Speech and Hearing Sciences - Doctoral Theses

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    Perceptual and acoustic features of speech in individuals with Down syndrome and their impact on speech intelligibility
    (University College Cork, 2020-10) O'Leary, Deirdre; Lee, Alice; O'Toole, Ciara; Gibbon, Fiona; Irish Research Council
    Speech production involves five major components: respiration, phonation, articulation, resonance, and prosody and number of methods can be used to evaluate these aspects. Perceptual analysis methods are frequently employed; however, their reliability has been called into question. Acoustic analysis methods can provide a more objective view of certain aspects of speech production. For example, mean fundamental frequency can provide an accurate measure for vocal pitch. Due to a number of factors such as anatomical features and neurological involvement, difficulties with all five of the components of speech production have been frequently reported for people with Down syndrome (DS). When producing speech, the five components combine to produce a spoken message via the acoustic signal. The amount of acoustic signal that is transferred from the speaker to the listener is referred to as speech intelligibility. When a speaker’s speech intelligibility is reduced, it can negatively impact on their communication and affect their quality of life. Difficulties with speech intelligibility are common in people with DS. Reduced speech intelligibility can affect people with DS of all ages and may never be fully resolved. Several methods also exist for specifically measuring speech intelligibility. The most commonly used methods are rating scales and orthographic transcription. Some studies have examined how aspects of speech production contribute to speech intelligibility scores in different clinical populations. However, to date, no study has evaluated all five components of speech production in people with DS in one study or examined their impact on speech intelligibility. It is important to understand more about the nature of reduced speech intelligibility for this group in order to plan and deliver appropriate intervention. This thesis includes four studies which aimed to address the gap in knowledge around the nature of speech intelligibility difficulties in people with DS and its measurement. The speakers in all four studies were 30 adolescents and adults with DS aged 16 years and over. Thirty typical adolescent and adult speakers matched for age and gender were included in the second study to provide a comparison for acoustic analysis findings. Sixteen experienced listeners were recruited to judge the speech samples to obtain a measure of speech intelligibility. Another group of 16 listeners who were not experienced, were also recruited to judge speech intelligibility for the fourth study. Recruiting a group of inexperienced (naive) listeners allowed for comparison of speech intelligibility scores when judged by listeners who were exposed and not exposed to hearing unclear speech. Study 1 used perceptual analysis methods to evaluate the five major components of speech production–respiration, phonation, articulation, resonance, and prosody–for the speakers with DS. The experienced listeners then completed orthographic transcription of sentences to obtain a measure of speech intelligibility for the speakers with DS. Regression analysis was used to examine which perceptual parameters impacted on speech intelligibility scores. Results showed that a measure of phonation, breathiness, and a measure of articulatory accuracy, percent consonants correct, were the two strongest predictors of speech intelligibility. Study 2 was similar to the first study in that it also used regression analysis to examine which parameters impacted on speech intelligibility scores for the speakers with DS. However, in this case, acoustic analysis methods were used to evaluate the five components of speech production and a group of typical speakers was included to serve as a comparison. Results showed that the slope of the second formant of /ɑ/ and the voice onset time of /d/ were the strongest acoustic predictors of speech intelligibility for the speakers with DS. Study 3 investigated how language ability impacted on speech intelligibility for the speakers with DS. Regression analysis was used to examine which receptive language measures and expressive language measures contributed to speech intelligibility scores. Results showed that mean length of utterance was the strongest predictor of intelligibility for those with DS. Study 4 compared speech intelligibility scores using two different methods to measure intelligibility; and involved listeners with varying levels of experience to judge intelligibility. Orthographic transcription and visual analogue scale of sentences were used as the measurement methods of intelligibility. Results showed that speech intelligibility scores were significantly higher when orthographic transcription was used as the method of measurement compared to visual analogue scale. Results also showed that speech intelligibility scores were significantly higher when judged by the group of experienced listeners compared to the naive listener group across both measurement methods. This thesis concludes that, when all aspects of speech production are considered, speech and language therapists (SLTs) should be aware that voice quality can play an influential role in the speech intelligibility of those with DS. They should also take into account articulation, motor speech performance, and language ability when assessing and treating speech intelligibility for this group. Additionally, when obtaining a measure of speech intelligibility, SLTs should be aware that the method of measurement they choose to employ can impact on outcome scores and that different methods may be measuring different aspects of speech intelligibility. SLTs should also bear in mind that, as an experienced listener, their judgement of speech intelligibility for a speaker with DS may be different compared to when judged by an inexperienced listener. That is, even if an SLT perceives a speaker with DS to have a high level of speech intelligibility, the same speaker may not be so intelligible to listeners who are not familiar with the speech characteristics of people with DS. These findings have provided more insight into the nature of speech intelligibility difficulties in individuals with DS. If SLTs knew about these difficulties, they would be more informed when making decisions regarding assessment and treatment and may lead to be better communicative performance and increased quality of life for those with DS.
