The relationship between articulatory control and improved phonemic accuracy in childhood apraxia of speech: a longitudinal case study

Treatment for Childhood Apraxia of Speech: Past, Present, and Future

PURPOSE

The purposes of this review article were to provide an introduction to and "bird's-eye" overview of the current evidence base for treatment of childhood apraxia of speech (CAS), identify some gaps and trends in this rapidly growing literature, and formulate some future research directions, in order to advance the evidence base and clinical practice for children with CAS.

METHOD

Following a brief introduction outlining important concepts, a narrative review of the CAS treatment literature is provided, and trends and future directions are identified based on this review. The review is organized around four fundamental treatment research questions: (a) "Does Treatment X work?", (b) "Does Treatment X work better than Treatment Y?", (c) "For whom does Treatment X work?", and (d) "What does 'work' mean, anyway?"

RESULTS

A wide range of CAS treatments with varying degrees of evidence for efficacy exists. Research is beginning to emerge that compares different treatments and seeks to determine optimal treatment parameters. Few studies to date have explored child-level predictors of treatment response, and the evidence base currently is limited in scope with respect to populations and outcomes studied.

CONCLUSIONS

A growing evidence base supports the efficacy of a number of treatments for CAS. However, many important gaps in the literature were identified that warrant redoubled and sustained research attention. Research is beginning to emerge that addresses treatment optimization, comparison, candidacy, and outcomes. Suggestions for future research are offered, and the concept of a hypothesized pathway was applied to CAS to illustrate how components of an intervention can effect change in a clinical goal and can help guide development and refinement of treatments for children with CAS.

Manual Rhythmic Sequencing Skills in Children With Childhood Apraxia of Speech

PURPOSE

Rhythm is one procedural mechanism that underlies language and motor skill acquisition and has been implicated in children with childhood apraxia of speech (CAS). The purpose of this study is to investigate manual rhythmic sequencing skills in children with a history of or current CAS (hx/CAS) compared to children with typical development (TD).

METHOD

Thirty-eight children (18 with hx/CAS, 20 with TD), ages 5;0-12;8 (years;months), from across the United States participated in an online study. Participants imitated two rhythms in two different conditions, clapping and tapping. We assessed overall accuracy, mean number of beats, pause marking, and rhythmic sequence variability using the Mann-Whitney U test. Effect sizes were calculated to examine the influence of coordinative complexity on performance.

RESULTS

Compared to children with TD, children with hx/CAS marked fewer trials with a pause in both conditions of the easier rhythm and showed lower overall accuracy and more variable rhythmic sequences in both rhythms and conditions. The mean number of beats produced by children with hx/CAS and children with TD did not differ in three out of four rhythms/conditions. Unlike children with TD, children with hx/CAS showed little improvement from clapping to tapping across most dependent measures; reducing coordination demands did not improve performance in children with hx/CAS.

CONCLUSIONS

We found that children with hx/CAS show manual rhythmic deficits that are similar to the deficits they display in speech. These findings provide support for a domain-general cognitive mechanisms account of the rhythmic deficits observed across linguistic and nonlinguistic tasks in children with hx/CAS.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24052821.

Dynamic Temporal and Tactile Cueing: Quantifying Speech Motor Changes and Individual Factors That Contribute to Treatment Gains in Childhood Apraxia of Speech

PURPOSE

Speech motor skill is refined over the course of practice, which is commonly reflected by increased accuracy and consistency. This research examined the relationship between auditory-perceptual ratings of word accuracy and measures of speech motor timing and variability at pre- and posttreatment in children with childhood apraxia of speech (CAS). Furthermore, the degree to which individual patterns of baseline probe word accuracy, receptive language, and cognition predicted response to treatment was explored.

METHOD

Probe data were collected from seven children with CAS (aged 2;5-5;0 [years;months]) who received 6 weeks of Dynamic Temporal and Tactile Cueing (DTTC) treatment. Using a multidimensional approach to measuring speech performance, auditory-perceptual (whole-word accuracy), acoustic (whole-word duration), and kinematic (jaw movement variability) analyses were conducted on probe words produced pre- and posttreatment. Standardized tests of receptive language and cognition were administered pretreatment.

