Developmental Verbal Dyspraxia
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RCSLT POLICY STATEMENT DEVELOPMENTAL VERBAL DYSPRAXIA Produced by The Royal College of Speech and Language Therapists © 2011 The Royal College of Speech and Language Therapists 2 White Hart Yard London SE1 1NX 020 7378 1200 www.rcslt.org DEVELOPMENTAL VERBAL DYSPRAXIA RCSLT Policy statement Contents EXECUTIVE SUMMARY ............................................................................................... 3 Introduction ............................................................................................................. 4 Process for consensus .............................................................................................5 Characteristics of Developmental Verbal Dyspraxia .....................................................5 Table 1: Characteristic Features of DVD ....................................................................7 Change over time ...................................................................................................8 Terminology issues ................................................................................................. 8 Table 2: Differences in preferred terminology ........................................................... 10 Aetiology ............................................................................................................. 10 Incidence and prevalence of DVD ........................................................................... 11 Co-morbidity ........................................................................................................ 12 The nature – nurture argument .............................................................................. 13 Vision and Values .................................................................................................... 14 External drivers .................................................................................................... 15 Internal drivers .................................................................................................... 16 SLT roles and responsibilities .................................................................................... 17 Theoretical understanding ..................................................................................... 21 Psycholinguistic approaches ................................................................................... 22 Intervention studies for children with features of DVD ............................................... 24 Early intervention ................................................................................................. 27 Changing presentation .......................................................................................... 27 Augmentative and alternative communication .......................................................... 29 Impact of the features of DVD on education and quality of life. .................................. 29 Other issues......................................................................................................... 31 Conclusions ......................................................................................................... 31 Acknowledgements ............................................................................................... 32 REFERENCES .......................................................................................................... 33 Appendix 1: Single case studies & key messages ....................................................... 44 Appendix 2: Service case studies .............................................................................. 56 © RCSLT 2011 2 EXECUTIVE SUMMARY Speech, language and communication skills are a basic human right1, yet speech and language difficulties are the most common developmental disability faced by children2. 1. One in six children is referred to local Speech and Language Therapy Services3 and almost 40% of these have a primary speech difficulty4, also classed as Speech Impairment5. 2. There is a wide range of developmental speech difficulties: • Structural difficulties such as cleft palate • Articulatory difficulties - incorrect placement for accurate sound production • Cognitive-linguistic difficulties with speech and language processing resulting in pronunciation difficulties. 3. Whilst these difficulties are classed as a developmental disability, very few presentations resolve without Speech and Language Therapy interventions6. These presentations can have long lasting 7 8 9 10 impacts for people including literacy difficulties , language impairment , educational achievement , 11 12 social interaction difficulties and possible offending behaviours . 4. One subset of Speech Impairment is the Developmental Verbal Dyspraxia (DVD) symptom cluster. This is now widely accepted13 but there is, as yet, no specific definition or agreed set of diagnostic characteristics; there is, however, general agreement about the types of features which contribute to the presentation14. 5. It is clear that the symptom cluster of Developmental Verbal Dyspraxia is rare15, that there is often over-identification of the presentation16 and that the DVD changes over time17, usually in response to clinical intervention. 6. It is recommended that the differential diagnosis and overall management of the Developmental Verbal Dyspraxia symptom cluster is led by a specialist Speech and Language Therapist with expertise in the field of Speech Impairment18. The management plan must include multi-agency negotiations in order that everyone involved, whether school, family, speech and language therapist or others, can support the child to reach their maximum potential. Within this document options for assessment and intervention are provided, but until further research evidence is available, no single approach can be identified as optimum. 7. This document provides a selection of single case studies and service studies as examples and exemplars of provision. It links to a range of other documents from RCSLT, together with providing a comprehensive reference list and additional bibliography. PLEASE NOTE This document has been developed primarily for the speech and language therapy workforce. The RCSLT hopes other professional groups and organisations together with parents, families and carers will find this to be a useful, relevant and informative resource. SLT specific terminology has been used in this document and if further explanation or guidance is needed please discuss this with a speech and language therapist. 1 Bercow 2008 2 Law 1992 3 Broomfield & Dodd 2005 4 ibid 5 Royal College of Speech and Language Therapists [RCSLT] 2009a 6 Broomfield & Dodd 2005, Wren & Roulstone 2008 7 RCSLT 2009a, Conti-Ramsden et al 2001, Law et al 1998, Stackhouse 1992b 8 Snowling & Stackhouse 1983 9 Lewis et al 2004 10 Teverovsky et al 2009 11 Conti Ramsden et al 2001 12 Snowling et al 2000 13 ASHA 2007, RCSLT 2009a 14 American Speech Language Hearing Association [ASHA] 2007 15 Shriberg et al 1997; Broomfield & Dodd 2005 16 Delaney & Kent 2004; Moriarty & Gillon 2006 17 Stackhouse 1992b 18 RCSLT 2006 © RCSLT 2011 3 Introduction 8. The political and social climate for speech and language therapists (SLTs) working with children with developmental communication impairment, also known as speech, language and communication needs (SLCN) continues to change and develop at a pace. The recent Bercow report (Bercow 2008) is testament to this fact. Speech and language difficulties are the most common developmental problem faced by young children (Law 1992), and around 40% of children with such difficulties have a primary speech difficulty (Broomfield & Dodd 2005). 9. The RCSLT Resource Manual for Commissioning and Planning Services for SLCN: Speech and Language Impairment (RCSLT 2009a) refers to this generic group of children as having Speech Impairment (SI). This top level term includes all types of speech difficulty, from structural (e.g. cleft palate) and articulatory to cognitive linguistic (phonological). It is this term that is adopted throughout the current document as the term to encompass the generic group. 10. Both ASHA (2007) [at www.asha.org/policy] and RCSLT (2009a) [at http://www.rcslt.org/speech_and_language_therapy/commissioning/resource_m anual_for_commissioning_and_planning_services] acknowledge that Developmental Verbal Dyspraxia (DVD) exists as a subtype of SI. It is this specific sub-type is the focus of the current document. Varying terminology is used across the world, including Childhood Apraxia of Speech (CAS) and Developmental Apraxia of Speech (DAS), but throughout this document, the preferred term will be Developmental Verbal Dyspraxia, in accordance with other UK documentation. 11. This document draws upon published evidence and expert consensus; specific evidence based guidelines cannot be produced until more research is conducted. 12. In recent years, the field of SI is increasingly acknowledged as being a specialist clinical area for SLTs, with specialist Speech and Language Therapy (SLT) posts being developed and specialist SLT clinical advisors being appointed. Furthermore, postgraduate qualifications in the specific area exist, for example there are postgraduate qualifications, including an MSc in Speech Difficulties at the University of Sheffield, together with PhD opportunities at Universities around the UK. 13. Children who present with SI, including DVD, may be unintelligible, even to familiar listeners, so they require support in terms of their ability to communicate