CASL
Permanent URI for this collectionhttps://eresearch.qmu.ac.uk/handle/20.500.12289/22
Browse
75 results
Search Results
Item An EPG therapy protocol for remediation and assessment of articulation disorders.(ICSLP, 2002) Wrench, Alan A.; Gibbon, Fiona; McNeill, Alison M.; Wood, Sara; Hansen, John H.L.; Pellom, BryanThis paper describes technical and methodological advances in the development of a procedure for measuring changes in accuracy and stability of linguapalatal (tongue-palate) contact patterns during a course of visual feedback therapy using electropalatography (EPG). The procedure is exemplified by a case in which therapy was aimed at resolving a pattern of velar fronting whereby phonetic targets /k, g,Item Changes in linguapalatal contact patterns during therapy for velar fronting in a 10-year-old with Down's syndrome.(2004) Gibbon, Fiona; McNeill, Alison M.; Wood, Sara; Watson, JocelynneBACKGROUND: Articulation errors in the speech of people with Down's 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 Down's 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 P's 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 Down's syndrome. A major issue still to be addressed, however, is the extent to which others will benefit from this approach to intervention.Item EPG characteristics of velar stops in normal adult English speakers(2007-08) Liker, Marko; Gibbon, FionaThis study aimed to determine the main characteristics of normal tongue palate patterns for velar stops. EPG data from the EUR-ACCOR database were analysed for nonsense VCV sequences containing /k/ in nine vowel contexts for seven English speaking adults. Incomplete EPG closure across the palate for /k/ occurred in 19% (range 4%-41%) of utterances with the most number of incomplete closures in /aka/ and the least in /uki/. As predicted, place of articulation was dependant on vowel context. The most fronted was the velar occlusion in /iki/ and the most retracted in /aka/. In terms of amount of contact, /k/ in /iki/ environment had almost twice as much tongue palate contact compared to /aka/ in all speakers (mean 42% for /iki/ compared to 22% for /aka/). There was considerable interspeaker variability in all variables. The implications of the results for diagnosing and treating speech disorders are discussed.Item Widening access to electropalatography for children with persistent sound system disorders.(American Speech-Language-Hearing Association, 1999-11) Gibbon, Fiona; Stewart, Fiona; Hardcastle, William J.Previous studies have demonstrated the value of using electropalatography (EPG) to assess, diagnose, and treat persistent sound system disorders in children. However, the application of EPG research has been limited in clinical contexts because most speech-language pathologists do not have access to the technique. This article provides an overview of recent EPG research on persistent sound system disorders and describes a network that has been established to widen access to EPG. The use of EPG via the network is illustrated in the case description of an 8-year-old boy, Robbie, who presented with a persisting speech disorder. The network was used because the clinician treating Robbie did not have an EPG. The main perceptual feature of Robbie's speech before EPG treatment was the deviant phonological process of backing /t/ and /d/ targets to velar place of articulation. EPG was used to assess articulatory patterns before treatment, to provide visual feedback as part of a treatment program, and to record changes in tongue-palate contact patterns as treatment progressed. Robbie achieved normal /t/ and /d/ articulatory patterns after treatment and was subsequently discharged. Factors that could have contributed to the successful outcome in this case are discussed, and areas requiring further research are identified.Item Quantifying lingual coarticulation using ultrasound imaging data collected with and without head stabilisation(2015-04-01) Zharkova, Natalia; Gibbon, Fiona; Hardcastle, William J.Previous studies reporting the use of ultrasound tongue imaging with clinical populations have generally provided qualitative information on tongue movement. Meaningful quantitative measures for use in the clinic typically require the speaker's head to be stabilised in relation to a transducer, which may be uncomfortable, and unsuitable for young children. The objective of this study was to explore the applicability of quantitative measurements of stabilisation-free tongue movement data, by comparing ultrasound data collected from 10 adolescents, with and without head stabilisation. Several measures of tongue shape were used to quantify coarticulatory influence from two contrasting vowels on four different consonants. Only one of the measures was completely unaffected by the stabilisation condition for all the consonants. The study also reported cross-consonant differences in vowel-related coarticulatory effects. The implications of the findings for the theory of coarticulation and for potential applications of stabilisation-free tongue curve measurements in clinical studies are discussed.Item Development of lingual motor control in children and adolescents(University of Glasgow: Glasgow, 2015-08-10) Zharkova, Natalia; Hardcastle, William J.; Gibbon, Fiona; Lickley, RobinAn important insight into speech motor control development can be gained from analysing coarticulation. Despite a growing number of acoustic and articulatory studies of lingual coarticulation in children, there are conflicting opinions on how the extent of coarticulation changes during