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

et al. 2017

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Purpose: Three previous articles provided rationale, methods, and several forms of validity support for a diagnostic marker of childhood apraxia of speech (CAS), termed the pause marker (PM). Goals of the present article were to assess the validity and stability of the PM Index (PMI) to scale CAS severity. Method: PM scores and speech, prosody, and voice precision-stability data were obtained for participants with CAS in idiopathic, neurogenetic, and complex neurodevelopmental disorders; adult-onset apraxia of speech consequent to stroke and primary progressive apraxia; and idiopathic speech delay. Three studies were completed including criterion and concurrent validity studies of the PMI and a temporal stability study of the PMI using retrospective case studies. Results: PM scores were significantly correlated with other signs of CAS precision and stability. The best fit of the distribution of PM scores to index CAS severity was obtained by dividing scores into 4 ordinal severity classifications: mild, mild-moderate, moderate-severe, and severe. Severity findings for the 4 classifications and retrospective longitudinal findings from 8 participants with CAS supported the validity and stability of the PMI. Conclusion: Findings support research and clinical use of the PMI to scale the severity of CAS.A four-article series (Shriberg et al., 2017a(Shriberg et al., , 2017b(Shriberg et al., , 2017c, and the present article) to develop and assess the theoretical and clinical utility of a singlesign, behavioral marker of childhood apraxia of speech (CAS) poses the following three questions: 1.Do findings from construct and criterion validity studies support the diagnostic accuracy of a behavioral marker, the pause marker (PM), to discriminate CAS from speech delay (SD)?2. Do findings from the PM and other measures support the hypothesis of core representational and transcoding deficits in CAS, and is the PM theoretically coherent with those deficits?3. Do findings from cross-sectional and retrospective longitudinal case studies support an ordinal scale of PM scores, the Pause Marker Index (PMI), to quantify the severity of CAS for research and clinical applications?The short-term goal of the PM is to provide a behavioral marker of CAS for research and clinical practice. A longer term goal of the PM is to provide quantitative inclusionary and exclusionary criteria to identify participants who are true positive for CAS in studies to identify and validate a biomarker of CAS. The present article addresses both goals. As proposed in the first article in this series (PM I; Shriberg et al., 2017a, Table 1), a highly valued attribute of diagnostic markers is generality, that is, a marker has research and clinical utility beyond identifying presence or absence of a disorder. In the present context, a behavioral marker of CAS has research and clinical generality when in addition to being diagnostically sensitive to and specific for a prior, active, and/or future disorder, it also quantifies the severity of the disorder. The three...

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confidence: 99%

“…A four-article series (Shriberg et al, 2017a(Shriberg et al, , 2017b(Shriberg et al, , 2017c, and the present article) to develop and assess the theoretical and clinical utility of a singlesign, behavioral marker of childhood apraxia of speech (CAS) poses the following three questions:…”

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confidence: 99%

A Diagnostic Marker to Discriminate Childhood Apraxia of Speech From Speech Delay: IV. The Pause Marker Index

et al. 2017

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“…It is useful to reproduce Figure 1 from the first article in this series (PM I; Shriberg et al, 2017a), which will be referenced throughout the present article. Figure 1, the research framework for the PM termed the Speech Disorders Classification System (SDCS), includes a sevenelement generic representation of speech processing stages.…”

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confidence: 99%

“…Figure 1, the research framework for the PM termed the Speech Disorders Classification System (SDCS), includes a sevenelement generic representation of speech processing stages. Recall (PM I; Shriberg et al, 2017a) that Figure 1 is the finalized version of the SDCS with the exception of some updates at Level III and Level IV that are not pertinent in the present context (Shriberg, Strand, & Mabie, 2017). The following sections describe relevant terms and concepts in CAS research, followed by brief literature overviews of research addressing two hypotheses about speech processing deficits in CAS.…”

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confidence: 99%

A Diagnostic Marker to Discriminate Childhood Apraxia of Speech From Speech Delay: III. Theoretical Coherence of the Pause Marker with Speech Processing Deficits in Childhood Apraxia of Speech

et al. 2017

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Purpose Previous articles in this supplement described rationale for and development of the pause marker (PM), a diagnostic marker of childhood apraxia of speech (CAS), and studies supporting its validity and reliability. The present article assesses the theoretical coherence of the PM with speech processing deficits in CAS. Method PM and other scores were obtained for 264 participants in 6 groups: CAS in idiopathic, neurogenetic, and complex neurodevelopmental disorders; adult-onset apraxia of speech (AAS) consequent to stroke and primary progressive apraxia of speech; and idiopathic speech delay. Results Participants with CAS and AAS had significantly lower scores than typically speaking reference participants and speech delay controls on measures posited to assess representational and transcoding processes. Representational deficits differed between CAS and AAS groups, with support for both underspecified linguistic representations and memory/access deficits in CAS, but for only the latter in AAS. CAS–AAS similarities in the age–sex standardized percentages of occurrence of the most frequent type of inappropriate pauses ( abrupt ) and significant differences in the standardized occurrence of appropriate pauses were consistent with speech processing findings. Conclusions Results support the hypotheses of core representational and transcoding speech processing deficits in CAS and theoretical coherence of the PM's pause-speech elements with these deficits.

“…T he first article in this series (PM I; Shriberg et al, 2017a) includes a review of the development of a diagnostic marker of childhood apraxia of speech (CAS) termed the Pause Marker (PM). The goal was to develop a procedure that maximally meets the seven attributes of a highly valued diagnostic marker described and prioritized in that article's Table 1.…”

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confidence: 99%

A Diagnostic Marker to Discriminate Childhood Apraxia of Speech From Speech Delay: II. Validity Studies of the Pause Marker

et al. 2017

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Purpose: The purpose of this 2nd article in this supplement is to report validity support findings for the Pause Marker (PM), a proposed single-sign diagnostic marker of childhood apraxia of speech (CAS). Method: PM scores and additional perceptual and acoustic measures were obtained from 296 participants in cohorts with idiopathic and neurogenetic CAS, adult-onset apraxia of speech and primary progressive apraxia of speech, and idiopathic speech delay.Results: Adjusted for questionable specificity disagreements with a pediatric Mayo Clinic diagnostic standard, the estimated sensitivity and specificity, respectively, of the PM were 86.8% and 100% for the CAS cohort, yielding positive and negative likelihood ratios of 56.