Investigating the development of a developmental disorder : mapping the trajectory of lexical development in specific language impairment

PhD ThesisThere is increasing consensus that to understand developmental disorders we must apply developmental theoretical models and methodologies. To develop a fully specified developmental model of a developmental disorder we must understand both the nature of the innate causal processing deficits of the disorder and also how these deficits in early processing mechanisms then change the developmental process. This study aimed to examine the second of these issues with respect to Specific Language Impairment (SLI) and so describe the altered trajectory of development in this group of children. Explanatory models which propose hypothetical trajectories of development from impaired processing mechanisms in the infant to the patterns of linguistic impairments typically found in SLI are beginning to be developed. To date however there is very little empirical research which maps these trajectories. This study sought to contribute to that necessary empirical data and so to our understanding of the development of SLI. In addition it aimed to consider whether the application of a developmental methodology and perspective adds to our understanding of this disorder. A series of longitudinal case studies of children with SLI were completed. The participants were seen for four blocks of comprehensive assessment of language processing, language knowledge and "language relevant" processing over a 15 month time period. Cross sectional data from 38 typically developing (TD) children was also collected for comparison purposes. The data presented represents a part of this larger study and focuses on the development of the lexicon in SLI. Lexical and phonological processing and their interaction with phonological working memory capacity are thought to be crucial to the ontogeny of SLI. A series of tasks were developed to create a window into the nature of the developing lexicon. Data is presented from a novel non-word repetition task which manipulated the phonological characteristics of the stimuli and from a fast-mapping task where both phonological and lexical variables were manipulated. The influence of these factors on performance and changes in their influence across development were examined. Analysis of the trajectory of development of the two measures in TD children showed evidence of increasing abstraction of sub-lexical/phonological knowledge from lexical knowledge across development. In addition the developmental trajectory of fast mapping abilities demonstrated a significant and radical shift in processing bias across the age range. This result suggests that functional reorganisation in the developing lexicon, and hence the speech processing mechanism, may be taking place and which may occur as a result of increasing sub-lexical/phonological abstraction. The developmental trajectories of the children with SLI suggest that this group of children develop a different lexical processing architecture from typically developing children which does not reach the levels of efficiency of TD children's speech processing mechanisms. There is tentative support for a deficit in schema abstraction across the lexicon and an absence of functional reorganisation. The possibility that these results represent entrenchment within a self-organising network, and the possible relationship to issues of timing and critical periods is discussed. In addition it appears that compensatory strategies for this inefficient speech processing architecture may result in impaired semantic learning and so may have effects on the wider trajectory of atypical language development in SLI. Applying a developmental emergent perspective to SLI and so considering trajectories of development rather than static group comparisons can begin to uncover the nature of change within an interactive system and the nature of interdependence of processing mechanisms across development. Such an approach holds promise for revealing the nature of SLI and providing a more ecologically valid explanation of this complex disorder. The implications of developmental emergent conceptualisations of language impairment for research methodologies, diagnosis and therapy are discussed

The Role of Social and Emotional Adjustment in Mediating the Relationship Between Early Experiences and Different Language Outcomes

Background: Studies have highlighted the relationship between early childhood experiences and later language and communication skills on the one hand and social and emotional adjustment on the other. Less is known about this relationship between different types of early experiences and their relationship to different communication skills over time. Equally important is the extent to which the child's behaviour is related to later outcomes affecting the relationship between the child's environment and aspects of their communication development. Method: Drawing on data from 5,000 children in Growing Up in Scotland, a representative sample of children born in 2003. This paper looks are the differential relationships between home learning environment (HLE) (reads books/storeys, engages in painting or drawing, reads nursery rhymes and teaches letter/shapes and parental mental health (PMH) (Depression, Anxiety and Stress Scale (DASS) in the first year of life and both structural language skills (“Listening Comprehension” and “Expressive Vocabulary” subtests of The Wechsler Individual Achievement Tests) and pragmatic competence (The Children's Communication Checklist) at 11 years and explores the extent to which they are mediated by social and emotional adjustment at school entry. Results: PMH was associated with pragmatics but not listening comprehension or vocabulary. By contrast HLE was associated with all three measures of communication. In the final mediated model social and emotional adjustment mediated the relationship between PMH and all three measures of communication. The mediation was statistically significant for the relationship between HLE and both pragmatics and listening comprehension but not for expressive vocabulary. The results are discussed in terms of the relationships concerned and what they tell us about the potential for targeted early interventions. Conclusions: The mediating role of socio-emotional adjustment at school entry points to the need for careful monitoring of children's social and emotional development in primary and middle childhood. Services and policy aimed at improving child outcomes through improving home learning environments must work hand in hand with those responsible for offering support for the mental health, social-emotional adjustment and wellbeing of parents and children from birth and into the school years

Training community health nurses to measure parent–child interaction: a mixed-methods study

