Rachael-Anne Knight

How should children with speech sound disorders be classified? A review and critical evaluation of current classification systems

BACKGROUND Children with speech sound disorders (SSD) form a heterogeneous group who differ in terms of the severity of their condition, underlying cause, speech errors, involvement of other aspects of the linguistic system and treatment response. To date there is no universal and agreed-upon classification system. Instead, a number of theoretically differing classification systems have been proposed based on either an aetiological (medical) approach, a descriptive-linguistic approach or a processing approach. AIMS To describe and review the supporting evidence, and to provide a critical evaluation of the current childhood SSD classification systems. METHODS & PROCEDURES Descriptions of the major specific approaches to classification are reviewed and research papers supporting the reliability and validity of the systems are evaluated. MAIN CONTRIBUTION Three specific paediatric SSD classification systems; the aetiologic-based Speech Disorders Classification System, the descriptive-linguistic Differential Diagnosis system, and the processing-based Psycholinguistic Framework are identified as potentially useful in classifying children with SSD into homogeneous subgroups. The Differential Diagnosis system has a growing body of empirical support from clinical population studies, across language error pattern studies and treatment efficacy studies. The Speech Disorders Classification System is currently a research tool with eight proposed subgroups. The Psycholinguistic Framework is a potential bridge to linking cause and surface level speech errors. CONCLUSIONS & IMPLICATIONS There is a need for a universally agreed-upon classification system that is useful to clinicians and researchers. The resulting classification system needs to be robust, reliable and valid. A universal classification system would allow for improved tailoring of treatments to subgroups of SSD which may, in turn, lead to improved treatment efficacy.

The effect of pitch span on intonational plateaux

Previous research has indicated that the H (high) of a nuclear accent may be realized as a flat stretch of contour rather than as a single turning point. Both the duration of this plateau and its alignment within the accented syllable are affected by the segmental and prosodic structure of the utterance. The present work investigates whether a non-structural variable, namely pitch span, also affects the realization of the plateau. Speakers replicated all-sonorant utterances in different pitch spans. Results show that both the duration and alignment of the plateau vary with pitch span but in ways different from the way they vary with prosodic structure. Importantly, results also indicate that, when using a proportional measure of alignment, the end of the plateau is anchored within the syllable for each speaker and may be a marker of linguistic structure.

The shape of nuclear falls and their effect on the perception of pitch and prominence: peaks vs. plateaux.

This article investigates the perceptual effect of a high plateau in the intonation contour. Plateaux are flat stretches of contour and have been observed associated with high tones in Standard Southern British (SSB) English. The hypothesis that plateaux may make the accents with which they are associated sound higher in pitch than sharp peaks of the same maximum frequency is tested experimentally. In the first experiment listeners heard pairs of resynthesized utterances where the nuclear accent differed only in shape, not frequency. They indicated which stimulus they thought contained the higher pitched accent. Results showed that plateau-shaped accents sound higher than peaks. In the second experiment the effect of a plateau on prominence relations within an utterance is investigated. Listeners heard resynthesized sentences, and compared two accents. One group indicated which accent sounded higher in pitch and the other indicated which sounded more prominent. Results again indicated that plateau-shaped accents sound higher in pitch and also more prominent; judgments of pitch and prominence were very similar to one another. The results from both experiments indicated that accent shape is a perceptually important variable, although such a fine level of detail is not taken into account by autosegmental-metrical theories of intonation.

Assessing the temporal reliability of rhythm metrics

Despite the current popularity of rhythm metrics, there has been relatively little work aimed at establishing their validity or reliability, important characteristics of any empirical measure. The current paper focuses on the stability, or temporal reliability, of rhythm metrics by establishing if they give consistent results for the same speakers, in the same task, on successive occasions. Four speakers of Southern British English were recorded reading ‘The North Wind and the Sun’ (NWS) passage on three consecutive days. Results indicated that some measures correlate more highly across time than others, and the choice of a measure that is both reliable and valid is discussed. It is suggested that the metric that best fits these criteria is formulated in terms of the proportion of vowels within an utterance (%V).

Cross-accent intelligibility of speech in noise: Long-term familiarity and short-term familiarization

Listeners must cope with a great deal of variability in the speech signal, and thus theories of speech perception must also account for variability, which comes from a number of sources, including variation between accents. It is well known that there is a processing cost when listening to speech in an accent other than ones own, but recent work has suggested that this cost is reduced when listening to a familiar accent widely represented in the media, and/or when short amounts of exposure to an accent are provided. Little is known, however, about how these factors (long-term familiarity and short-term familiarization with an accent) interact. The current study tested this interaction by playing listeners difficult-to-segment sentences in noise, before and after a familiarization period where the same sentences were heard in the clear, allowing us to manipulate short-term familiarization. Listeners were speakers of either Glasgow English or Standard Southern British English, and they listened to speech in either their own or the other accent, thereby allowing us to manipulate long-term familiarity. Results suggest that both long-term familiarity and short-term familiarization mitigate the perceptual processing costs of listening to an accent that is not ones own, but seem not to compensate for them entirely, even when the accent is widely heard in the media.

