Using Orthographic Representations in Speech and Language Therapy

Word learning, and in particular, productive word learning is associated with three important processes in the phonological domain: first, the child must encode the acoustic-phonetic form of the word in the language input; second the child must transform this representation into a lexical representation, generally considered to take on a more abstract phonological form; finally the child must retrieve the representation to reproduce it. The first process is reliant on speech processing abilities that have been shown to be impaired in many children with speech, language and reading deficits, as shown by for example by Ben Munson and colleages (@benjyraymunson) and Nina Kraus and colleages. Phonological encoding is enhanced by access to repeated high-quality but variable inputs as shown by Richtmeier et al for normally developing children and by Rice et al for children with SLI. The majority of children with SSD have difficulties with encoding: we have a paper in press with the American Journal of Speech-Language Pathology showing that speech accuracy in these children can be improved with an approach that focuses largely on the provision of intense high quality input – I will have more to say on this subject when it (finally) emerges in print.

The second process, forming a phonological representation and storing it in the lexicon, involves articulatory recoding which can be a serious problem for children with severe SSD, accounting for deficits in speech accuracy (especially in association with inconsistency), nonword repetition, word learning, productive vocabulary, word finding, rapid automatic naming, and other phonological processing skills. These children are often diagnosed with motor planning disorders but I have pointed out previously that the problem is actually at the level of phonological planning. I have further pointed out the very close relationship between speech planning and memory. Children who are having difficulty with phonological planning may not show the same benefit from a therapy approach that is focused on the provision of high quality inputs. Therefore a new paper on the use of orthographic inputs to teach new words caught my eye.  Ricketts et al taught children with SLI and ASD as well as younger and age-matched children with typical language to label nonsense objects with new names, using a computer program. For some words, the children were exposed only to the object–auditory word pairing; for others they saw the object, heard the word and saw a printed version (orthographic representation) as well. All children found it easier to learn the new words when they were exposed to the orthographic representation along with the auditory word.

This study reminded me of the research we are doing with children who are referred to our clinic with an apraxia diagnosis due to inconsistent speech errors. So far, 40% of those children have difficulty with phonological planning rather than motor planning as revealed by the syllable repetition test, as I have explained in a previous blog. We have been using a single subject randomization design to compare the relative efficacy of two treatment approaches with these children. The Phonological Memory & Planning (PMP) intervention pairs the phonemes in the target words with visual referents that include letters as shown here. Imitative models are avoided and the child is encouraged to create their own phonological plan and produce the word using the visual symbols when necessary. An alternative treatment, the Auditory-Motor Integration (AMI) Treatment is quite different with a heavy emphasis on prior auditory stimulation and self-judgments of the match between auditory inputs and outputs. A third condition is a usual care CONtrol condition focusing on high intensity practice. In all cases we teach nonsense words paired with real objects, with the words structured to target the children’s phonological needs in the segmental and prosodic domains.

The results are assessed by applying a resampling test to probe scores and then combining p-values across the children. These are the statistical results (F and t tests by resampling test) for the Same Day Probe Scores, with p-values combined across the 5 children who have proven to have phonological planning problems in concert with a severe inconsistent speech disorder:

TASC PMP results Aug 2015

The results in the third column show that all of the children obtained a significant treatment effect. The findings in the remaining columns pertain to planned comparisons with positive t values being in the expected direction. The combined p values indicate that all treatments are significantly different from each other and inspection of the mean scores across children show that the pattern of results is PMP > CON > AMI. The result is made more interesting by the fact that the pattern of results is the exact opposite for children with a motor planning disorder. Tanya Matthews and I will compare these two subgroups with data and video during our presentation at ASHA 2016 in Denver this coming fall.

Session Number: 1429
Session Title: Differential Diagnosis of Severe Phonological Disorder & Childhood Apraxia of Speech
Day: Friday, November 13, 2015
Time: 1:00 PM – 3:00 PM
Session Format: Seminar 2-hours

For now, the take away message is that learning new words involves (at least) three important processes: encoding the sound of the new word, memory processes for storing and retrieving the phonological representation and motor planning processes for planning and programming articulatory movements prior to production of the new word. There are published studies showing that intervention procedures targeting each of these processes help children with speech, language and reading difficulties. Increasing frequency of high quality input improves quality of the acoustic-phonetic representation. Pairing phonological segments with visual symbols helps with storage and retrieval of the phonological representation. High intensity speech practice with appropriate stimulation and feedback improves motor planning and motor programming. The trick is to figure out which children require which procedures at which time.

What’s in a name?

