WEDNESDAY, Nov. 28 (HealthDay News) -- Children diagnosed with autism have more gray matter in their brains than healthy children, report researchers who used a novel imaging technique to analyze brain structure.

The excess gray matter in the parietal region may make it harder for autistic children to learn how to function socially by watching other people's behaviors, the researchers suggest. In contrast, increased gray matter among healthy children correlated with higher IQ, the researchers said.

The researchers, at the Fay J. Lindner Center for Autism, North Shore-Long Island Jewish Health System in Bethpage, N.Y., were to present their findings Nov. 28 at the Radiological Society of North America annual meeting, in Chicago.

The researchers analyzed the brain images of 13 males who had either high-functioning autism or Asperger Syndrome, a developmental disorder in the autism spectrum. The researchers compared the results with images from 12 healthy children who did not have autism. On average, the preteens were 11 years old.

The researchers used a technology called diffusion tensor imaging (DTI) to produce a visual map of each child's brain. Scientists usually use DTI to visualize the brain's white matter, as well as the brain fibers. However, the research team applied it to the assessment of gray matter by employing apparent diffusion coefficient based morphometry (ABM), a new method that highlights brain regions with potential gray matter volume changes.

They found gray matter abnormalities throughout the brain, but particularly in the parietal lobe, which adds to previous research suggesting that mirror neurons found in that region play a key role in autism.

The increase in gray matter probably affects the action of the mirror neurons, said study investigator Manzar Ashtari, who is now a senior neuroscientist at Children's Hospital of Philadelphia. Mirror neurons are those cells that activate when you perform an action and then see someone else perform the same action, or vice versa. These neurons have been dubbed the "monkey-see, monkey-do" cells.

"Mirror neurons allow us to learn without knowing we are learning and then respond appropriately in certain situations," said Ashtari. She hopes to explore the link between autism and mirror neurons in future studies, using brain imaging techniques to find out when, and if, mirror neurons are engaged at the appropriate times.

The challenge with imaging studies is getting beyond measures of volume to understand smaller and more localized changes, Ashtari said. Adding ABM to DTI gave the study researchers the ability to detect subtle regional or localized changes in the gray matter, which was not possible before, she said.

The brain structures of people with autism change over their life span, explained Ashtari, which poses a problem for researchers trying to understand the disorder. "I believe it's a very complex process the brain goes through with autism and we don't know much" about that process, she said.

Unfortunately, this new imaging technique can't be used to diagnose autism, Ashtari cautioned.

"Everyone is trying to find something that is very robust, to be able to say 'you take this test, do this screening, and then you know,'" she said.

Dr. Stewart H. Mostofsky is a pediatric neurologist at the Kennedy Krieger Institute in Baltimore. He agreed that it is too soon to use any imaging technique as a part of diagnosing autism.

"We are dealing with a disorder that is defined by symptoms," said Mostofsky, who was not involved in the study. He added that there are many different possible causes of autism, which means many different brain abnormalities. "The question beyond that is whether there is a common neuromechanism. That is not entirely clear. There is no evidence that would support imaging as a diagnostic tool."

Further, he cautioned that the new study had a very small number of high-functioning participants, so conclusions about brain abnormalities cannot be generalized to all people with autism.

Another expert lauded the new findings.

Dr. Vilayanur S. Ramachandran, professor of psychology and director of the Center for Brain and Cognition at the University of California, San Diego, called the new research "a landmark anatomical study which lends support to the increasing evidence that mirror neurons are an underlying cause of autism." He said the finding of excess gray matter suggests that one of the issues with the autistic brain may be a matter of malfunctioning connections between neurons, rather than the neurons themselves.

Ramachandran and his colleagues published work earlier this year in the journal Cognitive Brain Research that suggested that autistic children have a faulty mirror neuron system.

In February, the U.S. Centers for Disease Control and Prevention released statistics indicating that one in every 150 American 8-year-olds has autism spectrum disorders. A decade ago, estimates ranged anywhere from one in 500 youngsters to one in 166.

But those new statistics -- from a 14-state survey conducted by the CDC -- failed to clear up the mystery of why autism might be striking more and more children with each passing year.

More information

To learn more about autism, visit the U.S. National Institute of Mental Health.

SUNDAY, Nov. 25 (HealthDay News) -- The dental health of Americans is improving as people take better care of their teeth. But that encouraging trend doesn't extend to some of the country's most vulnerable individuals -- children.

Studies have found that baby tooth decay is on the rise. One federal report found that decay in baby teeth among 2- to 5-year-olds increased from 24 percent to 28 percent from 1988 to 2004.

This decay can have unwanted lasting effects on a child's overall heath, ranging from impairment of permanent teeth to systemic illness caused by infection from bacteria in the mouth.

