Childhood speech disorders

Key points: • Speech sound disorder is common and a key health priority given impacts on psychosocial and literacy development and overall academic outcome. • It is critical to understand the type of speech sound error a child is making. It is the type of error pattern that predicts later speech outcome and performance in related skills of reading and spelling. • Speech Pathologist’s are trained clinician’s with the expertise to make an appropriate diagnosis, focused around error type. • Treatments have proven efficacious for sub-types of phonological speech disorder and evidence is building for the remaining diagnoses of dysarthria and childhood apraxia of speech. • There is a research evidence base in this field that could influence service delivery by using severity and type of error to drive wait list prioritisation.

Childhood speech disorders are the most common communication difficulty in childhood, constituting the largest proportion of paediatric Speech Pathologists case loads. Speech disorders emerge in early infancy and may persist through to adulthood, affecting the child’s social and academic development. This submission focuses on the presentation, prevalence and management of childhood speech disorders. Speech Disorders are distinct from Language Disorders (see Centre of Research Excellence in Child Language submission), although the two often occur together.

Children with speech disorders are a heterogeneous population. They may present with speech sound disorder due to genetic syndromes (e.g., Down syndrome), a structural deficit (e.g., cleft palate) or brain injury acquired at birth or in early life (e.g., following a motor vehicle accident). A very rare few may present with speech disorder associated with mutation in the only single gene identified in the field thus far, FOXP2 (Vargha-Khadem et al, 2005). FOXP2 mutation is most consistently associated with a specific speech diagnosis called childhood apraxia of speech as described below (Turner et al, 2013).

The most common form of speech disorder however, affects around 4% of children at age 6 and presents in the absence of any known organic cause (Shriberg, Tomblin & McSweeny, 1999).

Presentation and prevalence Children with speech disorders are difficult or impossible to understand. This large population varies in severity, the types of errors they make, their age of referral for assessment, associated difficulties in language and cognition, their response to their disorder (e.g., social withdrawal/behaviour disorder) and effectiveness of specific intervention approaches. The term ‘speech disorder’ encompasses a range of diagnoses that present with a different symptom complex:

• Articulation disorder: a problem with the motor act of producing sounds (e.g., lisps) in the absence of any known neurological deficits

• Dysarthria: a problem with the motor act of producing sounds in the presence of neurological disturbance (e.g., following acquired brain injury or Cerebral Palsy)

1 • Phonological disorder associated with cognitive-linguistic processing deficits with sub-types of: o Delay: children who produce error patterns typical of a younger child (e.g., producing errors at four years that are typical of a two year old; ‘poon’ spoon, ‘ban’ van, ‘tip’ ship, ‘lellow’ yellow). o Consistent disorder: children who produce atypical error patterns but apply these atypical rules consistently (e.g. all word initial consonants delete, so look, book, cook are all ‘ook’; all sound clusters a produced as [f], so tree is ‘fee’ and dress is ‘fess’. o Inconsistent disorder: children are likely to say the same word in a different way, every time they produce it. That is, producing the same lexical target using a range of different atypical errors (e.g., ‘TV’ – ‘mugug’ and ‘pikeg’).

• Childhood apraxia of speech: a problem with planning and programming of sounds, syllables and words. This is a complex diagnosis with the potential for deficits across a number of speech and language domains including prosody, word and syllable shapes, oral motor behaviours (e.g., blowing, kissing) and sequences (kiss and blow, poke out tongue and kiss), language and literacy. The features change across time with development of the child, but hallmark features include prosodic disturbance and omitting, adding or substituting sounds and producing more errors with increasing length and complexity of the word.

Speech disorder is debilitating for children and is associated with family anxiety, affecting parents and siblings, relationships and family activities. When children’s speech is characterised by multiple errors in words, it is unintelligible, in some cases even to their mothers. Breakdown in oral communication creates social barriers, or even total isolation, for the child. Speech disorder can also have further impacts on critical life skills including reading and spelling development (e.g., Rvachew et al., 2007). In particular, children with atypical errors are at greatest risk for impaired literacy (Dodd et al, 1995; Holm, Farrier & Dodd, 2007; Leitao & Fletcher, 2004; Foy & Mann, 2012, Preston et al, 2013).

Knowledge of the type of speech sound errors a child makes is critical for diagnosis of type of speech disorder, with each type linked to evidence-based intervention treatment approaches. Speech Pathologist’s are trained diagnostician’s able to make this critical differential diagnosis and implement appropriate treatment.

Management Following a thorough differential diagnosis, a Speech Pathologist will advise on the appropriate targeted intervention plan. Speech Pathologist’s may treat children face to face, or supervise agents of therapy such as parents, teacher aides or speech pathology assistants. Evidence for best practice with children who have speech disorders suggests that clinicians provide more effective and efficient therapy than agents of therapy who have not received thorough training in intervention techniques (Lancaster et al. 2011; Gardner, 2006).

