Comparison of word-, sentence-, and phoneme-based training strategies in improving the perception of spectrally distorted speech

Purpose: To compare the effectiveness of 3 self-administered strategies for auditory training that might improve speech perception by adult users of cochlear implants. The strategies are based, respectively, on discriminating isolated words, words in sentences, and phonemes in nonsense syllables. Method: Participants were 18 normal-hearing adults who listened to speech processed by a noise-excited vocoder to simulate the information provided by a cochlear implant. They were assigned randomly to word-, sentence-, or phoneme-based training and underwent 9 training sessions (20 min each) on separate days over a 2- to 3-week period. The effectiveness of training was assessed as the improvement in accuracy of discriminating vowels and consonants, as well as identifying words in sentences, relative to participants' best performance in repeated tests prior to training. Results: Word- and sentence-based training led to significant improvements in the ability to identify words in sentences that were significantly larger than the improvements produced by phoneme-based training. There were no significant differences between the effectiveness of word- and sentence-based training. No significant improvements in consonant or vowel discrimination were found for the sentence- or phoneme-based training groups, but some improvements were found for the word- based training group. Conclusion: The word- and sentence-based training strategies were more effective than the phoneme-based strategy at improving the perception of spectrally distorted speech.