Biomedical subjects

D J Thal

Publications and source records attributed to D J Thal.

5 recordsLinked to original sources

PubMed1994

Variability in early communicative development.

Data from parent reports on 1,803 children--derived from a normative study of the MacArthur Communicative Development Inventories (CDIs)--are used to describe the typical course and the extent of variability in major features of communicative development between 8 and 30 months of age. The two instruments, one designed for 8-16-month-old infants, the other for 16-30-month-old toddlers, are both reliable and valid, confirming the value of parent reports that are based on contemporary behavior and a recognition format. Growth trends are described for children scoring at the 10th-, 25th-, 50th-, 75th-, and 90th-percentile levels on receptive and expressive vocabulary, actions and gestures, and a number of aspects of morphology and syntax. Extensive variability exists in the rate of lexical, gestural, and grammatical development. The wide variability across children in the time of onset and course of acquisition of these skills challenges the meaningfulness of the concept of the modal child. At the same time, moderate to high intercorrelations are found among the different skills both concurrently and predictively (across a 6-month period). Sex differences consistently favor females; however, these are very small, typically accounting for 1%-2% of the variance. The effects of SES and birth order are even smaller within this age range. The inventories offer objective criteria for defining typicality and exceptionality, and their cost effectiveness facilitates the aggregation of large data sets needed to address many issues of contemporary theoretical interest. The present data also offer unusually detailed information on the course of development of individual lexical, gestural, and grammatical items and features. Adaptations of the CDIs to other languages have opened new possibilities for cross-linguistic explorations of sequence, rate, and variability of communicative development.

Birth Order↗

PubMed1992

Communicative gestures in children with delayed onset of oral expressive vocabulary.

Use of communicative gestures in a group of children with delayed onset of expressive oral vocabulary (late talkers) was compared with such use among normal-language-matched controls and age-matched controls. Analyses revealed that late talkers used significantly more communicative gestures and for a greater variety of communicative functions than did language-matched controls. However, a 1-year follow-up revealed that 4 of the late talkers remained delayed (truly delayed late talkers) and 6 caught up (late bloomers). Reanalyses of Year 1 data based on these follow-up outcomes demonstrated that only late bloomers used more communicative gestures than did language-matched controls. Truly delayed late talkers did not differ from language-matched controls either for number of gestures, type of gestures (symbolic vs. nonsymbolic), or number of different functions for which gestures were used. Late bloomers also used more communicative gestures than did age-matched controls, suggesting that they (the late bloomers) were using gestures to compensate for their small oral expressive vocabulary. Results are discussed in the context of early predictors of risk for language impairment and relationships between language and cognition.

Child Language↗

PubMed1991

Early lexical development in children with focal brain injury.

Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.

Brain Injuries↗

PubMed1990

Scripts or scraps: reconsidering the development of sequential understanding.

A growing literature attests to temporally ordered recall of events by children under 2 years of age. Other data suggest a developmental sequence wherein the ability to reproduce unfamiliar and/or arbitrarily ordered events, and familiar events in other than canonical order develops well after the first ordered productions of events. Early ordering is thus argued to be dependent upon familiarity, rather than upon general temporal principles. This suggestion was investigated by using elicited imitation to assess 21-month-olds' recall of familiar-canonical, familiar-reversed, novel-causal, and novel-arbitrary event sequences. Subjects reproduced canonical and both types of novel sequences in modeled order. On reversed sequences they vacillated between reproducing the events as modeled and "correcting" them to canonical order. The results suggest that temporal organization is not imposed upon an existing unordered event representation, but rather, is an integral aspect of the representation from its initial construction. It is suggested that young children's difficulty with reversed sequences may be attributed to a reluctance to reorganize existing representations, rather than to the absence of applicable temporal principles.

Attention↗

PubMed1983

Auditory processing and language impairment in children: stimulus considerations for intervention.

Two experiments were undertaken to examine the performance of language-impaired children on auditory identification and sequencing tasks which employed different stimuli. The purpose of Experiment I was to determine if introduction of linguistic stimuli (words) into tasks using nonlinguistic stimuli (complex tones) would change subjects' performance. Experiment II was designed to measure differences in response when words and tones were presented separately. Responses to utterances of increasing length (up to four words) were also measured. Results indicated that some children performed significantly better when words were used as stimuli. No child responded better when tones were used as stimuli and there were no significant differences between utterances of different length. Based on these results and on the related literature, considerations for choice of stimuli for intervention with language-impaired children are discussed.

Auditory Perception↗