RESULTS

There was a negative relationship between auditory-perceptual measures of word accuracy and movement variability. Higher word accuracy was associated with lower jaw movement variability following intervention. There was a strong relationship between word accuracy and word duration at baseline, which became less robust posttreatment. Furthermore, baseline word accuracy was the only child-specific factor to predict response to DTTC treatment.

CONCLUSIONS

Following a period of motor-based intervention, children with CAS appeared to refine speech motor control in conjunction with improvements in word accuracy. Those who demonstrated the poorest performance at treatment onset displayed the greatest degree of gains. Taken together, these results reflect a system-wide change following motor-based intervention.

Changes in variability during intervention for childhood apraxia of speech: implications for therapy

Typically developing children are variable in their speech production with decreasing variability indicating mastery of speech. Excessive variability which does not change over time may be an indication of unstable motor plans as often seen in children with childhood apraxia of speech (CAS). Dynamic Systems Theory (DST) provides a framework for understanding the role of variability in speech development and disorder. There are few studies that explore the impact of therapy on speech variability. This work explores the impact of therapy on perceptual speech production variability. It is a post-hoc analysis of data collected in two intervention studies of a motor-based treatment approach with children with CAS and explores DST variability effects in speech skill acquisition based on the case data from those studies. There were six participants in total across the two studies. Findings were mixed showing some non-linear changes in variability with larger changes in variability observed in participants who engaged in more extensive therapy. However, the pattern of variability change was not consistent across the participants. These findings suggest that targeting variability in therapy may be an effective way to improve the speech of children with CAS. A model for utilising variability in therapy is presented.

Children and adolescents with speech sound disorders are more likely to have orofacial dysfunction and malocclusion

Background

Children with speech sound disorders (SSD) form a heterogeneous group that differs in terms of underlying cause and severity of speech difficulties. Orofacial dysfunction and malocclusions have been reported in children with SSD. However, the association is not fully explored.

Objectives

Our aims were to describe differences in orofacial function and malocclusion between a group of children and adolescents with compared to without SSD and to explore associations between those parameters among the group with SSD.

Methods

A total of 105 participants were included, 61 children with SSD (6.0–16.7 years, mean age 8.5 ± 2.8, 14 girls and 47 boys) and 44 children with typical speech development (TSD) (6.0–12.2 years, mean age 8.8 ± 1.6, 19 girls and 25 boys). Assessments of orofacial function included an orofacial screening test and assessment of bite force, jaw stability, chewing efficiency, and intraoral sensory‐motor function. Possible malocclusions were also assessed.

Result

Children with SSD had both poorer orofacial function and a greater prevalence of malocclusion than children with TSD. Furthermore, children with SSD and poorer orofacial function had a greater risk of malocclusion.

Conclusion

Our result suggests that children with SSD are more prone to having poorer orofacial function and malocclusion than children with TSD. This illustrates the importance of assessing coexisting orofacial characteristics in children with SSD, especially since orofacial dysfunction may be linked to an increased risk of malocclusion. This result highlights the need for a multiprofessional approach.

Vowel variability and contrast in Childhood Apraxia of Speech: acoustics and articulation

Phoneme production may be affected by limited speech motor control in Childhood Apraxia of Speech (CAS), with a general instability of acoustic targets across multiple repetitions of speech stimuli. This acoustic and Ultrasound Tongue Imaging (UTI) study shows that increased variability and reduction of contrast in vowel production is found in native Italian speakers with CAS, particularly as far as the height dimension is concerned. The data suggest that vowel production should play a major role in CAS diagnosis and treatment. Moreover, this study shows that a combined acoustic and articulatory approach allows direct observation of lingual dynamics together with an estimation of changes in the acoustic dimension. The two dimensions are shown not to correspond in a straightforward way in the speech of children with CAS, and encourage consideration of articulatory compensation strategies aimed at saving the acoustic identity of vowels.

