Linguistic Processing in High-Functioning Adults with Autism or Asperger’s Syndrome. Is Global Coherence Impaired?

Therese Jolliffe’ and Simon Baron-Cohen Psychological Medicine, 2000, Vol 30, pp 1169-1187.

Linguistic processing was explored in normally intelligent adults with either autism or Asperger’s Syndrome, to test if global coherence was impaired. Global Coherence is the ability to establish causal connections and interrelate local chunks into higher-order chunks so that most linguistic elements are linked together thematically. Since individuals with autism are hypothesized to have weak central coherence then one would predict that the clinical groups would have difficulty integrating information globally so as to derive full meaning.

Two experiments were designed to test global coherence. Experiment 1 investigated whether individuals on the autism spectrum condition could arrange sentences coherently. Experiment 2 investigated whether they were less able to use context to make a global inference. The clinical groups were less able to arrange sentences coherently and use context to make a global inference.

The results suggest that individuals on the autism spectrum have impaired global coherence. Arranging sentences and making global inferences correlated highly, suggesting that central coherence may be a unitary force in these different tasks. Of the two clinical groups, the autism group had the greater deficit. The effect that such a deficit would have on one’s daily life is discussed along with possible explanations for the clinical groups’ difficulty and suggestions for future research.

Non-significance of early speech delay in children with autism and normal intelligence and implications for DSM-IV Asperger’s disorder

Dickerson Mayes, S. and Calhoun, S.L. (2001) Autism Vol 5 (1) 81-94.

According to the DSM-IV, children with Asperger’s disorder do not have significant cognitive or speech delays, whereas children with autistic disorder may or may not. In our study, children with normal intelligence who had clinical diagnoses of autism or Asperger syndrome were divided into two groups: those with and without significant speech delay. The purpose was to determine if clinically meaningful differences existed between the two groups that would support absence of speech delay as a DSM-IV criterion for Asperger’s disorder. No significant differences were found between the 23 children with a speech delay and the 24 children without a speech delay on any of the 71 variables analysed, including autistic symptoms and expressive language. Results suggest that early speech delay may be irrelevant to later functioning in children who have normal intelligence delay as a DSM-IV distinction between Asperger’s disorder and autism may not be justified.

Discussion
Research to date has failed to support the validity or existence of Asperger’s disorder as defined by the DSM-IV.

Simply changing the DSM-IV cutpoints for significant speech and cognitive delays would not alter these findings. All 157 children in the author’s study who had clinical diagnoses of autism or Asperger’s syndrome or disorder met the DSM-IV criteria for autism and not Asperger’s disorder, irrespective of the presence or degree of speech and cognitive delays.

High-functioning autism is already covered in the DSM-IV by an axis I diagnosis of autistic disorder without mental retardation coded on axis II. If Asperger’s disorder is indeed high functioning autism and not a diagnostic entity separate and distinct from autism, Asperger’s disorder should not be included in the next version of the DSM.

Analysis of Reading Skills in individuals with Asperger Syndrome Focus on Autism and other Developmental Disabilities

Spring 2002 v 17 i1 p44 (4) Brenda Smith Myles; Tracey D. Hilgenfeld; Gena P. Barnhill; Deborah E. Griswold; Taku Hagiwara; Richard L. Simpson.

The purpose of this study was to examine the reading performance of 16 individuals with Asperger Syndrome. The students were administered the Classroom Reading Inventory (Silvaroli, 1993), and the results were analysed to determine if individuals with Asperger Syndrome present similar reading deficits, as posited by researchers and practitioners in special education. Findings of the study discussed, to better understand how the reading characteristics of a student with Asperger Syndrome affect classroom performance.

Children and youth with Asperger Syndrome exhibited reading levels commensurate with the grade levels on three out of five CRI measures. Specifically, their Instructional, Frustration, and Listening Capacity did not differ significantly from their grade levels. Silent Reading and Independent Reading levels, however, were found to be below grade level. When asked to read silently, students performance was below grade level. This is important in that typical classroom-based silent reading tasks would be difficult for these students. The fact that reading ability improved when reading occurred out loud leads to speculation as to what accounts for this difference.

A test of central coherence theory: linguistic processing in high-functioning adults with autism or Asperger syndrome: is local coherence impaired?

By Baron-Cohen, S., and Jolliffe, T. (1999), Cognition, 71, 149-185

“Central coherence theory is addressed by exploring linguistic processing in normally intelligent adults with either autism or Asperger syndrome, to test whether local coherence is impaired. Local coherence is the ability to make contextually meaningful connections between linguistic information in short-term or working memory. Experiment 1 demonstrated that individuals with an autism spectrum condition were less likely to use the sentence context spontaneously to provide the context-appropriate pronunciation of a homograph. The findings from Experiments 2 and 3 suggest that individuals with autism or Asperger syndrome have a difficulty achieving local coherence, while the evidence from Experiment 1 suggests a preference not to strive for coherence. Taken together, these results suggests that individuals with an autism spectrum condition are impaired in achieving local coherence, and they have a preference not to strive for coherence unless instructed to do so, or unless they make a conscious decision to do so.“