Dynamic Assessment of Narratives: Efficient, Accurate Identification of Language Impairment in Bilingual Students.

Purpose: This study investigated the classification accuracy of a concentrated English narrative dynamic assessment (DA) for identifying language impairment (LI). Method: Forty-two Spanish-English bilingual kindergarten to third-grade children (10 LI and 32 with no LI) were administered two 25-min DA test-teach-test sessions. Pre- and posttest narrative retells were scored in real time. Using a structured intervention approach, examiners taught children missing story grammar elements and subordination. A posttest was administered using a parallel story. Results: Four classification predictors were analyzed: posttest scores, gain scores, modifiability ratings, and teaching duration. Discriminant function analysis indicated that an overall modifiability rating was the best classifier, with 100% sensitivity and 88% specificity after 1 DA session and 100% sensitivity and specificity after 2 sessions. Any 2 combinations of posttest scores, modifiability ratings, and teaching duration for just 1 session resulted in sensitivity and specificity rates over 90%. Receiver operating characteristic analyses were used to identify clinically usable cutoff points. Post hoc exploration indicated that similar results could be obtained after only one 5-10-min teaching cycle, potentially further abbreviating the DA process. Conclusion: Concentrated English narrative DA results in high classification accuracy for bilingual children with and without LI. This efficient version of DA is amenable to clinical use.

Effects of changing jaw height on F1 during babble: a case study at 9 months.

An empirical gap exists in our understanding of the extent that mandibular kinematics modulate acoustic changes in natural babble productions of infants. Data were recorded from a normal developing 9-month-old infant. Mandibular position was tracked from the infant during vowel and canonical babble. Linear predictive coding analysis was used to track estimates of formant center-frequency for F1. For each sample, a correlation coefficient was computed between changes in jaw height and formant history for F1. A Mann-Whitney rank sum test reached significance for differences among coefficients for vowel and canonical babble. Coefficients for vowel babble productions were nearest to -1 with a median of r=-0.76, showing the strongest relationship between jaw position and formant history, while the median for canonical babble coefficients was r=-0.54, indicating greater contribution of the tongue and lips. This 9-month-old infant exhibited plasticity for coordinating the jaw, tongue and lips among babble types.

Babbling and Chewing: Jaw Kinematics from 8 to 22 months.

Empirical gaps remain regarding infant mandibular kinematics observed during naturally occurring episodes of chewing and pre-linguistic vocalizations during the first 2-years of life. Vertical jaw displacement was measured from a typically developing infant from 8 to 22 months. Infant jaw kinematics was measured for vowel babble, non-variegated and variegated babble, and chewing. Results indicated that measures of kinematic variability were significantly less for chewing than all babble categories. These measures changed across age for chewing: (a) peak vertical jaw elevation decreased in variability, while (b) jaw displacement and (c) speed of movement increased in variability. Kinematics for vowel babble were characterized as exhibiting less jaw displacement with higher average vertical jaw position than other babble types and chewing. Developmentally, jaw kinematics for babble changed for jaw displacement and average vertical jaw position. These changes were related to decreased episodes for vowel babble productions and increased episodes for variegated babble and reduplicative syllables. These results suggest that developmental processes such as non-overlapping task-demands likely differentiate trajectories of jaw movement for infant chewing and babble. Infant jaw kinematics for babble cannot be predicted from observations of adult speakers or from non-speech behaviors observed for infants or adults.

Investigating the use of coherence analysis on mandibular electromyograms to investigate neural control of early oromandibular behaviours: A pilot study.

An empirical method for investigating differences in neural control of jaw movement across oromandibular behaviours is to compute the coherence function for electromyographic signals obtained from mandibular muscle groups. This procedure has been used with adults but not extended to children. This pilot study investigated if coherence analysis could reveal task-related differences in control for children by measuring mandibular electromyograms obtained from an infant and adult. Electromyographic signals were obtained from bilateral masseter and temporalis muscle groups during chewing and babble from a typically developing infant from 8-22 months, and chewing and speech were obtained from an adult. Coherence functions were computed. Measures obtained from the infant and adult exhibited a significant main effect for task, with peak coherence values within 20-60 Hz being significantly greater for chewing than vocalization. This pilot study suggests that coherence analysis of mandibular EMG is a sensitive measure for distinguishing task-related differences in neural organization for children.

Mandibular motor control during the early development of speech and nonspeech behaviors.

PURPOSE: The mandible is often portrayed as a primary structure of early babble production, but empiricists still need to specify (a) how mandibular motor control and kinematics vary among different types of multisyllabic babble, (b) whether chewing or jaw oscillation relies on a coordinative infrastructure that can be exploited for early types of multisyllables, and (c) whether the organization of motor control and associated kinematics varies across the nonspeech behaviors that are candidate motor stereotypies for speech. METHOD: Electromyographic signals were obtained from mandibular muscle groups, and associated kinematics were measured longitudinally from a typically developing infant from 9 to 22 months during jaw oscillation, chewing, and several types of early multisyllabic babble. RESULTS: Measures of early motor control and mandibular kinematics for multisyllabic productions indicated task-dependent changes across syllable types and significant differences across babble and nonspeech behaviors. Differences in motor control were also observed across nonspeech behaviors. CONCLUSIONS: Motor control for babble appears to be influenced by the balanced interaction between developing motor and linguistic systems, such that variation in linguistic complexity systematically evinces changes in motor organization apparently to meet these demands. This same effect was noted among chewing and jaw oscillation; task-dependent changes in mandibular control were noted across behaviors.

Babbling, chewing, and sucking: oromandibular coordination at 9 months.

PURPOSE: The ontogeny of mandibular control is important for understanding the general neurophysiologic development for speech and alimentary behaviors. Prior investigations suggest that mandibular control is organized distinctively across speech and nonspeech tasks in 15-month-olds and adults and that, with development, these extant forms of motor control primarily undergo refinement and rescaling. The present investigation was designed to evaluate whether these coordinative infrastructures for alimentary behaviors and speech are evident during the earliest period of their co-occurrence. METHOD: Electromyographic (EMG) signals were obtained from the mandibular muscle groups of 15 typically developing 9-month-old children during sucking, chewing, and speech. RESULTS: Unlike prior investigations of 12- and 15-month-olds and adults, 9-month-olds' analyses of peak correlations among agonist and antagonist comparisons of mandibular EMG data revealed weak coupling during sucking, chewing, and babble; associated lag values for antagonist muscle groups indicated greater synchrony during alimentary behaviors and less synchrony during babble. Unlike the speech data of 15-month-olds, 9-month-olds exhibited consistent results across speech subtasks. CONCLUSION: These findings were consistent with previous results in which mandibular coordination across behaviors was more variable for younger age groups, whereas the essential organization of each behavior closely reflected that seen in older infants and adults.