Ways to advance speech treatment research in developmental dysarthria

We all are aware that speech treatment in developmental motor speech disorders is an under-researched area. We also know how important it is to find out whether current treatments help children to communicate more successfully. However, one of the main challenges we are facing is the lack of detailed information on how the few treatment studies that were conducted were designed and carried out. This lack does not just affect research by making it more difficult to repeat treatments to confirm its success for other speakers. It also means that speech and language therapists, who want to apply the approaches described in the literature, have very little information that could assist them in understanding what made those approaches successful.

This issue was the starting point for Erika Levy’s most recent article published in the International Journal of Speech-Language Pathology. Unlike most articles, which usually focus on outcome and improvements in speech, it details how speech treatments were carried out in the Speech Production and Perception Lab at Teachers College, Columbia University. In her article, Levy focuses on two approaches that were successfully used in the past to improve speech function in children with CP and dysarthria:

-Speech Systems Approach

-Lee Silverman Voice Treatment

Both approaches featured in previous blog entries. The former aims at improving the functioning, coordination and control of breathing, phonation and articulation, whereas the latter focuses on producing loud and clear speech. For both approaches Levy describes treatment protocols which include specific information on preparation and progression of treatment sessions, session structure, the tasks that were used, and how children can be motivated to do these tasks repeatedly.

The article also describes how best to record speech, and how these speech samples could be used for acoustic analyses. It further refers to a range of games and apps that could be used to keep children engaged in the therapy process as well as provide feedback on their performance.

By providing treatment specifics and strategies Levy intends to reduce some barriers that exist when it comes to researching speech treatment in developmental dysarthria. I do hope that this article will trigger further clinical research with the ultimate aim of designing treatments that will help children to be successful communicators.

Levy, E. S. (2014). Implementing two treatment approaches to childhood dysarthria. International Journal of Speech-Language Pathology, Early Online, 1–11. 

Intelligibility: Do sentence length and word structure matter?

Speech intelligibility is a complex construct and many aspects are known to influence intelligibility in motor speech disorders. This includes the way people pronounce words, but also how well listeners can tune into people’s speech. Context also helps, which is why connected speech is usually more intelligible than single words. In a recent study, Kristen Allison and Katie Hustad explored another important aspect influencing speech intelligibility: the linguistic properties of speech. Two aspects were of particular interest to them: sentence length and phonetic complexity, i.e. the motoric difficulty of a word’s sound structure (e.g. the word ”no” involves less complex motoric movements than the word “complex”). Both, longer sentences and higher phonetic complexity are known to increase the motoric demands of producing an utterance, which can affect intelligibility.

In order to quantify their contribution to intelligibility problems in children with CP the authors asked 119 listeners to orthographically transcribe speech samples of 24 5-year old children. 16 children had CP, of which 8 were diagnosed with dysarthria. The speech of 8 typically developing children was transcribed as well. The speech samples were sentences of 2 to 7 words in length. Each listener was asked to transcribe about 60 sentences.

Results showed that both factors had an effect on intelligibility, but the effect was found to be greater for children with dysarthria. They were best understood in short sentences of 2 to 3 words, whereas children without speech problems were easily understood up to a sentence length of 6 words. A similar result was observed for phonetic complexity: whilst the effect for children without speech problems was small, intelligibility of children with dysarthria was significantly reduced in sentences with words that required more complex motoric movements. The findings indicate that reducing length as well as phonetic complexity may enhance intelligibility. However, considerable individual variation suggests that for some children sentence length was more of an issue and for others complexity. This highlights the importance of a child’s individual motor profile when considering treatment options.

Allison, K. & Hustad, K. (2014). Impact of sentence length and phonetic complexity on intelligibility of 5-year-old children with cerebral palsy. International Journal of Speech-Language Pathology.

How does communication and social interaction develop in school-aged children with CP over time?

This was the central question Petra van Schie and colleagues addressed in their article published in Research in Developmental Disabilities. According to the authors communication becomes more important as children grow older, and they were keen to find out how cerebral palsy affects the development of communication and social interaction.

Over a period of 3 years, van Schie and colleagues monitored the development of 108 children with CP in the Netherlands. The children joined the study when they were about 6 years of age. Information on their communication was collected each year through an extensive parental questionnaire (the Vineland Adaptive Behaviour Scales).

