Skip to main content

Evaluating Therapy Outcomes: From Theory to Therapy … And Back Again

Michelle Pascoe, Ph.D.

Working with children with persisting speech difficulties (PSDs) is a privilege, and also a great challenge. For this specific client group – as for all others – theory and therapy are inseparable. On the one hand our knowledge of theory needs to be used to drive therapy. On the other, therapy outcomes can inform our theoretical knowledge. Figure 1. below shows the circular relationship between therapy and theory.

Figure 1.

The cyclical and symbiotic relationship between theory and therapy (From Pascoe, Stackhouse and Wells, 2006, p. 19, published with permission from Wiley and Sons Ltd.)

image of therapy and theory relationship

Understanding the Therapy Process

Speech and language pathologists (SLPs) typically use games to make their intervention fun for children. We know that young children learn well when they are happy and enjoying themselves. It is not uncommon for parents (and children themselves) to remark after seeing their SLP that they ‘just played.’

But of course, intervention is not only about playing. The skill of the SLP lies in providing good entertainment while at the same time carrying out specific speech and language tasks to achieve specific goals. Rees (2001) refers to tasks as being made up of materials, procedures, feedback and optionally the use of specific techniques. This can be written as an equation as follows:

TASK = Materials + Procedure + Feedback (+ Technique)

Materials might include pictures of stimuli and puppets. Procedures might include getting the child to listen and make judgments about the puppet’s naming of the pictures. Feedback might entail stickers and verbal praise for correct judgments, while incorrect judgments would give opportunity for discussion and information-giving on the puppet’s performance and another chance to listen. Specific techniques might involve the use of visual cuing, or using an amplifier to ensure that the stimuli are more clearly heard.

This equation is one way which can help SLPs to reflect on the tasks they carry out in intervention. SLPs need to have explicit awareness of the rationale behind any given game. This is another example of how ‘theory’ and ‘therapy’ are linked. Schuell, Jenkins and Jimenez-Pabon (1964) note: “A good therapist should never be taken unawares by the question: “Why are you doing this?” (p.333)

Evidence-based Practice

While it is helpful to have access to an explicit theoretical framework and to be aware of the components of any therapy task, SLPs working with children with PSDs do not need to ‘reinvent the wheel’ each time. Evidence-based practice (EBP) is about looking at what others have done before and using information from such studies to guide decision making. This means considering how a particular intervention reported in the literature might be applied or adapted for use with an individual child.

Intervention for Childhood Apraxia of Speech traditionally involved a heavy focus on output work often at a non-speech oro-motor level or working on single sounds. However, there is increasing evidence to suggest that in order to improve speech, SLPs need to target speech input and output, linking this with literacy where appropriate, i.e. not necessarily to focus on non-speech oro-motor tasks alone (e.g. see Forrest. 2002). There is also evidence to suggest that connected speech work needs particular attention (Pascoe, Stackhouse and Wells, 2005, and Pascoe et al., 2006 Chapter 7), and tasks focusing on speech input may also be appropriate for some children (Waters, 2001). SLPs working with children with apraxia of speech need to have up to date knowledge of the evidence that has been collected about intervention for this client group, and to apply it to the individuals they are working with appropriately. Consideration of the individual is central to EBP (Baker and McLeod, 2004), and this fits with a psycholinguistic approach where each child’s strengths and weaknesses are individually considered.

Carrying out listening activities with a child with PSDs may seem strange to parents or teachers if a child has no known difficulties with hearing. An SLP might respond to the question: “Why are you doing this?” by suggesting that the child’s speech problems are because s/he has stored inaccurate or ‘fuzzy’ representations of words. Therapy aims to improve the accuracy of stored word knowledge as doing so may result in improved speech production. If the therapy results in improved speech production then the original hypothesis is confirmed. If therapy does not bring about the desired changes, then the hypothesis may need to be reconsidered. Working within an explicit theoretical framework helps us to answer the question: “Why are you doing this?” and to continually revise and reformulate hypotheses about a child’s difficulties.