There is a growing body of evidence demonstrating the efficacy of speech pathology administered treatments for managing speech disorder. A randomized controlled trial of children with a primary speech and/or language impairment demonstrated that an average of 6 hours of speech therapy in a 6 month period can produce a significant improvement in speech production performance and was much more effective than no treatment over the same period for a wait list control group (Broomfield & Dodd, 2011; see Law et al, 2004 for a meta-analysis).

2 Further, more advanced evidence comes from a study comparing two groups of children with severe phonological disorder: one group made atypical errors consistently, the other made inconsistent errors. Two therapy approaches where contrasted, each child received an 8 week block of each approach. All children made gains in speech accuracy during treatment although one group made significantly more progress with one therapy, while the other group did better when treated with the other therapy. The results emphasise the importance of matching the treatment approach to the child’s type of speech disorder (Crosbie, Holm & Dodd, 2005).

Less high quality evidence is available for management of childhood dysarthria and childhood apraxia of speech (Morgan et al, 2008; Morgan et al, 2008; Pennington et al, 2011), yet phase II studies and a randomised controlled trial have recently been conducted with groups of children with these diagnoses respectively, and evidence is mounting in support of speech pathology in these areas.

Biographies

Professor Barbara Dodd is Honorary Research Professor at the University of Melbourne (UoM). A speech-language pathologist, Barbara worked as a clinician, researcher, and university teacher in the UK and Australia. Her research led to novel assessment and treatment practice and better theoretical understanding of the nature of phonological development and disorder.

Dr. Angela Morgan is Co-Leader of the Language and Literacy Group at the Murdoch Childrens Research Institute and Senior Lecturer at UoM. Angela has worked clinically in education and health in Australia and as a clinical researcher in the UK and Australia. Her research focuses on genes-brain-behaviour relationships in childhood speech disorder.

Professor Sheena Reilly is Associate Director of the Murdoch Childrens Research Institute and Professor at UoM. Sheena’s research is focused on childhood language and its disorders. She is currently Chief Investigator on the Centre for Research Excellence in Child Language. She has worked as a clinician and a clinical researcher in Australia and the UK.

3 References

Broomfield J & Dodd B. (2011). Is Speech and Language Therapy effective for children with speech/language impairment? A report of an RCT. Int J Lang & Comm Dis, 46(6): 628-40.

Crosbie S, Holm A, & Dodd B. (2005) Intervention for children with severe speech disorder: a comparison of two approaches. Int J Lang & Comm Dis, 40(4):467-91.

Foy JG, Mann VA. Speech production deficits in early readers: predictors of risk. Read Writ, 25(4): 799-830.

Gardner H. (2006) Training others in the art of therapy for speech sound disorders: an interactional approach Child Lang Teaching & Therapy, 22(1): 27-46.

Holm A, Farrier, F & Dodd B. (2007). The phonological awareness, reading accuracy and spelling ability of children with inconsistent phonological disorder Int J Lang & Comm Dis, 42: 467-486.

Lancaster, G, Keusch, S, Levin A, Pring T & Martin S. (2010) Treating children with phonological problems: does an eclectic approach to therapy work? Int J Lang & Comm Dis, 45(2): 174–181.

Law J, Garrett Z, Nye C. (2004) The efficacy of treatment for children with developmental speech and language delay/disorder: a meta-analysis. J Speech Lang Hear Res, 47(4): 924-43.

Leitao S, Fletcher, J. (2004) Literacy outcomes for students with speech impairments: long term follow-up. Int J Lang & Comm Dis, 39: 245-56.

Morgan AT, Vogel AP. (2008). Intervention for dysarthria associated with acquired brain injury in children and adolescents. Cochrane Database Syst Rev. CD006279.

Morgan AT, Vogel AP. (2008). Intervention for childhood apraxia of speech. Cochrane Database Syst Rev. CD006278.

Pennington L, Miller N & Robson S. (2009). Speech therapy for children with dysarthria acquired before three years of age. Cochrane Database Syst Rev. CD006937.

Preston J, Hull M & Edwards M-L. (2013) Preschool Speech Error Patterns Predict Articulation and Phonological Awareness Outcomes in Children With Histories of Speech Sound Disorders. Am J Sp- Lang Path, 22: 173-184.

Rvachew S, Chiang PY, Evans N. (2007). Characteristics of speech errors produced by children with and without delayed phonological awareness skills. Lang, Speech Hear Services in Schools, 38(1): 60-71.

Shriberg LD, Tomblin BJ, & McSweeny JL. (1999). Prevalence of speech delay in 6-year-old children and comorbidity with language impairment. J Speech Lang Hear Res, 42(6): 1461-1481.

4 Turner SJ, Hildebrand MS, Block S, Damiano J, Fahey M, Reilly S, Bahlo M, Scheffer IE & Morgan AT. (2013). Small intragenic deletion in FOXP2 associated with childhood apraxia of speech and dysarthria. Am J Med Genet A, 161(9): 2321-6.

Vargha-Khadem F, Gadian DG, Copp A & Mishkin M. (2005). FOXP2 and the neuroanatomy of speech and language. Nat Rev Neurosci, 6(2): 131-8.

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