Simplification of syllable structure in childhood apraxia of speech: a 2-year follow-up French case study

Although Childhood Apraxia of Speech (CAS) has been extensively investigated in the clinical literature, most of the findings regarding impairments in the production of syllable structure, recorded within this population, have been mainly focused on English. The main purpose of this two-year follow-up case study was, therefore, to examine whether syllable complexity may be considered as a robust indicator in CAS and whether it can explain the persistence of errors and, if so, at what age. This was tested in a boy followed up annually from age 5 to 7 who was administered a narrative task. Data analyses used the Phon program to estimate accuracies of different syllabic structures, phones, singleton and cluster consonants. Overall, the findings suggest that this child experienced difficulty producing syllabic structure commensurately with the level of complexity of the target structures. Notably, the presence of syllable planning/sequencing deficit found in French data clearly supports the hypotheses according to which (a) there is a relationship between the level of complexity of syllabic structures and their simplification and (b) the persistence of errors on the most complex syllables remains, becoming a robust indicator for identifying CAS from other speech disorders. Further cross-language investigations on syllable complexity in CAS are needed to design better assessments and to plan efficient intervention.

The Effect of Practice on Variability in Childhood Apraxia of Speech: A Multidimensional Analysis

Purpose Variability has been interpreted in differing ways according to context (e.g., development, speech impairment, and learning). A challenge arises when interpreting variability in the context of learning for children with speech impairment characterized by high movement variability, as in childhood apraxia of speech (CAS). The objective of this study is to investigate changes in variability in CAS with practice in comparison to patterns seen in children with non-CAS speech sound disorders (SSD) and typical development. Method Speech production variability was examined in 24 children (5-6 years of age) with CAS, non-CAS SSD, and typical development in production of nonwords of varied motoric complexity. Multidimensional analyses were performed using measures of token-to-token speech consistency (percent word consistency), acoustic variability (acoustic spatiotemporal index), and movement variability (lip aperture spatiotemporal index). Changes in variability were examined in each group of children by comparing the first half to the last half of nonword tokens in the same data collection session. The impact of token complexity on practice effects was also explored across groups of children. Results All children displayed increased speech consistency within this practice period (p = .01). Only children with CAS displayed increased movement variability following practice (p = .01). Differences in acoustic and kinematic variability were observed across complexity levels in all groups, though these did not interact with practice effects. Discussion These findings suggest that increased movement variability in children with CAS might be facilitating perceptual consistency. It is believed that this finding reflects an inefficient strategy adapted by children with CAS in the absence of motor-based cueing and feedback to guide speech performance with practice.

Procedural Learning, Grammar, and Motor Skills in Children With Childhood Apraxia of Speech, Speech Sound Disorder, and Typically Developing Speech

Purpose This case-control study sought to determine if (a) children with childhood apraxia of speech (CAS), other speech sound disorders (SSDs), and typical development would perform differently on a procedural learning assessment and (b) whether grammatical ability would impact group differences. Method Communication, motor, and procedural learning abilities were assessed in 48 children with CAS (n = 13), SSD (n = 20), and typical development (n = 15), between 43 and 97 months of age (M = 66 months, SD = 12 months). Results On average, children with CAS demonstrated grammatical and motor impairments and required an increased number of exposures to the visuospatial sequence to demonstrate procedural learning, compared to peers with SSD or typical development. A subset of children from each group demonstrated an unanticipated procedural learning pattern wherein they evidenced an uptick in reaction time during the second sequenced block. Children with CAS with this pattern still evidenced procedural learning gains by the fifth sequenced block. In contrast, children with SSD and typical development with this pattern showed poor procedural learning outcomes and were characterized by lower scores on language and motor assessments as well. Conclusions This research provides partial support for the procedural learning deficit hypothesis in children with CAS and for a subset of children with SSD as well. Future research should examine the role of a serial reaction time task in identifying children at risk of multisystem communication and motor deficits. Supplemental Material https://doi.org/10.23641/asha.14173532.

Range of motion (ROM) in the lips and jaw during vowels assessed with 3D motion analysis in Swedish children with typical speech development and children with speech sound disorders

PURPOSE

The aim was to compare movement patterns of lips and jaw in lateral, vertical and anteroposterior directions during vowel production in children with typical speech development (TSD) and in children with speech sound disorders (SSD) persisting after the age of six.

METHODS

A total of 93 children were included, 42 children with TSD (6:0-12:2 years, mean age 8:9 ± 1:5, 19 girls and 23 boys) and 51 children with SSD (6:0-16:7 years, mean age 8:5 ± 3:0, 14 girls and 37 boys). Range of motion (ROM) in lips and jaw in the vowels [a, ʊ, ɪ] produced in a syllable repetition task and median values in resting position were measured with a system for 3D motion analysis. The analysis was based on the coordinates for the mouth corners and the chin centre.

