The 6 Trajectories of Autism

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While most autistic children follow the high or low trajectory of their diagnosis, a recent study found a minority are "bloomers" who jump from low to high trajectories. Image: Flickr/MilikaSekulic cc license

Calling autism “spectrum disorder” is spot on – it has as many degrees as the colors of the rainbow. That said, a recent article in the journal Pediatrics distinguishes six “trajectories” of autism – the major colors of this spectrum disorder. This Columbia University study followed 6,975 kids from time of diagnosis until age 14, and found (as you might expect) that in communication, social functioning and repetitive behaviors, children who were lowest-functioning when diagnosed showed the least gains over time, while kids who were higher functioning at time of diagnosis showed the most gains, further separating high from low as they aged – that is, with one extremely important exception.

Five of the six trajectories of autism are high, medium-high, medium, low-medium and low – kids are diagnosed and then stay on these tracks relative to each other, the higher the initial functioning, the more gain between diagnosis and age 14.

But Christine Fountain, PhD, postdoctoral researcher and the paper’s lead author calls the sixth group bloomers. “These are kids who started on the low-functioning trajectory and jumped groups to join the high-functioning trajectory by age 14,” she says.

What made these bloomers?

First, it takes IQ to be a bloomer. Kids who test as intellectually impaired in addition to autistic tend to stay on the track they’re diagnosed. Second, the study found that jumping from low- to high-functioning takes time, money and effort – the characteristics of a high socioeconomic family. Though not necessarily a pretty reality, the reality is that low-functioning autistic kids with high-functioning and high-means parents are much more likely to be bloomers than kids without similar advantages.

Fountain and colleagues write that “the intervening variables likely include home and neighborhood environments, quality and intensity of treatment, quality of education, and the efficacy with which parents are able to advocate for their children with institutions providing services.” (It will be interesting in follow-up studies to see which factors are most important.)

That said, many autistic children in this large study experienced substantial gains from diagnosis to age 14, especially in the window before age 6 (after which, development in all three trajectories – communication, social functioning and repetitive behaviors – tended to flatten out a bit). Gains were especially robust in communication, which tended to steadily increase over time. In comparison, social development was hit or miss, with kids who were higher functioning at time of diagnosis improving dramatically, while the social functioning of kids who were lower functioning at diagnosis stayed near the initial (low) baseline. Repetitive behaviors changed very little, irrespective of which trajectory children followed.

It’s important to keep in mind, though, that statistics are just statistics — they’re the general trends of a population made up of individuals. And while autistic children as a population generally follow these characteristics, any individual child can certainly vary. How will they vary? This study shows at least a slight chance that autistic children who are low-functioning at time of diagnosis will join the bloomers in jumping the track of their trajectory.

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