And Back Again! Therapy Informs Theory

SLPs can also contribute to the evidence-building process by carefully documenting the intervention they are carrying out and the outcomes achieved. A psycholinguistic framework can help structure this process by sharing common terminology so that others can benefit from the pooling of information (e.g. See Popple and Wellington, 2001). Wide-ranging outcomes measures allow SLPs to determine if any ‘micro’ changes in a child’s speech have occurred and how these relate to the aims of the intervention, and also whether any broader changes (e.g. in self-esteem) have been noted.

The relationship between ‘theory’ and ‘therapy’ works both ways since intervention and the outcomes achieved can cause us to reconsider theoretical models. Dorothy Bishop (1997) suggests:

“It is time for researchers to recognize that intervention studies are not just an optional, applied adjunct to experimental work, but that they provide the best method available for evaluating hypotheses and unconfounding correlated factors…” (p.240)

Intervention for children with PSDs poses an exciting challenge for SLPs. Not only do we have the opportunity to bring about positive changes in the lives of our clients and their families, but we also have the opportunity to draw on the experiences of our colleagues in the field through EBP, and in turn to contribute to the knowledge-base which can only be positive for the children we serve now and in the future. Although intervention might not always work as well as we hoped, if we have a clear answer to the question: “Why are you doing this?” then we will be in a stronger position to revise our intervention and reconsider why therapy activities work with some children better than with others.


Baker, E., & McLeod, S. (2004). Evidence-based management of phonological impairment in children. Child Language Teaching and Therapy, 20(3), 261-286.

Bishop, D. (1997a). Uncommon Understanding. London: Psychology Press.

Forrest, K. (2002). Are Oral-motor exercises useful in the treatment of Phonological / Articulatory Disorders. Seminars in Speech and Language, 23(1), 15-26.

Pascoe, M., Stackhouse, J. and Wells, B. (2006). Persisting Speech Difficulties in Children. Wiley Ltd: Chichester, UK.

Pascoe, M., Stackhouse, J., & Wells, B. (2005). Phonological therapy within a psycholinguistic framework: Promoting change in a child with persisting speech difficulties. International Journal of Language and Communication Disorders, 39, 1-32.

Popple, J., & Wellington, W. (2001). Working Together: The Psycholinguistic Approach within a School Setting. In J.

Stackhouse & B. Wells (Eds.), Children’s Speech and Literacy Difficulties. London: Whurr Publishers.

Rees, R. (2001). What do tasks really tap? In J. Stackhouse & B. Wells (Eds.), Children’s Speech and Literacy Difficulties: Identification and intervention. London: Whurr Publishers.

Schuell, H., Jenkins, J., & Jimenez-Pabon, E. (1964). Aphasia in adults: diagnosis, prognosis and treatment. New York: Harper & Row.

Stackhouse, J., & Wells, B. (1997). Children’s Speech and Literacy Difficulties I. London: Whurr Publishers.

Stackhouse, J., Pascoe, M., & Gardner, H. (2006). Intervention for a child with persisting speech and literacy difficulties: A psycholinguistic approach. Advances in Speech-Language Pathology, 8(3), 231-244.

Waters, D. (2001). Using input processing strengths to overcome speech output difficulties. In J. Stackhouse & B. Wells (Eds.), Children’s Speech and Literacy Difficulties: Identification and intervention. London: Whurr Publishers.

[ Michelle Pascoe is a registered Speech and Language Therapist in the United Kingdom. She is currently an Interdisciplinary ESRC (Economic and Social Research Council) / MRC (Medical Research Council). Fellow based at the Department of Human Communication Sciences at the University of Sheffield, U.K. Michelle’s current research focuses on intelligibility as a clinical outcomes measure for children with speech difficulties, and is carried out in collaboration with Professor Bill Wells, Professor Pam Enderby and Professor Joy Stackhouse from the University of Sheffield. Persisting Speech Difficulties in Children by Michelle Pascoe, Joy Stackhouse and Bill Wells (Wiley Ltd, 2006) is the third book in the Children’s Speech and Literacy Difficulties series. ]

© Apraxia-KIDS℠ – A program of The Childhood Apraxia of Speech Association (CASANA)