Sara Wood

Relationship between speech, oromotor, language and cognitive abilities in children with Down's syndrome

BACKGROUND Children and young people with Downs syndrome present with deficits in expressive speech and language, accompanied by strengths in vocabulary comprehension compared with non-verbal mental age. Intelligibility is particularly low, but whether speech is delayed or disordered is a controversial topic. Most studies suggest a delay, but no studies explore the relationship between cognitive or language skills and intelligibility. AIMS This study sought to determine whether severity of speech disorder correlates with language and cognitive level and to classify the types of errors, developmental or non-developmental, that occur in the speech of children and adolescents with Downs syndrome. METHODS & PROCEDURES Fifteen children and adolescents with Downs syndrome (aged 9-18 years) were recruited. Participants completed a battery of standardized speech, language and cognitive assessments. The phonology assessment was subject to phonological and phonetic analyses. Results from each test were correlated to determine relationships. OUTCOME & RESULTS Individuals with Downs syndrome present with deficits in receptive and expressive language that are not wholly accounted for by their cognitive delay. Receptive vocabulary is a strength in comparison with expressive and receptive language skills, but it was unclear from the findings whether it is more advanced compared with non-verbal cognitive skills. The majority of speech errors were developmental in nature, but all of the children with Downs syndrome showed at least one atypical or non-developmental speech error. CONCLUSIONS & IMPLICATIONS Children with Downs syndrome present with speech disorders characterized by atypical, and often unusual, errors alongside many developmental errors. A lack of correlation between speech and cognition or language measures suggests that the speech disorder in Downs syndrome is not simply due to cognitive delay. Better differential diagnosis of speech disorders in Downs syndrome is required, allowing interventions to target the specific disorder in each individual.

Changes in linguapalatal contact patterns during therapy for velar fronting in a 10‐year‐old with Down's syndrome

BACKGROUND Articulation errors in the speech of people with Downs syndrome are frequent and often resistant to speech therapy. This preliminary study investigates the use of electropalatography (EPG) to diagnose and treat abnormal articulation patterns associated with velar fronting in a 10-year-old girl. AIMS The study measured changes in the accuracy and stability of linguapalatal (tongue-palate) contact patterns during a 14-week course of visual feedback therapy using EPG. Therapy aimed to resolve a pattern of velar fronting whereby targets /k, g, eta/ had alveolar placement [t, d, n]. METHODS & PROCEDURES The participant was a girl (P) with Downs syndrome aged 10;11 years. P had a moderate-severe speech disorder, which included velar fronting. Her speech was recorded with EPG on three occasions during a 14-week course of therapy: first, before therapy; second, midway through therapy; and third, after therapy. Three analyses were conducted on the EPG data. The first used an EPG classification scheme that identified accuracy of placement for /t/ and /k/ targets. The second was a centre of gravity measure that detected whether P produced a significant difference between /t/ and /k/ targets. The third was a variability index that quantified the stability of contact patterns. OUTCOMES & RESULTS The results of the EPG classification showed that before therapy, /t/ and /k/ targets had identical alveolar placement, reflecting the process of velar fronting. The results after therapy showed that 87% of /k/ targets had accurate velar placement. The centre of gravity measure showed no difference in contact patterns for /t/ and /k/ before therapy, but a statistically significant difference at the second and third recordings. The variability index showed stable contact patterns before therapy for /t/ and /k/ targets, but both became highly unstable midway through therapy, with a return to stability at the third recording. We embed a discussion of Ps increased articulation instability during therapy in a recent theoretical framework--dynamic systems--that attempts to account for the emergence of new behavioural forms. CONCLUSIONS These preliminary results suggest that EPG has potential as an effective diagnostic and therapy procedure for articulation errors in people with Downs syndrome. A major issue still to be addressed, however, is the extent to which others will benefit from this approach to intervention.

Using electropalatography (EPG) to diagnose and treat articulation disorders associated with mild cerebral palsy: a case study

Some children with mild cerebral palsy have articulation disorders that are resistant to conventional speech therapy techniques. This preliminary study investigated the use of electropalatography (EPG) to diagnose and treat a long‐standing articulation disorder that had not responded to conventional speech therapy techniques in an 8‐year‐old boy (D) with a congenital left hemiplegia. The targets for EPG therapy were speech errors affecting velar targets /k, g, η/, which were consistently fronted to alveolar placement [t, d, n]. After 15 sessions of EPG therapy over a 4‐month period, Ds ability to produce velars improved significantly. The EPG data revealed two features of diagnostic importance. The first was an unusually asymmetrical pattern of tongue‐palate contact and the second was unusually long stop closure durations. These features are interpreted as a subtle form of impaired speech motor control that could be related to a mild residual neurological deficit. The results suggest that EPG is of potential benefit for diagnosing and treating articulation disorders in individuals with mild cerebral palsy.

Advances in EPG for treatment and research: an illustrative case study.

Electropalatography (EPG), a technique which reveals tongue‐palate contact patterns over time, is a highly effective tool for speech research. We report here on recent developments by Articulate Instruments Ltd. These include hardware for Windows‐based computers, backwardly compatible (with Reading EPG3) software systems for clinical intervention and laboratory‐based analysis for EPG and acoustic data, and an enhanced clinical interface with client and file management tools. We focus here on a single case study of a child aged 10± years who had been diagnosed with an intractable speech disorder possibly resulting ultimately from a complete cleft of hard and soft palate. We illustrate how assessment, diagnosis and treatment of the intractable speech disorder are undertaken using this new generation of instrumental phonetic support. We also look forward to future developments in articulatory phonetics that will link EPG with ultrasound for research and clinical communities.