Findings showed that more than half of the children (58%) had problems with communication and social interaction because of CP. This was particularly true for those children with a history of epilepsy, and – not surprisingly - speech problems. The results also showed that children who could not walk had greater problems with social interaction than those children who could walk or had walking aids. This shows that there is a link between motor abilities and communication, which mirrors findings from previous studies discussed here in this blog. However, even children in the latter group, i.e. who could walk, were not always successfully interacting with others. The authors thus conclude that a wide range of children with CP would benefit from intervention to support communication and social development.

This study highlights again how important intervention is to support communication development in children with CP…and how desperately needed intervention and intervention studies are to monitor progress…

Reference: van Schie et al. (2013). Development of social functioning and communication in school-aged (5-9) years children with cerebral palsy. Research in Developmental Disabilities, 34, 4485-4494.

Is there a link between communication and motor skills in 2 year-olds with CP?

This is the question Andrea Coleman and colleagues posed, and explored, in a recent study published in Archives of Physical Medicine and Rehabilitation. Whilst this is not the first time that this link is the focus of an investigation, Coleman and colleagues add a new dimension: Assessing very young children and using a standardised language assessment.

Their main aim was to explore the communication skills of 24-months old children with CP to identify those who might benefit from early intervention. At the same time, they were interested in exploring the relationship to general motor skills as well as risk factors for communication problems.

124 two-year old children with CP living in Australia were recruited to the study over a period of 4.5 years. Parents were asked to fill in a questionnaire about their children’s communicative development. This infant toddler checklist covered aspects of social communication such as gestures and gaze, expressive language as well as symbolic play. Two physiotherapists judged the children’s motor skills, and medical notes were consulted to obtain further information on children’s health.

Findings showed that 15% of the children did not yet use words or gesture to communicate; a further 10% employed gestures only. Another 23% used single words and 52% used two word combinations. The study also revealed that - based on the assessment - 62% of children were found to have communication problems that would meet the criteria for further, more extensive language assessment. This percentage is in stark contrast to the reported norms for typically developing children (20%) who were assessed using the same checklist. The authors conclude that children with CP do have higher communication needs than their typically developing peers, and would benefit from an early communication screening.

With regard to the question posed above, Coleman and colleagues found that communication problems were strongly associated with motor skills: Children with more severe motor problems were more likely to have delayed communication development, whereas children with mild motor impairment were less likely to have problems with verbal communication. At the same time, the authors found that poorer communication was more likely in children who were either born full-term or suffered from seizures. Overall, the study highlights the need to monitor language development in children with CP from an early age to identify those who will benefit from intervention...This, though, poses another series of questions: Where are we in terms of intervention? Where do we want to go, and how are we going to get there???

Coleman, A., Weir, K. A., Ware, R. S. & Boyd, R. N. (2013). Relationship between Communication Skills and Gross Motor Function in Preschool-Aged Children With Cerebral Palsy. Archives of Physical Medicine and Rehabilitation, 94, 2210-2217.

Viking Speech Scale

In my previous blog I have introduced a classification system for young children with CP that was developed to estimate their speech and language development over time. This blog presents another attempt at classifying speech performance in children with CP: The Viking Speech Scale (VSS).

The VSS was developed by an international team around Lindsay Pennington for use in CP surveillance registers to complement information on gross motor performance and manual abilities. Information on speech would help clinicians and researchers to obtain a clearer picture of presence and severity of motor problems that affect communication.

The VSS is intends to be a global measure of speech that captures how speech is produced in daily life. A combination of perceptual characteristics and intelligibility was used as a basis for the scale which comprises 4 levels:

   1. Speech is not affected by motor disorder

   2. Speech is imprecise but understandable to unfamiliar listeners out of context. Loudness
       is adequate; voice may be breathy and harsh; articulation is imprecise but difficulties do
       not affect intelligibility.

   3. Speech is unclear and not usually understandable out of context. Speech can be too loud
       or too quiet; speech can be hypernasal; voice may be harsh; breath control is difficult;
       pitch may change suddenly; only a small range of consonants can be produced.

   4. No understandable speech

The scale was tested using speech samples of 139 children with CP. Their speech was rated by parents and a range of health professionals including speech and language therapists through direct observation or case notes. Feedback was positive and the scale considered being a helpful tool to summarise speech performance of children with CP for clinical reports and research.