"Head movements taint the results of MRI brain imaging studies, especially in people with autism."

Petersen and his colleagues first noticed the head motion problem a couple of years ago, when they were measuring functional connectivity in people aged 7 to 303. Because one of the team members, Nico Dosenbach, was unusually meticulous, Petersen says, the team only analyzed data from participants with very little head motion.

The researchers found that these children’s brain activity patterns look fairly similar to those of the adults — an unnerving result, as one of their previous studies had reported a dramatic change across development4.

Around the same time, Petersen’s colleague Abraham Snyder noticed that, because of the physics involved in magnetic resonance imaging, small movements can produce large spikes or dips in functional connectivity scans. Head motion, Petersen says he realized, had tainted his earlier study.

“Let me tell you, denial was big,” Petersen says. “We had every explanation in the world other than that it was an artifact. But it’s an artifact.”
…

“It really, really, really sucks. My favorite result of the last five years is an artifact,” says lead investigator Steve Petersen, professor of cognitive neuroscience at Washington University in St. Louis.

It’s unclear how many published results head motion has skewed, and whether this changes the bottom-line conclusions. But many researchers are concerned.

“It’s going to impact some findings with regard to the robustness, but whether it completely wipes out the findings that are out there is another question,” says Damien Fair, assistant professor of behavioral neuroscience and psychiatry at Oregon Health and Science University. “It is going to require folks to reanalyze their data, controlling for these new ways of examining motion.”

(via)