Would you do speech therapy like this?

I was interested to read a paper about the relative efficacy of using traditional flash cards versus tablet presentation of pictures for articulation drill therapy because I have developed iPad apps myself (e.g., see www.DIALspeech.com) and have an interest in the potential of digital tools to enhance the speech therapy experience. The paper was recently published in the Online First section of Communication Disorders Quarterly by Krystel Werfel, Marren Brooks, and Lisa Fitton.

The study used a single subject alternating treatment design with four subjects, each kindergarten aged, —not clearly exhibiting signs of speech delay but none-the-less misarticulating two phonemes that could be practiced. Some statistical analyses (rather dubiously applied to single subject data) suggested that the children achieved mastery sooner in the flashcard condition but produced more correct responses in the tablet condition. To my eye, the data did not suggest a clear advantage to either condition. All the children did in fact master the treated phonemes (which were /z,s/, /pl,ɡl/, and /θ,ð/ (this pair for two children).

The authors make clear that the study is meant to be informative on the modality of stimulus presentation and not a test of the treatment protocol itself but I found myself alarmed at the possibility that readers might think that the treatment protocol would be reasonable in regular clinical practice and therefore I would like to address the way that the intervention was implemented. Often researchers implement a speech therapy intervention in a way that they would not in a regular clinical environment in an effort to exert more experimental control over all the variables than is typically necessary or desirable in an authentic clinical context. I can only hope that this explains some of the clinical choices that were made in this case. I am going to address several in turn as follows: (1) treatment approach; (2) treatment procedure; (3) reinforcement procedures; (4) cumulative intervention intensity; and (5) discharge criteria.

First, the authors state that they chose a traditional approach to therapy because there is empirical evidence that it works and clinicians prefer it. There is evidence of efficacy but in fact for most preschool aged children who qualify for speech services a phonological approach may be more efficacious as Francoise and I discuss in our text. Furthermore, the surveys indicating a preference for a traditional approach indicating that this is true in the United States but not elsewhere. Finally, there seems to be some confusion about what a “traditional” approach is. In some cases, traditional refers to a strict behaviorist intervention that focuses solely on speech production with a gradual increase in the complexity of speech units; in other cases it involves a sensory-motor approach with careful attention to variable speech practice and multiple targets; in other cases a traditional approach means Charles Van Riper’s approach which was properly sensory motor including both ear training, graduated speech practice and some principles of motor learning. The implementation in this paper was highly restricted involving only practice of single words and sometimes isolated sounds if necessary. If the speech therapist chooses a traditional rather than phonological approach it is best that the full sensory motor protocol be implemented.

Second, the drill based approach that was employed was selected again on empirical grounds. The study cited to support this approach was sound especially when treating children who have good speech perception abilities, most likely the case for the children in this study who did not have clear evidence of a speech disorder. Other approaches can be effective if procedures targeting phonological processing are incorporated into the intervention as shown by Hesketh and colleagues in the U.K. and also by me and Francoise with French-speaking children.

The strangest part of the whole intervention is that the children experienced over 25 treatment sessions each and throughout every session identical practice trials occurred: a stimulus prompt was presented, the child attempted to name the picture, the clinician provided feedback or extra support and then if the child’s response was correct he or she was permitted to mail the flash card or swipe the picture of the tablet. That was it. For eight weeks. I’m speechless. Enough said.

Regarding cumulative intervention intensity, I indicated in previous blogs that children should receive a minimum of 50 practice trials and ideally 100 practice trials per session. Furthermore, other single subject research using a minimal pairs procedures indicates that generalization goals are not usually met with fewer than 180 practice trials (when treating children with moderate or severe phonological delays). In Werfel’s study the children received treatment for two sounds in 20 minutes, so ten minutes per sound and 15 practice trials per sound or 10-minute block, therefore 30 practice trials per 20-minute treatment session. Reportedly, the mastery was achieved after 203 trials in the flashcard condition and 270 trials in the tablet condition (equivalent to 135 and 180 minutes of therapy respectively). However, increasing the number of practice trials to 50 during that 20-minute session could reduce the number of sessions or weeks in the intervention program by almost half. One way to do that would be to reduce the amount of feedback that was provided. The intervention was designed so that the clinician provided explicit feedback to the child after every practice attempt whereas the principles of motor learning suggest that less feedback is often better for speech motor learning. For example, a child can name five pictures in a row and be told that four of the five productions were correct. Another strategy is to practice at the challenge point at all times as described in detail by Francoise and I in Developmental Phonological Disorders: Foundations of Clinical Practice but also in our new undergraduate text Introduction to Speech Sound Disorders.

Finally, the discharge or stopping criteria in the study were set at 100% correct performance on the generalization probe over 3 consecutive sessions. The probe contained 5 treated words and 5 untreated words. This criterion meant that children practiced their targets for a long time past the point at which the practice material should have been made more difficult or the child should have been discharged to see if spontaneous generalization to natural speaking situations would occur. As Francoise and I review in Chapter 8 of our book, several studies have shown that children can be discharged after achieving between 40 and 80% correct responding on generalization probes. Most children will continue to make gains in production accuracy after this point. The four children in the Werfel et al study received an average of 5 unnecessary treatment sessions according to these criteria.

When conducting treatment studies, it is helpful to provide models of treatment procedures that are best practice in the clinical setting. Often interventions that are better than no intervention will prove to be effective in a research setting while not necessarily being best practice. These studies are confusing for a clinical audience I think. Furthermore, when asking clinical questions about new technologies it is interesting to ask, why would we want to bring it into our clinical practice? What benefit might it bring? How can we adapt these technologies so that the best of human interactions are retained and the most benefit of the technology is added? In my next blog I will address the Werfel study again, but this time imagining the questions we might ask about tablet-based implementations of articulation therapy.