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    Perspectives on ICT-delivered aphasia rehabilitation: exploring feasibility, usability and acceptance of this mode of rehabilitation
    (University College Cork, 2019-10-03) Kearns, Áine; Kelly, Helen; Pitt, Ian; Health Research Board
    Background: Speech and language therapy can provide positive outcomes for people with aphasia after stroke. The intensity of therapy is a key component for successful rehabilitation outcomes but, due to resource constraints, it can be a challenge for services to provide intensive face-to-face rehabilitation. The availability of information and communication technologies (ICT) and software rehabilitation programmes offer the opportunity for intensive self-managed aphasia rehabilitation. However, it is important to establish the feasibility and acceptance of this mode of rehabilitation among those who are involved in aphasia rehabilitation; the person with aphasia (PwA) and the speech and language therapists (SLTs) who work with them. Research Aims: This thesis provides a unique perspective on the acceptance and usage of ICT-delivered aphasia rehabilitation for post-stroke aphasia. It aims to 1) investigate the feasibility of self-administered intensive ICT-delivered aphasia rehabilitation targeting auditory sentence comprehension deficits 2) explore the experiences and perspectives of people with aphasia engaging in this form of rehabilitation and 3) explore the perspectives of SLTs on the use of ICT in aphasia rehabilitation. Methods: The research in this thesis employs a mixed methods research design including: 1) participatory health research techniques in order to develop a user-designed aphasia-accessible feedback questionnaire on ICT usability and functionality 2) a mixed methods feasibility study to examine the outcomes, acceptance and usability of ICT-delivered aphasia rehabilitation targeting auditory comprehension at sentence level and 3) a descriptive qualitative study to explore speech and language therapists’ views of ICT-delivered aphasia rehabilitation. Results: The co-design process highlighted that people with aphasia can, and should, be included in all stages of the research process and especially in the development and design of evaluation measures for use by people with aphasia. The findings of the feasibility study suggest that an ICT-delivered therapeutic programme underpinned by a general approach to auditory comprehension does not result in significant treatment effects outside of assessments that reproduce the therapy task approach. ICT-delivered aphasia rehabilitation may be acceptable to some people with aphasia and has a role within rehabilitation. However, face-to-face contact remains a valued aspect of aphasia rehabilitation for both people with aphasia and SLTs. Attention must be given to the facilitating conditions required to support the PwA and the SLTs to enable this mode of intervention. Conclusion: This research is timely, with the rapid growth in available technologies and increasing demands for services among an ageing population. The users’ perspectives, both the PwA and the SLTs working with them, must not be overlooked when considering the impact of this mode of rehabilitation. This research identifies the factors that influence acceptance and usage of ICT-delivered aphasia rehabilitation within an Irish context.
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    Living with motor neurone disease (MND) and dysphagia – the personal experiences of people with MND and their caregivers
    (University College Cork, 2018) Lisiecka, Dominika; Kelly, Helen; Jackson, Jeanne; Health Research Board
    Introduction MND is a rare progressive neurodegenerative illness for which there is no cure. There are approximately 350 people diagnosed with MND in Ireland at any one time. Dysphagia frequently occurs in neurodegenerative diseases such as MND. Dysphagia is generally reported to interfere with the quality of life of PwMND; however, little is known about how people living with MND understand and experience dysphagia. Aims To explore the experiences of dysphagia in MND from the perspectives of PwMND and their caregivers in order to investigate: (1) how they understand dysphagia, (2) how dysphagia impacts their lives, (3) their coping strategies in relation to dysphagia, and (4) their experiences of professional services received to manage dysphagia. Methods In - depth interviews (n=58) were conducted with 10 PwMND and 10 caregivers from Ireland. Data was analysed utilising Interpretative Phenomenological Analysis whereby an idiographic approach was followed by a cross - case analysis of each group. Results It emerged that both groups approached dysphagia in a different manner. PwMND aimed to manage dysphagia on their own; however, the caregivers wished for increased professional support in specific areas, such as the management of choking. A changed perception of food and diminished eating - related pleasure was observed in both groups. Also, a difference was noted between participants' perception of their dysphagia and their clinical presentation. Participants expressed their views in relation to professional services received for dysphagia. Conclusion This study suggests that the experience of dysphagia in MND is complex and should not be investigated / managed in isolation. PwMND and their caregivers understand dysphagia differently and may have different expectations regarding dysphagia management.
