Why is prosody in speech-language pathology so difficult?

An important question for speech-language pathologists is how best to define and characterize atypical prosody, with the eventual aim of designing effective intervention for it. With a view to investigating why prosodic atypicality should be hard to define and what considerations a speech-language pathologist should keep in mind, this paper begins by setting out some established functions of prosody and the forms that convey them, and goes on to review the neurological bases of prosodic disorder and some of the conditions in which prosodic disorder is known to occur. Factors in the perception of prosodic disorder are discussed, including the relationship between prosody and other aspects of communication, to identify the problems of distinguishing between prosody and interacting factors. The relationship between phonological prosodic categories and disordered prosody is considered, i.e., the problems of assigning disordered prosody to these categories for clinicians. Current methods of assessment, transcription and approaches to treatment are briefly considered, and an evaluation is made of how much progress has been made towards answering the initial question.casl11pub1162pub

Speech and Prosody in developmental disorders: Autism and Down's Syndrome

Language impairment is a key characteristic of many developmental disorders, with the relationship between linguistic and cognitive ability a critical topic for research in this field. Speech (articulation and phonology) and prosody have largely been absent from these discussions, perhaps because they are not universally impaired. The portfolio of published research critically appraised here addresses the relationships between speech and prosody and other domains, such as language and cognition, in two conditions in which disordered speech is common: primarily at the suprasegmental level in autism and at the segmental level in Down’s syndrome. Speech disorders were found in both conditions, though speech was much more severely impaired in Down’s syndrome. Errors were typically categorised as delayed phonological processes, implying a linguistic cause. However, through fine phonetic transcription and instrumental techniques it was shown that both conditions also presented with distortions that were more phonetic in nature and with non-developmental errors. Severity of speech disorder was not related to cognitive or linguistic ability as measured by standardised assessments, suggesting that a generalised delay in language or cognition was not the cause of disordered speech. In autism minor delays and distortions may be due to a lack of ability to identify with peers and impaired theory of mind, whereas in Down’s syndrome anatomical differences and difficulty with motor planning are likely causes. Both linguistic and paralinguistic prosody were found to be disordered in children with autism and correlations with linguistic ability were found. However, disordered prosody is more likely to be due to impaired theory of mind or weak central coherence than a result of delayed language. Both autism and Down’s syndrome present with speech that is disordered rather than simply delayed and this is unlikely to be due to delayed language, suggesting that specific, targeted intervention may be warranted.sub_shsunpub622_ethesesunpu

Brain Imaging Correlates of Developmental Coordination Disorder and Associated Impairments

Developmental Coordination Disorder (DCD) is a common developmental disorder characterised by an inability to learn age appropriate complex motor skills. The first aim of this thesis was to characterise additional cognitive impairments and their relationship with motor difficulties in school aged children with DCD. The second aim was to investigate grey and white matter neuroimaging correlates of motor and cognitive deficits identified. Thirty six children aged 8-10 years who met DSM-5 criteria for DCD and an age-matched typically developing group (N=17) underwent standardised assessments of motor, intellectual, attention, speech and language skills as well as structural and diffusion-weighted MRI scans. Grey matter correlates of impairments were identified using subcortical volumetrics and surface-based analyses of cortical morphology. White matter correlates were examined using tractography and fixel-based fibre morphology of the pyramidal tracts, corpus callosum and cerebellar peduncles. Alongside impaired motor skills, children with DCD performed poorer than controls on several domains of executive function (attention and processing speed) and speech motor control. Motor skills did not correlate with impairments in other domains. Cortical thickness was significantly reduced in the left central sulcus in children with DCD compared to controls. Poor motor skills correlated with measures in left sensorimotor circuitry, posterior cingulate cortex and anterior insula. Poor speech motor control was associated with measures in the thalamus and corticobulbar tract. Poor sustained attention was linked to measures in the right superior cerebellar peduncle. Lower processing speed was associated with reduced mean cortical surface area. Children with DCD show co-occurring impairments in attention and speech motor control. DCD is associated with sensorimotor circuits as well as regions that form part of the default mode and salience networks. Disruption of subcortical circuits may underlie additional impairments. This study provides novel evidence of the neural correlates of DCD

Discrimination of duration differences of typically developing children and children with suspected childhood apraxia of speech

