Deficits in sequential processing manifest in motor and linguistic tasks in a multigenerational family with childhood apraxia of speech

Relationships Among Motor, First, and Second Language Skills Among Bilingual Children With Language Disorders

PURPOSE

The purpose of this study was to determine the significance and directions of the relationships among oral and manual fine motor skills and language abilities among Spanish-English bilingual children. If such relationships exist, this would support a shared biological influence on motor and language development.

METHOD

Participants included 56 bilingual children, 24 of whom met criteria for developmental language disorder (DLD), recruited based on teacher concern for language and/or reading comprehension abilities. Students participated in a battery of baseline tests to determine motor, language, and cognitive abilities. Correlations among all variables were examined for direction of relationships. Regression models explored the predictive power of motor skills with Spanish and English language ability as the outcome measure.

RESULTS

Oral fine motor abilities (diadochokinetic rate productions of /pa/ and /pata/) predicted Spanish (but not English) oral language abilities in the expected direction (i.e., faster rates were associated with better language). Manual fine motor performance on computer tapping tasks was not related to performance in either language.

CONCLUSIONS

Oral fine motor abilities are related to language abilities in bilingual children, but only for the native language. We did not find reliable differences in oral and manual fine motor skills between groups of bilingual children with and without DLD. These findings support a limited role of shared biological influences on motor and language development.

The Reliability of Expert Diagnosis of Childhood Apraxia of Speech

PURPOSE

The current standard for clinical diagnosis of childhood apraxia of speech (CAS) is expert clinician judgment. The psychometric properties of this standard are not well understood; however, they are important for improving clinical diagnosis. The purpose of this study is to determine the extent to which experts agree on the clinical diagnosis of CAS using two cohorts of children with mixed speech sound disorders (SSDs).

METHOD

Speech samples of children with SSDs were obtained from previous and ongoing research from video recordings of children aged 3-8 years (n = 36) and audio recordings of children aged 8-17 years (n = 56). A total of 23 expert, English-speaking clinicians were recruited internationally. Three of these experts rated each speech sample to provide a description of the observed features and a diagnosis. Intrarater reliability was acceptable at 85% agreement.

RESULTS

Interrater reliability on the presence or absence of CAS among experts was poor both as a categorical diagnosis (κ = .187, 95% confidence interval [CI] [0.089, 0.286]) and on a continuous "likelihood of CAS" scale (0-100; intraclass correlation = .183, 95% CI [.037, .347]). Reliability was similar across the video-recorded and audio-only samples. There was greater agreement on other diagnoses (such as articulation disorder) than on the diagnosis of CAS, although these too did not meet the predetermined standard. Likelihood of CAS was greater in children who presented with more American Speech-Language-Hearing Association CAS consensus features.

CONCLUSIONS

Different expert raters had different thresholds for applying the diagnosis of CAS. If expert clinician judgment is to be used for diagnosis of CAS or other SSDs, further standardization and calibration is needed to increase interrater reliability. Diagnosis may require operationalized checklists or reliable measures that operate along a diagnostic continuum.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23949105.

The Relationship Between Speech Accuracy and Linguistic Measures in Narrative Retells of Children With Speech Sound Disorders

BACKGROUND

Speech and language are interconnected systems, and language disorder often co-occurs with childhood apraxia of speech (CAS) and non-CAS speech sound disorders (SSDs). Potential trade-off effects between speech and language in connected speech in children without overt language disorder have been less explored.

METHOD

Story retell narratives from 24 children (aged 5;0-6;11 [years;months]) with CAS, non-CAS SSD, and typical development were analyzed in Systematic Analysis of Language Transcripts (SALT) regarding morphosyntactic complexity (mean length of C-unit in words [MLCU]), lexical diversity (moving-average type-token ratio [MATTR]), and linguistic accuracy (any linguistic error/bound morpheme omissions) and compared to 128 age-matched children from the SALT database. Linear and mixed-effects logistic regressions were performed with speech accuracy (percent phonemes correct [PPC]) and diagnostic group as predictors of the narrative variables.

RESULTS

PPC predicted all narrative variables. Poorer PPC was associated with lower MLCU and MATTR as well as a higher likelihood of linguistic errors. Group differences were only observed for the error variables. Comparison to the SALT database indicated that 13 of 16 children with CAS and SSD showed a higher-than-expected proportion of linguistic errors, with a small proportion explained by individual speech errors only.

CONCLUSIONS

The high occurrence of linguistic errors, combined with the relationship between PPC and linguistic errors in children with CAS/SSD, suggests a trade-off between speech accuracy and language output. Longitudinal studies are needed to investigate whether children with SSDs without language disorder show more language difficulties over time as linguistic demands increase.

