Speech Disorders Classification System Research Articles

Estimates of the prevalence of speech and motor speech disorders in adolescents with Down syndrome

ABSTRACTAlthough there is substantial rationale for a motor component in the speech of persons with Down syndrome (DS), there presently are no published estimates of the prevalence of subtypes of motor speech disorders in DS. The goal of this research is to provide initial estimates of the prevalence of types of speech disorders and motor speech disorders in adolescents with DS.Conversational speech samples from a convenience sample of 45 adolescents with DS, ages 10 to 20 years old, were analysed using perceptual and acoustic methods and measures in the Speech Disorders Classification System (SDCS). The SDCS cross-classified participants into five mutually exclusive speech classifications and five mutually exclusive motor speech classifications. For participants meeting criteria for Childhood Dysarthria or for Childhood Dysarthria concurrent with Childhood Apraxia of Speech, the SDCS provided information on participants’ percentile status on five subtypes of dysarthria.A total of 97.8% of participants met SDCS criteria for Speech Disorders and 97.8% met criteria for Motor Speech Disorders, including Childhood Dysarthria (37.8%), Speech Motor Delay (26.7%), Childhood Dysarthria and Childhood Apraxia of Speech (22.2%), and Childhood Apraxia of Speech (11.1%). Ataxia was the most prevalent dysarthria subtype.Nearly all participants with DS in the present sample had some type of speech and motor speech disorder, with implications for theory, assessment, prediction, and treatment. Specific to treatment, the present findings are interpreted as support for motor speech disorders as a primary explanatory construct to guide the selection and sequencing of treatment targets for persons with DS.Abbreviations: CAS: Childhood Apraxia of Speech; CD: Childhood Dysarthria; DS: Down syndrome; NSA: Normal(ized) Speech Acquisition; PSD: Persistent Speech Delay; PSE: Persistent Speech Errors; SD: Speech Delay; SDCS: Speech Disorders Classification System; SE: Speech Errors; SMD: Speech Motor Delay

Speech and motor speech disorders and intelligibility in adolescents with Down syndrome

ABSTRACTThe goal of this research was to assess the support for motor speech disorders as explanatory constructs to guide research and treatment of reduced intelligibility in persons with Down syndrome (DS). Participants were the 45 adolescents with DS in the prior paper who were classified into five mutually-exclusive motor speech classifications using the Speech Disorders Classification System. An ordinal index classified participants’ percentage of intelligible words in conversation as High (≥ 85%), Moderate (80% – 84.9%), or Low (< 80%). Statistical analyses tested for significant differences in intelligibility status associated with demographic, intelligence, and language variables, and intelligibility status associated with motor speech classifications and speech, prosody, and voice variables.For the 10 participants who met criteria for concurrent Childhood Dysarthria and Childhood Apraxia of Speech at assessment, 80% had reduced (Moderate or Low) intelligibility and 20% had High intelligibility (significant effect size: 0.644). Proportionally more of the 32 participants who met criteria for either dysarthria or apraxia had reduced intelligibility (significant effect size: 0.318). Low intelligibility was significantly associated with across-the-board reductions in phonemic and phonetic accuracy and with inappropriate prosody and voice.Findings are interpreted as support for motor speech disorders in adolescents with DS as explanatory constructs for their reduced intelligibility. Pending cross-validation of findings in diverse samples of persons with DS, studies are needed to assess the efficacy of motor speech classification status to guide selection of treatment methods and intelligibility targets.Abbreviations: CAS: Childhood Apraxia of Speech; CD: Childhood Dysarthria; DS: Down syndrome; II: Intelligibility Index; No MSD: No Motor Speech Disorder; OII: Ordinal Intelligibility Index; PSD: Persistent Speech Delay; SDCS: Speech Disorders Classification System; SMD: Speech Motor Delay

Motor Speech Disorders in Idiopathic Speech Delay and in Complex Neurodevelopmental Disorders using the Speech Disorders Classification System: Introduction

ABSTRACTThis introduction to a special issue of Clinical Linguistics & Phonetics includes an overview of the contents of each of the six articles. Each of the articles use the finalized version of the Speech Disorders Classification System (SDCS).