RESULTS

There were significant differences between the groups on movements in lateral direction in both lips and jaw. Children with TSD had generally smaller and more, symmetrical movements in the lips and jaw, in all three dimensions compared to children with SSD. There were no significant differences between the groups in resting position.

CONCLUSION

Children with SSD persisting after the age of six years show more asymmetrical and more variable movement patterns in lips and jaw during vowel production compared with children with TSD in a simple syllable repetition task. Differences were more pronounced in lateral direction in both lips and jaw.

A Framework of Motoric Complexity: An Investigation in Children With Typical and Impaired Speech Development

Introduction The current work presents a framework of motoric complexity where stimuli differ according to movement elements across a sound sequence (i.e., consonant transitions and vowel direction). This framework was then examined in children with childhood apraxia of speech (CAS), other speech sound disorders (SSDs), and typical development (TD). Method Twenty-four children (CAS, n = 8; SSD, n = 8; TD, n = 8), 5-6 years of age, participated in this study. The children produced words that varied in motoric complexity while transcription, acoustic, and kinematic data were collected. Multidimensional analyses were conducted to examine speech production accuracy, speech motor variability, and temporal control. Results Analyses revealed poorer accuracy, longer movement duration, and greater speech motor variability in children with CAS than TD (across all measures) and other SSDs (accuracy and variability). All children demonstrated greater speech motor variability and longer duration as movement demands increased within the framework of motoric complexity. Diagnostic grouping did not mediate performance on this task. Conclusions Results of this study are believed to reveal gradations of complexity with increasing movement demands, thereby supporting the proposed framework of motoric complexity. This work also supports the importance of considering motoric properties of sound sequences when evaluating speech production skills and designing experimental and treatment stimuli.

How the Study of Speech Motor Control Can Inform Assessment and Intervention in Childhood Apraxia of Speech

Purpose

The study of speech motor control has led to great advancements in the current understanding of childhood apraxia of speech (CAS). There remains a significant need to bridge the gap between theory and practice to fully understand the clinical implications of past research.

Method

This review article reviews the speech motor control research in CAS and discusses how these works have offered key information about the underlying motor deficits (Grigos et al., 2015; Terband et al., 2019), the influence of structured practice on speech performance (Case & Grigos, 2016; Grigos & Case, 2018), and the role of task complexity (Case, 2019; Case & Grigos, 2016; Grigos & Case, 2018). We highlight salient points from this existing literature and clinical implications to the assessment and treatment of CAS.

Conclusion

The study of speech motor control has shed light on a number of key factors related to CAS. Even within perceptually accurate speech, children with CAS display differences in movement patterning and timing control. Assessment must aim to more directly tax speech motor skills to obtain a thorough and accurate illustration of production deficits. Intervention is challenged with the task of not only improving production accuracy but also facilitating more efficient motor planning and programming. Motor-based intervention that applies motor learning principles and introduces variability across motor, phonetic, and prosodic contexts is believed to achieve this goal, though research is needed to better understand changes in speech motor control with treatment.

Assessment of Childhood Apraxia of Speech: A Review/Tutorial of Objective Measurement Techniques

Background With respect to the clinical criteria for diagnosing childhood apraxia of speech (commonly defined as a disorder of speech motor planning and/or programming), research has made important progress in recent years. Three segmental and suprasegmental speech characteristics-error inconsistency, lengthened and disrupted coarticulation, and inappropriate prosody-have gained wide acceptance in the literature for purposes of participant selection. However, little research has sought to empirically test the diagnostic validity of these features. One major obstacle to such empirical study is the fact that none of these features is stated in operationalized terms. Purpose This tutorial provides a structured overview of perceptual, acoustic, and articulatory measurement procedures that have been used or could be used to operationalize and assess these 3 core characteristics. Methodological details are reviewed for each procedure, along with a short overview of research results reported in the literature. Conclusion The 3 types of measurement procedures should be seen as complementary. Some characteristics are better suited to be described at the perceptual level (especially phonemic errors and prosody), others at the acoustic level (especially phonetic distortions, coarticulation, and prosody), and still others at the kinematic level (especially coarticulation, stability, and gestural coordination). The type of data collected determines, to a large extent, the interpretation that can be given regarding the underlying deficit. Comprehensive studies are needed that include more than 1 diagnostic feature and more than 1 type of measurement procedure.

