Can visual feedback help to improve articulation disorders that are resistant to conventional speech therapy?

Speech and language therapy usually relies on auditory feedback (listening to the sounds, words and sentences client and therapist produce) to change speech patterns. A team of Swedish researchers around Ann Nordberg wanted to find out whether visual feedback could help children with CP and dysarthria to change articulation patterns that were resistant to conventional therapy.

The visual feedback technique they used is called electropalatography (EPG). EPG allows to record when and where the tongue makes contact with the roof of the mouth, the hard palate, during speech. An artificial palate with electrodes - which looks a bit like a dental brace - records the tongue movements. That means the client gets direct feedback where the tongue is and can try and change its position to produce a sound that is closer to the desired sound. Using EPG the authors examined how children with CP produce dental and alveolar targets sounds (t, d, n and s) in different positions in single words before and after therapy.

Five children (mean age 9.4 years) with CP and mild or severe dysarthria took part in the study. The majority of them practiced at home for 15 minutes a day for 5 days a week over a period of 8 weeks. Weekly EPG exercises included the production of target sounds in syllables, words and short sentences. Speech materials to monitor progress consisted of 70 pictures from a Swedish Articulation Test.

A detailed analysis of the EPG patterns revealed that before therapy the children had unusual articulation patterns such as producing sounds far back in the mouth (retracted articulation). After therapy, EPG analysis and perceptual evaluation revealed that the tongue made more precise contact in dental and alveolar positions leading to an improvement in articulation. This improvement was observed for sounds in word-initial and -medial positions but not in word-final positions. Overall, the authors conclude that EPG can be valuable for the description of articulation patterns in CP and to document changes after speech therapy. Due to the instrumental nature of the intervention EPG may not be readily available everywhere as a therapy approach, but seems worthwhile pursuing for children who have not responded to conventional articulation therapy.


Nordberg, A., Carlsson, G. & Lohmander, A. (2011). Electropalatography in the description and treatment of speech disorders in five children with cerebral palsy. Clinical Linguistics & Phonetics, 25(10), 831-852

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.

LSVT LOUD

LSVT LOUD (Lee Silverman Voice Treatment) is a treatment approach that was originally developed for people with Parkinson’s disease to raise their voice and be heard more clearly. Cynthia Fox and Carol Boliek took this intensive voice treatment approach as a starting point to work on the breathing and phonation patterns in children with CP. Improving breathing for speech is important as is lays the foundation to work on other speech subsystems such as articulation.

Four children with dysarthria due to spastic CP were recruited for the therapy study. The children had 16 therapy sessions overall (4 sessions a week for 4 consecutive days), and were given exercises to practice at home. Improvement in vocal functioning was measured using a combination of perceptual evaluation and acoustic measures. Seven speech and language therapists were asked to listen to speech samples recorded prior to therapy, directly after therapy and six weeks after the end of the treatment, and to judge which one they preferred.

Results were somewhat mixed. Although the therapists judged that the speech of the children - for features such as loudness and voice quality - improved directly after the intensive treatment, the improvement could not be maintained. In addition, acoustic measures taken prior to and after therapy did not suggest significant improvement in the children’s voices.
 

At the same time though, parents reported that after the treatment their children spoke with less effort and their voices sounded less strangled. This raises the question whether the perceptual and acoustic measures employed in this study were simply not suited to capture the actual improvements in the children’s voices. This observation leaves us with two questions: 1.) How can we best measure decreased effort? And 2.) What exactly is the basis of listener perception?

 

Any ideas?

Fox, C. M. & Boliek, C. A. (2012). Intensive Voice Treatment (LSVT LOUD) for Children with Spastic Cerebral Palsy and dysarthria. Journal of Speech, Language, and Hearing Research, 55, 930-945.

PROMPT

Improving intelligibility is the common goal of most intervention studies in dysarthria. Therapy approaches differ, though, regarding how to achieve this improvement. While it is well-known that modification to breathing can lead to gains in intelligibility, the benefit of improving timing and coordination of oro-facial movements during speech is underresearched, according to a team of researchers in Australia. Roslyn Ward and colleagues therefore intended to examine the effectiveness of a motor-speech intervention programme to improve intelligibility in CP. They did this by evaluating changes of lips and jaw movements in six children with moderate to severe dysarthria due to CP before, during and after participation in PROMPT.

PROMPT stands for Prompts for Restructuring Oral-Muscular Phonetic Targets. It is a specifically designed treatment approach that employs tactile-kinaesthetic-proprioceptive (...that is our sense of position) information to jaw, lips and tongue to guide the child’s speech movements.

Children participated in two blocks of intervention, each lasting 10 weeks (one 45-minute session per week). For each child a specific protocol was designed which identified intervention priorities for each child in terms of jaw, lip or lingual control. Speech intelligibility and kinematic movements were assessed prior to intervention, after each intervention block and 8 weeks after the end of the intervention. Findings were compared to the speech of 12 typically developing peers.

Results were promising as they showed significant changes in jaw and lip movements for all children with CP. For instance, they showed improvements in jaw stability as well as a decrease in lip rounding, rendering their movements after intervention more similar to those of their peers. These changes in kinematic control were accompanied by considerable gains in intelligibility for all children. Most importantly, the changes in intelligibility were maintained 8 weeks post-treatment.

Despite the successful intervention, it is important to highlight that other approaches that do not provide sensory information such as the LSVT® (Lee Silverman Voice Treatment) to name but one have also improved jaw movements in children with CP. This implies that the exact contribution of the tactile input remains somewhat unclear and further research is needed to find out which patients might benefit most from the motor based approach. It should also be considered that the children’s age ranged from 3 to 11, i.e. they were at different stages in their speech acquisition process.

 

Ward, R., Strauss, G. & Leitão, S. (2013). Kinematic changes in jaw and lip control of children with cerebral palsy following participation in a motor-speech (PROMPT) intervention. International Journal of Speech-Language Pathology, 15(2), 136-155.