The speech sound disorder, childhood apraxia of speech (CAS), has perplexed clinicians and researchers for many years. The perplexity has stemmed, in part, from questions about identifying characteristics that distinguish it from other childhood speech disorders. Given the reported vowel duration deficits cited in the speech production of children with sCAS, the research for this population is deficient in assessing the ability of these children to discriminate vowel duration differences. The present study represents an initial attempt to address duration discrimination in a systematized experimental design for a group of school-age TD children (n = 21) and a smaller group of school-age children diagnosed with sCAS (n = 11). All children were asked to judge whether pairs of non-word single syllable tokens (digital recordings of single syllable /ba/ varying in vowel duration only) were the same or different. Using an AX paradigm, children in the current study compared a stimulus (X), which varied across trials, with a constant standard (A). The standard A interval was the stimulus with the shortest vowel duration (208 ms) and the X interval was the comparison stimuli (i.e., vowel duration = 208 ms, 248 ms, 288 ms, 328 ms, 368 ms, 408 ms, 448 ms, or 488 ms). Fundamental frequency and amplitude measures were controlled to remain uniform. Assessing the ability of the TD population to detect duration differences in a specific experimental paradigm was prerequisite to addressing the ability of children with sCAS to detect duration differences in the same experimental task. The results of this preliminary investigation of discrimination of vowel duration in children with sCAS suggest that further research on duration discrimination skills is warranted in this population. As a group, children with sCAS displayed poorer performance on the vowel duration discrimination experimental task, compared to a similarly-aged TD group

An automated lexical stress classification tool for assessing dysprosody in childhood apraxia of speech

Childhood apraxia of speech (CAS) commonly affects the production of lexical stress contrast in polysyllabic words. Automated classification tools have the potential to increase reliability and efficiency in measuring lexical stress. Here, factors affecting the accuracy of a custom-built deep neural network (DNN)-based classification tool are evaluated. Sixteen children with typical development (TD) and 26 with CAS produced 50 polysyllabic words. Words with strong–weak (SW, e.g., dinosaur) or WS (e.g., banana) stress were fed to the classification tool, and the accuracy measured (a) against expert judgment, (b) for speaker group, and (c) with/without prior knowledge of phonemic errors in the sample. The influence of segmental features and participant factors on tool accuracy was analysed. Linear mixed modelling showed significant interaction between group and stress type, surviving adjustment for age and CAS severity. For TD, agreement for SW and WS words was >80%, but CAS speech was higher for SW (>80%) than WS (~60%). Prior knowledge of segmental errors conferred no clear advantage. Automatic lexical stress classification shows promise for identifying errors in children’s speech at diagnosis or with treatment-related change, but accuracy for WS words in apraxic speech needs improvement. Further training of algorithms using larger sets of labelled data containing impaired speech and WS words may increase accuracy

Models and Analysis of Vocal Emissions for Biomedical Applications

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies

Exploring the use of Technology for Assessment and Intensive Treatment of Childhood Apraxia of Speech

Given the rapid advances in technology over the past decade, this thesis examines the potential for automatic speech recognition (ASR) technology to expedite the process of objective analysis of speech, particularly for lexical stress patterns in childhood apraxia of speech. This dissertation also investigates the potential for mobile technology to bridge the gap between current service delivery models in Australia and best practice treatment intensity for CAS. To address these two broad aims, this thesis describes three main projects. The first is a systematic literature review summarising the development, implementation and accuracy of automatic speech analysis tools when applied to evaluation and modification of children’s speech production skills. Guided by the results of the systematic review, the second project presents data on the accuracy and clinical utility of a custom-designed lexical stress classification tool, designed as part of a multi-component speech analysis system for a mobile therapy application, Tabby Talks, for use with children with CAS. The third project is a randomised control trial exploring the effect of different types of feedback on response to intervention for children with CAS. The intervention was designed to specifically explore the feasibility and effectiveness of using an app equipped with ASR technology to provide feedback on speech production accuracy during home practice sessions, simulating the common service delivery model in Australia. The thesis concludes with a discussion of future directions for technology-based speech assessment and intensive speech production practice, guidelines for future development of therapy tools that include more game-based practice activities and the contexts in which children can be transferred from predominantly clinician-delivered augmented feedback to ASR-delivered right/wrong feedback and continue to make optimal gains in acquisition and retention of speech production targets

The role of autistic traits in the perception of emotion from faces and voices: a behavioural and fMRI investigation