A case with cardiac, skeletal, speech, and motor traits narrows the subtelomeric 19p13.3 microdeletion region to 46 kb

Subtelomeric 19p13.3 deletions have been associated with diverse anatomical and developmental phenotypes. A recent study of eight patients with subtelomeric interstitial 19p13.3 microdeletions at 0.3-1.4 Mb (hg 19) showed associations with growth restrictions, skeletal deformities, craniofacial anomalies, congenital heart defects, renal malformations, hernias, immune system deficits, fine and gross motor delays, speech delays, and developmental and learning delays. The authors defined two small regions of overlap containing four and 11 genes, respectively, with potential haploinsufficiency. Here, we present a new case with a de novo 184 kb deletion containing eight genes, three of which fall into the second previously identified small region of overlap, reducing the shared region to 46 kb. Phenotypic traits include most of the core findings in the previously reported cases but not growth restrictions, craniofacial anomalies, renal malformation, and learning disability. A closer look at the speech and motor delays reveals apraxic speech and discoordination in the fine and gross motor domain, consistent with cerebellar involvement across motor systems. Findings are consistent with a role of AZU1 in the observed immune deficiencies and PTBP1 in the observed skeletal, abdominal, speech, language, motor, and sensory traits. This case thus contributes to a more nuanced understanding of the subtelomeric 19p13.3 deletion region.

Three children with different de novo BCL11A variants and diverse developmental phenotypes, but shared global motor discoordination and apraxic speech: Evidence for a functional gene network influencing the developing cerebellum and motor and auditory cortices

BCL11A is implicated in BCL11A-Related Intellectual Development Disorder (BCL11A-IDD). Previously reported cases had various types of BCL11A variants (copy-number variations [CNVs], singlenucleotide variants [SNVs]). Phenotypes included global, cognitive, and motor delays, autism spectrum disorder (ASD), craniofacial dysmorphology, and speech and language delays described generally, with only two reports specifying childhood apraxia of speech (CAS). Here, we present three additional children with CAS and de novo BCL11A variants, a p.Ala182Thr nonconservative missense and a p.GLu611.Ter nonsense variant, both in exon 4, and a 106 kb deletion harboring exons 1 and 2. All three children have fine and gross motor discoordination, feeding difficulties, and visual motor disorders. Intellectual and learning disabilities and disordered language skills were seen only in the child with the missense variant and the child with the deletion. These findings align with, and expand, previous findings in that BCL11A variants have significant and highly penetrant apraxic effects across motor systems, consistent with cerebellar involvement. The deletion of exons 1 and 2 is the smallest BCL11A CNV with the full phenotypic expression reported to date. The present results support previous findings in that BCL11A-IDD can result from BCL11A variants regardless of type (deletion, SNVs). A gene expression study shows that BCL11 is expressed highly in the early developing cerebellum and primary motor and auditory cortices. Significant co-expression rates in these regions with genes previously implicated in disorders of spoken language and in ASD support the phenotypic overlaps in children with BCL11A-IDD, CAS, and ASD.

An Investigation of Developmental Coordination Disorder Characteristics in Children With Childhood Apraxia of Speech

PURPOSE

Children with childhood apraxia of speech (CAS) evidence a high rate of co-occurring fine and gross motor deficits. This clinical focus article reports a preliminary investigation of characteristics of developmental coordination disorder (DCD), a neurodevelopmental disorder categorized by poor motor proficiency and functional limitations, in this population.

METHOD

Children with CAS underwent a comprehensive motor evaluation using the Movement Assessment Battery for Children-Second Edition, the Developmental Coordination Disorder Questionnaire, and a developmental history questionnaire to determine if they met criteria for a DCD diagnosis as specified in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).

RESULTS

Six out of seven participants met DCD criteria based on the DSM-5 criteria. Four of these children had a co-occurring diagnosis of developmental language disorder, and all met criteria for DCD.

CONCLUSIONS

Consistent with previous research, the majority of participants demonstrated motor deficits and 85% met criteria for DCD. Despite this high rate of motor deficits, only 57% had previously undergone a physical/occupational therapy evaluation and intervention and only one had a previous diagnosis of DCD. These findings suggest that formal movement assessments are essential for children with a CAS diagnosis.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.20540193.

