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

Enhancing Speech Rehabilitation in a Young Adult with Trisomy 21: Integrating Transcranial Direct Current Stimulation (tDCS) with Rapid Syllable Transition Training for Apraxia of Speech

Apraxia of speech is a persistent speech motor disorder that affects speech intelligibility. Studies on speech motor disorders with transcranial Direct Current Stimulation (tDCS) have been mostly directed toward examining post-stroke aphasia. Only a few tDCS studies have focused on apraxia of speech or childhood apraxia of speech (CAS), and no study has investigated individuals with CAS and Trisomy 21 (T21, Down syndrome). This N-of-1 randomized trial examined the effects of tDCS combined with a motor learning task in developmental apraxia of speech co-existing with T21 (ReBEC RBR-5435x9). The accuracy of speech sound production of nonsense words (NSWs) during Rapid Syllable Transition Training (ReST) over 10 sessions of anodal tDCS (1.5 mA, 25 cm) over Broca's area with the cathode over the contralateral region was compared to 10 sessions of sham-tDCS and four control sessions in a 20-year-old male individual with T21 presenting moderate-severe childhood apraxia of speech (CAS). The accuracy for NSW production progressively improved (gain of 40%) under tDCS (sham-tDCS and control sessions showed < 20% gain). A decrease in speech severity from moderate-severe to mild-moderate indicated transfer effects in speech production. Speech accuracy under tDCS was correlated with Wernicke's area activation (P3 current source density), which in turn was correlated with the activation of the left supramarginal gyrus and the Sylvian parietal-temporal junction. Repetitive bihemispheric tDCS paired with ReST may have facilitated speech sound acquisition in a young adult with T21 and CAS, possibly through activating brain regions required for phonological working memory.

Prosodic skills in Spanish-speaking adolescents and young adults with Down syndrome

BACKGROUND

Down syndrome (DS) is a neurodevelopmental disorder of genetic origin with a cognitive-behavioural profile that distinguishes it from other syndromes. Within this profile, language difficulties are particularly marked, having been more studied in childhood than in adulthood. More generally, there is a paucity of research on the prosodic skills of individuals with DS, despite the relevance of this linguistic component for effective communication.

AIMS

This study aimed to analyse, for the first time, the prosodic profile of Spanish-speaking teenagers and young adults with DS. We hypothesized that participants with DS would show significantly lower skills for the perception and production of prosodic functions and forms when compared to peers with intellectual disability (ID) of unknown origin. We also hypothesized that teenagers and young adults with DS would have better prosody perception than prosody production.

METHODS & PROCEDURES

The final sample included in the study comprised 28 Spanish-speaking teenagers and young adults with DS and 29 teenagers and young adults with other ID matched on chronological age and nonverbal cognition. Their prosodic skills were tested by means of the Profiling Elements of Prosody for Speech and Communication battery. This battery allows for the separate evaluation of the comprehension and expression of the communicative functions of prosody and the discrimination and production of the forms that carry out such functions.

OUTCOMES & RESULTS

In the prosody function tasks, which are the most adaptive tasks for the communicative process, we found, as expected, significantly lower scores on the turn-end, chunking, and focus tasks in the group with DS. However, no significant between-group differences were found for the affect tasks. Participants with DS also had significantly lower scores on the prosodic form tasks than participants with other ID. The results of the comparison between prosodic perception and production skills showed that a generalization about a better profile in comprehension versus production is not possible and that there is a dependence on the demands of the prosodic task undertaken.

CONCLUSIONS & IMPLICATIONS

The findings contribute to the ongoing development of the language profile of teenagers and young adults with DS and imply the need to design prosodic intervention programs based on their specific profile.