Jean Connor, a dental hygienist in Cambridge, Mass., and president of the American Dental Hygienists Association, said parents need to teach their children that a clean mouth is just as desirable as clean ears or hands or feet.

"It's just another part of the body that must be kept clean," Connor said. "If you have a dirty mouth, you're carrying bacteria and infections around."

Baby teeth are often thought of as disposable or temporary. But if left to decay, those teeth can fill the mouth with bacteria that could harm the permanent teeth as they come in. And if baby teeth are pulled early due to decay, the permanent teeth behind them can come in crooked.

Oral cleanliness can come from a variety of techniques. Parents should teach their kids how to brush and floss and also how to keep their mouth clean by watching what they eat.

This care can start even before a child is born, said Diann Bomkamp, a dental hygienist in St. Louis, and president-elect of the American Dental Hygienists Association (ADHA).

Expecting mothers can give their unborn children an advantage by taking special care of their dental health during pregnancy, Bomkamp said.

"If the pregnant woman does not have good dental care, she could have more of the decay-producing bacteria in her mouth, and it's very likely she could pass these bugs on to her child," Bomkamp said.

Once the child is born, parents should start keeping the mouth clean even before the first baby tooth has erupted.

The ADHA recommends thoroughly cleaning an infant's gums after each feeding with a water-soaked infant washcloth or gauze pad to stimulate the gum tissue and remove food.

"Even before they have teeth, you can clean out their mouths and get the kids used to the idea of it," Connor said.

When the baby's teeth begin to erupt, parents should brush them gently with a small, soft-bristled toothbrush using a pea-sized amount of fluoridated toothpaste.

At age 2 or 3, a parent can begin to teach their child proper brushing techniques. However, the child will need help with brushing and flossing up through age 7 or 8. By then, they will have developed the dexterity to do it alone.

Parents also should be cautious about inadvertently sharing their own mouth's bacteria with their child, through even the most seemingly innocuous behavior.

"Decay bugs can be transmitted through sharing food and drink, through sharing a toothbrush or sharing utensils," Bomkamp said. "Even blowing on food, your saliva can be transmitted to the child."

Watching what children eat also can help protect them from developing cavities or large amounts of decay bacteria in their mouths. This includes making sure that kids are fed regular meals throughout the day, especially breakfast, to keep them from feeling the need to snack on unhealthy foods.

One recent study found that the odds of decay in baby teeth were greater in the children with poor eating habits. Children who don't eat breakfast every day had higher levels of tooth decay, the study found, as did those who don't eat five servings of fruits and vegetables a day.

"If they're eating several snacks a day, they probably aren't eating foods that are good for them," Bomkamp said.

Also, don't let a young child go to bed with a bottle, Bomkamp said, and avoid allowing them to run around with sippy cups filled with sugary juices.

Another potential problem is the increased use of bottled water, she said. Tap water in almost all U.S. cities contains fluoride, which helps prevent tooth decay. "Most bottled water doesn't have the fluoride levels we'd like to see," Bomkamp said.

Dental hygienists also urge parents to get their kids in to see a dentist as early as possible, within six months of the eruption of their first baby tooth or by their first birthday.

"Parents often don't think to take their child to the dentist until it's too late to prevent problems," Connor said.

More information

To learn more, visit the American Dental Hygienists Association  .

WEDNESDAY, Nov. 21 (HealthDay News) -- Hardly any of the children who receive lung transplants because of severe damage caused by cystic fibrosis benefit from the risky operation, a study concludes.

It is a controversial conclusion, made more controversial because the transplant rules have been changed since the study was done, said Dr. Theodore G. Liou, associate professor of internal medicine at the University of Utah, and lead author of a report in the Nov. 22 New England Journal of Medicine.

CF is a hereditary disease in which the lungs and digestive tract become clogged with mucus. People with CF die at a relatively young age. Previous studies have shown some survival benefit for adult cystic fibrosis sufferers who received lung transplants as a last resort, Liou said.

The new report is one of very few looking at such transplants in children, he said. "In 2005, we published one [study] showing no difference in outcome between patients who were transplanted and those who were not, although they were equally sick as far as we could tell," Liou said. "That got us into a lot of trouble, because people didn't like the results."

The new study looked at 514 children with cystic fibrosis who were on the waiting list for lung transplants from 1992 to 2002. A total of 248 of the children did undergo the procedure during the study period.

The researchers found a significant estimated benefit for only five of those who had transplants, with "a significant risk of harm" associated with lung transplantation for 315 of the young patients, meaning that other treatment would have benefited them more.

