It's Mine, . . . It's Mine: Unsolicited Repetitions Are Reduced in Toddlers.

A phenomenon called "repetition reduction" can increase articulation rate in adults by facilitating phonetic and motor processes, which indicates flexibility in the control of articulation rate. Young children, who speak much slower, may not have the same speech motor flexibility resulting in the absence of the repetition reduction effect. In this study, we tested whether spontaneous repetitions of young children are produced with a faster articulation rate than their original utterances. Twelve monolingual English-speaking children were observed at four time points between 2;0 and 3;0 years of age. A significant increase in articulation rate and syllable count was found using multilevel models for all utterances over the 1-year period. At each time point, however, the repeated utterances were produced significantly faster than the original utterances even though the content and syllable count differed minimally. Our findings conform to the pattern of adult studies suggesting that a "naturistic" form of repetition reduction is already present in the speech of children at 2;0 years. Although certain aspects of speech motor control are undergoing rapid development, existing motor capability at 2;0 already supports flexible changes in articulation rate including repetition reduction.

Parent Interventions Improve Behavior After Pediatric Traumatic Brain Injury: A Systematic Review and Meta-analysis.

OBJECTIVE: To examine child behavior change scores from randomized controlled trials (RCTs) of parent interventions for pediatric traumatic brain injury (TBI). METHODS: MEDLINE, EMBASE, PsycINFO, and CINAHL were searched to identify studies that examined parent interventions for pediatric TBI. Inclusion criteria included (i) a parent intervention for children with TBI; (ii) an RCT study design; (iii) statistical data for child behavior outcome(s); and (iv) studies that were published in English. RESULTS: Seven studies met inclusion criteria. All interventions reported improved child behavior after pediatric TBI; however, child and parent factors contributed to behavior change scores in some interventions. Factors found to contribute to the level of benefit included age of child, baseline behavior levels, sociodemographics (eg, parent income, parent education), and parent mental health. CONCLUSION: Improved child behavior outcomes resulting from parent interventions for pediatric TBI are well supported by the evidence in the peer-reviewed literature. Clinicians are encouraged to consider child and parent factors as they relate to child behavior outcomes.

Brain and Language Associations in Autism Spectrum Disorder: A Scoping Review.

Examining brain and behaviour associations for language in autism spectrum disorder (ASD) may bring us closer to identifying neural profiles that are unique to a subgroup of individuals with ASD identified as language impaired (e.g. ASD LI+). We conducted a scoping review to examine brain regions that are associated with language performance in ASD. Further, we examined methodological differences across studies in how language ability was characterized and what neuroimaging methods were used to explore brain regions. Seventeen studies met inclusion criteria. Brain regions specific to ASD LI+ groups were found, however inconsistencies in brain and language associations were evident across study findings. Participant age, age-appropriate language scores, and neuroimaging methods likely contributed to differences in associations found.

Paradoxical facilitation alongside interhemispheric inhibition.

Neurophysiological experiments using transcranial magnetic stimulation (TMS) have sought to probe the function of the motor division of the corpus callosum. Primary motor cortex sends projections via the corpus callosum with a net inhibitory influence on the homologous region of the opposite hemisphere. Interhemispheric inhibition (IHI) experiments probe this inhibitory pathway. A test stimulus (TS) delivered to the motor cortex in one hemisphere elicits motor evoked potentials (MEPs) in a target muscle, while a conditioning stimulus (CS) applied to the homologous region of the opposite hemisphere modulates the effect of the TS. We predicted that large CS MEPs would be associated with increased IHI since they should be a reliable index of how effectively contralateral motor cortex was stimulated and therefore of the magnitude of interhemispheric inhibition. However, we observed a strong tendency for larger CS MEPs to be associated with reduced interhemispheric inhibition which in the extreme lead to a net effect of facilitation. This surprising effect was large, systematic, and observed in nearly all participants. We outline several hypotheses for mechanisms which may underlie this phenomenon to guide future research.

Early Speech Rate Development: A Longitudinal Study.

Purpose Our knowledge of speech rate development remains inadequate because of limited longitudinal data and lack of data from children under age 3;0 (years;months). The purpose of this longitudinal study was to test the pattern of speech rate development between ages 2;0 and 3;0. Method Speech rate was assessed at 4 time points between ages 2;0 and 3;0. The analysis employed multilevel models to characterize the development of speech rate (syllables per second), phonemes per second (PPS), length of active declarative sentences, and mean length of utterance. Results The results indicate a significant linear increase in speech rate, PPS, length of active declarative sentences, and mean length of utterance occurring over the 1-year period. Male and female children differed in speech rate, PPS, and utterance length, suggesting sex is a potential factor in early speech rate development. Conclusions Our findings indicate that the speech motor system develops rapidly during the period when grammar emerges. Speech rate has the potential to be an important metric for understanding typical speech development and speech disorders.

Delayed Phonological Encoding in Stuttering: Evidence from Eye Tracking.

Stuttering is a multifactorial disorder that is characterized by disruptions in the forward flow of speech believed to be caused by differences in the motor and linguistic systems. Several psycholinguistic theories of stuttering suggest that delayed or disrupted phonological encoding contributes to stuttered speech. However, phonological encoding remains difficult to measure without controlling for the involvement of the speech-motor system. Eye-tracking is proposed to be a reliable approach for measuring phonological encoding duration while controlling for the influence of speech production. Eighteen adults who stutter and 18 adults who do not stutter read nonwords under silent and overt conditions. Eye-tracking was used to measure dwell time, number of fixations, and response time. Adults who stutter demonstrated significantly more fixations and longer dwell times during overt reading than adults who do not stutter. In the silent condition, the adults who stutter produced more fixations on the nonwords than adults who do not stutter, but dwell-time differences were not found. Overt production may have resulted in additional requirements at the phonological and phonetic levels of encoding for adults who stutter. Direct measurement of eye-gaze fixation and dwell time suggests that adults who stutter require additional processing that could potentially delay or interfere with phonological-to-motor encoding.