This thesis combined behavioural and fMRI approaches in the study of the role of autistic traits in the perception of emotion from faces and voices, addressing research questions concerning: behavioural recognition of a full range of six basic emotions across multiple domains (face, voice, and face-voice); neural correlates during the processing of a wide range of emotional expressions from the face, the voice and the combination of both; neural circuity in responding to an incongruence effect (incongruence vs. congruence). The behavioural study investigated the effects of autistic traits as quantified by the Autism- Spectrum Quotient (AQ) on emotional processing in forms of unimodal (faces, voices) and crossmodal (emotionally congruent face-voice expressions) presentations. In addition, by taking into account the degree of anxiety, the role of co-morbid anxiety on emotion recognition in autistic traits was also explored. Compared to an age and gender-matched group of individuals with low levels of autistic traits (LAQ), a trend of no general deficit was found in individuals with high levels of autistic traits (HAQ) in recognizing emotions presented in faces and voice, regardless of their co-morbid anxiety. However, co-morbid anxiety did moderate the relationship between autistic traits and the recognition of emotions (e.g., fear, surprise, and anger), and this effect tended to be different for the two groups. Specifically, with greater anxiety, individuals with HAQ were found to show less probility of correct response in recognizing the emotion of fear. In contrast, individuals with LAQ showed greater probability of correct response in recognizing fear expressions. For response time, anxiety symptoms tended to be significantly associated with greater response latency in the HAQ group but less response latency in the LAQ group in the recognition of emotional expressions, negative emotions in particular (e.g., anger, fear, and sadness); and this effect of anxiety was not restricted to specific modalities. Despite the absence of finding a general emotion recognition deficit in individuals with considerable autistic traits compared to those with low levels of autistic traits, it did not necessarily mean that these two groups shared same neural network when processing emotions. Therefore, it was useful to explore the neural correlates engaged in processing of emotional expressions in individuals with high levels of autistic traits. Results of this investigation tended to suggest a hypo activation of brain areas dedicated to multimodal integration, particularly for displays showing happiness and disgust. However, both the HAQ group and LAQ group showed similar patterns of brain response (mainly in temporal regions) in response to face-voice combination. In response to emotional stimuli in single modality, the HAQ group activated a number of frontal and temporal regions (e.g., STG, MFG, IFG); these differences may suggested a more effortful and less automatic processing in individual with HAQ. In everyday life, emotional information is often conveyed by both the face and voice. Consequently, concurrently presented information by one source can alter the way that information from the other source is perceived and leads to emotional incongruence if information from the two sources was incongruent. Using fMRI, the present work also examined the neural circuity involved in responding to an incongruence effect (incongruence vs. congruence) from face-voice pairs in a group of individuals with considerable autistic traits. In addition, the differences in brain responses for emotional incongruity between explicit instructions to attend to facial expression and explicit instructions to attend to tone of voice in autistic traits was also explored. It was found that there was no significant incongruence effect between groups, given that individuals with a high level of autistic traits are able to recruit more normative neural networks for processing incongruence as individuals with a low level of autistic traits, regardless of instructions. Though no between group differences, individuals with HAQ showed negative activation in regions involved in the default- mode network. However, taken into account changes of instructions, a stronger incongruence effect was more likely to be occurred in the voice-attend condition for individuals with HAQ while in the face-attend condition for individuals with LAQ

Early speech motor and language skills in childhood apraxia of speech: evidence for a core deficit in speech motor control?

