A study examined the frequency and cognitive correlates of enlarged head circumference in 63 children with autism (ages 4-14). Macrocephaly occurred at a significantly higher frequency. Children with discrepantly high nonverbal abilities had a mean standardized head circumference that was more than 1 standard deviation greater than the reference…

This report discusses the outcomes of a study that examined 216 comparably aged children and adolescents (ages 2-18) with fragile X or autism to determine whether longitudinal change in cognitive ability and adaptive behavior was similar in the two groups. Results found decreases in Intelligence Quotient scores in young children with fragile X as…

A Canadian study compared the rate of cognitive disabilities in 156 relatives of 49 individuals with autism to that found in 55 relatives of 18 individuals with mental retardation. No differences were found; however, female and low IQ individuals were found to have higher family histories of cognitive disabilities. (Author/CR)

A study involving 35 children (age 9) with high-functioning autism, 31 children with developmental language disorder, 40 children with low-functioning autism, and 17 children with low IQ, found IQ was predictive of adaptive behavior in both low-functioning groups, but language and verbal memory predicted adaptive behavior in higher functioning…

This final report reviews the second phase of a life-span study of boys with fragile X syndrome (FSX), the most common known inherited cause of mental retardation. Males with the syndrome are more severely affected than females and in males, delays are usually evident in all the developmental domains, although cognitive and communication skills…