Estimates of the prevalence of motor speech disorders in children with idiopathic speech delay

ABSTRACTThe goal of this research was to obtain initial estimates of the prevalence of each of four types of motor speech disorders in children with idiopathic Speech Delay (SD) and to use findings to estimate the population-based prevalence of each disorder.Analyses were completed on audio-recorded conversational speech samples from 415 children recruited for research in idiopathic SD in six USA cities during the past three decades. The speech and motor speech status of each participant was cross-classified using standardized measures in the finalized version of the Speech Disorders Classification System described in the Supplement. Population-based prevalence estimates for the four motor speech disorders were calculated from epidemiological studies of SD conducted in Australia, England, and the USA.A total of 82.2% of the 415 participants with SD met criteria for No Motor Speech Disorder at assessment, 12% met criteria for Speech Motor Delay, 3.4% met criteria for Childhood Dysarthria, 2.4% met criteria for Childhood Apraxia of Speech, and 0% met criteria for concurrent Childhood Dysarthria and Childhood Apraxia of Speech. The estimated population-based prevalence of each of the first three motor speech disorders at 4 to 8 years of age were Speech Motor Delay: 4 children per 1,000; Childhood Dysarthria: 1 child per 1,000; and Childhood Apraxia of Speech: 1 child per 1,000. The latter finding cross-validates a prior prevalence estimate for Childhood Apraxia of Speech of 1–2 children per 1,000. Findings are interpreted to indicate a substantial prevalence of motor speech disorders in children with idiopathic SD.Abbreviations: CAS, childhood apraxia of speech; CD, childhood dysarthria; CND, complex neurodevelopmental disorders; DI, dysarthria index; DSI, dysarthria subtype indices; MSD, motor speech disorder; No MSD, no motor speech disorder; NSA, normal(ized) speech acquisition; PEPPER, programs to examine phonetic and phonologic evaluation records; PM, pause marker; PMI, pause marker index; PSD, persistent speech delay; PSE, persistent speech errors; SD, speech delay; SDCS, speech disorders classification system; SDCSS, speech disorders classification system summary; SE, speech errors; SMD, speech motor delay.

A Diagnostic Marker to Discriminate Childhood Apraxia of Speech From Speech Delay: I. Development and Description of the Pause Marker.

The goal of this article (PM I) is to describe the rationale for and development of the Pause Marker (PM), a single-sign diagnostic marker proposed to discriminate early or persistent childhood apraxia of speech from speech delay. The authors describe and prioritize 7 criteria with which to evaluate the research and clinical utility of a diagnostic marker for childhood apraxia of speech, including evaluation of the present proposal. An overview is given of the Speech Disorders Classification System, including extensions completed in the same approximately 3-year period in which the PM was developed. The finalized Speech Disorders Classification System includes a nosology and cross-classification procedures for childhood and persistent speech disorders and motor speech disorders (Shriberg, Strand, & Mabie, 2017). A PM is developed that provides procedural and scoring information, and citations to papers and technical reports that include audio exemplars of the PM and reference data used to standardize PM scores are provided. The PM described here is an acoustic-aided perceptual sign that quantifies one aspect of speech precision in the linguistic domain of phrasing. This diagnostic marker can be used to discriminate early or persistent childhood apraxia of speech from speech delay.

Data-driven subclassification of speech sound disorders in preschool children.

The purpose of the study was to determine whether distinct subgroups of preschool children with speech sound disorders (SSD) could be identified using a subgroup discovery algorithm (SUBgroup discovery via Alternate Random Processes, or SUBARP). Of specific interest was finding evidence of a subgroup of SSD exhibiting performance consistent with atypical speech motor control. Ninety-seven preschool children with SSD completed speech and nonspeech tasks. Fifty-three kinematic, acoustic, and behavioral measures from these tasks were input to SUBARP. Two distinct subgroups were identified from the larger sample. The 1st subgroup (76%; population prevalence estimate = 67.8%-84.8%) did not have characteristics that would suggest atypical speech motor control. The 2nd subgroup (10.3%; population prevalence estimate = 4.3%-16.5%) exhibited significantly higher variability in measures of articulatory kinematics and poor ability to imitate iambic lexical stress, suggesting atypical speech motor control. Both subgroups were consistent with classes of SSD in the Speech Disorders Classification System (SDCS; Shriberg et al., 2010a). Characteristics of children in the larger subgroup were consistent with the proportionally large SDCS class termed speech delay; characteristics of children in the smaller subgroup were consistent with the SDCS subtype termed motor speech disorder-not otherwise specified. The authors identified candidate measures to identify children in each of these groups.

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

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. To describe and review the supporting evidence, and to provide a critical evaluation of the current childhood SSD classification systems. Descriptions of the major specific approaches to classification are reviewed and research papers supporting the reliability and validity of the systems are evaluated. 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. 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.

