Docs Urged To Test Toddlers For Mild Cases Of Autism
Physicians should take an extra five minutes on each visit to check children for signs of autism, according to a research panel convened by the American Academy of Neurology and 11 other professional organizations.
"Some kids are being missed because physicians aren't really trained in diagnosing autism," said lead researcher Dr. Pauline Filipek, professor of pediatrics and neurology at University of California, Irvine. "Autism has a much broader definition than it had in the past."
Filipek said that nearly every physician can recognize the most severe cases because of the child's "extreme remoteness, muteness, repetitive hand slapping and stereotypic behavior."
But it is the subtle signs of the milder cases that are too often being missed by physicians and other early childhood workers, according to the report published in the December issue of the Journal of Autism and Developmental Disorders.
"By 12 months of age, most children should be pointing as a nonverbal communication gesture and babbling," said Filipek. "They should have in their vocabulary words other than 'momma' and 'dadda' by 16 months of age. By 24 months of age, they should be using phrases."
When children have not reached these developmental milestones, "these are the red flag indicators," said Filipek. "Parents should not fall for the reassurance that the child will grow out of it, or boys do this later than girls," she added.
The report cited extensive evidence in the research literature that when parents are concerned about their child's behavior, their concern is almost always warranted.
Autism is a behavioral disorder characterized by a marked reluctance to socialize with other people, a delay in development of verbal and nonverbal communication, and restrictive and repetitive patterns of behavior.
Researchers no longer consider autism to be a rare disorder. At one time only two to four children per 10,000 were considered autistic, but now with milder cases factored in, one in 500 children is now considered to be autistic to some degree.
"The milder kids may still talk, but often they just recite video scripts," said Filipek. "They're talking, but it's not appropriate for them to be reciting the script for a video as their only language."
According to Filipek, this evident lack of a will to communicate can be differentiated from other language disorders. "A child who can't talk, but just has a language disorder," she said, "is usually standing on his head spitting wooden nickels to gesture and mime to get his point across."
Filipek maintained that children with milder cases can make a lot of progress if the condition is diagnosed early enough and with the correct intervention.
"You can teach what in developing children is innate, things like making eye contact, communicating, gesturing, reading other people's body language and using body language themselves."
The panel recommends that physicians question parents about their child's behavior. The physician can also observe the child for autistic behavior, but this can be difficult since children are often upset at being at the doctor's office in normal circumstances, said Filipek.
The tests to diagnose autism take about five minutes of a physician's time.
Filipek noted that parents are becoming more aware of autism, and their concerns should be taken seriously by physicians and other health care professionals.
Journal of Autism and Developmental Disorders (1999;29:437-482)
No Single Cause, No Single Cure
By Julie Fields in the Bergen Record.
It was late in the day, and Patricia Rodier was tired.
Hours before, the University of Rochester researcher had given a lecture on birth defects at a conference in Tucson, Ariz. She'd hoped for a quick nap before dinner, but the topic of another talk caught her ear:
Was there a link between the baffling disorder of autism and thalidomide, the notorious drug that disfigured thousands of infants in the 1960s?
As she listened, Rodier realized the work would dovetail with her own research on fetal development. And by the end of the session, she had embraced a new mission -- to search for the elusive roots of autism.
Rodier's decision to focus on autism is just one sign that the developmental disorder -- long ignored by researchers and relegated to a footnote in medical school -- is finally beginning to get its due.
In the six years since the conference in Tucson, the United States has launched its first major effort to understand how autistic brains differ from others, and what goes awry to interfere with speech, social interactions, and complex thinking.
Slowly, Rodier and dozens of other scientists are beginning to assemble theories, to identify pieces of the puzzle. It is far too early to talk of a cure, they say, but it's no longer science fiction to hope for an answer to the question that haunts parents of autistic children: Why?
"It's infuriating that we haven't figured it out yet, but at the same time, I feel like we're getting there," says Rodier, a professor of obstetrics and gynecology.
Though funding still lags behind diseases such as cystic fibrosis and multiple sclerosis, public and private research dollars are on the rise. The National Institutes of Health in Bethesda, Md., distributes the bulk of the money, with an estimated $27 million devoted to autism in 1999.
And in New Jersey, long known for its programs to educate autistic children, Governor Whitman recently signed a bill expected to give a boost to fledgling research efforts. With $1.5 million earmarked for the disorder, the hope is that in the future parents will no longer have to travel to New Haven, Conn., and Baltimore for the latest studies and treatment.
Collaboration among experts, from geneticists to immunologists, also is increasing. And parents' groups, once focused exclusively on obtaining therapy and services, are now actively promoting research by awarding competitive grants, collecting samples of human DNA, and emphasizing the need for brain tissue.
