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. 

LSVT Loud versus systems approach

As indicated in earlier blogs there is a desperate need for intervention research in developmental dysarthria to find out which interventions lead to meaningful changes in speech, and if so why.

Hot off the press is an article by Erika Levy and colleagues that compares the effects of two interventions:  LSVT Loud and speech subsystems approach (what they termed traditional approach). Levy and colleagues recruited three girls with spastic type CP (aged 3-9 years) with mild to moderate dysarthria. The allocation to intervention was somewhat arbitrary with those girls who could commit to therapy 4 days a week getting LSVT Loud, whereas one girl received therapy following the traditional approach twice a week. LSVT focused on increasing loudness; the traditional approach targeted posture, speech clarity and breath control.

Changes - measured by means of caregiver questionnaires, articulation tests and listener perception tests of single words and spontaneous speech – were positive: caregivers reported a positive impact of therapy on speech, articulation tests showed greater articulatory precision, and listeners preferred the post-therapy speech samples. Interestingly, LSVT seemed to increase speech function and loudness, whereas the traditional approach resulted in better speech but had no effect on loudness.

Although overall results suggest an improvement in speech function, individual performances show a highly variable picture. For instance, in terms of loudness one girl undergoing LSVT treatment improved at word level, whereas the other one showed improvements in spontaneous speech. This is not the only reason why the results of the study should be interpreted carefully:

• The interventions were administered by different therapists/students
• It is unclear whether the frequency of intervention had an effect
• The allocation to intervention was arbitrary
• Relation of the findings to intelligibility were not examined
• Results were not tested for statistical significance

The study is a step into the right direction, and raises one important issue: How can we predict which intervention approach is the best for a particular child?

Levy, E. S., Ramig, L. O. & Camarata, S. (2012) The Effects of Two Speech Interventions on Speech Function in Pediatric Dysarthria. Journal of Medical Speech-Language Pathology, 20(4), 82-87.

treatment effectiveness

Although a number of articles describing treatment approaches for developmental dysarthria were published over the years, to date only few studies were conducted to test whether dysarthria intervention in children with CP is actually effective.

A series of therapy studies conducted by Lindsay Pennington’s research group in Newcastle addressed this research gap. Pennington, Smallman and Farrier (2006) started off with a small scale intervention study in which six children with CP received individual dysarthria therapy targeting breath support and volume across utterances. Improvement was measured by means of intelligibility of single words and connected speech. Four of the six children were more intelligible directly after therapy, although improvement was only maintained in one speaker seven weeks later.

This study was followed by a more extensive investigation in 2010. Pennington and colleagues wanted to find out whether a systems approach targeting breath support, phonation and speech rate can increase the speech intelligibility of older children with CP. Sixteen children with moderate to severe dysarthria aged 12 to 18 years attended three therapy sessions per week over a period of six weeks. As in the previous study, improvement was measured in terms of intelligibility in single words and connected speech across four time points (6 and 1 week pre-therapy, and 1 and 6 weeks post-therapy). The intervention was found to increase speech intelligibility for familiar and unfamiliar listeners for both measures. Importantly, changes were maintained after 6 weeks, indicating acquisition of stable motor patterns.

A recent study by the same lead author examined intensive dysarthria therapy for younger children with CP. Just as the previous study, the intervention targeted breath support, phonation and speech rate. Fifteen children were recruited aged 5 to 11 years. The therapy success was measured in terms of intelligibility and participation in conversational interactions across five points: 6 and 1 week pre-therapy and 1, 6 and 12 weeks post-therapy. Overall, gains in intelligibility and participation in interaction were observed, although scores in the latter did not correlate with changes in the former. This finding shows that some children interacted more following therapy - perhaps due to increased confidence - irrespective of how much their speech intelligibility improved.

Pennington, L., Smallman, C., & Farrier, F. (2006). Intensive dysarthria therapy for older children with cerebral palsy: Findings from six cases. Child Language Teaching & Therapy, 22, 255–273.

Pennington, L., Miller, N., Robson, S. & Steen, N. (2010). Intensive speech and language therapy for older children with cerebral palsy: a systems approach. Developmental Medicine & Child Neurology, 52, 337–344.

Pennington, L., Roelant, E., Thompson, V., Robson, S., Steen, N. & Miller, N. (2013). Intensive dysarthria therapy for younger children with cerebral palsy. Developmental Medicine & Child Neurology, 55, 464–71.