Extensions to the Speech Disorders Classification System (SDCS)

This report describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). Part I describes a classification extension to the SDCS to differentiate motor speech disorders from speech delay and to differentiate among three sub-types of motor speech disorders. Part II describes the Madison Speech Assessment Protocol (MSAP), an ∼ 2-hour battery of 25 measures that includes 15 speech tests and tasks. Part III describes the Competence, Precision, and Stability Analytics (CPSA) framework, a current set of ∼ 90 perceptual- and acoustic-based indices of speech, prosody, and voice used to quantify and classify sub-types of Speech Sound Disorders (SSD). A companion paper provides reliability estimates for the perceptual and acoustic data reduction methods used in the SDCS. The agreement estimates in the companion paper support the reliability of SDCS methods and illustrate the complementary roles of perceptual and acoustic methods in diagnostic analyses of SSD of unknown origin. Examples of research using the extensions to the SDCS described in the present report include diagnostic findings for a sample of youth with motor speech disorders associated with galactosemia, and a test of the hypothesis of apraxia of speech in a group of children with autism spectrum disorders. All SDCS methods and reference databases running in the PEPPER (Programs to Examine Phonetic and Phonologic Evaluation Records) environment will be disseminated without cost when complete.

Perceptual and acoustic reliability estimates for the Speech Disorders Classification System (SDCS)

A companion paper describes three extensions to a classification system for paediatric speech sound disorders termed the Speech Disorders Classification System (SDCS). The SDCS uses perceptual and acoustic data reduction methods to obtain information on a speaker's speech, prosody, and voice. The present paper provides reliability estimates for the two perceptual methods (narrow phonetic transcription; prosody-voice coding) and the acoustic analysis methods the SDCS uses to describe and classify a speaker's speech competence, precision, and stability. Speech samples from 10 speakers, five with significant motor speech disorder and five with typical speech, were re-measured to estimate intra-judge and inter-judge agreement for the perceptual and acoustic methods. Each of the speakers completed five speech tasks (total = 50 datasets), ranging in articulatory difficulty for the speakers, with consequences for the difficulty level of data reduction. Point-to-point percentage of agreement findings for the two perceptual methods were as high or higher than reported in literature reviews and from previous studies conducted within the laboratory. Percentage of agreement findings for the acoustics tasks of segmenting phonemes, editing fundamental frequency tracks, and estimating formants ranged from values in the mid 70% to 100%, with most estimates in the mid 80% to mid 90% range. Findings are interpreted as support for the perceptual and acoustic methods used in the SDCS to describe and classify speakers with speech sound disorders.

Treatment of Children With Speech Oral Placement Disorders (OPDs): A Paradigm Emerges

Epidemiological research was used to develop the Speech Disorders Classification System (SDCS). The SDCS is an important speech diagnostic paradigm in the field of speech-language pathology. This paradigm could be expanded and refined to also address treatment while meeting the standards of evidence-based practice. The article assists that process by initiating a clinical exchange of ideas on the topic of speech treatment. It explores: (a) the treatment of children with speech oral placement disorders (OPD; a new term suggested by the authors), (b) the various types of speech oral placement therapy (OPT) used to treat OPD, (c) the relationships of OPT to current motor learning theories and oral motor treatment, as well as (c) the critical need for appropriately designed, systematic research on OPT.

The Speech Disorders Classification System (SDCS)

A companion paper includes rationale for the use of 10 metrics of articulation competence in conversational speech (Shriberg, Austin Lewis, McSweeny, & Wilson, 1997). The present paper reports lifespan reference data for these measures using records from a total of 836 3- to 40(+)-year-old speakers with normal and disordered speech. The reference data are subdivided by diagnostic classification based on extensions to an instrument titled the Speech Disorders Classification System (SDCS; Shriberg, 1993). Appendices provide procedural information on the SDCS and statistical rationale for the reference data.

Four New Speech and Prosody-Voice Measures for Genetics Research and Other Studies in Developmental Phonological Disorders

Research in developmental phonological disorders, particularly emerging subgroup studies using behavioral and molecular genetics, requires qualitative and continuous measurement systems that meet a variety of substantive and psychometric assumptions. This paper reviews relevant issues underlying such needs and presents four measurement proposals developed expressly for causal-correlates research. The primary qualitative system is the Speech Disorders Classification System (SDCS), a 10-category nosology for dichotomous and hierarchical polychotomous classification of speech disorders from 2 years of age through adulthood. The three quantitative measures for segmental and suprasegmental analyses are (a) the Articulation Competence Index (ACI), an interval-level severity index that adjusts a subject's Percentage of Consonants Correct (PCC) score for the relative percentage of distortion errors; (b) Speech Profiles, a series of graphic-numeric displays that profile a subject's or group's severity-adjusted consonant and vowel-diphthong mastery and error patterns; and (c) the Prosody-Voice Profile, a graphic-numeric display that profiles a subject's or group's status on six suprasegmental domains divided into 31 types of inappropriate prosody-voice codes. All data for the four measures are derived from one sample of conversational speech, which obviates the limitations of citation-form testing; enables speech assessment as a qualitative, semi-continuous, and continuous trait over the life span; and provides a context for univariate and multivariate statistical analyses of phonetic, phonologic, prosodic, and language variables in multiage, multidialectal, and multicultural populations. Rationale, procedures, validity data, and examples of uses for each measure are presented.