WHAT THIS PAPER ADDS

What is already known on the subject Prosody is a fundamental element of language, and its mastery affects the effectiveness of communication. However, research on prosody in Down syndrome (DS) that offers a holistic view from a psycholinguistic approach is still scarce. To date, studies focused on providing a detailed profile of prosodic skills in individuals with DS have been mainly conducted with a few English-speaking children. These studies have shown that the comprehension and production of prosody is severely impaired, especially when considering affect and focus production, as well as the perception and production of prosodic forms. During childhood, greater efficacy is found in prosody comprehension than in prosody expression. What this study adds This is the first study analysing the prosodic profile of a large group of Spanish-speaking teenagers and young adults with DS. Poorer performance in the perception and production of both prosodic functions and forms was observed in participants with DS compared to participants with intellectual disability of unknown origin matched on chronological age and nonverbal cognition. Unlike what has been previously found in children, teenagers and young adults with DS performed at the same level as the control group on the understanding and expression of affect through prosodic cues. Results also showed that a generalization about a better prosody profile in comprehension versus production is not possible. What are the clinical implications of this work? This study provides new data on the prosodic skills of Spanish-speaking teenagers and young adults with DS. Given the impact of prosody on effective communication and the pattern of difficulties found in this study, speech and language therapists working with individuals with DS should consider including prosodic skills in interventions not only in childhood but also in adolescence and adulthood. Therefore, the prosodic profile of strengths and weaknesses in individuals with DS found in this research has direct implications for clinical practice.

Vocal Characteristics of Infants at Risk for Speech Motor Involvement: A Scoping Review

PURPOSE

The purpose of this scoping review was to (a) summarize methodological characteristics of studies examining vocal characteristics of infants at high risk for neurological speech motor involvement and (b) report the state of the high-quality evidence on vocal characteristic trends of infants diagnosed or at high risk for cerebral palsy (CP).

METHOD

The PRISMA (Preferred Reporting Items of Systematic Reviews and Meta-Analyses) extension for scoping reviews was followed for reporting our review. Studies measured prelinguistic vocal characteristics of infants under 24 months with birth risk or genetic conditions known to commonly present with speech motor involvement. Fifty-five studies met criteria for Part 1. Eleven studies met criteria for synthesis in Part 2.

RESULTS

A smaller percentage of studies examined infants with or at risk for CP compared to studies examining genetic conditions such as Down syndrome. The median year of publication was 1999, with a median sample size of nine participants. Most studies were conducted in laboratory settings and used human coding of vocalizations produced during caregiver-child interactions. Substantial methodological differences were noted across all studies. A small number of high-quality studies of infants with or at risk for CP revealed high rates of marginal babbling, low rates of canonical babbling, and limited consonant diversity under 24 months. Mixed findings were noted across studies of general birth risk factors.

CONCLUSIONS

There is limited evidence available to support the early detection of speech motor involvement. Large methodological differences currently impact the ability to synthesize findings across studies. There is a critical need to conduct longitudinal research with larger sample sizes and advanced, modern technologies to detect vocal precursors of speech impairment to support the accurate diagnosis and prognosis of speech development in infants with CP and other clinical populations.

Ultrasonic vocalization phenotypes in the Ts65Dn and Dp(16)1Yey mouse models of Down syndrome

Down syndrome (DS) is a developmental disorder associated with a high incidence of challenges in vocal communication. DS can involve medical co-morbidities and structural social factors that may impact communication outcomes, which can present difficulties for the study of vocal communication challenges. Mouse models of DS may be used to study vocal communication differences associated with this syndrome and allow for greater control and consistency of environmental factors. Prior work has demonstrated differences in ultrasonic vocalization (USV) of the Ts65Dn mouse model of DS at a young adult age, however it is not known how USV characteristics are manifested at mature ages. Given that the aging process and age-related co-morbidities may also impact communication in DS, addressing this gap in knowledge may be of value for efforts to understand communication difficulties in DS across the lifespan. The current study hypothesized that the Ts65Dn and Dp(16)1Yey mouse models of DS would demonstrate differences in multiple measures of USV communication at a mature adult age of 5 months.

METHODS

Ts65Dn mice (n = 16) and euploid controls (n = 19), as well as Dp(16)1Yey mice (n = 20) and wild-type controls (n = 22), were evaluated at 5 months of age for USV production using a mating paradigm. Video footage of USV sessions were analyzed to quantify social behaviors of male mice during USV testing sessions. USV recordings were analyzed using Deepsqueak software to identify 10 vocalization types, which were quantified for 11 acoustic measures.

RESULTS

Ts65Dn, but not Dp(16)1Yey, showed significantly lower proportions of USVs classified as Step Up, Short, and Frequency Steps, and significantly higher proportions of USVs classified as Inverted U, than euploid controls. Both Ts65Dn and Dp(16)1Yey groups had significantly greater values for power and tonality for USVs than respective control groups. While Ts65Dn showed lower frequencies than controls, Dp(16)1Yey showed higher frequencies than controls. Finally, Ts65Dn showed reductions in a measure of complexity for some call types. No significant differences between genotype groups were identified in analysis of behaviors during testing sessions.