Volubility, Consonant Emergence, and Syllabic Structure in Infants and Toddlers Later Diagnosed With Childhood Apraxia of Speech, Speech Sound Disorder, and Typical Development: A Retrospective Video Analysis

Purpose Studies of infants' early vocalizations have proven helpful in describing the developmental characteristics of various communication disorders. However, few studies have addressed the early vocalizations of infants and toddlers who were later diagnosed, as older children, with childhood apraxia of speech (CAS). We refer to these infants and toddlers as LCAS. Extant studies also often lack a comparison group of infants and toddlers who were later diagnosed, as older children, with a speech sound disorder (SSD). We refer to these infants and toddlers as LSSD. We aimed to compare the volubility, consonant emergence, and syllabic structure from birth to age of 2 years, as observed in home videos, among 3 groups of infants and toddlers: LCAS, LSSD, and typically developing (TD). Method We assessed the speech-language skills of 17 children (3.5-8.8 years old; 7 with CAS, 5 with SSD, and 5 TD) and transcribed home videos (obtained from parents) of these same children from birth to age of 2 years. Early vocalizations were coded as nonresonant or resonant. Nonresonant vocalizations could not be transcribed with the International Phonetic Alphabet. Resonant (speechlike) vocalizations were broadly transcribed, and resonant consonants were categorized by place, manner, and voicing. Results Effect size comparisons revealed LCAS infants and toddlers were less voluble, used fewer resonant consonants, had a less diverse phonetic repertoire, and acquired resonant consonants later than either the LSSD or TD participants. For LSSD infants and toddlers, means for these dependent variables were lower than the means demonstrated by the TD group, but effect size were not strong due to LSSD variability. Conclusions Findings imply there might be clinical "red flags" that could assist the identification of infants and toddlers at risk for later diagnosis of CAS. Data did not support red flags for identifying infants and toddlers at risk for later diagnosis of SSD. Because of significant study limitations, results obtained should be considered preliminary. Supplemental Material https://doi.org/10.23641/asha.8233334.

Language Skill Mediates the Relationship Between Language Load and Articulatory Variability in Children With Language and Speech Sound Disorders

PURPOSE

The aim of the study was to investigate the relationship between language load and articulatory variability in children with language and speech sound disorders, including childhood apraxia of speech.

METHOD

Forty-six children, ages 48-92 months, participated in the current study, including children with speech sound disorder, developmental language disorder (aka specific language impairment), childhood apraxia of speech, and typical development. Children imitated (low language load task) then retrieved (high language load task) agent + action phrases. Articulatory variability was quantified using speech kinematics. We assessed language status and speech status (typical vs. impaired) in relation to articulatory variability.

RESULTS

All children showed increased articulatory variability in the retrieval task compared with the imitation task. However, only children with language impairment showed a disproportionate increase in articulatory variability in the retrieval task relative to peers with typical language skills.

CONCLUSION

Higher-level language processes affect lower-level speech motor control processes, and this relationship appears to be more strongly mediated by language than speech skill.

Changes in movement transitions across a practice period in childhood apraxia of speech

This study examined changes in speech motor control across a movement transition between sounds within a motor learning task in children with apraxia of speech (CAS) and typical development (TD). It was investigated whether oral articulator movement was refined with practice and whether practice gains generalized to words not included in the practice session. A total of 16 children (ages 5-6) with CAS (n = 8) and TD (n = 8) participated in this study. Novel and real word tokens were produced at three time points. Kinematic data was collected using facial motion tracking at each time point. Children completed a practice session following baseline data collection session that integrated motor learning principles. Three tokens were included in the practice session and the remaining stimuli assessed carryover of practice gains. Kinematic data was then collected immediately following practice and 3 days later. Kinematic analyses were conducted on the movement gesture for the first syllable of each word. Narrow transcription analyses examined speech production accuracy. Children in the CAS group displayed increased consonant and vowel accuracy only for the practised tokens. Adjustments to spatial control and movement variability were observed in the CAS group, though only for practised words. Children in the TD group altered spatial and temporal domains of movement and variability across both practised and non-practised tokens. Interestingly, the CAS group displayed a pattern of increased displacement along with decreased variability, which was not observed in the TD group. The degree to which these findings reflect facilitative or maladaptive changes are discussed. Results are also interpreted in relation to vowel properties, novel/real word status and variable practice of novel and real words.