Translating principles of precision medicine into speech-language pathology: Clinical trial of a proactive speech and language intervention for infants with classic galactosemia

Precision medicine is an emerging approach to managing disease by taking into consideration an individual’s genetic and environmental profile toward two avenues to improved outcomes: prevention and personalized treatments. This framework is largely geared to conditions conventionally falling into the field of medical genetics. Here, we show that the same avenues to improving outcomes can be applied to conditions in the field of behavior genomics, specifically disorders of spoken language. Babble Boot Camp (BBC) is the first comprehensive and personalized program designed to proactively mitigate speech and language disorders in infants at predictable risk by fostering precursor and early communication skills via parent training. The intervention begins at child age 2 to 5 months and ends at age 24 months, with follow-up testing at 30, 42, and 54 months. To date, 44 children with a newborn diagnosis of classic galactosemia (CG) have participated in the clinical trial of BBC. CG is an inborn error of metabolism of genetic etiology that predisposes up to 85% of children to severe speech and language disorders. Of 13 children with CG who completed the intervention and all or part of the follow-up testing, only one had disordered speech and none had disordered language skills. For the treated children who completed more than one assessment, typical speech and language skills were maintained over time. This shows that knowledge of genetic risk at birth can be leveraged toward proactive and personalized management of a disorder that manifests behaviorally.

Implicit learning in children with Childhood Apraxia of Speech

BACKGROUND

Childhood Apraxia of Speech is a severe and persistent clinical subtype of Speech Sound Disorder. Given the difficulties in the acquisition, programming and control of the movements underlying speech and the slowdown in a wide range of non-linguistic skills, the difficulty in implicit learning of sequential information could play a role in the disorder, contributing to understand its etiopathological mechanisms and behavioral manifestations.

AIMS

The present study was aimed at investigating implicit learning in children with Childhood Apraxia of Speech.

METHODS AND PROCEDURES

Twenty-five children with Childhood Apraxia of Speech, aged between 4 and 12 years, were matched for IQ and age to a control group of 25 typically developing children. Implicit learning of participants was assessed by Serial Reaction Time Task.

OUTCOME AND RESULTS

Children with Childhood Apraxia of Speech did not show implicit learning, as documented by the absence of differences between reaction times in the sequenced block and the random block, usually considered as a measure of implicit learning effect.

CONCLUSION AND IMPLICATIONS

Our results underline an implicit learning deficit in children with Childhood Apraxia of Speech, supporting the concept of a disorder not only confined to the speech domain, but also involving non-linguistic skills, in a composite and complex picture.

Differences and Commonalities in Children with Childhood Apraxia of Speech and Comorbid Neurodevelopmental Disorders: A Multidimensional Perspective

Childhood apraxia of speech (CAS) is a motor speech disorder often co-occurring with language impairment and complex neurodevelopmental disorders. A cohort of 106 children with CAS associated to other neurodevelopmental disorders underwent a multidimensional investigation of speech and language profiles, chromosome microarray analysis and structural brain magnetic resonance (MR). Our aim was to compare the clinical profiles of children with CAS co-occurring with only language impairment with those who, in addition to language impairment, had other neurodevelopmental disorders. Expressive grammar was impaired in the majority of the sample in the context of similar alterations of speech, typical of the core symptoms of CAS. Moreover, children with complex comorbidities also showed more severe and persistent receptive language deficits. About 25% of the participants harbored copy number variations (CNVs) already described in association to neurodevelopmental disorders. CNVs occurred more frequently in children with complex comorbidities. MR structural/signal alterations were found in a small number of children and were of uncertain pathogenic significance. These results confirm that CAS needs multidimensional diagnostic and clinical management. The high frequency of language impairment has important implications for early care and demands a personalized treatment approach in which speech and language goals are consistently integrated.

Psychosocial Comorbidities in Adolescents With Histories of Childhood Apraxia of Speech

Purpose Adolescent psychosocial outcomes of individuals with histories of childhood apraxia of speech (CAS) were compared to outcomes of individuals with histories of speech sound disorders (SSD) only and SSD with language impairment (LI). It was hypothesized that individuals with more severe and persistent disorders such as CAS would report poorer psychosocial outcomes. Method Groups were compared using analyses of variance on a psychosocial assessment battery that included measures of hyperactivity and inattention, anxiety, depression, internalizing and externalizing behaviors, thought problems, and social outcomes. Results Results revealed significant group differences on self-report of social problems and parent report of hyperactivity, thought problems, and social problems at adolescence. Compared to the SSD-only group, the CAS group had significantly higher parental ratings of hyperactivity and social problems in adolescence. The CAS and SSD + LI groups did not differ on psychosocial measures, possibly due to the high rate of comorbid LI in the CAS group. The CAS group also had more individuals who scored in the borderline/clinical range on self-report of social problems than the SSD-only group. The CAS group did not differ from the SSD + LI group in the number of participants scoring in the borderline/clinical range on measures. Conclusions Individuals with histories of CAS demonstrate increased rates of social problems and hyperactivity based on parent ratings compared to adolescents with histories of SSD only; however, most do not score within the clinical range. The persistence of speech sound errors combined with self-reported and parent-reported social difficulties suggests that speech-language pathologists should be sensitive to the social and emotional impact of CAS and make appropriate referrals to mental health professionals when warranted.

