Purpose: Our objective was to delineate components of motor performance in specific language impairment (SLI); specifically, whether deficits in timing precision in one effector (unimanual tapping) and in two effectors (bimanual clapping) are observed in young children with SLI. Method: Twenty-seven 4-to 5-year-old children with SLI and 21 age-matched peers with typical language development participated. All children engaged in a unimanual tapping and a bimanual clapping timing task. Standard measures of language and motor performance were also obtained. Results: No group differences in timing variability were observed in the unimanual tapping task. However, compared with typically developing peers, children with SLI were more variable in their timing precision in the bimanual clapping task. Nine of the children with SLI performed greater than 1 SD below the mean on a standardized motor assessment. The children with low motor performance showed the same profile as observed across all children with SLI, with unaffected unimanual and impaired bimanual timing precision. Conclusions: Although unimanual timing is unaffected, children with SLI show a deficit in timing that requires bimanual coordination. We propose that the timing deficits observed in children with SLI are associated with the increased demands inherent in bimanual performance.

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 (TD). 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.

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.

Purpose Poor nonword repetition accuracy is a hallmark of children with developmental language disorder (DLD). However, other diagnostic categories also show impaired nonword repetition performance relative to children with typical development (TD); therefore, this task is currently a sensitive but nonspecific index of DLD. In this study, we investigated segmental and kinematic aspects of nonword repetition performance to further specify the diagnostic utility of nonword repetition tasks (NRTs) in diagnosing DLD. Method Forty children, ages 48–86 months, participated, including children with DLD ( n = 12), speech sound disorder (SSD; n = 14), and TD ( n = 14). All children completed an assessment battery to determine group classification, a classic NRT ( Dollaghan & Campbell, 1998 ), and an experimental NRT designed to measure segmental and articulatory (specifically lip aperture) variability. We assessed nonword repetition accuracy in the classic and experimental NRTs and segmental and kinematic variability in the experimental NRT. Results In both the classic and experimental NRTs, children with SSD and DLD produced nonwords with lower phoneme and consonant accuracy compared to children with TD. Children with DLD produced more vowel errors compared to children with TD in both tasks. In the experimental NRT, children with DLD produced nonwords with high levels of segmental variability compared to children with TD. Children with SSD did not differ from children with TD or children with DLD in the vowel accuracy or the segmental variability measures. The articulatory variability measure did not reveal any group differences. Conclusions In the presence of speech sound difficulties, low nonword repetition accuracy does not aid in the diagnosis of DLD. However, vowel accuracy and segmental variability appear specific to DLD status in NRTs.

Childhood apraxia of speech (CAS) is a pediatric neurological motor speech disorder characterized by impaired speech execution in the absence of neuromuscular deficits. Children with CAS show distinct speech features, including sequencing, coarticulation, and prosodic deficits, compared to children with other speech disorders. The core deficit in CAS is at the level of planning and programming the precise spatiotemporal parameters of movement sequences necessary to produce natural-sounding speech. This study will investigate spatiotemporal variability in children with CAS compared to children with typical development (TD) using the acoustic spatiotemporal index (aSTI). The aSTI measures spatiotemporal variability in the amplitude envelope of speech sounds across multiple repetitions of an utterance; higher aSTI values reflect higher movement variability. In the current project, children with CAS and TD were recruited nationally to participate in an online study investigating language and motor skills. Children produced 10 repetitions of “Buy Bobby a puppy” and “Mom pets the puppy”; we analyzed these two sentences using the aSTI. Data from 20 children (CAS = 10; TD = 10), ranging in age from 7- to 12-years-old, will be presented. We predict that children with CAS will show higher aSTI values compared to children with TD.