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

Purpose: To compare the effectiveness of three 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 normally-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 nine 20-minute training sessions on separate days over a 2-3-week period. The effectiveness of training was assessed as the improvement in accuracy of discriminating vowels and consonants, and 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. Conclusions: The word- and sentence-based training strategies were more effective than the phoneme-based strategy at improving the perception of spectrally-distorted speech

The effect of audiovisual speech training on the phonological skills of children with specific language impairment (SLI)

We developed a computerized audiovisual training programme for school-aged children with specific language impairment (SLI) to improve their phonological skills. The programme included various tasks requiring phonological decisions. Spoken words, pictures, letters and written syllables were used as training material. Spoken words were presented either as audiovisual speech (together with the talking face), or as auditory speech (voice alone). Two groups (10 children/group) trained for six weeks, five days per week: the audiovisual group trained with audiovisual speech, and the other group received analogically the same training but with auditory speech. Before and after training, language skills and other cognitive skills were assessed. The audiovisual group improved in a non-word-repetition test. Such improvement was not observed with auditory training. This result suggests that audiovisual speech may be helpful in the rehabilitation of children with SLI.Peer reviewe

Development of Bisyllabic Speech Audiometry Word Lists for Adult Malay Speakers

Standardised speech audiometry material is essential in assessing hearing for speech; however, material in Malay language, particularly for speech reception threshold test, is limited and not thoroughly validated. This thesis examines the development of standardised, phonemically-balanced bisyllabic Malay speech reception threshold (SRT) test word lists for Malay-speaking adults. The effect of having a mixture of familiar and nonsense words on speech recognition is also explored. The processes of developing the word lists include selecting and compiling the words using content analysis research method, testing for homogeneity and consistency and validating the acoustic content, both using correlational research method, and assessing the clinical validity using concurrent validity method. The familiar words were selected from a corpus of familiar words extracted from daily newspapers while the nonsense words were formed based on linguistic properties of Malay. The preliminary set consisted of fifteen lists with 10 familiar words and 5 nonsense words in each. The analyses of the findings show consistency of speech discrimination using the word lists using Friedman test to have statistically no significant difference in correct scores achieved using any of the word lists, Χ2 = 19.584, p>0.05. Homogeneity test for all lists using Cronbach’s alpha showed a value of 0.78, indicating a strong agreement and good homogeneity among the lists. When five lists with inter-item correlation ≤0.8 were excluded from the homogeneity analysis, the alpha value for the remaining 10 lists increased to 0.88. Consistency analysis of acoustic content using repeated measures ANOVA showed no significant difference between the list and the LTASS, F=1.229, p>0.05. All 15 lists were then tested for clinical validity. Two versions of list content were assessed, an all-words version (AWL) containing all 15 words each list, and a meaningful-words only version (MWL) containing 10 meaningful words for each list. Correlation analyses between half peak level (HPL) of the speech recognition curve and pure tone (PT) thresholds showed that, in consideration of both normal hearing and hearing impaired listeners, the HPL correlated best with PT average of 250, 500, 1000, 2000 and 4000 Hz for both AWL (r = 0.67 to 0.95) and MWL (r = 0.65 to 0.95). A comparison between HPL and PT average of 250, 500, 1000, 2000 and 4000 Hz showed mean differences of 4 dB (SD = 3) and 3 dB (SD = 4) with the range of tolerance (95% confidence) of ±7 dB and ±8 dB for AWL and MWL respectively. Sensitivity, specificity, and positive and negative predictive values, when set at tolerance level of ±10 dB, were mostly >0.90 for normal hearing and hearing loss listeners using either versions. It was concluded that the addition of nonsense words does not significantly affect SRT. The correlation between the SRT obtained using the bisyllabic Malay word lists and the PT thresholds suggested that the word lists were robust enough to be used in assessing speech hearing clinically. In conclusion, the current study has achieved to develop and produce a standardised, phonemically balanced bisyllabic Malay speech audiometry (BMSA) word lists for assessing speech reception threshold and discrimination in adult Malay speakers

Auditory training and adult rehabilitation:a critical review of the evidence

Auditory Training (AT) describes a regimen of varied listening exercises designed to improve an individual’s ability to perceive speech. The theory of AT is based on brain plasticity (the capacity of neurones in the central auditory system to alter their structure and function) in response to auditory stimulation. The practice of repeatedly listening to the speech sounds included in AT exercises is believed to drive the development of more efficient neuronal pathways, thereby improving auditory processing and speech discrimination. This critical review aims to assess whether auditory training can improve speech discrimination in adults with mild-moderate SNHL. The majority of patients attending Audiology services are adults with presbyacusis and it is therefore important to evaluate evidence of any treatment effect of AT in aural rehabilitation. Ideally this review would seek to appraise evidence of neurophysiological effects of AT so as to verify whether it does induce change in the CAS. However, due to the absence of such studies on this particular patient group, the outcome measure of speech discrimination, as a behavioural indicator of treatment effect is used instead. A review of available research was used to inform an argument for or against using AT in rehabilitative clinical practice. Six studies were identified and although the preliminary evidence indicates an improvement gained from a range of AT paradigms, the treatment effect size was modest and there remains a lack of large-sample RCTs. Future investigation into the efficacy of AT needs to employ neurophysiological studies using auditory evoked potentials in hearing-impaired adults in order to explore effects of AT on the CAS