Spelling errors reveal underlying sequential and spatial processing deficits in adults with dyslexia

Recent studies showed that some adults with dyslexia have difficulty processing sequentially arranged information. In a companion study, this deficit manifested as low accuracy during a word pair comparison task involving same/different decisions when two words differed in their letter sequences. This sequential deficit was associated with left/right spatial letter confusion. In the present study, we found the same underlying difficulty with sequential and spatial letter processing during word spelling. Participants were the same 22 adults with dyslexia and 20 age- and gender-matched controls as in the companion study. In the spelling task, sequential error rates were higher in the dyslexia group, compared to the controls. Measures of accuracy of serial letter order during the spelling task and the word comparison task were correlated. Only three participants, each with dyslexia, produced left/right letter reversals during spelling. These were the same participants who produced left/right errors when naming single letters. They also had profound difficulty with sequential and left/right letter processing in the spelling and word comparison tasks, and they had the most severe spelling impairment. We conclude that this pervasive, persistent difficulty with sequential and spatial reversals contributes to a severe dyslexia subtype. In the dyslexia group as a whole, additional and separate sources of errors were underspecified word representations in long-term memory and homophone errors that likely represent language-based deficits in word knowledge. In the participants, these three factors (sequential/spatial letter confusion, underspecified word form representation, language-based deficits) occurred either as single factors or in combination with each other.

Comparing global motor characteristics in children and adults with childhood apraxia of speech to a cerebellar stroke patient: evidence for the cerebellar hypothesis in a developmental motor speech disorder

Individuals with childhood apraxia of speech (CAS) have motor deficits in systems beyond speech and also global deficits in sequential processing, consistent with cerebellar dysfunction. We investigated the cerebellar hypothesis of CAS in 18 children and adolescents with CAS, 11 typical controls, an adult with a probable CAS history, and an adult with a history of a cerebellar stroke. Compared to the controls, children and adolescents with CAS had the greatest difficulty with rapid syllable repetition when alternating between two different syllables types, less difficulty when switching among three different syllables, and no difficulty when repeating the same syllable. They also showed difficulty with alternating but not repetitive key tapping. Motor speeds during the syllable repetition and key tapping tasks where correlated, consistent with a central motor delimiter that governs both systems. Participants with CAS obtained low scores in a test of fine motor ability, where the tasks required rapid integration of complex hand movement sequences. The adult with the probable CAS history obtained motor performance scores that generally resembled those in the children and adolescents with CAS, consistent with motor deficits that persist into adulthood. The participant with the cerebellar stroke history showed deficits in tests of fine and gross motor ability as well as balance. His repetitive and alternating key tapping was slow in the ipsilateral hand relative to the stroke lesion. The shared deficits in sequential motor functions among all participants with CAS and the cerebellar stroke patient are consistent with persisting cerebellar dysfunctions in CAS.

Feature-driven classification reveals potential comorbid subtypes within childhood apraxia of speech

Background

Childhood apraxia of speech (CAS) is a neurodevelopmental disorder with heterogeneous communication and other comorbid manifestations. While previous studies have characterized speech deficits associated with CAS, few studies have examined variability in reading and language and/or other developmental comorbidities. We sought to identify comorbid subgroups within CAS that could be clinically relevant as well as genetically distinctive.

Methods

In a group of 31 children with CAS and 8 controls, we performed hierarchical cluster analysis utilizing measures of articulation, vocabulary, and reading. We also conducted a chart review of the children with CAS to examine other clinical characteristics in these children and their association with subgroup membership.

Results

We identified 3 comorbid subgroups within CAS of varying severity. The high severity subgroup was characterized by poor reading and vocabulary, and the moderate severity subgroup by poor reading and non-word repetition but average vocabulary, compared to the mild severity subgroup. Subgroups were indistinguishable with respect to speech sound production, the hallmark of CAS, all demonstrating poor articulation. Children in the most severe subgroup were more likely to have early problems feeding (p = 0.036).