Background This study aims to determine whether the Parental Responsiveness Rating Scale (PaRRiS) completed at child age 24–30 months can be used by community child health nurses (CCHNs) to reliably measure the quality of parent–child interactions in practice. Methods A mixed-methods design was used involving CCHNs working in public health settings. Five CCHNs recruited from the North-East of England were trained to use PaRRiS. Thirty parent–child dyads attending their routine 24–30-month check were observed. Nurses rated parent–child dyads during 5 min of free-play using PaRRiS. The free-play sessions were video recorded and rated blind by the first author to the nurse observation. Semi-structured phone interviews were conducted with the five CCHNs once observations of parent–child interactions were complete. Interviews were audio-recorded, transcribed, anonymized and thematically analyzed. Results Two-thirds of participating parents were mothers. Half the families (15/30) were from the 10% most deprived areas based on the English Index of Multiple Deprivation. The average PaRRiS score was 3.03 [standard deviation (SD) = 0.8; all ratings were <5.0]. Reliability between the first author (‘gold standard’) and CCHNs was excellent [Intra-class correlation coefficient (ICC): 0.85; 95% confidence interval (CI): 0.67–0.93]. CCHNs found PaRRiS aligned well with current practice and was acceptable to parents. There was no evidence of a relationship between social disadvantage and PaRRiS scores. Conclusions With further development and evaluation work, PaRRiS could potentially be incorporated into existing universal health services to provide child health nurses with an additional tool for identifying families most likely to be in need of parent–child interaction interventions

Developmental Language Disorder: Ask the experts

Dr Pauline Frizelle and Professor Cristina McKean examine dosage effects in interventions for children and young people with developmental language disorder

Pupillometry registers toddlers’ sensitivity to degrees of mispronunciation

AbstractThis study introduces a method ideally suited for investigating toddlers’ ability to detect mispronunciations in lexical representations: pupillometry. Previous research has established that the magnitude of pupil dilation reflects differing levels of cognitive effort. Building on those findings, we use pupil dilation to study the level of detail encoded in lexical representations with 30-month-old children whose lexicons allow for a featurally balanced stimulus set. In each trial, we present a picture followed by a corresponding auditory label. By systematically manipulating the number of feature changes in the onset of the label (e.g., baby∼daby∼faby∼shaby), we tested whether featural distance predicts the degree of pupil dilation. Our findings support the existence of a relationship between featural distance and pupil dilation. First, mispronounced words are associated with a larger degree of dilation than correct forms. Second, words that deviate more from the correct form are related to a larger dilation than words that deviate less. This pattern indicates that toddlers are sensitive to the degree of mispronunciation, and as such it corroborates previous work that found word recognition modulated by sub-segmental detail and by the degree of mismatch. Thus, we establish that pupillometry provides a viable alternative to paradigms that require overt behavioral response in increasing our understanding of the development of lexical representations

The development and productivity of a measure for identifying low language abilities in children aged 24 – 36 months

Acknowledgements First, we would like to acknowledge the leadership, mentorship and unparalleled contribution to the field of child language research of Professor James Law, OBE, who led this study. Professor Law passed away in October 2021. We also acknowledge the contribution of Professor Sue Roulstone, Caitlin Holme and Rose Watson in aspects of the wider study which contributed to the successful data collection in this study. We would like to express sincere thanks to all the practitioners and parents who gave their time, expertise, and insights in the workshop and codesign activities. The team also wish to acknowledge the role of Sheena Carr and Renvia Mason and colleagues at Public Health England and The Department for Education for their feedback on the original report. Funding The project was funded by the UK’s Department for Education in conjunction with Public Health England.Peer reviewedPublisher PD

What makes screening of preschool children’s speech and language acceptable?:A study of parents’ perspectives

Background:Screening for speech, language and communication needs (SLCN) in the preschool years promotes early identification and provision of support. However, developmental screening is also associated with practical and ethical concerns (Carlton et al., 2021). For example, given variability in early language development, screening may create unnecessary anxiety in parents. Therefore, it is important that we understand what contributes to acceptability of screening for SLCN from parents' perspectives. Sekhon, Cartwright and Francis (2018) developed the ‘Theoretical Framework of Acceptability’ (TFA) as a way to assess acceptability of healthcare interventions. However, to date there are few examples of this framework being used to assess parents’ views about outcomes for their children. Aim / Objectives:This study aimed to explore the applicability of the TFA to the context of screening for speech and language during children’s developmental reviews.Methods:Parents attending the nationally mandated 24-30 month developmental review completed a survey (n=433) based on the TFA. Follow-up qualitative interviews with 40 parents explored perspectives of the speech and language component of the developmental review. Parents were recruited purposively to cover a range of factors, including demographics as well as their level of concern about their child’s language development.Results:Quantitative results from the survey supported acceptability of the screening process, however qualitative results provided a more mixed picture. Some themes from the TFA were relevant, including coherence of the assessment. However, additional themes were found that were specific to the screening context, for example the importance of individualisation, the relationship with the practitioner and the value that parents placed on the outcome of the assessment for their child. Conclusions / take home message:The TFA provided a useful initial framework for exploring acceptability, however this study identified additional elements of acceptability specific to the context of speech and language screening during the developmental review