Autism diagnosis

Author: Dr. Francesc Cuxart (ASEPAC-Barcelona-ES)

Diagnosis

Introduction

After five decades since the first definition of the autistic syndrome, the diagnosis of the autistic spectrum disorders is still causing important difficulties in a significant amount of cases and, particularly in the earliest ages. We should look for the causes essentially in the deep inter-individual differences of the affected population and the deficit description of some symptoms, but also in certain concepts, which in my opinion are erroneous, related to the core symptoms of some psychopathologies with onset during childhood that show certain common features with the autistic disorders.

Early diagnosis

The great heterogeneity of the autistic syndromes makes impossible to establish a prototypical pattern of their initial development. Therefore, the early detection and diagnosis use to constitute complex tasks. In the most severe cases, the first alert signs use to be related to global delays of development (hypotonia, hypo-reactivity) and the prototypical symptoms of autism appear later. Nevertheless, when the development delay is not so severe, the perception of impairments can be delayed until the middle of the second year of life.

Screening instruments

The Baron-Cohen studies (Baron-Cohen, 1992 and 1996; Baird et al., 2000) have allowed the development of a screening instrument (CHAT) for the detection of autism starting at the 18 months of life, based on the lack of three behaviours: proto-declaratives, visual co-orientation and simulation play. Results indicate that those children that do not present any of the mentioned behaviours when they are 18 months old have an 83% of possibilities to receive a future diagnosis of autism. Although CHAT constitutes an important advance in the way of early detection of autism, its low sensibility in front of “high-functioning” individuals with autism represents a significant limitation and partially questions the attribution of psychological markers of autism regarding the three mentioned behaviours...

Download full document. 132 KB