CONCLUSION

While both Ts65Dn and Dp(16)1Yey show significant differences in USV measures at 5 months of age, of the two models, Ts65Dn shows a relatively greater numbers of differences. Characterization of communication phenotypes in mouse models of DS may be helpful in laying the foundation for future translational advances in the area of communication difficulties associated with DS.

Sentence Length Effects on Intelligibility in Two Groups of Older Children With Neurodevelopmental Disorders

PURPOSE

The purpose of this study was to examine the impact of sentence length on intelligibility in two groups of older children with neurodevelopmental disabilities.

METHOD

Nine children diagnosed with cerebral palsy (CP) and eight children diagnosed with Down syndrome (DS), between the ages of 8 and 17 years, repeated sentences varying in length from two to seven words. Three hundred forty adult listeners (20 listeners per child) provided orthographic transcriptions of children's speech, which were used to calculate intelligibility scores.

RESULTS

There was a significant main effect of sentence length on intelligibility for children with CP. Intelligibility significantly increased from two- and three-word sentences to four-, five-, and six-word sentences, then significantly decreased from four-, five-, and six-word sentences to seven-word sentences. There was a main effect of sentence length on intelligibility for children with DS. Intelligibility significantly increased from two-word sentences to four-, five-, and six-word sentences.

CONCLUSIONS

The primary findings of this study include the following: (a) Unlike in typically developing children, sentence length continues to influence intelligibility well into adolescence for children with neurodevelopmental disorders, and (b) sentence length may influence intelligibility differently in children with CP than in children with DS; however, other factors besides the type of neurodevelopmental disorder (e.g., severity of speech motor involvement and/or cognitive-linguistic impairment) could play a role in the relationship between sentence length and intelligibility and must be investigated in future studies.

Motor Speech Phenotypes in Children With Epilepsy: Preliminary Findings

PURPOSE

This exploratory study aimed to characterize motor speech impairments in a small sample of children with epilepsy, both with and without a known seizure etiology. A secondary aim was to evaluate the validity of the Profile for Childhood Apraxia of speech and Dysarthria (ProCAD), a newly developed tool for differential diagnosis of childhood apraxia of speech and dysarthria.

METHOD

Thirteen children with seizure disorders completed a comprehensive speech and language assessment. Three expert speech-language pathologists rated the presence of auditory-perceptual features of motor speech impairment using the ProCAD. Motor speech features, diagnoses, and standardized test scores were compared between children with a known seizure etiology and children with idiopathic epilepsy.

RESULTS

Nine of the 13 children exhibited motor speech impairment; dysarthria was the most common diagnosis. Most children (11/13) exhibited language impairment. Group comparisons showed that children with a known seizure etiology had more atypical motor speech features and lower language scores than children with idiopathic seizures.

CONCLUSION

These preliminary findings suggest a high rate of motor speech impairment among children with epilepsy.

Differential Impacts of Sentence Length on Speech Rate in Two Groups of Children With Neurodevelopmental Disorders

PURPOSE

The primary purpose of this study was to examine the effect of sentence length on speech rate and its characteristics, articulation rate, and pauses in children with neurodevelopmental disorders.

METHOD

Nine children diagnosed with cerebral palsy (CP) and seven children diagnosed with Down syndrome (DS) repeated sentences varying in length from two to seven words. Children were between the ages of 8 and 17 years. Dependent variables included speech rate, articulation rate, and proportion of time spent pausing.

RESULTS

For children with CP, there was a significant effect of sentence length for speech rate and articulation rate but not for the proportion of time spent pausing. In general, the longest sentences were produced with a faster speech and articulation rate than the shortest sentences. For children with DS, there was a significant effect of sentence length for the proportion of time spent pausing but not for speech rate or articulation rate. In general, children with DS spent significantly more time pausing in the longest sentences, particularly seven-word sentences, than in any other sentence length.

CONCLUSIONS

Primary findings include the following: (a) Articulation rate and pause time are differentially impacted by sentence length, and (b) children with CP and children with DS respond differently to increases in cognitive-linguistic load.

