with more accurate word recognition and greater talker adaptation for hard words. Finally, word recognition accuracy for hard words was moderately related to multiple-talker sentence recognition and QoL. Conclusion: Findings demonstrate a limited talker adaptation benefit for recognition of hard words in adult CI users. Both auditory sensitivity and neurocognitive skills contribute to performance, suggesting additional benefit from adaptation for individuals with stronger skills. Finally, processing differences related to talker adaptation and lexical difficulty may be relevant to real-world functioning