Children with childhood apraxia of speech (CAS) present with significant speech production deficits, the effects of which often persist well into late childhood (American Speech-Language-Hearing Association, 2007; Lewis, Freebairn, Hansen, Iyengar, & Taylor, 2004). Debate has historically surrounded whether the features of CAS are the result of an impairment in linguistic or speech motor systems, or both (American Speech-Language-Hearing Association, 2007). Most research, however, has failed to explicitly consider a developmental perspective of the disorder, arguably limiting the associated interpretations that often (implicitly) assume an established underlying system (Maassen, 2002). One of the key tenets of such a developmental perspective is the possibility of an original core deficit in one system, with negative consequences for aspects of the system that subsequently develop.A mixed-methodology paradigm was employed in the present research in order to explore the core deficit in CAS. Similar paradigms have been applied to the study of dyslexia (Koster et al., 2005; Lyytinen et al., 2001; Viholainen et al., 2006) and autism spectrum disorders (Coonrod & Stone, 2004; Dawson, Osterling, Meltzoff, & Kuhl, 2000; Iverson & Wozniak, 2007), but have yet to be applied to CAS.Study 1 sought to quantify parental report of vocalisation behaviours in children with a clinical diagnosis of CAS. The parents of 20 children with suspected CAS (sCAS) completed a questionnaire focussing on the prelinguistic development of their children as infants. Responses were compared to those from parents of 20 children with Specific Language Impairment (SLI) and 20 children with typically developing (TD) speech and language development. The sCAS children were reported to be significantly less vocal, less likely to have babbled, later in the emergence of first words and later in the emergence of two-word combinations than the TD children. However, the SLI children were reported similarly on many (but not all) items. Despite this similarity, the sCAS group were unique in terms of the presence of reported babbling (35% were reported not to have babbled at all, compared to the TD and SLI children who were all recalled as having babbled in infancy), and the emergence of two word combinations (significantly later than both the TD and SLI groups). In addition, the motor milestones of age of crawling and age of walking were significantly correlated with age of emergence of two-word combinations in the sCAS group, suggesting commonly constrained speech and motor development. Overall, the results provided preliminary support for the notion of atypical prelinguistic vocal development in children with sCAS, and highlighted the importance of further research on the topic.Study 2 applied a retrospective data paradigm in exploring the prelinguistic vocal development of children with CAS. Nine clinically-ascertained children, aged 3 to 4 years and presenting with a range of speech and language profiles (including 3 with suspected CAS), were characterised in terms of operationally-defined CAS characteristics in the first stage (2A) of this study. The battery of tasks included standardised speech and language assessments as well as non-standardised tasks targeting speech production ability. A group of 21 age-matched children with typically developing speech and language skills provided comparison data for the non-standardised tasks. This phase of the study documented CAS characteristics in five of the nine clinical sample participants, with two of these children showing all five of the features investigated. Study 2B examined the early speech, language and motor development of the clinical sample children, via analysis of data available retrospectively for this unique group of children.Their infant profiles were compared to those of 205 infants who had been part of the same community program that the clinical sample had been involved in (and thus had infant data available) but who did not have identified ongoing speech and language issues. Single case comparisons (Crawford & Garthwaite, 2005) revealed that the child with the greatest number and severity of CAS features at preschool age demonstrated significantly poorer expressive skills and a significant dissociation in receptive-expressive abilities in infancy, compared to the typically developing children. Profiles for the other clinical sample children varied considerably.In the third study (Study 3), the development of infants with a family history of CAS (n = 8) was compared to that of infants with no such familial risk (n =8) to further examine the proposed core deficit in CAS. Early speech, language and motor development was tracked at 9, 12, 15, 18 and 24 months. The siblings as a group demonstrated significantly poorer expressive language, speech sound development and fine motor ability than the comparison group, consistent with the notion of a verbal trait deficit (Lewis, Freebairn, Hansen, Taylor et al., 2004). At two years of age, two siblings (and none of the comparison infants) showed clinically-important delays in speech and language development. Inspection of their profiles suggested one infant (SIB2) to present with features consistent with putative early features of CAS (Davis & Velleman, 2000); the other (SIB1) to present with language difficulties not suggestive of CAS.Analysis of their vocalisation samples revealed that while SIB2’s rate of vocalisations at 9 months was not different to that of the comparison group, the nature of the vocalisations were different. While all comparison infants were using canonical syllables at 9 months, SIB2 had not entered this important stage until 12 months, and showed a significantly reduced proportion of canonical syllables at this age (2.5% compared to the comparison infants, who averaged 17%, with none producing less than 6%). Acoustic analyses performed on prelinguistic canonical syllables showed that while duration did not differ, a restricted use of the F1:F2 planar space was noted for SIB2 compared to the typically developing infants, suggesting limited vowel production. Furthermore, a particularly strong correlation between F1 and F2 was observed, suggesting stronger coupling of the articulators. Importantly, the vocalisation data, together with data from standardised assessments, showed a dissociation between speech motor and conceptualiser areas, with a deficit in speech motor control evident in the context of intact conceptual skills for this infant. In contrast, SIB1 (who showed a language delayed profile at 2 years, with no CAS features) did not evidence the types of anomalies identified for SIB2.Taken together, the results of the present research provide support for the viability of a speech motor control deficit account of CAS, when interpreted in a developmental context. As such, they highlight the importance of the prelinguistic period and longitudinal investigations in examining the underlying core deficit in CAS, and suggest important implications for theoretical and clinical conceptualisations of the disorder