Vowel Production in Children and Adults With Down Syndrome: Fundamental and Formant Frequencies of the Corner Vowels

PURPOSE

Atypical vowel production contributes to reduced speech intelligibility in children and adults with Down syndrome (DS). This study compares the acoustic data of the corner vowels /i/, /u/, /æ/, and /ɑ/ from speakers with DS against typically developing/developed (TD) speakers.

METHOD

Measurements of the fundamental frequency (f o) and first four formant frequencies (F1-F4) were obtained from single word recordings containing the target vowels from 81 participants with DS (ages 3-54 years) and 293 TD speakers (ages 4-92 years), all native speakers of English. The data were used to construct developmental trajectories and to determine interspeaker and intraspeaker variability.

RESULTS

Trajectories for DS differed from TD based on age and sex, but the groups were similar with the striking change in f o and F1-F4 frequencies around age 10 years. Findings confirm higher f o in DS, and vowel-specific differences between DS and TD in F1 and F2 frequencies, but not F3 and F4. The measure of F2 differences of front-versus-back vowels was more sensitive of compression than reduced vowel space area/centralization across age and sex. Low vowels had more pronounced F2 compression as related to reduced speech intelligibility. Intraspeaker variability was significantly greater for DS than TD for nearly all frequency values across age.

DISCUSSION

Vowel production differences between DS and TD are age- and sex-specific, which helps explain contradictory results in previous studies. Increased intraspeaker variability across age in DS confirms the presence of a persisting motor speech disorder. Atypical vowel production in DS is common and related to dysmorphology, delayed development, and disordered motor control.

Communication and Social Interaction Experiences of Youths With Congenital Motor Speech Disorders

PURPOSE

The purpose of this study was to explore the communication and social interaction experiences of adolescents with congenital motor speech disorders due to cerebral palsy or Down syndrome, with the aim of identifying clinical and research needs to support the development and implementation of speech-language interventions.

METHOD

Five male youths (ages 14-18 years) with congenital motor speech disorders and one of their parents participated in face-to-face, semistructured interviews designed to understand communication and social experiences in daily life. Interviews were audio-recorded and orthographically transcribed offline. Content was coded according to topic areas emerging in the data. Themes were developed to illustrate the most salient and representative aspects of participants' experiences according to the phenomenological tradition that recognizes that participants are experts in their "lived experience."

RESULTS

Participants described the youths' day-to-day communication experiences, including facilitators and barriers to successful social interactions. Thematic analysis revealed three main themes: (a) strong core relationships amidst sparse, superficial interactions in daily life; (b) the complicated picture of why; and (c) how speech-language pathologists can help.

CONCLUSIONS

Participants reported that the impact of congenital motor speech disorders on social interactions and experiences became more apparent in adolescence than in earlier childhood. Addressing communication challenges to meet the unique social demands of this period requires tailored interventions that target multiple contributing factors beyond speech impairment, such as social communication skills, negative communication partner attitudes, and participation opportunities. Shifting practice toward a life participation approach to communication intervention stands to substantially improve the long-term social outcomes of adolescents with motor speech disorders.

A Tool for Differential Diagnosis of Childhood Apraxia of Speech and Dysarthria in Children: A Tutorial

PURPOSE

While there has been mounting research centered on the diagnosis of childhood apraxia of speech (CAS), little has focused on differentiating CAS from pediatric dysarthria. Because CAS and dysarthria share overlapping speech symptoms and some children have both motor speech disorders, differential diagnosis can be challenging. There is a need for clinical tools that facilitate assessment of both CAS and dysarthria symptoms in children. The goals of this tutorial are to (a) determine confidence levels of clinicians in differentially diagnosing dysarthria and CAS and (b) provide a systematic procedure for differentiating CAS and pediatric dysarthria in children.

METHOD

Evidence related to differential diagnosis of CAS and dysarthria is reviewed. Next, a web-based survey of 359 pediatric speech-language pathologists is used to determine clinical confidence levels in diagnosing CAS and dysarthria. Finally, a checklist of pediatric auditory-perceptual motor speech features is presented along with a procedure to identify CAS and dysarthria in children with suspected motor speech impairments. Case studies illustrate application of this protocol, and treatment implications for complex cases are discussed.

