Studies comparing the strengths and weaknesses of intellectually retarded and superior groups are reviewed, with particular attention given to studies in which these extreme groups were matched with each other on mental age. (Author)

The social skills and problem behaviours of children with high-functioning autism and Asperger's Disorder were compared using parent and teacher reports on the Social Skills Rating System. The participants were 20 children with high-functioning autism, 19 children with Asperger's Disorder, and 17 typically developing children, matched on…

Background: It is not known whether those with co-morbid fragile X syndrome (FXS) and autism represent a distinct subtype of FXS; whether the especially severe cognitive delays seen in studies of young children with co-morbid FXS and autism compared with those with only FXS continue into adolescence and young adulthood; and whether autism in those…

Exploratory behaviors of Down Syndrome and nondelayed young children between the mental ages of 16 and 32 months were examined in four situations in which they tried to find things which they saw reflected in a mirror. Down Syndrome and nondelayed children differed in number, type, and frequency of exploratory behaviors. (PCB)

Background: This study describes a new caregiver-report assessment, the Sensory Experiences Questionnaire (SEQ), and explicates the nature of sensory patterns of hyper- and hyporesponsiveness, their prevalence, and developmental correlates in autism relative to comparison groups. Method: Caregivers of 258 children in five diagnostic groups…

Verbal short-term memory, as measured by digit or word span, is generally impaired in individuals with Down's syndrome (DS) compared to mental age-matched controls. Moving from the working memory model, the present authors investigated the hypothesis that impairment in some of the articulatory loop sub-components is at the base of the deficient…

This pilot study was designed to examine mental rotation ability in individuals with Down syndrome. 7 individuals with Down syndrome (mean mental age = 8.18 +/- 2.73 years; mean chronological age = 29.8 +/- 5.4 years) and a group of 9 typically developing children, matched for mental age, (mean mental age = 8.40 +/- 1.73 years; mean chronological…

Retarded and borderline intelligence adolescents (MA 8-12 years) and nonretarded children (MA 6-12 years) were given logical problem solving tasks. Results showed a profound deficiency in low IQ individuals on certain tasks requiring foresight and logic; MA markedly overestimates the performance of these individuals relative to the performance of…

Research supported by NICDH research grant HD-MH-03008.

Understanding of the cardinality principle in children with Williams Syndrome (WS) was compared to that of typically developing children. Findings indicated that such understanding was extremely delayed in WS children and only at the level predicted by their visuo-spatial mental age. Findings suggested that visuo-spatial ability played a greater…

Examined empathy and conservation abilities of nonretarded children with autism and compared their performance to that of normally developing children. Autistic children performed surprising well, but not as well as normal children. There was a closer association between cognitive abilities and affective understanding among the autistic children…

Examined the nature of repetitive, ritualistic, and compulsive-like behaviors in typically developing and children and individuals with Down Syndrome (DS), matched on mental age (MA). Found that that both groups showed similar MA-related changes in compulsive-like behaviors. Younger children showed more compulsive-like behaviors than older.…

Describes three experiments that tested autistic children's nonverbal and verbal categorization abilities. Concludes that autistic children do not suffer a specific cognitive deficit in ability to categorize and form abstract concepts. (HOD)

Examined the relation between a history of maltreatment and cognitive control functioning in two groups of preschool and early school-age maltreated and nonmaltreated children. Maltreated children showed developmentally impaired cognitive control functioning on a number of tasks. (RH)

This study compared the fears and behavior problems of 25 children with an autism spectrum disorder (ASD), 43 children with Down syndrome (DS), 45 mental age (MA) matched children, and 37 chronologically age (CA) matched children. Children's fears, phobias, anxieties and behavioral problems were assessed using parent reports. Significant…