An exploratory study of the influence of load and practice on segmental and articulatory variability in children with speech sound disorders

This exploratory treatment study used phonetic transcription and speech kinematics to examine changes in segmental and articulatory variability. Nine children, ages 4 to 8 years old, served as participants, including two with childhood apraxia of speech (CAS), five with speech sound disorder (SSD) and two who were typically developing. Children practised producing agent + action phrases in an imitation task (low linguistic load) and a retrieval task (high linguistic load) over five sessions. In the imitation task in session one, both participants with CAS showed high degrees of segmental and articulatory variability. After five sessions, imitation practice resulted in increased articulatory variability for five participants. Retrieval practice resulted in decreased articulatory variability in three participants with SSD. These results suggest that short-term speech production practice in rote imitation disrupts articulatory control in children with and without CAS. In contrast, tasks that require linguistic processing may scaffold learning for children with SSD but not CAS.

Articulatory Control in Childhood Apraxia of Speech in a Novel Word-Learning Task

PURPOSE

Articulatory control and speech production accuracy were examined in children with childhood apraxia of speech (CAS) and typically developing (TD) controls within a novel word-learning task to better understand the influence of planning and programming deficits in the production of unfamiliar words.

METHOD

Participants included 16 children between the ages of 5 and 6 years (8 CAS, 8 TD). Short- and long-term changes in lip and jaw movement, consonant and vowel accuracy, and token-to-token consistency were measured for 2 novel words that differed in articulatory complexity.

RESULTS

Children with CAS displayed short- and long-term changes in consonant accuracy and consistency. Lip and jaw movements did not change over time. Jaw movement duration was longer in children with CAS than in TD controls. Movement stability differed between low- and high-complexity words in both groups.

CONCLUSIONS

Children with CAS displayed a learning effect for consonant accuracy and consistency. Lack of change in movement stability may indicate that children with CAS require additional practice to demonstrate changes in speech motor control, even within production of novel word targets with greater consonant and vowel accuracy and consistency. The longer movement duration observed in children with CAS is believed to give children additional time to plan and program movements within a novel skill.

Speech Sound Disorders: What's Motor Got To Do With It?

Speech sound disorders (SSDs) are commonly viewed as involving impaired articulation and/or phonological skills. Speech language pathologists working with individuals with (SSDs) assess the articulation of speech sounds and the coordination of articulatory structures with other components of the speech mechanism, including the phonatory, respiratory, and resonatory subsystems. The sound system of the language and the rules that govern how phonemes are combined are equally critical for clinicians to explore. While the terms “articulation” and “phonology” provide clinicians with a framework for classification, children who are broadly identified with (SSDs) may also display characteristics of a motor speech impairment, which can obscure the decision making process with respect to both diagnosis and treatment. One such motor speech disorder is childhood apraxia of speech (CAS). The focus of this paper is to discuss motor speech deficits in children and to review research that aims to distinguish motor speech patterns in children with (SSDs) with and without CAS. We will also address the relationship between emerging speech motor and linguistic skills.

Perceptual, durational and tongue displacement measures following articulation therapy for rhotic sound errors

Outcomes of articulation therapy for rhotic errors are usually assessed perceptually. However, our understanding of associated changes of tongue movement is limited. This study described perceptual, durational and tongue displacement changes over 10 sessions of articulation therapy for /ɹ/ in six children. Four of the participants also received ultrasound biofeedback of their tongue shape. Speech and tongue movement were recorded pre-therapy, after 5 sessions, in the final session and at a one month follow-up. Perceptually, listeners perceived improvement and classified more productions as /ɹ/ in the final and follow-up assessments. The durations of VɹV syllables at the midway point of the therapy were longer. Cumulative tongue displacement increased in the final session. The average standard deviation was significantly higher in the middle and final assessments. The duration and tongue displacement measures illustrated how articulation therapy affected tongue movement and may be useful for outcomes research about articulation therapy.