RESULTS

The majority (60%) of clinician respondents reported low or no confidence in diagnosing dysarthria in children, and 40% reported they tend not to make this diagnosis as a result. Going forward, clinicians can use the feature checklist and protocol in this tutorial to support the differential diagnosis of CAS and dysarthria in clinical practice.

CONCLUSIONS

Incorporating this diagnostic protocol into clinical practice should help increase confidence and accuracy in diagnosing motor speech disorders in children. Future research should test the sensitivity and specificity of this protocol in a large sample of children with varying speech sound disorders. Graduate programs and continuing education trainings should provide opportunities to practice rating speech features for children with dysarthria and CAS.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19709146.

Intensive Voice Treatment (Lee Silverman Voice Treatment [LSVT LOUD]) for Children With Down Syndrome: Phase I Outcomes

PURPOSE

This study examined the effects of an intensive voice treatment Lee Silverman Voice Treatment (LSVT LOUD) on children with Down syndrome (DS) and motor speech disorders.

METHOD

A Phase I, multiple baseline, single-subject design with replication across nine participants with DS was used. Single-word intelligibility, acoustic measures of vocal functioning, and parent perceptions of pre- and posttreatment communication function were used as treatment outcome measures.

RESULTS

All participants completed the full dose of LSVT LOUD and showed gains on one or more of the outcome measures. Patterns of posttreatment improvements were not consistent across participants but were more frequently observed on trained maximum performance tasks compared to tasks reflecting generalization of the treatment skillset. Some participants exhibited a stronger response to treatment, whereas others showed a mixed or weaker response. Parents liked the treatment protocol, perceived benefits from intensive intervention, and indicated they would strongly recommend LSVT LOUD to other parents who have children with DS and motor speech disorders.

CONCLUSIONS

These preliminary results show that children with DS tolerated intensive voice treatment without adverse effects and made select meaningful therapeutic gains. The treatment evidence from this study warrants Phase II treatment studies using LSVT LOUD with a larger group of children with DS.

Retrospective Case-Control Study of Communication and Motor Abilities in 143 Children With Suspected Childhood Apraxia of Speech: Effect of Concomitant Diagnosis

Purpose

This study sought to determine if children with childhood apraxia of speech (CAS) plus another major diagnosis (CAS+) are equivalent in communication and motor profiles to those with a primary diagnosis of CAS and no indication or report of any other diagnosis (CAS-Primary).

Method

This retrospective case-control study included a chart review of 143 children who were suspected of having CAS at Children's Hospital-Wisconsin between 1998 and 2004. Participants were between 30 and 127 months old and included 107 males. Participants were assigned to the suspected CAS-Primary group (n = 114) if they had characteristics of CAS but no other major diagnosis (e.g., galactosemia) and to the CAS+ group (n = 29) if a comorbid diagnosis was present. Groups were compared across demographic, communication, and motor characteristics.

Results

Children with CAS+ evidenced more severe motor profiles than those with CAS-Primary, χ² = (1, n = 122) = 4.952, p = .026, and a small-to-medium effect size (Φ = .201). On average, communication profiles also tended to be more severe among those with CAS+ wherein receptive language was poorer and phonemic inventories were smaller than those with CAS-Primary.

Conclusions

These retrospective data suggest that comorbid diagnosis may play an important role in communication and motor development in children with suspected CAS. These exploratory findings should motivate future prospective studies that consider the role of concomitant diagnoses in symptom profile and response to treatment in children with CAS.

Auditory-Perceptual Features of Speech in Children and Adults With Down Syndrome: A Speech Profile Analysis

Purpose The aim of this study was to determine how the speech disorder profiles in Down syndrome (DS) relate to reduced intelligibility, atypical overall quality, and impairments in the subsystems of speech production (phonation, articulation, resonance, and prosody). Method Auditory-perceptual ratings of intelligibility, overall quality, and features associated with the subsystems of speech production were obtained from recordings of 79 children and adults with DS. Ratings were made for sustained vowels (62 of 79 speakers) and short sentences (79 speakers). The data were analyzed to determine the severity of the affected features in each speaking task and to detect patterns in the group data by means of principal components analysis. Results Reduced intelligibility was noted in 90% of the speakers, and atypical overall speech quality was noted in 100%. Affected speech features were distributed across the speech production subsystems. Principal components analysis revealed four components each for the vowel and sentence tasks, showing that individuals with DS are not homogeneous in the features of their speech disorder. Discussion The speech disorder in DS is complex in its perceptual features and reflects impairments across the subsystems of speech production, but the pattern is not uniform across individuals, indicating that attention must be given to individual variation in designing treatments.

