Categorical and dimensional structure of autism spectrum disorders: the nosologic validity of Asperger Syndrome.

There is an ongoing debate whether a differentiation of autistic subtypes, especially between Asperger Syndrome (AS) and high-functioning-autism (HFA) is possible and if so, whether it is a categorical or dimensional one. The aim of this study was to examine the possible clustering of responses in different symptom domains without making any assumption concerning diagnostic appreciation. About 140 children and adolescents, incorporating 52 with a diagnosis of AS, 44 with HFA, 8 with atypical autism and 36 with other diagnoses, were examined.

Dimensional structure of the autism phenotype: relations between early development and current presentation.

The dimensional structure of higher functioning autism phenotype was investigated by factor analysis. The goal of this study was to identify the degree to which early symptoms of autism (measured using the ADI-R) could be predictive of the current symptoms of autism as identified using the ADOS, the adaptive behavior scales, IQ scores and theory of mind scores. Participants included 140 subjects with Full Scale IQ > 70 (104 with autism spectrum diagnosis, 36 with non autism diagnosis, age range 6-24).

Twin study on heritability of activity, attention, and impulsivity as assessed by objective measures.

Objective: The purpose of this study was to assess heritability of activity, attention, and impulsivity by comparing young monozygotic (MZ) twins with dizygotic (DZ) twins using objective measures.

Method: The OPTAx test is an infrared motion analysis to record the movement pattern during a continuous performance test. Seventeen MZ and 12 same sexed DZ twin pairs in the range of 6 to 12 years were tested.