childhood. There is also increasing evidence that age-related patterns vary depending on speech sounds involved. The present study employed ultrasound tongue imaging to compare anticipatory V-on-C coarticulation in 13-year-old adolescents and 5-year-old children, using the consonants /p/ and /t/, which differ in the amount of lingual coarticulation in adult speech. For /p/, the two groups had a similar amount of coarticulation. For /t/, both groups had a vowel effect on the extent of tongue bunching, while only adolescents had an effect on the location of tongue bunching. Token-to-token variability in absolute tongue position was larger in the 5-year-olds. We discuss the findings in relation to previous studies and existing theoriesItem Normal adult speakers' tongue palate contact patterns for alveolar oral and nasal stops(Taylor & Francis, 2007-03) Gibbon, Fiona; Yuen, Ivan; Lee, Alice; Adams, LynneThis study compared tongue palate contact patterns for oral stops (/t/, /d/) with those for the nasal stop /n/ in order to provide normative data for diagnosing and treating individuals with speech disorders. Electropalatographic (EPG) data were recorded from 15 English speaking adults for word initial /t/, /d/ and /n/ in a high and a low vowel context. EPG frames were classified according to three criteria: (1) anterior constriction; (2) bilateral constriction; and (3) zero posterior central contact. Total amount of contact and variability were also measured. The results showed that almost all (99%) stops met Criteria 1 and 3, with fewer articulations (88% of /t/; 83% of /d/ and 55% of /n/) meeting Criterion 2. Although all stops had similar spatial patterns, /t/ and /d/ had more contact and were more likely to have bilateral constriction than /n/. There were no differences in variability between /t/, /d/ and /n/, however. The clinical implications of the results for the management of individuals with speech disorders are discussed.Item Lingual kinematics and coordination in speech-disordered children exhibiting differentiated versus undifferentiated lingual gestures(2007) Gooze, Justine; Murdoch, Bruce; Ozanne, Anne; Cheng, Yan; Hill, Anne; Gibbon, FionaBackground: Electropalatographic investigations have revealed that a proportion of children with articulation/phonological disorders exhibit undifferentiated lingual gestures, whereby the whole of the tongue contacts the palate simultaneously during lingual consonant production. These undifferentiated lingual gestures have been interpreted to reflect a 'motor constraint', with the tongue tip and body incapable of operating independently. Aims: The present study aimed to provide further insight into the speech motor control abilities of children with articulation/phonological disorders by using electromagnetic articulography to track the movements (velocity, acceleration, distance, duration) of, and the coordination between, the tongue tip and tongue body during lingual consonant production. Methods & Procedures: Comparisons were made between two children with persistent articulation/phonological disorders who exhibited differentiated electropalatographic gestures (9.58 and 10 years), one child with persistent articulation/phonological disorder who demonstrated undifferentiated lingual gestures (11 years), and a group of four control children (mean age = 10.98 years, standard deviation = 0.48). The children were asked to read aloud single-syllable words containing word-initial /t, s, k/ consonants, with tongue tip and tongue body movements recorded using the electromagnetic articulography AG200 system (Carstens Medizinelektronik GmbH, Germany). Outcomes & Results: Kinematic analysis revealed increased kinematic values for /s/ for the two children with articulation/phonological disorders and differentiated electropalatographic gestures compared with the control group. One of these children also exhibited increased /k/ duration. Reduced acceleration was exhibited by one child with differentiated electropalatographic gestures during /t/ production, and by the child with undifferentiated lingual gestures during /k/. Regarding coordination, lag times between the tongue tip and body were variable between and within children. Spatial contribution to consonant production discriminated between the children with differentiated electropalatographic gestures and undifferentiated lingual gestures, with excessive movement of the tongue body exhibited for alveolar consonants by the child with undifferentiated lingual gestures. Conclusions: All three of the children with articulation/phonological disorders demonstrated aberrant lingual kinematics. The child who exhibited undifferentiated lingual gestures further exhibited excess tongue body movement during alveolar consonants, suggestive of poor motor control, an immature or deviant bracing system, and/or a compensatory mechanism to counteract potential disturbances in tongue tip fine motor control. Electromagnetic articulography provided a means of examining speech motor control deficits, including disturbances in tongue movement and coordination, in children with articulation/phonological disorders. 2007 Royal College of Speech & Language Therapists.Item Covert contrast as a stage in the acquisition of phonetics and phonology : working paper(QMU Speech Science Research Centre, 1996) Scobbie, James M.; Gibbon, Fiona; Hardcastle, William J.; Fletcher, PaulPaper adds to the growing body of evidence that children can acquire phonological systems before they are able to master the phonetic skills needed to convey the contrasts in that system