Northeastern University, Boston, MA, USA.
J Speech Lang Hear Res. 2011 Jun;54(3):959-80. doi: 10.1044/1092-4388(2010/10-0197). Epub 2010 Nov 8.
Improved speech recognition in binaurally combined acoustic-electric stimulation (otherwise known as bimodal hearing) could arise when listeners integrate speech cues from the acoustic and electric hearing. The aims of this study were (a) to identify speech cues extracted in electric hearing and residual acoustic hearing in the low-frequency region and (b) to investigate cochlear implant (CI) users' ability to integrate speech cues across frequencies.
Normal-hearing (NH) and CI subjects participated in consonant and vowel identification tasks. Each subject was tested in 3 listening conditions: CI alone (vocoder speech for NH), hearing aid (HA) alone (low-pass filtered speech for NH), and both. Integration ability for each subject was evaluated using a model of optimal integration--the PreLabeling integration model (Braida, 1991).
Only a few CI listeners demonstrated bimodal benefit for phoneme identification in quiet. Speech cues extracted from the CI and the HA were highly redundant for consonants but were complementary for vowels. CI listeners also exhibited reduced integration ability for both consonant and vowel identification compared with their NH counterparts.
These findings suggest that reduced bimodal benefits in CI listeners are due to insufficient complementary speech cues across ears, a decrease in integration ability, or both.
当听众整合来自声学和电听觉的语音线索时，双模式听力（即电声联合刺激）中的语音识别可能会得到改善。本研究的目的是：（a）确定在低频区域从电听觉和残余声学听觉中提取的语音线索；（b）研究人工耳蜗（CI）使用者在跨频率上整合语音线索的能力。
正常听力（NH）和 CI 受试者参加了辅音和元音识别任务。每位受试者接受了 3 种听力条件的测试：仅 CI（NH 的声码器语音）、仅助听器（NH 的低通滤波语音）和两者。使用最优整合模型-预标记整合模型（Braida，1991）评估每位受试者的整合能力。
只有少数 CI 听众在安静环境中对音位识别表现出双模优势。从 CI 和 HA 中提取的语音线索对于辅音高度冗余，但对于元音互补。与 NH 对照组相比，CI 听众在辅音和元音识别方面的整合能力也有所下降。
这些发现表明，CI 听众的双模优势降低是由于双耳之间缺乏互补的语音线索、整合能力下降或两者兼而有之。
