Development and efficacy of a frequent-word auditory training protocol for older adults with impaired hearing.

OBJECTIVES: The objective of this study was to evaluate the efficacy of a word-based auditory-training procedure for use with older adults who have impaired hearing. The emphasis during training and assessment is placed on words with a high frequency of occurrence in American English. DESIGN: In this study, a repeated-measures group design was used with each of the two groups of participants to evaluate the effects of the word-based training regimen. One group comprised 20 young adults with normal hearing and the other consisted of 16 older adults with impaired hearing. The group of young adults was not included for the purpose of between-group comparisons. Rather, it was included to demonstrate the efficacy of the training regimen, should efficacy fail to be demonstrated in the group of older adults, and to estimate the magnitude of the benefits that could be achieved in younger listeners. RESULTS: Significant improvements were observed in the group means for each of five measures of post-training assessment. Pretraining and post-training performance assessments were all based on the open-set recognition of speech in a fluctuating speech-like background noise. Assessment measures ranged from recognition of trained words and phrases produced by talkers heard during training to the recognition of untrained sentences produced by a talker not encountered during training. In addition to these group data, analysis of individual data via 95% critical differences for each assessment measure revealed that 75 to 80% of the older adults demonstrated significant improvements on most or all of the post-training measures. CONCLUSIONS: The word-based auditory-training program examined here, one based on words having a high frequency of occurrence in American English, has been demonstrated to be efficacious in older adults with impaired hearing. Training on frequent words and frequent phrases generalized to sentences constructed from frequently occurring words whether spoken by talkers heard during training or by a novel talker.

Auditory speech recognition and visual text recognition in younger and older adults: similarities and differences between modalities and the effects of presentation rate.

PURPOSE: To examine age-related differences in auditory speech recognition and visual text recognition performance for parallel sets of stimulus materials in the auditory and visual modalities. In addition, the effects of variation in rate of presentation of stimuli in each modality were investigated in each age group. METHOD: A mixed-model design was used in which 3 independent groups (13 young adults with normal hearing, 10 elderly adults with normal hearing, and 16 elderly hearing-impaired adults) listened to auditory speech tests (a sentence-in-noise task, time-compressed monosyllables, and a speeded-spelling task) and viewed visual text-based analogs of the auditory tests. All auditory speech materials were presented so that the amplitude of the speech signal was at least 15 dB above threshold through 4000 Hz. RESULTS: Analyses of the group data revealed that when baseline levels of performance were used as covariates in the group analyses the only significant group difference was that both elderly groups performed worse than the young group on the auditory speeded-speech tasks. Analysis of individual data, using correlations, factor analysis, and linear regression, was generally consistent with the group data and revealed significant, moderate correlations of performance for similar tasks across modalities, but stronger correlations across tasks within a modality. This suggests that performance on these tasks was mediated both by a common underlying factor, such as cognitive processing, as well as modality-specific processing. CONCLUSION: Performance on measures of auditory processing of speech examined here was closely associated with performance on parallel measures of the visual processing of text obtained from the same participants. Young and older adults demonstrated comparable abilities in the use of contextual information in each modality, but older adults, regardless of hearing status, had more difficulty with fast presentation of auditory speech stimuli than young adults. There were no differences among the 3 groups with regard to the effects of presentation rate for the visual recognition of text, at least for the rates of presentation used here.

Effect of training on word-recognition performance in noise for young normal-hearing and older hearing-impaired listeners.

OBJECTIVE: The objective of this study was to evaluate the effectiveness of a training program for hearing-impaired listeners to improve their speech-recognition performance within a background noise when listening to amplified speech. Both noise-masked young normal-hearing listeners, used to model the performance of elderly hearing-impaired listeners, and a group of elderly hearing-impaired listeners participated in the study. Of particular interest was whether training on an isolated word list presented by a standardized talker can generalize to everyday speech communication across novel talkers. DESIGN: Word-recognition performance was measured for both young normal-hearing (n = 16) and older hearing-impaired (n = 7) adults. Listeners were trained on a set of 75 monosyllabic words spoken by a single female talker over a 9- to 14-day period. Performance for the familiar (trained) talker was measured before and after training in both open-set and closed-set response conditions. Performance on the trained words of the familiar talker were then compared with those same words spoken by three novel talkers and to performance on a second set of untrained words presented by both the familiar and unfamiliar talkers. The hearing-impaired listeners returned 6 mo after their initial training to examine retention of the trained words as well as their ability to transfer any knowledge gained from word training to sentences containing both trained and untrained words. RESULTS: Both young normal-hearing and older hearing-impaired listeners performed significantly better on the word list in which they were trained versus a second untrained list presented by the same talker. Improvements on the untrained words were small but significant, indicating some generalization to novel words. The large increase in performance on the trained words, however, was maintained across novel talkers, pointing to the listener's greater focus on lexical memorization of the words rather than a focus on talker-specific acoustic characteristics. On return in 6 mo, listeners performed significantly better on the trained words relative to their initial baseline performance. Although the listeners performed significantly better on trained versus untrained words in isolation, once the trained words were embedded in sentences, no improvement in recognition over untrained words within the same sentences was shown. CONCLUSIONS: Older hearing-impaired listeners were able to significantly improve their word-recognition abilities through training with one talker and to the same degree as young normal-hearing listeners. The improved performance was maintained across talkers and across time. This might imply that training a listener using a standardized list and talker may still provide benefit when these same words are presented by novel talkers outside the clinic. However, training on isolated words was not sufficient to transfer to fluent speech for the specific sentence materials used within this study. Further investigation is needed regarding approaches to improve a hearing aid user's speech understanding in everyday communication situations.