Oral Articulatory Control in Childhood Apraxia of Speech

PURPOSE

The purpose of this research was to examine spatial and temporal aspects of articulatory control in children with childhood apraxia of speech (CAS), children with speech delay characterized by an articulation/phonological impairment (SD), and controls with typical development (TD) during speech tasks that increased in word length.

METHOD

The participants included 33 children (11 CAS, 11 SD, and 11 TD) between 3 and 7 years of age. A motion capture system was used to track jaw, lower lip, and upper lip movement during a naming task. Movement duration, velocity, displacement, and variability were measured from accurate word productions.

RESULTS

Movement variability was significantly higher in the children with CAS compared with participants in the SD and TD groups. Differences in temporal control were seen between both groups of children with speech impairment and the controls with TD during accurate word productions. As word length increased, movement duration and variability differed between the children with CAS and those with SD.

CONCLUSIONS

These findings provide evidence that movement variability distinguishes children with CAS from speakers with SD. Kinematic differences between the participants with CAS and those with SD suggest that these groups respond differently to linguistic challenges.

Differential diagnosis of children with suspected childhood apraxia of speech

PURPOSE

The gold standard for diagnosing childhood apraxia of speech (CAS) is expert judgment of perceptual features. The aim of this study was to identify a set of objective measures that differentiate CAS from other speech disorders.

METHOD

Seventy-two children (4-12 years of age) diagnosed with suspected CAS by community speech-language pathologists were screened. Forty-seven participants underwent diagnostic assessment including presence or absence of perceptual CAS features. Twenty-eight children met two sets of diagnostic criteria for CAS (American Speech-Language-Hearing Association, 2007b; Shriberg, Potter, & Strand, 2009); another 4 met the CAS criteria with comorbidity. Fifteen were categorized as non-CAS with phonological impairment, submucous cleft, or dysarthria. Following this, 24 different measures from the diagnostic assessment were rated by blinded raters. Multivariate discriminant function analysis was used to identify the combination of measures that best predicted expert diagnoses.

RESULTS

The discriminant function analysis model, including syllable segregation, lexical stress matches, percentage phonemes correct from a polysyllabic picture-naming task, and articulatory accuracy on repetition of /pətəkə/, reached 91% diagnostic accuracy against expert diagnosis.

CONCLUSIONS

Polysyllabic production accuracy and an oral motor examination that includes diadochokinesis may be sufficient to reliably identify CAS and rule out structural abnormality or dysarthria. Testing with a larger unselected sample is required.

Interarticulatory Coordination of the Lips and Jaw in Childhood Apraxia of Speech

Childhood apraxia of speech (CAS) is often characterized by an ability to produce phonemes in isolation, but not in more complex phonetic sequences. This has led to the hypothesis that articulator coordination is impaired in CAS, This study explored whether coordination between the lips and jaw during speech production is impaired in this group. We used two methods to investigate interarticulatory relationships. Cross-correlation analysis directly measures spatial-temporal coupling of articulator movements. The spatiotemporal index (STI; Smith, Goffman, Zelaznik, Ying, & MeGillem, 1995) measures repetition stability and has also been used as an indirect measure of interarticulatory coordination by providing an index of the coordinative consistency of the relationship between articulators within a pair (Smith & Zelaznik, 2004). Three groups of children were included: children with CAS; children with a speech sound disorder involving articulation, phonological errors, or both (the SD group); and typically developing (TD) children. A facial motion capture system was used to track upper lip, lower lip, and jaw movement during a naming task in which stimuli varied by word length. The CAS, SD, and TD children did not significantly differ in spatial-temporal coupling; however, coefficients of variation of the spatial and temporal coupling measures did differentiate the CAS and SD groups. Additionally, the CAS children were distinguished from the SD children by higher lip aperture STI values, indicating that the CAS group had more difficulty generating stable movement plans.