The process has changed since the study was conducted, partly in ways that work against transplantation, Liou noted. Children selected for lung transplants now are first put on an intensive course of treatment intended to strengthen them for the surgery, he said, and "conventional treatments have gotten to be very good," he added.

The rules for actual performance of a transplant have also changed, said Dr. Julian L. Allen, chief of the division of pulmonary medicine at the cystic fibrosis center at the Children's Hospital of Philadelphia. He is also co-author of an accompanying editorial in the journal.

Until 2005, all children awaiting a lung transplant were placed on a single list, receiving organs as they became available. Now, the decision to transplant includes consideration of the patient's condition, with sicker children getting the operation sooner, Allen said.

"In some cases, children who were put on intensive therapy were deferred, because they got better," he said. "There was something about the children in that group who didn't get transplanted that made them get better."

The bottom line, Liou said, is that a decision that has always been complex has gotten even more so. "Maybe people will pay attention and try to be more careful about selecting patients for lung transplants," he said.

"You need to be careful about who you refer," Allen said. "You need to see if the results in this study hold true under the current rules. Also, the quality of life after a transplant has to be looked at. We need future studies that evaluate the quality of life."

One complicating factor with younger recipients of lung transplants is the need to be sure that they adhere to the strict regimen needed to prevent rejection of the organ, Allen added. The better success rate with older cystic fibrosis recipients is due partly to their better ability to follow instructions, he said.

More information

There's more on cystic fibrosis at the Cystic Fibrosis Foundation  .

MONDAY, Nov. 5 (HealthDay News) -- Preschool boys exposed to violent television -- even cartoons -- are more likely to become aggressive later in life, researchers warn.

Their findings don't definitively prove that TV makes children act up, and girls seemed entirely unaffected by violent fare, according to the researchers. But the link does appear solid in the case of boys, said study lead author Dr. Dimitri Christakis, professor of pediatrics at the University of Washington, Seattle.

"If parents are really interested in their kids' behavior, they have to be very selective and thoughtful about what their children watch," Christakis said. "That requires a fair amount of education on their part. They can't think, 'It's a cartoon, and it's harmless.' They have to be more thoughtful."

A number of studies have linked violence on television to aggression among children, but the new research is unusual, because it looked at the effects of television watching on kids between the ages of 2 and 5, Christakis said.

Working with University of Washington colleague Frederick Zimmerman, Christakis reviewed data from a study of 8,000 U.S. families. They focused on the television habits of preschoolers -- 184 boys and 146 girls. The researchers then checked up on reports of the youngsters' behavior when they reached 7 and 10 years of age.

The findings are published in the November issue of the journal Pediatrics.

Christakis' team found that for each hour a day spent watching violent TV during the preschool years, boys were three times more likely to develop behavioral problems at age 7.

It's possible that boys with aggressive tendencies may simply prefer watching violent television in the first place, of course. But the study used information about the children's early behaviors to help control for that, Christakis said.

Violence on television did not seem to have any effect on the behavior of girls. Also, watching non-violent programs didn't appear to make boys or girls more aggressive later in life, the team found.

"Parents need to know what really does constitute aggression-laden programming," Christakis said. "It's not just what parents think."

Indeed, the study suggests that trouble may lurk in cartoon programming as seemingly innocuous as Power Rangers and the animated Spiderman series, he said. Conceivably, he added, even old Warner Brothers' classics, such as the Wile E. Coyote-Road Runner series, could spell trouble.

"Kids in the 2- to 5-year-old age range don't understand the difference between cartoon and real violence," Christakis explained," particularly how it shows aggression without consequence. It sends the wrong message."

Not all children, of course, will become more aggressive by simply watching such cartoons, he said, but their risk for such behavior will grow.

L. Rowell Huesmann, director of the Research Center for Group Dynamics at the University of Michigan, said the study is "very well done," even though it does not prove that TV violence causes aggression.

"While the bad behavior being predicted is still behavior in childhood, society should be concerned about this effect, because the more aggressive child tends to grow up to be the more aggressive adult," he said. "So, if TV violence is increasing the aggression of preschoolers, it is likely to increase how aggressive they will be later in life as well."

Another expert agreed.

"For children who are first learning how to properly behave, exposure to aggressive and violent behavior featured on many programs and cartoons is counterproductive," Alan Hilfer, director of psychology at Maimonides Medical Center in New York City, said in a statement. "Parents must seek to create curious, intelligent and socially skilled children -- not children whose answer to a situation is a physical or aggressive response."

But that can be a tall order for stressed out moms and dads, he added. According to Hilfer, "Even new parents are aware of the shortcomings of TV, but television has long been, and continues to be, the quintessential baby sitter when parents are overwhelmed."

More information

There's more on television and kids at the American Academy of Pediatrics  .