"Autism research has had a shot in the arm since 1995," says Dr. Eric London, director of medical affairs for the Princeton-based National Alliance for Autism Research and the father of an autistic son.
Still, London's enthusiasm is tempered by the fact that so many hurdles remain. Researchers are still unsure of the precise function of some regions of the brain, and how they interact with each other. As a result, he says, science's understanding of the complex disorder that affects an estimated 400,000 Americans remains "dreadfully below our knowledge of most other diseases."
Autism was first identified in 1943 by Dr. Leo Kanner, but was quickly labeled a psychological disorder and blamed on "cold" mothers who withheld affection. That view, which stalled medical research for decades, was eventually dispelled.
Scientists now believe that genetics plays a crucial role in autism.
Yet studies of identical twins indicate that DNA alone cannot explain the wide variation of symptoms and severity. One twin, for example, may be unable to speak or communicate at all, while the other has none of the classic characteristics of autism. Thus, other factors -- such as environmental toxins, viruses, childhood immunizations, or difficulties during a pregnancy or at childbirth -- are thought to be involved.
Ultimately, more than one theory is likely to prove correct. With such a broad spectrum of symptoms, experts suspect that what is now called autism will be defined in the future as a disorder with shared symptoms but separate causes. They cite Fragile X syndrome, a genetic disorder often mistaken for autism because of similar symptoms until the defect responsible for it was found.
"People talk about curing autism," said Marie Bristol-Power, who oversees autism research at the National Institute of Child Health and Human Development, part of the NIH. "But there is not a single cause, so there will not be a single cure."
Rodier is among the researchers who have developed a hypothesis to explain autism. She thinks it arises from an injury to the developing fetus, possibly from an environmental toxin, as early as the third week of pregnancy.
Using the thalidomide study presented in Tucson as a starting point, she studied adults exposed to the drug in utero and found that many had minor ear malformations. Drawing on her knowledge of other birth defects and fetal development, she reasoned that the exposure must have occurred between the 20th and 24th days after conception, at the time the neural tube was closing.
At that point, the fetus has only a brain stem. The rest of the brain has not yet developed. Scientists had always assumed an injury at such an early stage would prove fatal because the brain stem controls breathing and the beating of the heart.
Rodier theorized, however, that the injury was mild enough to allow survival, but damaged the cranial nerves that control hearing, eye movement, smell, and equilibrium. That damage, she believes, could also cause a chain reaction of problems as nerves and other cells in the brain develop.
While only a tiny fraction of autism cases were caused by exposure to thalidomide, Rodier is convinced they offer a window for understanding the disorder. Perhaps other unknown toxic substances, she says, also cause autism if the timing of the exposure is the same.
In her crowded warren of labs in Rochester, she and her assistants are now working to test the theory by exposing genetically altered mice to toxic substances.
"I don't think we can explain all the symptoms of autism by changes in the brain stem at all, but that doesn't mean that the brain stem isn't the start of the problem," she said. "And I do think the brain stem is the start of the problem."
But Rodier's theory also has limitations. While it adds weight to the idea that autism starts before birth, some scientists are not convinced the problems begin as early as the first trimester. And there is no clear understanding of how a brain stem injury would interfere with the development of the limbic system, frontal cortex, and other regions of the brain thought to be responsible for autism.
Moreover, Rodier's theory does not explain why roughly a third of autistic children appear to develop normally until the age of 18 months to 2 years, then suddenly lose vocabulary and other skills.
"What she has done is very elegant. It certainly applies to those cases as a subgroup," said Dr. Nancy Minshew, a pediatric neurologist at the University of Pittsburgh. "But I think with the majority, that's not happening."
Minshew suspects that autism begins later, when the brain's nervous system is forming. It's possible that nerve pathways between different regions are never established, that the neurons don't have enough channels to connect with other cells. Or that something causes the neurotransmitters to stop working.
Others suspect the disorder originates from a process known as "synaptic pruning," in which nerve connections strengthen or die off as an infant responds to stimuli in the world.
Under a microscope, autistic brains generally appear normal. But a few, subtle abnormalities have been found. They tend to be slightly heavier, for example. And autopsies have found a higher than normal density of nerve cells in the limbic system, a crossroads for processing emotions and other information.
"If the signal gets jammed in there, a lot of things can happen," said Rebecca Landa, a professor of psychiatry at Johns Hopkins School of Medicine and director of the Kennedy Krieger Center for Autism and Related Disorders.
There also are signs of abnormalities in cells of the cerebellum, Landa said, which could interfere with attention and balance.
It's difficult, however, to pinpoint biological reasons to explain many of the classic characteristics of autism, such as spinning, hand-biting, and other repetitive actions.
Some speculate that repetition may be an autistic child's attempt to find calm. "A lot of times kids will do this stuff when they're in an uncomfortable situation ... kind of soothing themselves with it," Landa said.