A comparison of two treatments for childhood apraxia of speech: methods and treatment protocol for a parallel group randomised control trial

Background

Childhood Apraxia of Speech is an impairment of speech motor planning that manifests as difficulty producing the sounds (articulation) and melody (prosody) of speech. These difficulties may persist through life and are detrimental to academic, social, and vocational development. A number of published single subject and case series studies of speech treatments are available. There are currently no randomised control trials or other well designed group trials available to guide clinical practice.

Methods/Design

A parallel group, fixed size randomised control trial will be conducted in Sydney, Australia to determine the efficacy of two treatments for Childhood Apraxia of Speech: 1) Rapid Syllable Transition Treatment and the 2) Nuffield Dyspraxia Programme – Third edition. Eligible children will be English speaking, aged 4–12 years with a diagnosis of suspected CAS, normal or adjusted hearing and vision, and no comprehension difficulties or other developmental diagnoses. At least 20 children will be randomised to receive one of the two treatments in parallel. Treatments will be delivered by trained and supervised speech pathology clinicians using operationalised manuals. Treatment will be administered in 1-hour sessions, 4 times per week for 3 weeks. The primary outcomes are speech sound and prosodic accuracy on a customised 292 item probe and the Diagnostic Evaluation of Articulation and Phonology inconsistency subtest administered prior to treatment and 1 week, 1 month and 4 months post-treatment. All post assessments will be completed by blinded assessors. Our hypotheses are: 1) treatment effects at 1 week post will be similar for both treatments, 2) maintenance of treatment effects at 1 and 4 months post will be greater for Rapid Syllable Transition Treatment than Nuffield Dyspraxia Programme treatment, and 3) generalisation of treatment effects to untrained related speech behaviours will be greater for Rapid Syllable Transition Treatment than Nuffield Dyspraxia Programme treatment. This protocol was approved by the Human Research Ethics Committee, University of Sydney (#12924).

Discussion

This will be the first randomised control trial to test treatment for CAS. It will be valuable for clinical decision-making and providing evidence-based services for children with CAS.

Trial Registration

Australian New Zealand Clinical Trials Registry: ACTRN12612000744853

Feedback frequency in treatment for childhood apraxia of speech

PURPOSE

To examine the role of feedback frequency in treatment for childhood apraxia of speech (CAS). Reducing the frequency of feedback enhances motor learning, and recently, such feedback frequency reductions have been recommended for the treatment of CAS. However, no published studies have explicitly compared different feedback frequencies in this population.

METHOD

Using an alternating treatments single-subject design with multiple baselines across behaviors, retention and transfer of learning were compared following high-frequency feedback and low-frequency feedback in 4 children with CAS. Feedback frequency was manipulated in the context of an integral stimulation treatment. Changes in perceptual accuracy were quantified with effect sizes and were compared across conditions.

RESULTS

Findings were mixed, with 2 children showing an advantage for low-frequency feedback, 1 child showing a small advantage for high-frequency feedback, and 1 child showing no clear improvement in either condition.

CONCLUSION

These findings suggest that reducing the frequency of feedback may be beneficial for some children with CAS, although this may vary with the child's age or severity of apraxia. Caution is warranted in extrapolating from the nonspeech motor learning literature to speech treatment for CAS. Finally, this study contributes another replication to the literature on the efficacy of integral stimulation treatment for children with CAS.

Clear as mud: another look at autism, childhood apraxia of speech and auditory processing

PURPOSE OF REVIEW

Autism, childhood apraxia of speech and central auditory processing disorder are associated with significant disability. These conditions can be more difficult to diagnose. With significant controversy surrounding their definitions and most effective treatment options, understanding these conditions better may optimize outcomes.

RECENT FINDINGS

As earlier diagnosis and treatment become more commonplace, the type and intensity of intervention provided continue to be a topic of extensive interest and research. The protean nature of speech and language disorders requires careful consideration of several diagnostic causes. Problems with speech may reflect motor coordination or apraxia, problems with processing language may reflect an auditory processing disorder, whereas more profound delays may reflect cognitive disability or autism. Early consideration of different causes of delay will aid in the choice and application of appropriate therapies.

SUMMARY

Early identification and treatment of speech and language problems are known to result in better outcomes. By expanding one's differential diagnosis for speech and language disorders and understanding the link between early communication delay and later language learning, one hopes to mitigate the long-term effects these conditions have on children.