Virginia Hughes

About 80 percent of adults with autism exhibit restricted or repetitive behaviors, such as hand flapping, teeth grinding, or rocking back and forth. A new fMRI study of 15 autistic people finds that these repetitive behaviors are associated with abnormal activity in the “executive” brain system that’s responsible for attention, planning, and for inhibiting inappropriate behaviors.

Older brain-imaging research on people with autism overwhelmingly focused on social aspects of behavior, such as the processing of faces.

Testing for neural changes during repetitive behaviors is more difficult because of the constraints of an fMRI machine, in which subjects must lie still. “More than three to four millimeters of head motion will invalidate an entire study,” says Hofstra University neuroscientist Keith Shafritz, lead author of the new study.

To jump this hurdle, Shafritz used a novel testing paradigm that forced subjects to activate the cognitive processes behind repetitive behaviors without actually making any motions.

…read the rest of my latest piece at the Simons Foundation website

I was cranky tonight after the evening news mentioned Jenny McCarthy’s crackpot “green the vaccines” rally in DC this weekend. She and Jim Carrey are scheduled to appear on Good Morning America tomorrow. Ugh.

Orac, thankfully, snapped me out of my funk, by posting an (albeit mild) counter-response: an open letter to Congress on immunization policy written by a slew of doctors and public health experts. The money quote (emphasis mine):

Well-designed scientific studies are the only valid method of demonstrating medical cause and effect. In contravention of this fundamental principle, beliefs not based on science have led increasing numbers of parents to choose not to immunize their children. The implications of this choice are profound.

For those who don’t know, McCarthy, whose son is autistic, is now the high-profile spokesperson of those who believe that vaccines are the cause of the rising prevalence of autism in the U.S. On March 9, she distributed a letter online urging parents of children with autism to call the White House and “demand” the resignation of CDC director Julie Gerberding, who has led the CDC, in McCarthy’s words, “during a time when the autism epidemic has only gotten worse.”

Though the idea of an autism “epidemic” originated several years ago, it’s received massive media attention in the last year thanks to celebrities like McCarthy and Don Imus and the 4,800 families who are suing the government in federal “Vaccine Court.”

It’s true that autism diagnoses across the world have skyrocketed in the past few decades. Before 1990, the reported autism prevalence in America was 4.7 out of every 10,000 children; it’s now 60 per 10,000. The anti-vaccination gang says this correlates exactly with the rise in the number of childhood vaccinations, which went from 10 in 1983 to 36 in 2007. But scientists say the rise in autism diagnoses is instead a result of a broadened definition and better awareness of autism spectrum disorders in the medical establishment.

Don’t let their cute children fool you: The Antivaccers are a scary bunch. If Jenny and Jim have their way, the anti-vaccination movement will bankrupt the Vaccine Compensation Fund, start suing the pharmaceutical companies who manufacture the vaccines, and cause a public health disaster. Here’s hoping for rain in D.C. this weekend.

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Some scientists say that children with autism may show signs of the disease when they are younger than a year old.

But some children with autism seem to develop normally in the first two years of life — making eye contact, waving goodbye, even saying a few words. Then, according to their parents and pediatricians, these children seem to abruptly lose those skills.

This ‘autistic regression’, reported in about one-third of children with the disorder, is baffling researchers.

“We haven’t found any biological markers to say why this child regressed and another didn’t,” says pediatrician Michael Davidovitch, chairman of the Israeli Association of Child Development and Rehabilitation. “And we don’t know if their prognosis will be better or worse.”

About 20 years ago, researchers began asking whether autistic regression could be a distinct subgroup of autism, with its own telltale biological markers. Since then, dozens of contradictory behavioral, physiological and genetic studies have left the field no closer to finding the answer.

…read the rest of my latest article at the Simons Foundation website.

I found a delicious historical nugget tonight while researching for an article-in-progress about the link between autism and prenatal infection.

In 1971, Stella Chess published a paper about the 1964 rubella epidemic in New York City. She found that an unusually high number of kids with autism in 1970 were born to women who had been infected with rubella. That’s interesting (especially for my article). But what really shocked me was something Chess mentioned briefly at the end of the introduction:

A 1964 British survey of children in Middlesex aged 8 to 10 years found that 4.5 per 10,000 children were autistic….We recognize that the diagnosis of autism requires rigorous justification. The condition is often loosely defined and overdiagnosed.

Wait a minute…4.5 per 10,000 and she thought doctors were overdiagnosing? Now a half-century since that survey, autism is found in about 1 of every 150 kids, and most researchers I’ve interviewed say that even that is probably an underestimate.

Of course, now I’m going to get a few anti-vaxers in the comments telling me that this is evidence of an “autism epidemic” in the last few decades. This is almost certainly not true, as I’ve reported twice. Still, it’s interesting to see how the field’s perspective has changed since then. And how it hasn’t: Autism, unfortunately, is still “often loosely defined.”