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

The importance of "scaffolding" in clinical approach to deafness across the lifespan

Throughout the present work of thesis, the concept of scaffolding will be used as a fil rouge through the chapters. What I mean for “scaffolding approach”, therefore, is an integrated and multidisciplinary clinical and research methodology to hearing impairments that could take into account persons as a whole; an approach that needs to be continuously adapted and harmonized with the individuals, pursuant to their progress, their limits and resources, in consideration of their audiological, cognitive, emotional, personal, and social characteristics. The following studies of our research group will be presented: A study (2020) designed to assess the effects of parent training (PT) on enhancing children’s communication development (chapter two); Two studies of our research group (2016; 2020) concerning variables influencing comprehension of emotions and nuclear executive functions in deaf children with cochlear implant (chapter three and chapter four) In chapter five a presentation and description of our Mind-Active Communication program, main topics and aims, multidisciplinary organizations of group and individual sessions with a description of used materials and methodology is given. Finally, a preliminary evaluation to explore the use of this multidisciplinary rehabilitative program on quality of life, psychological wellbeing, and hearing abilities in a sample of cochlear implanted elderly persons is reported

The Effects of Neurocognitive Aging on Sentence Processing

Across the lifespan, successful language comprehension is crucial for continued participation in everyday life. The success of language comprehension relies on the intact functioning of both language-specific processes as well as domain-general cognitive processes that support language comprehension in general. This two-sided nature of successful language comprehension may contribute to the two diverging observations in healthy aging: the preservation and the decline of language comprehension on both the cognitive and the neural level. To date, our understanding of these two competing facets is incomplete and unclear. While greater language experience comes with increasing age, most domain-general cognitive functions, like verbal working memory, decline in healthy aging. The here presented thesis shows that when the electrophysiological network relevant for verbal working memory is already compromised at rest, language comprehension declines in older adults. Moreover, it could be shown that, as verbal working memory capacity declines with age, resources may be- come insufficient to successfully encode language-specific information into memory, yielding language comprehension difficulties in old age. Age differences in the electrophysiological dynamics underlying sentence encoding indicate that the encoding of detailed information may increasingly be inhibited throughout the lifespan, possibly to avoid overloading the verbal working memory. However, limitations in verbal working memory could be attenuated by the use of language-specific constraints. That is, semantic and syntactic constraints can be used to establish relations between words which reduces the memory load from individual word information to information about word group. Here, it was found that older adults do not benefit from the use of syntactic constraints as much as younger adults while the benefit of using semantic constraints was comparable across age. Overall, the here presented thesis suggests that previous findings on language comprehension in healthy aging are not contradictory but rather converge on a simultaneous combination of selective preservation and decline of various language-specific processes, burdened by domain-general neurocognitive aging

Individual and environment-related acoustic-phonetic strategies for communicating in adverse conditions

In many situations it is necessary to produce speech in ‘adverse conditions’: that is, conditions that make speech communication difficult. Research has demonstrated that speaker strategies, as described by a range of acoustic-phonetic measures, can vary both at the individual level and according to the environment, and are argued to facilitate communication. There has been debate as to the environmental specificity of these adaptations, and their effectiveness in overcoming communication difficulty. Furthermore, the manner and extent to which adaptation strategies differ between individuals is not yet well understood. This thesis presents three studies that explore the acoustic-phonetic adaptations of speakers in noisy and degraded communication conditions and their relationship with intelligibility. Study 1 investigated the effects of temporally fluctuating maskers on global acoustic-phonetic measures associated with speech in noise (Lombard speech). The results replicated findings of increased power in the modulation spectrum in Lombard speech, but showed little evidence of adaptation to masker fluctuations via the temporal envelope. Study 2 collected a larger corpus of semi-spontaneous communicative speech in noise and other degradations perturbing specific acoustic dimensions. Speakers showed different adaptations across the environments that were likely suited to overcome noise (steady and temporally fluctuating), restricted spectral and pitch information by a noise-excited vocoder, and a sensorineural hearing loss simulation. Analyses of inter-speaker variation in both studies 1 and 2 showed behaviour was highly variable and some strategy combinations were identified. Study 3 investigated the intelligibility of strategies ‘tailored’ to specific environments and the relationship between intelligibility and speaker acoustics, finding a benefit of tailored speech adaptations and discussing the potential roles of speaker flexibility, adaptation level, and intrinsic intelligibility. The overall results are discussed in relation to models of communication in adverse conditions and a model accounting for individual variability in these conditions is proposed

The development of the Arabic lexical neighbourhood test

Speech perception is a primary outcome measure in children using cochlear implants (CI). Saudi Arabia has a high prevalence of hearing loss, however, there are no appropriate measures to assess communication skills in these children post cochlear implantation. This thesis describes the development and application of an Arabic version of the Lexical Neighbourhood Test (Kirk, Pisoni, & Osberger, 1995) for children using CIs in Saudi Arabia. Study 1 consisted of language sampling and developing the Arabic Lexical Neighbourhood Test (ALNT) word lists. Study 2 examined performance of normal hearing (NH) children on the ALNT in two conditions: in noise and in quiet via vocoded speech simulating a CI. Study 3 investigated the performance of CI children on the ALNT in quiet over time, with 3 measurements made over a period of approximately 18 months. In general, results indicated that the ALNT was a reliable speech perception test. Both CI and NH children consistently scored higher on the easy words than the hard words which is consistent with the effects of the lexical factors of word frequency and neighbourhood density on speech perception. Another factor that was also explored was whether repeated administration of test items affected performance. In NH children, when time intervals between first and second administration was 2-4 weeks, repetition effects were evident. In CI children however, when the test intervals between repeated administrations was 6-9 months apart, repetition effects were not evident. This demonstrates that the ALNT can be used repeatedly without affecting speech perception performance. Finally, the sensitivity of the ALNT to change in performance over time was compared to a nonsense CV test that was also administered to CI children over three sessions. The CV test was found to be more sensitive to change over time than the ALNT

Re-examining Phonological and Lexical Correlates of Second Language Comprehensibility:The Role of Rater Experience

Few researchers and teachers would disagree that some linguistic aspects of second language (L2) speech are more crucial than others for successful communication. Underlying this idea is the assumption that communicative success can be broadly defined in terms of speakers’ ability to convey the intended meaning to the interlocutor, which is frequently captured through a listener-based rating of comprehensibility or ease of understanding (e.g. Derwing & Munro, 2009; Levis, 2005). Previous research has shown that communicative success – for example, as defined through comprehensible L2 speech – depends on several linguistic dimensions of L2 output, including its segmental and suprasegmental pronunciation, fluency-based characteristics, lexical and grammatical content, as well as discourse structure (e.g. Field, 2005; Hahn, 2004; Kang et al., 2010; Trofimovich & Isaacs, 2012). Our chief objective in the current study was to explore the L2 comprehensibility construct from a language assessment perspective (e.g. Isaacs & Thomson, 2013), by targeting rater experience as a possible source of variance influencing the degree to which raters use various characteristics of speech in judging L2 comprehensibility. In keeping with this objective, we asked the following question: What is the extent to which linguistic aspects of L2 speech contributing to comprehensibility ratings depend on raters’ experience