Originally created 02/12/02

MCG doctors' brain study advances autism research



The purple crayon slashes across the paper in a furious up and down stroke, leaving long streaks on the page. A few seconds later, it goes side to side, back and forth, filling in the Fairy Godmother's attire. Becky Claffey is absorbed by the drawings as she bends over the Disney coloring book, talking to herself in a rapid-fire singsong voice in what sounds like movie dialogue.

"We're going to have to hurry," she says dramatically to the page, still coloring strenuously.

Becky looks like any other 12-year-old girl - except inside her head. In a groundbreaking study published today in the journal Neurology, Medical College of Georgia researcher Manuel Casanova and his team say they have found fundamental physical differences in the brains of autism patients such as Becky that can help explain their symptoms. It might also point the way to better treatments and ways of preventing autism from developing in children.

Autism is an often severe developmental disorder in which children might have trouble communicating and interacting with others and often engage in repetitive and ritualistic behaviors and obsessions.

The reason could lie in a unit of the brain's architecture called the minicolumn, a grouping of neurons and signal pathways that make up what Dr. Casanova calls the "chips" of the brain's circuitry.

The columns are smaller and more numerous in the brains of autism patients, there is less buffer between the columns, and more columns are connected to each other. This could make it easier for a sensory signal to spread from column to column, meaning there would be more excitation from a stimulus and a stronger reaction than an average person might feel, Dr. Casanova said.

"They have too much signal-to-noise, which actually does explain some of their hypersensitivity," said Dr. Casanova, a neurologist and neuropathologist. "All of their senses seem to be hypersensitive (because) there's a deficit in the inhibition, meaning that they need more inhibition" or dampening of the signal coming in.

It may explain, for instance, the reluctance to make eye contact that is often a symptom of the disorder, Dr. Casanova said.

"An autistic person can look at you and it's almost like looking into the sun," Dr. Casanova said. "There are too many features. There's too much intensity. What do you do when you look at the sun? You turn away. You try to shield yourself from that sensory impact. That may actually provide for a very nice clinical/pathological correlation."

There is no effective treatment other than behavior modification therapy and drugs to try to calm autism patients. Because they need more inhibition, Dr. Casanova said, an anti-convulsant drug might help as long as it is given early enough.

"There is a critical time period for everything. And that period of plasticity is in the first few years after birth," Dr. Casanova said. "So there's a chance to create a definite change in hard-wire in the brains of anyone, not only autistics."

There may be an evolutionary element at work in autism. Because the skull physically limits the size of the brain, the only way for the brain to grow is in surface area, which would mean more cells and more folding, called gyrification, Dr. Casanova said. The next step of research is to look for those signs on brain imaging scans of autistics, Dr. Casanova said.

For Becky and her 11-year-old brother, Pete Jr., it is a struggle to learn to fit in to a world seemingly ill-suited for them. Their parents, Liz and Peter Claffey, also must adjust. Doors are locked, for example, lest Becky wanderto the house with the interesting dog or to her uncle's house where the Disney videos are not as carefully tucked away.

The couple says they are encouraged by their experience with behavioral programs such as Judevine at Gracewood State School and Hospital, and by research including Dr. Casanova's.

"There's more knowledge coming out now than ever before," Mrs. Claffey said.

Reach Tom Corwin at (706) 823-3213 or tomc@augustachronicle.com.



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