Enhanced visual search abilities in children who have autism are present early on in their infancy before any onset of clinical symptoms, suggests a study that used eye-tracking technology to test the children's advanced perceptual skills.
The research means that "superior perception" could become the focus among autism's features, rather than the condition's social interaction and communication problems, say the authors publishing in the journal Current Biology.
The particular perceptual skill that children with autism seem to excel in is the ability to pick out an odd item in a series - for example, the letter S among a sea of Zs.
Teodora Gliga, PhD, from the UK's University of London, took advantage of the fact that infants with autism will spontaneously orient their gaze to anything that pops out in a visual scene, using an eye tracker to record the kids' gazes as they were presented with letters on a screen.
Dr. Gliga, who works in the university's Babylab, part of its center for brain and cognitive development at Birkbeck College, also used standard screening with her team to assess the children for signs of autism at 9 months, 15 months and 2 years of age.
The results of her study show that infants with enhanced visual searching ability at 9 months also had more symptoms of emergent autism at 15 months and 2 years.
The researchers say this finding suggests that the unusual perceptual ability of infants with autism is "intrinsically linked to the emerging autism phenotype."
Possible new direction for autism science
The conclusion could result in a shift in the way autism is viewed - most research studies have focused on language and social interaction impairments rather than perception differences.
To make their findings, the team followed 82 infants, 37 of whom were girls at high risk of developing autism because their siblings had already been diagnosed, alongside 27 low-risk controls.
The researchers knew that around 20% of younger siblings of children with autism are also diagnosed with autism themselves, and another 30% show elevated levels of autism symptoms, so finding babies likely to become cases was done via families.
Dr. Gliga says: "We know now that we have to give more attention to possible differences in the development of sensation and perception." She adds:
"It is the sensory unpredictability of social interaction, but also of many other aspects of daily life, that people with autism most often report as distressing, and we hope this study and others will bring autism research questions closer to the needs of those directly affected."
Eye-tracking technology could follow from this study to form part of future screening tests for the early signs of autism.
The team is keen to know what exactly makes children with autism better at visual searches.
They also intend to research the links between increased visual perception or attention, and difficulties in social interaction, learning and communication.
We reported in April on scientists' claim to an autism discovery - that brain imaging revealed language development differences.