On the Developmental Trajectories of Relational Concepts Among Children and Adolescents With Intellectual Disability of Undifferentiated Etiology.

The aim of this study was to examine the developmental trajectories of comprehension of relational concepts among 557 participants with intellectual disability (ID) of undifferentiated etiology (M age  =  12.20 years, SD  =  3.18) and 557 typically developing (TD) participants (M age  =  4.

Does the Development of Syntax Comprehension Show a Premature Asymptote Among Persons With Down Syndrome? A Cross-Sectional Analysis.

Uncertainty persists regarding the post-childhood trajectory of syntactic acquisition of persons with Down syndrome (DS). In some studies, asymptote is reached in the early teens, whereas others find syntax continuing to develop at least into early adulthood. This study addressed the issue using a cross-sectional approach.

An Item Analysis of the French Version of the Test for Reception of Grammar Among Children and Adolescents With Down Syndrome or Intellectual Disability of Undifferentiated Etiology.

Purpose: An item analysis of Bishop's (1983) Test for Reception of Grammar (TROG) in its French version (F-TROG; Lecocq, 1996) was conducted to determine whether the difficulty of items is similar for participants with or without intellectual disability (ID).

Method: In Study 1, responses to the 92 F-TROG items by 55 participants with Down syndrome (DS), 55 with ID of undifferentiated etiology (UND), and 55 typical children (TYP) matched on their F-TROG total score were compared using the transformed item difficulties method, a statistical approach designed to detect differential item functioning (DIF) between groups. In Study 2, an additional comparison involving 526 TYP participants and 526 participants with UND was conducted to increase the statistical power of the analysis.

A qualitative analysis of general receptive vocabulary of adolescents with Down syndrome.

This study aimed to discover whether general receptive vocabulary is qualitatively phenotypical in Down syndrome. Sixty-two participants with Down syndrome (M age=16.74 years, SD=3.

Angoff's delta method revisited: improving DIF detection under small samples.

Most methods for detecting differential item functioning (DIF) are suitable when the sample sizes are sufficiently large to validate the null statistical distributions. There is no guarantee, however, that they will still perform adequately when there are few respondents in the focal group or in both the reference and the focal group. Angoff's delta plot is a potentially useful alternative for small-sample DIF investigation, but it suffers from an improper DIF flagging criterion.

On the difficulty of relational concepts among participants with Down syndrome.

The aim of the study was to compare the difficulty of relational concepts among participants with and without intellectual disability. The French versions of the Boehm Tests of Basic Concepts Third Edition (Preschool and Kindergarten to 2nd grade) were administered to three groups of 47 participants individually matched on their total raw score on the tests. The first group comprised participants with intellectual disability of undifferentiated etiology, the second, participants with Down syndrome and the third, typical children.

Beyond matching on the mean in developmental disabilities research.

The matching of groups is a traditional way to control for confounding variables in developmental disabilities research. The equivalency of means across groups is routinely checked for these variables, but not the homogeneity of their variances or the shapes of their distributions. In the present paper, it is argued that group matching can go seriously wrong unless it directly confronts the distributional concerns by the use of well-known statistical indices and very simple graphical displays of the distributions.

Increasing compliance with medical examination requests directed to children with autism: effects of a high-probability request procedure.

The purpose of this study was to evaluate the effectiveness of a high-probability (high-p) request sequence as a means of increasing compliance with medical examination tasks. Participants were children who had been diagnosed with autism and who exhibited noncompliance during general medical examinations. The inclusion of the high-p request sequence effectively increased compliance with medical examination tasks.

An item analysis of Raven's Colored Progressive Matrices among participants with Down syndrome.

Standardized tests are widely used in intellectual disability research, either as dependent or control variables. Yet, it is not certain that their items give rise to the same performance in various groups under study. In the present work, 48 participants with Down syndrome were matched on their raw score on Raven's Colored Progressive Matrices (RCPM) with 48 participants with intellectual disability of undifferentiated etiology and 48 typical children.

A controlled single-case treatment of severe long-term selective mutism in a child with mental retardation.

The aim of the present study was to demonstrate the efficacy of combining two operant learning procedures--shaping and fading--for treating selective mutism. The participant was a 12-year-old boy with mental retardation presenting a severe long-term selective mutism. The treatment was aimed at increasing the loudness of his vocalizations in an increasingly social milieu.

A cross-sectional test of the similar-trajectory hypothesis among adults with mental retardation.

The similar-sequence and the similar-structure hypotheses are the two mainstays of the developmental approach to mental retardation. In the present study, a third way, the similar-trajectory hypothesis, is described and illustrated using the WAIS-R results of adults with and without mental retardation aged from 20 to 54 years. The whole sample (N=633) comprised 306 participants with mental retardation and 327 without mental retardation.

The reinforcing effect of contingent attention on verbal perseverations of two children with severe visual impairment.

The frequency of verbal perseverations of two children with severe visual impairment was reduced using differential reinforcement of appropriate speech coupled with extinction of perseverative utterances. A reversal design in which baseline and intervention were alternated in an A-B-A-B sequence was employed to show the functional relationship between the target behaviors and the treatment procedure. There was a marked increase in appropriate utterances and a correlated decrease in perseverative ones.

Chronological age, receptive vocabulary, and syntax comprehension in children and adolescents with mental retardation.

This study was designed to examine the association of CA with syntax and vocabulary comprehension in children and adolescents with mental retardation. It was conducted using the PPVT-R and the Test for Reception of Grammar. The cognitive level of participants was estimated by means of three nonverbal intelligence tests.