Despite reasoning skills, Asperger boys struggle to focus

Attention deficit: Children with Asperger syndrome have trouble remembering where a colored square is located on a gray field.

Teenage boys with Asperger syndrome who have higher-than-average scores on tests of abstract reasoning fare worse than controls on short-term memory and ability to filter out distractions. Researchers reported the findings in a poster Saturday at the International Meeting for Autism Research in San Diego.

The results are surprising because in healthy people, superior abstract reasoning skills usually dovetail with better working memory — the short-term storage and management of information — and enhanced ability to filter out distractions.

Boys with Asperger syndrome consistently score better on tests assessing the ability to reason abstractly compared with typical peers of either sex.

In 2010, the first study to look at gender differences in abstract reasoning among children with Asperger syndrome showed that boys also score higher than girls with the disorder.

In the new study, researchers compared 34 teenagers with Asperger syndrome — 17 males and 17 females — with 34 typically developing controls on tasks assessing working memory and ability to filter out distractions.

All study participants score average or above average in verbal intelligence, but the boys with Asperger syndrome score higher on fluid intelligence, or abstract reasoning, than the girls with the disorder and typical controls.

To assess working memory in the participants, the researchers flashed an image of two colored squares on a screen for 150 milliseconds. After a 900-millisecond rest interval, just one square flashed on the screen. The participants had to recall the previous locations of the squares in order to say whether the single square was in the same location as in the previous screen.

The task progressively became more difficult, and participants had to recall the location of six colored squares in order to correctly pinpoint the location of one remaining square.

In a related task assessing the ability to filter out distractions, the researchers mixed in four rectangles with two squares on the first screen. The participants had to ignore the rectangles in order to correctly identify the location of the square in the second screen.

The researchers found no difference between males and females with Asperger syndrome on these tests — they both performed worse than the control group on both tasks.

“Working memory and attentional filtering do not appear to be the mechanisms driving this superior fluid intelligence performance in boys with Asperger syndrome,” said lead investigator Tasha Oswald, a graduate student in the laboratory of Louis Moses, associate professor of psychology at the University of Oregon.

Oswald was pleased to see several studies exploring gender differences in autism at this year’s conference. For the first time in IMFAR’s ten-year history, she noted, an entire session was devoted to the topic.

Though her study shows that boys and girls with Asperger syndrome share deficits in memory and attention, it doesn’t explain why boys with the disorder are better at abstract reasoning, she said.

Nor does it explain why girls with the disorder seem to be more prone to depression, a phenomenon she encountered in recruiting study participants.

“People are just starting to recognize that maybe we shouldn’t be making all these assumptions about girls with Asperger syndrome based on boys,” she said.