No abstract

Individuals with autism spectrum disorder (ASD) have impaired ability to use context, which may manifest as alterations of relatedness within the semantic network. However, impairment in context use may be more difficult to detect in high-functioning adults with ASD. To test context use in this population, we examined the influence of context on memory by using the ''false memory'' test. In the false memory task, lists of words were presented to high-functioning subjects with ASD and matched controls. Each list consists of words highly related to an index word not on the list. Subjects are then given a recognition test. Positive responses to the index words represent false memories. We found that individuals with ASD are able to discriminate false memory items from true items significantly better than are control subjects. Memory in patients with ASD may be more accurate than in normal individuals under certain conditions. These results also suggest that semantic representations comprise a less distributed network in high-functioning adults with ASD. Furthermore, these results may be related to the unusually high memory capacities found in some individuals with ASD. Research directed at defining the range of tasks performed superiorly by high-functioning individuals with ASD will be important for optimal vocational rehabilitation.A utism is associated with disordered social interaction and communication (1). These behaviors have been attributed to ''weak central coherence'' or impaired ability to use context (2, 3), which may manifest as dysfunction of the neural networks that interrelate the meanings of words (semantics). When words are placed into syntactic or semantic context, normal individuals will remember more words than when words are not placed into context (4). Autistic children demonstrate less of an increase in recall than nonautistic controls when words are placed into syntactic or semantic context (5-7). However, this difference is less detectable among high-functioning adults with autism spectrum disorder (ASD; ref. 3). We wished to assess this highfunctioning population with a more sensitive test for alterations in context use.The ''false memory'' test depends on semantic and associative context to induce illusory recognition of certain index words. Specifically, a list of words that are closely related in meaning to (semantically related) or frequently co-occur with (associatively related) an index word can induce illusory recognition of that word. Our hypothesis was that comparison of illusory and true recognition from this test might prove sensitive to variations in use of semantic and associative context. Therefore, subjects with ASD would be expected to discriminate true items from ''false'' items better than matched control subjects on this test. MethodsSubjects. Eight high-functioning adults with ASD and 16 nonautistic adults, matched for age, gender, performance scale Wechsler Adult Intelligence Scale-Revised Intelligence Quotient (WAIS-R IQ), verbal scale WAIS-R IQ, full-scale WAIS-R IQ,...