Electropalatographic therapy for children and young people with Down's syndrome

Articulation disorders in Downs syndrome (DS) are prevalent and often intractable. Individuals with DS generally prefer visual to auditory methods of learning and may therefore find it beneficial to be given a visual model during speech intervention, such as that provided by electropalatography (EPG). In this study, participants with Downs syndrome, aged 10:1 to 18:9, received 24 individualized therapy sessions using EPG. Simultaneous acoustic and EPG recordings were made pre- and post-intervention during 10 repetitions of a word list containing lingua-palatal consonants. Participants also completed the DEAP phonology sub-test at both time points. Post-treatment, all participants showed qualitative and quantifiable differences in EPG patterns and improvements in DEAP percentage consonants correct. EPG assessment and therapy appears a positive approach for identifying and improving articulatory patterns in children with DS.

The use of electropalatography (EPG) in the assessment and treatment of motor speech disorders in children with Down's syndrome: Evidence from two case studies

Background: Many children experience significant difficulties in developing key aspects of speech. For some, these communication difficulties are compounded by co-occurring intellectual disabilities. Method: This paper presents two case studies from a larger on-going longitudinal study of the effectiveness of using electropalatography (EPG) to address the intelligibility problems experienced by many children and young people with Downs syndrome (DS). EPG, an innovative computer-based tool for assessing and treating speech motor difficulties, enables the speaker to ‘see’ the placement of his or her tongue during speech and to attempt to correct any lingual palatal errors. Results: This visual supplementation of auditory feedback offers potential therapeutic benefits for children with intellectual disabilities, many of whom show relative strengths in visual vs. auditory and simultaneous vs. sequential processing. EPG also provides therapists with an objective measure of articulatory ability. Conclusions: Findings from these two case studies demonstrate the potential utility of EPG in both the assessment and treatment of speech motor disorders in DS.

ARTICULATORY DRIFT IN THE SPEECH OF CHILDREN WITH ARTICULATION AND PHONOLOGICAL DISORDERS

This study used electropalatography to identify articulatory drift in alveolar stops (/t/ and /d/) produced by 10 children with functional articulation and phonological disorders. Drift involves an abnormal change in place of articulation that occurs during stop closure. An index was used to measure drift, with higher values indicating greater drift. The results showed that drift was higher for children who produced undifferentiated gestures (articulations with increased tongue-palate contact). Drift is an important characteristic of articulation because it is believed to reflect impaired speech motor control. In addition, drift could explain some perceptually based speech errors that are frequently reported in functional disorders.

An EPG analysis of /t/ in young people with Down's syndrome

Many studies have pointed to impaired speech intelligibility in young people with Down’s syndrome (DS). Some have attributed these problems to delayed phonological development, while others have identified disordered speech patterns, which could be related to a dyspraxic element in their speech. This study uses electropalatography (EPG) to examine the speech of 25 young people with DS, focusing on their production of the obstruent /t/. For the EPG analysis, participants produced the target obstruent in the word ‘toe’, repeated 10 times. An investigative analysis was carried out. A new descriptive taxonomy of EPG error patterns was developed and these errors were related to perceptually based transcriptions. The measures are discussed in relation to current knowledge of the anatomical and physiological characteristics of DS.

A perceptual and electropalatographic study of /∫/ in young people with Down's syndrome

Speech production in young people with Downs syndrome has been found to be variable and inconsistent. Errors tend to be more in the production of sounds that typically develop later, for example, fricatives and affricates, rather than stops and nasals. It has been suggested that inconsistency in production is a result of a motor speech deficit. Late acquired fricatives such as /s/ and /∫/ are complex articulations, which may require more precise motor programming and may therefore show highly inconsistent productions. Other factors potentially affecting speech production in this population are abnormal palatal structure, hearing loss, and hypotonia. A group of 20 young people with Downs syndrome were recorded using Electropalatography (EPG), reading a wordlist containing the phrase ‘a sheep’. The wordlist contained seven other phrases and was repeated 10 times. Eight typically developing, cognitively matched children and eight adults were also recorded producing the same data set. Articulatory (EPG pattern analysis) and perceptual analyses of the 10 productions of /∫/ were carried out. /∫/ production was found to be inconsistent in the young people with Downs syndrome, with more errors both in the auditory analysis and articulatory analysis than in the typical sample, which may be due to a motor programming or motor control problem. There were a greater number of errors in the EPG analysis than in the perceptual analysis. This suggests that some young people with DS were able to produce perceptually acceptable /∫/ with atypical EPG patterns. The use of typical, adult-modelled /∫/ EPG patterns in therapy may be inappropriate for some children with DS who present with atypical palatal structures.

EPG patterns in a patient with phonemic paraphasic errors

Auditorily-detected phonemic paraphasias such as substitutions are said to characterize aphasias such as Wernicke’s and conduction aphasia. However previous research has shown that the articulatory details underlying such substitutions recorded by techniques such as Electropalatography (EPG) may reveal a level of complexity not detected by the auditory analysis alone. Articulatory anomalies such as so-called Misdirected Articulatory Gestures (MAGs) may accompany the production of the substitutions and are variously perceived by listeners. A perceptual study is carried out in which 16 adult listeners rate sounds identified on the basis of EPG analysis as potential substitutions, on a scale from alveolar to velar. Some of the target sounds looked like ‘pure’ substitutions from the EPG patterns and some exhibited MAGs. Listener judgements were not always entirely predictable on the basis of EPG patterns. The occurrence of the anomalous EPG patterns (and the auditory results) is explored further in terms of a modified spreading activation model and implications for clinical management are discussed.