Conclusions

Children with CAS may potentially be classified into comorbidity groups based on performance on vocabulary and reading measures, providing additional insight into the heterogeneity within CAS with implications for educational interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-020-02421-1.

Reading Outcomes for Individuals With Histories of Suspected Childhood Apraxia of Speech

Purpose The primary aims of this study were to examine the speech-language correlates of decoding difficulties in children with histories of suspected childhood apraxia of speech (sCAS) and to identify predictors of low-proficiency reading levels. Method Participants were school-age children and adolescents, 7-18 years of age, diagnosed with sCAS (n = 40) or speech sound disorder but no sCAS (SSD-no sCAS; n = 119). The sCAS and SSD-no sCAS reading groups were compared on measures of performance IQ, oral language, phonological awareness, rapid automatic naming, diadochokinetic rates, single word articulation, and multisyllable and nonsense word repetition. Logistic regression analyses were employed to identify predictors of low-proficiency reading in the sCAS and SSD-no sCAS groups. Results Sixty-five percent of the participants with sCAS compared to 24% of those with SSD-no sCAS were classified as low-proficiency readers based on nonsense and single word decoding. Analysis failed to reveal significant differences in reading, oral language, or phonological awareness between low-proficiency readers with sCAS and low-proficiency readers with SSD-no sCAS. Oral language and phonological awareness skills were the best predictors of reading level for all participants, followed by performance on multisyllabic word repetition and diadochokinetic rate. Conclusions The language and phonological awareness deficits of children with sCAS are related to their risks for reading failure. To a lesser degree, motor speech deficits and speech sound production also increase risks for reading difficulties. The findings justify early intervention for this subset of children.

Looking to the Future: Speech, Language, and Academic Outcomes in an Adolescent with Childhood Apraxia of Speech

OBJECTIVE

The clinical course of childhood apraxia of speech (CAS) is poorly understood. Of the few longitudinal studies in the field, only one has examined adolescent outcomes in speech, language, and literacy. This study is the first to report long-term speech, language, and academic outcomes in an adolescent, Liam, with CAS.

METHODS

Speech, language, literacy, and academic outcome data were collected, including 3 research-based assessments. Overall, data were available at 17 time points from 3;10 to 15 years.

RESULTS

Liam had moderate-to-severe expressive language impairment and poor reading, writing, and spelling up to 10 years. His numeracy was at or above the national average from 8 to 14 years. He made gains in preadolescence, with average expressive language at 11 years and above average reading and writing at 14 years. Nonword reading, reading comprehension, and spelling remained areas of weakness. Receptive language impairment was evident at 13 years, which was an unexpected finding.

CONCLUSION

Findings from single cases can be hypothesis generating but require verification in larger cohorts. This case shows that at least some children with CAS may gain ground in adolescence, relative to same age peers, in expressive language and academic areas such as reading and writing.

Sequential processing deficit as a shared persisting biomarker in dyslexia and childhood apraxia of speech

The purpose of this study was to investigate the hypothesis that individuals with dyslexia and individuals with childhood apraxia of speech share an underlying persisting deficit in processing sequential information. Levels of impairment (sensory encoding, memory, retrieval, and motor planning/programming) were also investigated. Participants were 22 adults with dyslexia, 10 adults with a probable history of childhood apraxia of speech (phCAS), and 22 typical controls. All participants completed nonword repetition, multisyllabic real word repetition, and nonword decoding tasks. Using phonological process analysis, errors were classified as sequence or substitution errors. Adults with dyslexia and adults with phCAS showed evidence of persisting nonword repetition deficits. In all three tasks, the adults in the two disorder groups produced more errors of both classes than the controls, but disproportionally more sequencing than substitution errors during the nonword repetition task. During the real word repetition task, the phCAS produced the most sequencing errors, whereas during the nonword decoding task, the dyslexia group produced the most sequencing errors. Performance during multisyllabic motor speech tasks, relative to monosyllabic conditions, was correlated with the sequencing error component during nonword repetition. The results provide evidence for a shared persisting sequential processing deficit in the dyslexia and phCAS groups during linguistic and motor speech tasks. Evidence for impairments in sensory encoding, short-term memory, and motor planning/programming was found in both disorder groups. Future studies should investigate clinical applications regarding preventative and targeted interventions towards cross-modal treatment effects.

