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

Abstract

Speech production in young people with Down's 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 /integral/ 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 Down's 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 /integral/ were carried out. /integral/ production was found to be inconsistent in the young people with Down's 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 /integral/ with atypical EPG patterns. The use of typical, adult-modelled /integral/ EPG patterns in therapy may be inappropriate for some children with DS who present with atypical palatal structures.

Measures to evaluate the effects of DBS on speech production

“…As reviewed by McAuliffe and Ward (2006), several of these studies show differences in EPG patterns between speakers with dysarthria and neurologically-normal speakers, but the differences are often difficult (if not impossible) to interpret. For example, reports of apparently “atypical” palatal contact patterns associated with perception of a correct lingual consonant are fairly common (see cases reviewed by McAuliffe and Ward, 2006; and similar mismatches between EPG patterns and the perception of /Σ/ reported by Timmins et al (2009) for speakers with Down syndrome). McAuliffe, Ward, and Murdoch (2006) report the opposite effect for speakers with Parkinson disease, wherein apparently “normal” EPG patterns for lingual consonants are associated with consonants perceived as “imprecise”.…”

“…EPG has been used to study lingual consonant production in speakers with dysarthria, including speakers with PD (see, for example, McAuliffe, Ward, & Murdoch, 2006 a, b; Kuruvilla, Murdoch, & Goozée, 2009; Timmins et al, 2009; and review in McAuliffe & Ward, 2006). As reviewed by McAuliffe and Ward (2006), several of these studies show differences in EPG patterns between speakers with dysarthria and neurologically-normal speakers, but the differences are often difficult (if not impossible) to interpret.…”

Motor Equivalent Strategies in the Production of German /∫/ under Perturbation

“…Our results are in line with findings from some other earlier studies. Timmins, Cleland, Wood, Hardcastle, and Wishart (2009), for example, investigated the production of /∫/ in young people with Down’s syndrome. They show that many of those speakers, who differ from typically developing children in their palate shape, managed to produce perceptually acceptable productions of the fricative even if the articulation differed as compared to that of typically developing children and adults.…”

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

“…Hamilton (1993) noted increased tongue-palate contact for children with DS. Timmins et al (2007Timmins et al ( , 2009 found increased articulatory variability in fricative production of young people with DS when compared with a typically developing (TD) group matched for cognitive age. These detailed studies help to provide more answers regarding the specific speech errors displayed in children with DS.…”

“…However, most of these studies look at phonological processes (Stoel-Gammon, 1980;Smith and Stoel-Gammon, 1983;Bleile and Schwarz, 1984;Crosley and Dowling, 1989) and lack detailed phonetic analyses. A few studies have provided more detailed phonetic analyses of speech in DS using instrumental techniques such as acoustic analysis and electropalatography (EPG) (Hamilton, 1993;Brown-Sweeney and Smith, 1996;Callahan Mandaluk, Zajac, Harris, Roberts, and Cox, 2006;Timmins, Hardcastle, Wood, McCann, and Wishart, 2007;Timmins, Cleland, Wood, Hardcastle, and Wishart, 2009). Hamilton (1993) noted increased tongue-palate contact for children with DS.…”