Perceptual Judgments of Resonance, Nasal Airflow, Understandability, and Acceptability in Speakers With Cleft Palate: Ordinal Versus Visual Analogue Scaling

Objective To investigate the reliability of ordinal versus visual analogue scaling (VAS) ratings for perceptual judgments of nasal resonance, nasal airflow, understandability, and acceptability in speakers with cleft palate. Design Within-subjects comparative study. Setting Multisite. Participants Five specialist speech and language therapists from U.K. Regional Cleft Centres. Outcome Measures Participants rated 30 audio speech samples obtained from the Speech and Language Therapy archives of Great Ormond Street Hospital. They rated the identified speech parameters using each scaling method, with 1 month between rating tasks. The model of best fit was determined to examine validity, and both intra- and inter-rater reliability were also computed. Results VAS ratings were valid for all parameters when plotted against ordinal ratings, and the model of best fit revealed only a slightly stronger curvilinear than linear relationship between the scaling methods. Intra-rater reliability was high for both rating methods across all six speech parameters. There was also high inter-rater reliability for both ordinal and VAS ratings of hypernasality, nasal emission, nasal turbulence, understandability, and acceptability, and for the ordinal ratings of hyponasality. Conclusions Perceptual judgments of nasal resonance, nasal airflow, understandability, and acceptability were similar using VAS and ordinal scaling, indicating that both scaling methods were appropriate for measuring the cleft speech parameters. VAS, however, may offer statistical advantages, and there is a growing body of evidence advocating its use for the measurement of prothetic speech parameters.

Transcribing Nonsense Words: The Effect of Numbers of Voices and Repetitions.

Transcription skills are crucially important to all phoneticians, and particularly for speech and language therapists who may use transcriptions to make decisions about diagnosis and intervention. Whilst interest in factors affecting transcription accuracy is increasing, there are still a number of issues that are yet to be investigated. The present paper considers how the number of voices and the number of repetitions affects the transcription of nonsense words. Thirty-two students in their second year of study for a BSc in Speech and Language Therapy were participants in an experiment. They heard two nonsense words presented 10 times in either one or two voices. Results show that the number of voices did not affect accuracy, but that accuracy increased between six and ten repetitions. The reasons behind these findings, and implications for teaching and learning, and further research are discussed.

Viva Survivors – the effect of peer-mentoring on pre-viva anxiety in early-years students

Viva voce exams are used in many disciplines as a test of students’ knowledge and skills. Whilst acknowledged as a useful form of assessment, vivas commonly lead to a great deal of anxiety for students. This anxiety is also apparent for vivas in phonetics, where the students must produce and recognise sounds drawn from across the world’s languages, and pervious work has shown that viewing a video of a mock-viva does not reduce this anxiety. To address anxiety prior to phonetics vivas, 63 students, across 3 cohorts, engaged in a brief, isolated, peer-mentoring session with previously successful students (‘viva survivors’). Anxiety about the viva was measured before and after the mentoring experience, using the short form of the State-Trait Anxiety Inventory. There was a significant reduction in anxiety after mentoring, and a significant correlation between anxiety before mentoring and the decrease in anxiety after mentoring. Short-term mentoring is posited as a time- and cost-effective method to decrease viva-related anxiety across disciplines.

CitySCaPE: Moving beyond indifference in education for pre-registration nurses about learning disability

People with learning disabilities and Autism continue to suffer from the delivery of ineffective and inadequate care from health services CitySCaPE (City Simulated Community and Practice Environment) is a multi media resource delivering a simulation of situations student nurses may encounter in relation to service users with learning disabilities. The resource is applicable to adult, mental health and childrens nursing. It is delivered in a blended approach to students in the first part of their programme as part of their simulated practice. Following the implementation of the resource an evaluation of student experience was undertaken using a mixed methods approach. 146 responses were obtained to a questionnaire containing quantitative and qualitative data. The findings indicate that this is a pedagogy that suits a variety of learning styles, is deemed to be realistic and improves the understanding of nursing students about the care of people with learning disabilities in generic practice areas. It is anticipated that CitySCaPE can be used as a model for delivery of practice based learning in areas that are often challenging to teach and demonstrate using a service user and person centred approach.

Ingressive Speech Errors: A Service Evaluation of Speech-Sound Therapy in a Child Aged 4;6.

BACKGROUND A pattern of ingressive substitutions for word-final sibilants can be identified in a small number of cases in child speech disorder, with growing evidence suggesting it is a phonological difficulty, despite the unusual surface form. Phonological difficulty implies a problem with the cognitive process of organizing speech into sound contrasts. AIMS To evaluate phonological therapy approaches in the remediation of non-pulmonic speech errors. Thus, adding to evidence concerning the nature of ingressive substitutions and their remediation whilst highlighting their occurrence within child speech disorder population for practising and training speech and language therapists. METHODS & PROCEDURES Child KO, a boy aged 4;6, was identified through a screening of speech, language and communication needs at his school. Word-final, non-pulmonic-egressive substitutes for fricatives and plosives were identified using the Diagnostic Evaluation of Articulation and Phonology (DEAP). Treatment took place in five, weekly school-based sessions with a care-giver present, and targeted two phonemes /f/ and /ʃ/ in word-final position. Word-final /s/ was monitored throughout to capture any change in other word-final fricatives. Phonemes /ɡ/ and /p/ were used as controls, as no change was expected in word-final plosives as a result of therapy targeting fricatives. Production of single words in the DEAP, pre- and post-therapy were transcribed by two independent therapists, (transcription agreement was 86.6% (pre) and 83.7% (post), with all 140 consonants within the DEAP transcribed), and change in consonants correct was analysed using a Wilcoxon test. Picture description tasks and telling of familiar stories were videoed post-therapy to analyse use of word-final fricative egression in connected speech. OUTCOME & RESULTS Percentage consonants correct in single-words post-treatment was significantly higher than pre-treatment at single-word level. Generalization of target fricatives into connected speech and modest generalization of non-target phonemes occurred. CONCLUSIONS & IMPLICATIONS Although ingressive speech sounds are largely absent in the sound system of English, they do occur as speech-sound errors in child speech disorder and respond to phonological therapy within the context of home and school environment. Therefore, training in the phonetic identification of speech sounds outside the system of English is essential. Additionally, non-lexical factors associated with ingression also influence the childs intelligibility and should be explored further in future research.