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    Sealbhú na Gaeilge ag naíonáin: early language acquisition of Irish
    (University College Cork, 2009) O'Toole, Ciara; Fletcher, Paul; Health Service Executive, Ireland
    Speech and language therapy (SLT) services are coming under increased pressure to provide people living in linguistic minority communities with assessment and intervention in the language of the community in which the client lives. In Ireland, Irish, although a minority language, enjoys a positive attitude and a high status as the first official language of Ireland. However, there is little known about Irish language acquisition in typically developing children, let alone assessment or developmental pathways for speech and language therapists to work with. Furthermore, the study of Irish can make a valuable contribution to cross-linguistic research as it has structures which are very different to English such as a VSO word order, and complex morphophonological inflections in its initial mutations.  This study adapted a well-known research tool, the MacArthur-Bates Communicative Development Inventories, to Irish in order to measure vocabulary and grammatical development longitudinally for twenty-one children aged between 16 and 40 months. Results from the parent-checklists were validated against spontaneous language samples and elicitation tasks, and compared to crosslinguistic studies of early language development. The analysis explored theoretical questions such as whether there is a noun advantage in Irish, how grammar is acquired, and the nature of the relationship between the lexicon and grammar. In addition, other theoretical aspects such as the effect of gender, birth order and maternal education on early language milestones were investigated. The findings indicate that Irish-speaking children develop vocabulary at a relatively similar rate to other children but the content of their vocabulary is somewhat different, with a relative advantage in grammatical words once they have 400 words in their vocabulary. On the other hand, many inflectional morphemes are acquired relatively late, and this is largely due to their relative complexity. The outcomes of this study not only give SLTs a descriptive framework of the development of vocabulary and grammar in Irish but also contribute to the body of cross linguistic research.
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    Investigating relative clauses in children with specific language impairment
    (University College Cork, 2011) Frizelle, Pauline; Fletcher, Paul; Health Research Board
    Background: It is well documented that children with Specific Language Impairment (SLI) experience significant grammatical deficits. While much of the focus in the past has been on their morphosyntactic difficulties, less is known about their acquisition of complex syntactic structures such as relative clauses. The role of memory in language performance has also become increasingly prominent in the literature. Aims: This study aims to investigate the control of an important complex syntactic structure, the relative clause, by school age children with SLI in Ireland, using a newly devised sentence recall task. It also aims to explore the role of verbal and short-termworking memory in the performance of children with SLI on the sentence recall task, using a standardized battery of tests based on Baddeley’s model of working memory. Methods and Procedures: Thirty two children with SLI, thirty two age matched typically developing children (AM-TD) between the ages of 6 and 7,11 years and twenty younger typically developing (YTD) children between 4,7 and 5 years, completed the task. The sentence recall (SR) task included 52 complex sentences and 17 fillers. It included relative clauses that are used in natural discourse and that reflect a developmental hierarchy. The relative clauses were also controlled for length and varied in syntactic complexity, representing the full range of syntactic roles. There were seven different relative clause types attached to either the predicate nominal of a copular clause (Pn), or to the direct object of a transitive clause (Do). Responses were recorded, transcribed and entered into a database for analysis. TheWorkingMemory Test Battery for children (WMTB-C—Pickering & Gathercole, 2001) was administered in order to explore the role of short-term memory and working memory on the children’s performance on the SR task. Outcomes and Results: The children with SLI showed significantly greater difficulty than the AM-TD group and the YTD group. With the exception of the genitive subject clauses, the children with SLI scored significantly higher on all sentences containing a Pn main clause than those containing a transitive main clause. Analysis of error types revealed the frequent production of a different type of relative clause than that presented in the task—with a strong word order preference in the NVN direction indicated for the children with SLI. The SR performance for the children with SLI was most highly correlated with expressive language skills and digit recall. Conclusions and Implications: Children with SLI have significantly greater difficulty with relative clauses than YTD children who are on average two years younger—relative clauses are a delay within a delay. Unlike the YTD children they show a tendency to simplify relative clauses in the noun verb noun (NVN) direction. They show a developmental hierarchy in their production of relative clause constructions and are highly influenced by the frequency distribution of the relative clauses in the ambient language.