Differences and Similarities in Predictors of Expressive Vocabulary Development between Children with Down Syndrome and Young Typically Developing Children

The purpose of this study was to examine potential differences in the predictors of expressive vocabulary development between children with Down syndrome and typically developing children to support preparation for intervention development. An age cohort of 43 children with Down syndrome and 57 typically developing children with similar nonverbal mental age levels were assessed at three time points. Linear mixed models were used to investigate the predictors of expressive vocabulary over time. Both groups achieved progress in expressive vocabulary. The typically developing children had steeper growth than the children with Down syndrome (1.38 SD vs. 0.8 SD, p < 0.001). In both groups, receptive vocabulary, auditory memory, and the home literacy environment were significant predictors of development. In the children with Down syndrome, the phonological awareness and oral motor skills were also significant. Group comparisons showed that receptive vocabulary, auditory memory and oral motor skills were stronger predictors in the children with Down syndrome than in the typically developing children. These results indicate that children with Down syndrome are more vulnerable when it comes to risk factors that are known to influence expressive vocabulary than typically developing children. Children with Down syndrome therefore require early broad-based expressive vocabulary interventions.

Exploring Expressive Communication Skills in a Cross-Sectional Sample of Individuals With a Dual Diagnosis of Autism Spectrum Disorder and Down Syndrome

Individuals with a comorbid diagnosis of Down syndrome (DS) and autism spectrum disorder (ASD) have been found to exhibit greater deficits in expressive communication than individuals with DS only. We hypothesized that individuals with a comorbid diagnosis (n = 430) would have significantly lower Communication Matrix scores and specifically social communication scores than individuals with DS alone (n = 4,352). In a sample of 4,782 individuals with DS, scores for individuals with a comorbid diagnosis were on average 18.01 points and 7.26 points lower for total score and social score respectively as compared to individuals with DS. Comorbid diagnosis accounted for 10.5% of the variance in communication scores. Between-group differences in referential gestures and symbolic communication behaviors were also observed.

Vowel Acoustics and Speech Intelligibility in Young Adults With Down Syndrome

Purpose Speech production deficits and reduced intelligibility are frequently noted in individuals with Down syndrome (DS) and are attributed to a combination of several factors. This study reports acoustic data on vowel production in young adults with DS and relates these findings to perceptual analysis of speech intelligibility. Method Participants were eight young adults with DS as well as eight age- and gender-matched typically developing (TD) controls. Several different acoustic measures of vowel centralization and variability were applied to tokens of corner vowels (/ɑ/, /æ/, /i/, /u/) produced in common English words. Intelligibility was assessed for single-word productions of speakers with DS, by means of transcriptions from 14 adult listeners. Results Group differentiation was found for some, but not all, of the acoustic measures. Low vowels were more acoustically centralized and variable in speakers with DS than TD controls. Acoustic findings were associated with overall intelligibility scores. Vowel formant dispersion was the most sensitive measure in distinguishing DS and TD formant data. Conclusion Corner vowels are differentially affected in speakers with DS. The acoustic characterization of vowel production and its association with speech intelligibility scores within the DS group support the conclusion of motor control deficits in the overall speech impairment. Implications are discussed for effective treatment planning.

Speech profile in Down syndrome: speech apraxia x speech disorder of musculoskeletal origin

ABSTRACT This study presents an analysis of linguistic aspects at the segmental and suprasegmental levels in individuals with Down syndrome with or without a diagnosis of speech apraxia. Ten individuals of both sexes, aged between 13 and 32 years, participated in the study. Data collection was performed, individually and separately, in a video recorded therapeutic session. Speech tasks consisted of word repetition, repetition of sentences and automatic speech. The speech samples were submitted to phonetic transcription with a description and analysis of phonoarticulatory alterations, typology of disfluencies and prosodic alterations. The data were submitted to descriptive and inferential statistical analysis, using the Mann-Whitney test for independent samples and considering p-value≤0.05 as significant. Individuals with speech apraxia (n=6), compared with those without it (n=4), presented a higher occurrence of phonoarticulatory alterations, with a statistically significant difference between the two groups in omission (p=0.018) and articulatory inaccuracy (p=0.030) alterations; a higher occurrence of disfluencies, mainly of the syllable repetition type; and the occurrence of prosodic alterations (83.3%), which was not found in the group without speech apraxia. The importance of the differential diagnosis of speech disorders in Down syndrome is revealed with an evaluation that considers the different linguistic aspects resulting from the differentiation of the characteristics of speech. Clinical intervention should be early and guided by specific parameters.