And they speculate that the aggressive behavior arises from frustation over their inability to communicate their thoughts and needs, and an inability to regulate their impulses.
The behaviors, Landa said, probably stem from problems in more than one area of the brain. "This is something that's really being debated," she said. "Nobody knows."
One of the biggest challenges in autism research is identifying who has it. There is no blood test, no brain scan, no physical marker. Diagnoses are based on a specific number and combination of behaviors. Until recently, experts in the United States and Europe did not even share a common definition of autism.
But Bristol-Power of the NIH hopes that the creation of an international network of more than 75 scientists will overcome such obstacles. The $30 million five-year project requires participants to meet regularly, share results, and pool data on a thousand families with a history of autism.
Yet competition still drives the science. "Within this network, there are people who simply don't agree about the cause of autism," said Bristol-Power. "They're out to prove each other wrong, and that's good."
Convinced that the brains of autistic children are damaged before birth, a number of researchers are searching for the first signs of a problem. Roughly three-quarters of people with autism are classified as mentally retarded or below normal intelligence. And about half never learn to speak.
Educational experts have found that early intervention -- by the age of 3 or 4 -- can make a huge difference in helping autistic children compensate for their disabilities.
Specialists also hope that monitoring the infant siblings of autistic children -- 4 to 10 percent of whom are expected to develop autism -- will help them develop theories on which brain systems break down.
One of the most provocative theories to arise in recent years points to childhood vaccines as a possible culprit. Dr. Andrew Wakefield touched off a furor in March 1998 when he published a study in the British medical journal The Lancet suggesting a link between the MMR (measles, mumps, and rubella) vaccine, inflammatory bowel disease, and autism.
Doctors and public health officials quickly denounced the report as flawed, emphasizing that vaccination programs have saved millions of lives worldwide. Two months later, Finnish researchers announced they had found no evidence the vaccine caused autism or bowel disease after studying the records of millions of children.
Critics of the Finnish study consider the research to be so flawed as to approach fraud. Critics of the vaccine theory also point out that the shot is usually given around the time that parents begin to notice the first developmental signs of autism. But this coincidence, they say, should not be mistaken for cause and effect.
Nonetheless, thousands of parents remain suspicious of the MMR. And Wakefield, who stressed in The Lancet that his work did not prove a link, still thinks it deserves further research.
"It's clearly something that should be done, and done independently of either public health or commercial interests," he said.
In a recent phone interview, Wakefield said it's possible that the diarrhea, finicky eating habits, and other gastrointestinal problems common among autistic children may be related to the cause of the disorder.
Wakefield suggests that vaccinations may somehow injure the bowel, causing an inflammation and chemical reactions that then interfere with the brain's function and development.
The idea of a "brain-gut" connection also gained attention following a "Dateline NBC" report last fall about an autistic 4-year-old boy who improved dramatically after being given secretin, a hormone that stimulates the pancreas and is used to diagnose digestive problems.
Studies have shown that proteins found in the gut, including secretin, also exist in the brain. But it's unknown how they function there, or how they might lessen the effects of autism.
Concerned about the safety of secretin, the NIH is launching tests to measure its effectiveness. Thousands of children have received multiple doses of the drug, at levels four to eight times the recommended dose.
And the sudden demand has created a black market, with some parents reportedly paying as much as $5,000 for a vial that sells for $179 wholesale.
"We're getting calls that people are literally mortgaging their homes to get money to get this drug," said Bristol-Power of the NIH.
The NIH trial will test two forms of secretin -- one synthetic, the other derived from the intestines of pigs -- against a control group.
"I would love for us to find something that works for these children," said Alan Unis, an associate professor of psychiatry at the University of Washington who is overseeing the NIH clinical trial.
But until the results are in, Unis remains wary. "Nobody knows if this works. You don't want to spin your wheels speculating if you don't even know that it works," he said.
While fundamental questions about the autistic brain remain unanswered, progress is being made in another area: identifying genes that create a predisposition to the disorder.
Experts estimate that three to eight genes are involved, though the number could be higher. A combination of at least two or three is needed, they say, to create a predisposition.
"If it was the same two for everybody with autism, we would know exactly which two they are," said Ed Cook, an associate professor of psychiatry and pediatrics at the University of Chicago.
So far, researchers have identified four candidate genes, and abnormalities on four different chromosomes. Rodier thinks she has found evidence that mutations on two genes controlling early development of the fetus are involved.
The different genes also may explain the variation in autism, which can range from profound mental retardation to the gifted savant of Dustin Hoffman's "Rain Man" character.
It's likely to take years or decades to find all the genes. But with two or three, the possibilities for genetic screening, or the development of drugs to control symptoms, would greatly improve.
Cook believes at least one will be confirmed within two years. "It is absolutely, positively only an issue of resources," he said.
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