The role of short-term memory impairment in nonword repetition, real word repetition, and nonword decoding: A case study

In a companion study, adults with dyslexia and adults with a probable history of childhood apraxia of speech showed evidence of difficulty with processing sequential information during nonword repetition, multisyllabic real word repetition and nonword decoding. Results suggested that some errors arose in visual encoding during nonword reading, all levels of processing but especially short-term memory storage/retrieval during nonword repetition, and motor planning and programming during complex real word repetition. To further investigate the role of short-term memory, a participant with short-term memory impairment (MI) was recruited. MI was confirmed with poor performance during a sentence repetition and three nonword repetition tasks, all of which have a high short-term memory load, whereas typical performance was observed during tests of reading, spelling, and static verbal knowledge, all with low short-term memory loads. Experimental results show error-free performance during multisyllabic real word repetition but high counts of sequence errors, especially migrations and assimilations, during nonword repetition, supporting short-term memory as a locus of sequential processing deficit during nonword repetition. Results are also consistent with the hypothesis that during complex real word repetition, short-term memory is bypassed as the word is recognized and retrieved from long-term memory prior to producing the word.

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

Purpose

The goal of this article (PM I) is to describe the rationale for and development of the Pause Marker (PM), a single-sign diagnostic marker proposed to discriminate early or persistent childhood apraxia of speech from speech delay.

Method

The authors describe and prioritize 7 criteria with which to evaluate the research and clinical utility of a diagnostic marker for childhood apraxia of speech, including evaluation of the present proposal. An overview is given of the Speech Disorders Classification System, including extensions completed in the same approximately 3-year period in which the PM was developed.

Results

The finalized Speech Disorders Classification System includes a nosology and cross-classification procedures for childhood and persistent speech disorders and motor speech disorders (Shriberg, Strand, & Mabie, 2017). A PM is developed that provides procedural and scoring information, and citations to papers and technical reports that include audio exemplars of the PM and reference data used to standardize PM scores are provided.

Conclusions

The PM described here is an acoustic-aided perceptual sign that quantifies one aspect of speech precision in the linguistic domain of phrasing. This diagnostic marker can be used to discriminate early or persistent childhood apraxia of speech from speech delay.

Cognitive, Linguistic, and Motor Abilities in a Multigenerational Family with Childhood Apraxia of Speech

Objective

This study describes the phenotype in a large family with a strong, multigenerational history of severe speech sound disorder (SSD) persisting into adolescence and adulthood in approximately half the cases. Aims were to determine whether a core phenotype, broader than speech, separated persistent from resolved SSD cases; and to ascertain the uniqueness of the phenotype relative to published cases.

Method

Eleven members of the PM family (9–55 years) were assessed across cognitive, language, literacy, speech, phonological processing, numeracy, and motor domains. Between group comparisons were made using the Mann–WhitneyU-test (p < 0.01). Participant performances were compared to normative data using standardized tests and to the limited published data on persistent SSD phenotypes.

Results

Significant group differences were evident on multiple speech, language, literacy, phonological processing, and verbal intellect measures without any overlapping scores. Persistent cases performed within the impaired range on multiple measures. Phonological memory impairment and subtle literacy weakness were present in resolved SSD cases.

Conclusion

A core phenotype distinguished persistent from resolved SSD cases that was characterized by a multiple verbal trait disorder, including Childhood Apraxia of Speech. Several phenotypic differences differentiated the persistent SSD phenotype in the PM family from the few previously reported studies of large families with SSD, including the absence of comorbid dysarthria and marked orofacial apraxia. This study highlights how comprehensive phenotyping can advance the behavioral study of disorders, in addition to forming a solid basis for future genetic and neural studies.

Genetic Candidate Variants in Two Multigenerational Families with Childhood Apraxia of Speech

Childhood apraxia of speech (CAS) is a severe and socially debilitating form of speech sound disorder with suspected genetic involvement, but the genetic etiology is not yet well understood. Very few known or putative causal genes have been identified to date, e.g., FOXP2 and BCL11A. Building a knowledge base of the genetic etiology of CAS will make it possible to identify infants at genetic risk and motivate the development of effective very early intervention programs. We investigated the genetic etiology of CAS in two large multigenerational families with familial CAS. Complementary genomic methods included Markov chain Monte Carlo linkage analysis, copy-number analysis, identity-by-descent sharing, and exome sequencing with variant filtering. No overlaps in regions with positive evidence of linkage between the two families were found. In one family, linkage analysis detected two chromosomal regions of interest, 5p15.1-p14.1, and 17p13.1-q11.1, inherited separately from the two founders. Single-point linkage analysis of selected variants identified CDH18 as a primary gene of interest and additionally, MYO10, NIPBL, GLP2R, NCOR1, FLCN, SMCR8, NEK8, and ANKRD12, possibly with additive effects. Linkage analysis in the second family detected five regions with LOD scores approaching the highest values possible in the family. A gene of interest was C4orf21 (ZGRF1) on 4q25-q28.2. Evidence for previously described causal copy-number variations and validated or suspected genes was not found. Results are consistent with a heterogeneous CAS etiology, as is expected in many neurogenic disorders. Future studies will investigate genome variants in these and other families with CAS.

