Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Theses
    • View Item
    • espace Home
    • espace
    • Curtin Theses
    • View Item

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

    187520_Highman2010.pdf (1.156Mb)
    Access Status
    Open access
    Authors
    Highman, Chantelle D.
    Date
    2010
    Supervisor
    Dr Suze Leitão
    Dr Neville Hennessy
    Type
    Thesis
    Award
    PhD
    
    Metadata
    Show full item record
    School
    School of Psychology and Speech Pathology
    URI
    http://hdl.handle.net/20.500.11937/1634
    Collection
    • Curtin Theses
    Abstract

    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.

    Related items

    Showing items related by title, author, creator and subject.

    • Prelinguistic communication development in children with childhood apraxia of speech: A retrospective analysis
      Highman, Chantelle; Leitao, Suze; Hennessey, Neville; Piek, Jan (2012)
      In a retrospective study of prelinguistic communication development, clinically referred preschool children (n = 9) aged 3–4 years, who as infants had failed a community-based screening program, were evaluated for features ...
    • The relationship between early feeding and communication development in preterm and term infants : birth to 12 months
      Smart, Sharon J (2008)
      The relationship between feeding development and early speech production has received increasing interest over the past 30 years. If a relationship between the motor control systems for feeding and communication is present, ...
    • Retrospective parent report of early vocal behaviours in children with suspected Childhood Apraxia of Speech (sCAS)
      Highman, Chantelle; Hennessey, Neville; Sherwood, M.; Leitao, Susan (2008)
      Parents of children with suspected Childhood Apraxia of Speech (sCAS, n = 20), Specific Language Impairment (SLI, n = 20), and typically developing speech and language skills (TD, n = 20) participated in this study, which ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.