Children with autism found to have specific memory problems that may underlie aspects of disorder

Jan 23 2006

If children with autism can't see the forest for the trees, that may be partly because the burden of processing all those trees at once makes it harder to lock in the scene.

Researchers at the University of Pittsburgh School of Medicine and Veterans Affairs Pittsburgh Healthcare System have found that children with autism differ from other children in two specific memory capabilities.

The research is in January’s Neuropsychology, which is published by the American Psychological Association (APA).

Researchers including neurologist Nancy Minshew, MD, studied 76 children from ages 8 to 16. Half were verbal individuals with autism, half were normal controls matched for age, IQ and gender. The diagnosis of autism reflected social and communication impairments of the autistic type along with restricted interests and patterns of behavior.

First, the children with autism, compared to the matched controls, had poorer memory for complex information (many individual elements or one complicated element) in both word and picture form. In essence, the children with autism found it hard to remember information if they needed a cognitive organizing strategy to aid recall or if they had to detect such an organizing element in the information itself.

The authors speculate that, "People with autism don’t have the automatic cross talk between brain systems -- the reasoning and the memory systems -- that tells their brain what is most important to notice or how to organize it thematically."

Second, children with autism also had poor working memory for spatial information, or remembering over time where something was located once it was out of sight. Although working memory for verbal information was fine, a "Finger Windows" subtest of recall of a spatial sequence easily distinguished between children with and without autism. Spatial working memory depends on a specific region of the frontal cortex that is known to be dysfunctional in autism.

Despite these two impairments, the children with autism did not have global memory problems. They showed good associative learning ability, verbal working memory and recognition memory. Because their memories differed in only two specific ways, memory in autism appears to be organized differently than in normal individuals -- reflecting differences in the development of brain connections with the frontal cortex.

Says Minshew, "If the brain does not, from the start, automatically identify and store key information, that seriously impairs the capacity to interact, communicate and solve problems. Children with autism can be easily overwhelmed by the complex information in most everyday experiences."

She explains how these memory problems can affect behavior. "Typical people automatically notice and focus on what’s important or relevant," she says. "But because people with autism focus on details instead, they can't recall or respond to what most people think is important."

Let’s say some teenagers see a poster for a new movie about a small-town romance. They talk about going to the movie and joke about the love story. One boy, though, interrupts with how great it will be to see a football film. Hearing this seeming non sequitur, the other kids stop talking. The boy, who has autism, doesn’t understand why they aren’t interested in what he is saying. He was responding to what he saw - not the larger-than-life stars embracing, but the small background detail of a man in a football jersey.

Minshew and her colleagues believe that a growing appreciation of memory deficits and their impact on social function in autism will extend research beyond the traditional diagnostic triad of the social, language and reasoning problems. The Pittsburgh group has, in prior studies, found autism-related problems with motor, sensory and balance systems. "With autism, there seems to be a widespread problem with how the brain copes with or processes all types of information," Minshew says. Thus, she urges scientists to look more broadly at the brain in autism to find whatever causes such widespread involvement.

Article: "The Profile of Memory Function in Children with Autism," Diane L. Williams, MD, University of Pittsburgh School of Medicine; Gerald Goldstein, MD, University of Pittsburgh School of Medicine and Veterans Affairs Pittsburgh Healthcare System; Nancy J. Minshew, MD, University of Pittsburgh School of Medicine; Neuropsychology, Vol. 20, No. 1.