[outofstyle]

Why didn't they find a way to prevent head movement?

In an autistic patient, this would require general anesthesia. That's an increased risk & an increased expense. And for what? This does not help anybody in the short term. It's all related to research.

[neverdem]

In an autistic patient, this would require general anesthesia.

Maybe in those on the more profound end of autistic spectrum disorder, but this connectivity hypothesis is also proposed for Asperger syndrome, IIRC.