‘The cognitive profile of autism’
Dr. Theodora Papadopoulou
Special Education Department at New York College
www.nyc.gr, 2103225961
Asperger syndrome (AS) and autistic disorder are two subtypes of pervasive developmental disorders (PDD), but there has been considerable debate over whether AS and autistic disorder without mental retardation (IQ ≥ 70), called high-functioning autism (HFA), are distinct conditions or not. There is an argument among scientists whether there is an unusual degree of unevenness in the cognitive abilities of children with autism spectrum disorder (ASD) and whether different cognitive profiles among children with ASD might index etiologically significant subgroups.
The argument focuses on whether there is any relevance of IQ to the etiology and symptomatic expression of autism. According to scientific results approximately three-quarters of individuals with autism have below-average IQ (< 70). On the other hand though, autism can occur with equal severity in individuals of average and above-average IQ. There has also been a longstanding interest in the uneven intellectual abilities of individuals with autism (Bailey, Phillips, & Rutter, 1996).
Autism was first described by Leo Kanner almost 60 years ago. He described a severe form of autism, typified by the silent and aloof child. Hans Asperger about 15 years ago described children with another form of autism. The children he described could produce speech and were active participants in social interactions. In 1994 the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) provided diagnostic criteria for Asperger's syndrome. According to DSM IV in 2000, Asperger's syndrome could be differentiated from autism by an examination of the child's early development and the existence of some characteristics that were rare in children with autism. It is considered that early language and cognitive skills are not delayed significantly in children with Asperger's syndrome. There is also no clinically significant delay in age-appropriate self- help skills, adaptive behaviour and curiosity about the environment in childhood.
There is general agreement that children with Asperger's syndrome may not show any conspicuous cognitive delay in early childhood. It is true that some individuals with Asperger syndrome can be quite talented in terms of learning to read, numerical abilities and in some aspects of their constructive play and memory. Individuals with autism, on the other hand, can be recognised as having developmental delay in their cognitive abilities from infancy. They are diagnosed at the age of 18 months. Children with Asperger's syndrome are often not diagnosed until after they start school with a mean age of diagnosis of eleven years (Howlin and Asgharian 1999). It should be noted that the signs of Asperger's syndrome in very young children may be more subtle and not easily discernible at home and school.
Many researches have been conducted which included comparison of the cognitive profile of adolescents with autism and Asperger's syndrome. The studies have examined the cognitive profile of what is referred to as 'High Functioning Autism', that is children with a diagnosis of autism with an Intelligence Quotient in the normal range, i.e. above 70. The cognitive abilities of this group of children were then compared to the cognitive profile of children with Asperger's syndrome, who did not have a history of early cognitive or language delay. The results of the research has not established a distinct and consistent profile for each group. Ehlers, Nyden, Gillberg, Dahlgren Sanberg, Dahlgren, Hjelmquist and Oden (1997) found that only a minority of each diagnostic group showed a characteristic profile.
Wing and Gould (1978) firstly identified a Triad of Impairments in people who belong to the autistic spectrum. This triad of impairments includes
- Impairment of social relationships
- Impairment of social communication, and
- Impairment of imagination
Autism arises as a consequence of the interaction of these three impairments. Thus, all three must be evident to diagnose Autism. The degree to which an individual is affected by each of the three impairments can vary significantly from person to person.
As stated above, autistic children have deficits in social cognition (theory of mind), executive functions, and central coherence. Each of these concepts should be considered in relation to the joint attention deficits that are obvious in autism.
To be more specific, joint attention is a family of social abilities ("social pragmatic abilities") that help individuals regulate, respond to, and engage in social interactions with others. These types of joint attention events are termed triadic social interactions.
There are many ways to view the repertoire of social pragmatic behaviours in the early developmental period of an individual.
It should be stated that children with autism show deficits
in the frequency and complexity of joint attention behaviours, as well as differences in the qualitative patterns of strengths and weaknesses in joint attention as related to other social pragmatic behaviours. Autism is characterized by generally poor social and communication skills. Children with autism show severe deficits in the frequency with
which they initiate joint attention bids (I}A) as well in their ability to
monitor and respond to joint attention bids of others (RJA).
Children with autism may also show deficits in the complexity of
requests. That means failure to use pointing or poor coordination of eye contact, vocalizations, and other communicative means when making requests.
SOCIAL COGNITIVE DEFICITS IN AUTISM
The ‘Theory of Mind’ is the ability of an individual to reason about the intentions and beliefs of others.
According to a research conducted by Baron-Cohen and colleagues, individuals with autism were unable to reason about the false beliefs of protagonists in a series of vignettes. This deficit has been widely replicated in following research. One influential theory argues that TOM abilities are rooted in a discrete information-processing ability hat allows children to represent the thoughts of others.
EXECUTIVE FUNCTION DEFICITS.
Executive functions (EF) are a broad class of cognitive abilities involved in the regulation of thought and action.
This class of higher cognitive abilities supports such functions as strategic planning, impulse control, working memory, organization of mean-end behaviours, and flexibility in thought and action. The frontal lobes are heavily involved in these processes.
Deficits in EF are well replicated in children with autistic disorder.
However, research indicates that autism is related to a specific pattern
of deficits in executive skills; i.e., deficits in planning efficiency and
preservative responses that indicate difficulties in shifting response set. These patterns have been found to differentiate the executive performance of autistic individuals from those with ADHD and other neuro-developmental disorders. Children with ADHD are most likely to show deficits in response inhibition, whereas autistic individuals tend not to show evidence of such dysfunction on EF batteries.
CENTRAL COHERENCE
Frith proposed the concept of central coherence in an attempt to explain the cognitive style of individuals with autism. Central
coherence is described as the tendency to integrate
information to form a whole, coherent meaning, reflects a cognitive style that allows an individual to "see the forest for the trees."
This theory aimed to explain why individuals with autism perform
better on certain cognitive tasks; e.g., the embedded figures task, where an individual is required to identify a figure (e.g., a triangle) embedded in a meaningful picture.
Indicative References
Ehler, S., Nyden A., Gillberg C. Dahlgren Sandberg A., Dahlgren S.O., Hjelmquist, E., and Oden A. (1997). Asperger syndrome, autism and attention disorders: A comparative study of the cognitive profiles of 120 children. Journal of Child Psychology and Psychiatry (38). pp. 207-217.
Howlin P. and Asgharian A. (1999). The diagnosis of autism and Asperger syndrome: findings from a survey of 770 families. Developmental Medicine and Child Neurology (41), pp.834-839.
Manjiviona, J. and Prior M. (1999). Neuropsychological profiles of children with Asperger syndrome and autism. Autism (3), pp.327-356.
Ozonoff S., South M., and Miller J.N. (2000). DSM-IV defined Asperger syndrome: Cognitive, behavioural and early history differentiation from High Functioning Autism. Autism (4), pp.29-46.