Françoise and I are starting to get feedback on our book and we are beginning to hear that in the Québec community we are considered to be somewhat “out there” (in the words of one reader, “those two think differently”). Having spent 928 pages expounding on the many ways in which we think differently on the topic of developmental phonological disorders we are pleased that readers are noticing this. But we are surprised to find that the evidence of our “different thinking” is apparently in the title: readers are suspicious of the content of the book because our use of the use of the term “developmental phonological disorders” diverges from ASHA’s term “speech sound disorders”. Given that the preferred descriptor for children with inaccurate or unintelligible speech in Québec is “troubles phonologiques” this is somewhat puzzling but to be sure there are a myriad of terms in use and plenty of room for confusion. In fact we do not eschew the term “speech sound disorder” but see it as a broader cover term that encompasses all of the categories of speech problems that may be observed in children while “developmental phonological disorder” is a more specific subcategory described in the Speech Disorders Classification System (Shriberg et al., 1997).

Nonexaustive list of historical and current terms used to describe children who have poor speech accuracy (all combinations of items across the three columns are possible)

Developmental

Nondevelopmental

Primary

Secondary

Functional

Specific

(null)

Speech

Speech sound

Articulation

Phonological

Delay

Disorder

Impairment

Deficiency

Difference

In reference to the 1997 Speech Disorders Classification System the term Developmental Phonological Disorder refers to children with Speech Delay (persisting substitution and deletion errors in children younger than 9 years of age), or Developmental Apraxia of Speech, or Residual Speech Errors (an update to this nosological framework is described in Shriberg et al. 2010 and in our book). Nondevelopmental Speech Disorders and Speech Differences are excluded from the category. I retain the term Developmental Phonological Disorders from the 1997 framework because, as we demonstrate in our book, children in all these categories (Speech Delay, Apraxia, Residual Errors) face developmental challenges in the acquisition and integration of knowledge at the acoustic-phonetic, articulatory-phonetic and phonological levels of representation. Furthermore and most importantly, a majority across all three subcategories have specific underlying problems with phonological processing.

Speaking for myself, I am profoundly uninterested in any arguments about what to call this particular population of children. I would not criticize anyone else’s choice anymore than I would argue about whether the four footed friend currently sleeping on the dining table should be called “that darn cat” or “le maudit chat”. Ultimately, speech-language pathologists (or speech therapists or orthophistes) are constrained by local rules and customs. In the U.S. the terms “developmental” and “delay” are both avoided because the insurance companies apparently won’t support the treatment of developmental delays regardless of whether this makes any sense at all. Some battles are not worth fighting. We can let the insurance companies tell us what to call things but we shouldn’t let insurance companies (or psychologists or psychiatrists or neurologists or anyone else) tell our profession how to think about the children that we treat. It is important to always be clear about the characteristics of the children to whom we are referring. For example, it is quite common for reviewers to suggest that my research not be funded because, after all, speech delay is not really important given that children with speech delay have good outcomes unlike children with language impairment. This is a misreading of the long term follow-up studies in which the sub-population with “speech disorder” is usually defined to cover residual errors, voice and fluency cases. In those same studies, the selection of cases called “language impaired” will include children with concomitant speech sound errors or a past history of speech delay.  And as Anne Tyler has shown in her lab and we have shown in ours, children with poor speech intelligibility inevitably have difficulties with finite verb morphology, long considered to be a primary marker for specific language impairment. In other words, speech sound disorders cannot be less important than language impairment because many times we are talking about the same kids with the same underlying neurodevelopmental disorder of phonological processing.

Reading

Beitchman, J. H., Wilson, B., Brownlie, E. B., Walters, H., & Lancee, W. (1996). Long-term consistency in speech/language profiles: I. Developmental and academic outcomes. Journal of the American Academy of Child and Adolescent Psychiatry, 35. 804-814. http://www.jaacap.com/article/S0890-8567(09)60818-2/abstract

Haskill, A. M., & Tyler, A. A. (2007). A comparison of linguistic profiles in subgroups of children with specific langauge impairment. American Journal of Speech-Language Pathology, 16, 209-221. http://www.ncbi.nlm.nih.gov/pubmed/17666547?dopt=Abstract

Mortimer, J., & Rvachew, S. (2010). A longitudinal investigation of morpho-syntax in children with Speech Sound Disorders. Journal of Communication Disorders, 43, 61-76. http://www.sciencedirect.com/science/article/pii/S0021992409000823

Shriberg, L. D., Austin, D., Lewis, B. A., McSweeny, J. L., & Wilson, D. L. (1997). The Speech Disorders Classification System (SDCS): Extensions and lifespan reference data. Journal of Speech, Language, and Hearing Research, 40(4), 723-740. http://www.ncbi.nlm.nih.gov/pubmed/9263939?dopt=Abstract

Shriberg, L. D., Fourakis, M., Hall, S. D., Karlsson, H. B., Lohmeier, H. L., McSweeny, J. L., et al. (2010). Extensions to the Speech Disorders Classification System (SDSC). Clinical Linguistics & Phonetics, 24, 795-824.http://informahealthcare.com/doi/full/10.3109/02699206.2010.503006