Phonological Memory and Phonological Planning

I have been writing about the children in our intervention study for children with Childhood Apraxia of Speech (CAS). So far about half of the children referred to us appear to have difficulties in the domain of phonological memory with their overt phenotype corresponding to the subtype described by Dorothy Bishop Dodd as Inconsistent Deviant Disorder. Shriberg et al. (2012) have developed the Syllable Repetition Task as one means of identifying deficits in “memory processes that store and retrieve [phonemic, sublexical, and lexical] representations. We have been using this SRT test to differentiate children who have deficits in phonological planning versus motor planning. I described the profile that corresponds to difficulties with motor planning (transcoding) in a previous post. Today I will discuss the phonological memory or phonological planning profile that we see in approximately half of the children that are referred to us with suspected CAS.

These children can be identified by a qualitative analysis of their SRT performance and by their performance on the Inconsistency Test of the DEAP. Starting with the SRT, one child in our study for example was able to achieve 12/18 consonants correct when imitating 2-syllable items but only 5/18 consonants correct when imitating 3-syllable items, thus exemplifying the classic profile of a child with phonological memory difficulties – better nonword repetition performance for short versus long items. Qualitatively he tended toward consonant harmony errors even with some 2-syllable items, /bama/=[mama],  /maba/=[mama],  and then more frequently with the 3-syllable items, /nabada/=[mamada]. Addition of syllables and vowel errors also occurred, /manaba/ = [mamadada],  /manabada/=[mimadama]. Poor maintenance of phonotactic structure and vowel errors were also observed on the Inconsistency Test, “helicopter” = [hokopapɚ], “elephant”= [ɛmpɩnt], which yielded an overall inconsistency score of 78% as many words were produced with multiple variants, e.g., “butterfly”= [bʌtfaɩ], [bʌtwaɩ], [bʌtətwaɩ].

The most striking illustration of the difficulties these children have with the storage and retrieval of phonological representations comes during our treatment sessions however. In this research program we are teaching the children nonsense words in meaningful contexts. For example in one scenario we teach the children the names of “alien flowers” and in one of the treatment conditions we use graphic stimuli, paired with gestural cues if necessary, to represent the syllables and phonemes in the words and phrases that we are teaching. Many of the children in our study learn all of the nonsense words without difficulty (5 words per goal/condition introduced over 6 45-minute sessions). However children with the phonological memory difficulties have great difficulty learning the words (SLP: This is a speet. Say speet. Child: speet. That’s right, speet. What is it? Child: I don’t know. SLP: Yes, you do it’s speet, the purple one, the purple one is speet, remember, say speet. Child: ‘speet’. SLP, you’ve got it, the purple flower is speet, it’s a speet, what is it, it’s a … Child: um, I don’t know, and so on).

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The most effective intervention to use with these children closely mirrors the procedures described by Barbara Dodd as the “core vocabulary” approach and demonstrated by Sharon Crosbie in the video that accompanies their chapter in the Williams, McLeod and McCauley (2010) book. The video is lovely and shows how to use graphic stimuli and a chaining procedure to teach the child to produce a word consistently – the idea is to encourage the child to develop and implement their own phonological/motor plan rather than relying on an imitative model. The children respond to this technique really well and will learn to say the new words such as “speet” and “stoon” quickly and accurately. The trouble begins when our student SLPs want the children to use the new words spontaneously in phrases (e.g., “water the speet”). They have great difficulty remembering the word or even the carrier phrase without the imitative model and I have to work really hard to teach the student clinicians to withhold the imitative model in favour of using other cues to stimulate spontaneous production of the target words and phrases (SLP: What is it? Let’s start with the snake sound here…).

We have wonderful video of student SLPs learning these techniques as well as children achieving their goals. Tanya Matthews and I will be presenting them at ASHA 2014. The difference in the way that you implement therapy with these children is subtle but important. I am pretty sure that Case Study 8-4 in our book had a phonological planning deficit rather than the motor planning disorder that he was treated for. I can’t help but think that if he was treated with these techniques he might have made some progress in the three years that we followed his case (whereas he made literally no progress at all until he was treated with a synthetic phonics approach in second grade). I’d love to hear from you if you have any other ideas about how best to treat children with phonological memory problems and inconsistent deviant disorder.

 

 

 

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4 Comments

  1. Gabrielle Miller

     /  June 16, 2014

    Thank you so much for this great information. The idea that you can distinguish between motor planning and phonological memory/planning deficits for SSDs with an assessment like the SRT and DEAP and then differentially utilize cues (graphic or gestural, versus imitative) to improve student performance is clinically very interesting and helpful.

    Your description of the children who cannot retrieve the nonsense labels during intervention (lots of I don’t know responses) reminds me of language impaired kids who cannot successfully encode vocabulary without multiple exposures and then sometimes still can’t retain the word. It occurs to me that the young children with SSDs with issues of storage and retrieval of phonological representations might also have difficulty encoding new vocabulary as they get older (perhaps longer words or Tier Two vocabulary); I know from experience, however, that this is not the case for many kids with SSDs. Perhaps different systems of phonological encoding are involved with the kids who have issues with receptive/expressive vocabulary and language difficulties?

    Might you at some point in the future follow these groups of children with issues of storage and retrieval of phonological representations to see how they might differ from each other, and also differ from the motor planning group in terms of outcomes for literacy and/or language impairment? I am asking because I work with dyslexic students – now fourth graders some of whom have overt language difficulties and residual speech problems.

    I am very much looking forward to hearing all the details about the study and seeing the videos of the student SLPs demonstrating this intervention at ASHA this fall!!!

    Reply
  2. Hello Gabrielle, some of these children with phonological memory and planning difficulties have passed through the treatment program and have made good progress with speech but are reportedly having noticeable problems with word finding which is not surprising. Kids with more ordinary phonological delays encode incoming speech information poorly so they may have fuzzy representations for individual speech sounds but not necessarily have difficulty with storing or retrieving those representations from the lexicon. Longitudinal follow-up of these kids with phonological and motor planning problems would be fabulous but sadly this research program, excepting a very small grant from CASANA in the first year, is unfunded because currently the federal government funding in my lab is directed at “industry partnerships” – kids who do not speak clearly are not a priority. But we are doing the best we can with a wonderful support from our clinical program and my doctoral student Tanya Matthews. We can be pretty sure that both groups of children in this CAS study will have difficulties with literacy in the future but they are such complicated children it is probably fair to say that each child will be reading disabled in his or her own way.

    Reply
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