Understanding Language from a Genomic Perspective

Language is a defining characteristic of the human species, but its foundations remain mysterious. Heritable disorders offer a gateway into biological underpinnings, as illustrated by the discovery that FOXP2 disruptions cause a rare form of speech and language impairment. The genetic architecture underlying language-related disorders is complex, and although some progress has been made, it has proved challenging to pinpoint additional relevant genes with confidence. Next-generation sequencing and genome-wide association studies are revolutionizing understanding of the genetic bases of other neurodevelopmental disorders, like autism and schizophrenia, and providing fundamental insights into the molecular networks crucial for typical brain development. We discuss how a similar genomic perspective, brought to the investigation of language-related phenotypes, promises to yield equally informative discoveries. Moreover, we outline how follow-up studies of genetic findings using cellular systems and animal models can help to elucidate the biological mechanisms involved in the development of brain circuits supporting language.

Cognitive Functions in Childhood Apraxia of Speech

PURPOSE

Childhood apraxia of speech (CAS) is diagnosed on the basis of specific speech characteristics, in the absence of problems in hearing, intelligence, and language comprehension. This does not preclude the possibility that children with this speech disorder might demonstrate additional problems.

METHOD

Cognitive functions were investigated in 3 domains: complex sensorimotor and sequential memory functions, simple sensorimotor functions, and nonrelated control functions. Seventeen children with CAS were compared with 17 children with normal speech development at 2 occasions within 15 months.

RESULTS

The children with CAS showed overall lower scores but similar improvement at Occasion 2 compared with the typically developing controls, indicating an overall delay in the development of cognitive functions. However, a specific deviant development in sequential abilities was found as well, indicated by significantly lower scores at Occasion 2 as compared with younger control children at Occasion 1. Furthermore, the scores on the complex sensorimotor and sequential memory tasks were significantly correlated with the severity of the speech impairment.

CONCLUSIONS

These results suggest that CAS involves a symptom complex that not only comprises errors of sequencing speech movements but implicates comorbidity in nonverbal sequential functioning in most children with CAS.

Adolescent outcomes of children with early speech sound disorders with and without language impairment

PURPOSE

In this study, the authors determined adolescent speech, language, and literacy outcomes of individuals with histories of early childhood speech sound disorders (SSD) with and without comorbid language impairment (LI) and examined factors associated with these outcomes.

METHOD

This study used a prospective longitudinal design. Participants with SSD (n = 170), enrolled at early childhood (4-6 years) were followed at adolescence (11-18 years) and were compared to individuals with no histories of speech or language impairment (no SSD; n = 146) on measures of speech, language, and literacy. Comparisons were made between adolescents with early childhood histories of no SSD, SSD only, and SSD plus LI as well as between adolescents with no SSD, resolved SSD, and persistent SSD.

RESULTS

Individuals with early childhood SSD with comorbid LI had poorer outcomes than those with histories of SSD only or no SSD. Poorer language and literacy outcomes in adolescence were associated with multiple factors, including persistent speech sound problems, lower nonverbal intelligence, and lower socioeconomic status. Adolescents with persistent SSD had higher rates of comorbid LI and reading disability than the no SSD and resolved SSD groups.

CONCLUSION

Risk factors for language and literacy problems in adolescence include an early history of LI, persistent SSD, lower nonverbal cognitive ability, and social disadvantage.

Insights into the genetic foundations of human communication

The human capacity to acquire sophisticated language is unmatched in the animal kingdom. Despite the discontinuity in communicative abilities between humans and other primates, language is built on ancient genetic foundations, which are being illuminated by comparative genomics. The genetic architecture of the language faculty is also being uncovered by research into neurodevelopmental disorders that disrupt the normally effortless process of language acquisition. In this article, we discuss the strategies that researchers are using to reveal genetic factors contributing to communicative abilities, and review progress in identifying the relevant genes and genetic variants. The first gene directly implicated in a speech and language disorder was FOXP2. Using this gene as a case study, we illustrate how evidence from genetics, molecular cell biology, animal models and human neuroimaging has converged to build a picture of the role of FOXP2 in neurodevelopment, providing a framework for future endeavors to bridge the gaps between genes, brains and behavior.