Estimates of the Prevalence of Speech and Motor Speech Disorders in Youth With 22q11.2 Deletion Syndrome

Purpose Speech sound disorders and velopharyngeal dysfunction are frequent features of 22q11.2 deletion syndrome (22q). We report the first estimate of the prevalence of motor speech disorders (MSDs) in youth with 22q. Method Seventeen children and adolescents with 22q completed an assessment protocol that included a conversational speech sample. Data reduction included phonetic transcription, perceptual speech ratings, prosody-voice coding, and acoustic analyses. Data analyses included 3 motor speech measures and a cross-classification analytic. Prevalence estimates of speech and MSDs in youth with 22q were compared with estimates in speakers with other complex neurodevelopmental disorders: Down syndrome, fragile X syndrome, and galactosemia. Results Results indicated that 58.8% of the participants with 22q met criteria for speech delay, and 82.4% of the participants met criteria for MSDs, including 29.4% with speech motor delay, 29.4% with childhood dysarthria, 11.8% with childhood apraxia of speech, and 11.8% with concurrent childhood dysarthria and childhood apraxia of speech. MSDs were not significantly associated with velopharyngeal dysfunction. Conclusions In summary, 82.4% of the participants with 22q met criteria for 1 of 4 MSDs, predominantly speech motor delay and childhood dysarthria. Cross-validation of the present findings would support viewing MSDs as a core phenotypic feature of 22q.

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

The 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.

Estimates of the prevalence of speech and motor speech disorders in persons with complex neurodevelopmental disorders

Estimates of the prevalence of speech and motor speech disorders in persons with complex neurodevelopmental disorders (CND) can inform research in the biobehavioural origins and treatment of CND. The goal of this research was to use measures and analytics in a diagnostic classification system to estimate the prevalence of speech and motor speech disorders in convenience samples of speakers with one of eight types of CND. Audio-recorded conversational speech samples from 346 participants with one of eight types of CND were obtained from a database of participants recruited for genetic and behavioural studies of speech sound disorders (i.e., excluding dysfluency) during the past three decades. Data reduction methods for the speech samples included narrow phonetic transcription, prosody-voice coding, and acoustic analyses. Standardized measures were used to cross-classify participants' speech and motor speech status. Compared to the 17.8% prevalence of four types of motor speech disorders reported in a study of 415 participants with idiopathic Speech Delay (SD), 47.7% of the present participants with CND met criteria for one of four motor speech disorders, including Speech Motor Delay (25.1%), Childhood Dysarthria (13.3%), Childhood Apraxia of Speech (4.3%), and concurrent Childhood Dysarthria and Childhood Apraxia of Speech (4.9%). Findings are interpreted to indicate a substantial prevalence of speech disorders, and notably, a substantial prevalence of motor speech disorders in persons with some types of CND. We suggest that diagnostic classification information from standardized motor speech assessment protocols can contribute to research in the pathobiologies of CND. Abbreviations: 16p: 16p11.2 deletion and duplication syndrome; 22q: 22q11.2 deletion syndrome; ASD: Autism Spectrum Disorder; CAS: Childhood Apraxia of Speech; CD: Childhood Dysarthria; CND: Complex Neurodevelopmental Disorder; DS: Down syndrome; FXS: Fragile X syndrome; GAL: Galactosemia; IID: Idiopathic Intellectual Disability; MSD: Motor Speech Disorder; No MSD: No Motor Speech Disorder; NSA: Normal(ized) Speech Acquisition; PEPPER: Programs to Examine Phonetic and Phonologic Evaluation Records; 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; SSD: Speech Sound Disorders; TBI: Traumatic Brain Injury.

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

The 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.