Direct and octave-shifted pitch matching during nonword imitations in men, women, and children

OBJECTIVES

To evaluate whether children, women, and men match the speaker's fundamental frequency (F0) during nonword imitation directly when the target F0 is within the responders' vocal ranges and at octave-shifted levels when the target is outside their vocal ranges, and to evaluate the role of a history of speech sound disorder (SSD) in the adult participants.

STUDY DESIGN

Observational.

METHODS

Nonword sets spoken by a man and a woman were imitated by 14 men, 21 women, and 19 children. Approximately half of the adults and two-thirds of the children had a history of SSD. F0 in the imitations was compared with that in the targets and in the participants' nonimitated control word productions.

RESULTS

When the target F0 was within the responders' vocal ranges, the imitations approximated the target F0. Men imitating a woman's voice approximated F0 levels one octave below the target F0. Children imitating a man's voice approximated F0 levels one octave above the target F0. Women imitating a man's voice approximated the target F0 at a ratio of 1.5 known as the perfect fifth in music. A history of SSD did not influence the results.

CONCLUSIONS

This study replicates previous findings showing that target F0 was a salient aspect of the stimuli that was imitated along with the targets' segmental and prosodic components without explicit prompting. It is the first to show F0 convergence not only directly but also at relevant target/imitation intervals including the octave interval.

Neurophysiology of speech differences in childhood apraxia of speech

Event-related potentials (ERPs) were recorded during a picture naming task of simple and complex words in children with typical speech and with childhood apraxia of speech (CAS). Results reveal reduced amplitude prior to speaking complex (multisyllabic) words relative to simple (monosyllabic) words for the CAS group over the right hemisphere during a time window thought to reflect phonological encoding of word forms. Group differences were also observed prior to production of spoken tokens regardless of word complexity during a time window just prior to speech onset (thought to reflect motor planning/programming). Results suggest differences in pre-speech neurolinguistic processes.

De novo microdeletion of BCL11A is associated with severe speech sound disorder

In 10 cases of 2p15p16.1 microdeletions reported worldwide to date, shared phenotypes included growth retardation, craniofacial and skeletal dysmorphic traits, internal organ defects, intellectual disability, nonverbal or low verbal status, abnormal muscle tone, and gross motor delays. The size of the deletions ranged from 0.3 to 5.7 Mb, where the smallest deletion involved the BCL11A, PAPOLG, and REL genes. Here we report on an 11-year-old male with a heterozygous de novo 0.2 Mb deletion containing a single gene, BCL11A, and a phenotype characterized by childhood apraxia of speech and dysarthria in the presence of general oral and gross motor dyspraxia and hypotonia as well as expressive language and mild intellectual delays. BCL11A is situated within the dyslexia susceptibility candidate region 3 (DYX3) candidate region on chromosome 2. The present case is the first to involve a single gene within the microdeletion region and a phenotype restricted to a subset of the traits observed in other cases with more extensive deletions.

Associations among measures of sequential processing in motor and linguistics tasks in adults with and without a family history of childhood apraxia of speech: a replication study

The purpose of this study was to address the hypothesis that childhood apraxia of speech (CAS) is influenced by an underlying deficit in sequential processing that is also expressed in other modalities. In a sample of 21 adults from five multigenerational families, 11 with histories of various familial speech sound disorders, 3 biologically related adults from a family with familial CAS showed motor sequencing deficits in an alternating motor speech task. Compared with the other adults, these three participants showed deficits in tasks requiring high loads of sequential processing, including nonword imitation, nonword reading and spelling. Qualitative error analyses in real word and nonword imitations revealed group differences in phoneme sequencing errors. Motor sequencing ability was correlated with phoneme sequencing errors during real word and nonword imitation, reading and spelling. Correlations were characterized by extremely high scores in one family and extremely low scores in another. Results are consistent with a central deficit in sequential processing in CAS of familial origin.

The genetics of reading disabilities: from phenotypes to candidate genes

This article provides an overview of (a) issues in definition and diagnosis of specific reading disabilities at the behavioral level that may occur in different constellations of developmental and phenotypic profiles (patterns); (b) rapidly expanding research on genetic heterogeneity and gene candidates for dyslexia and other reading disabilities; (c) emerging research on gene-brain relationships; and (d) current understanding of epigenetic mechanisms whereby environmental events may alter behavioral expression of genetic variations. A glossary of genetic terms (denoted by bold font) is provided for readers not familiar with the technical terms.