Saturday, March 28, 2009

Study Links Anesthesia To Learning Disabilities

Does it take more than 2 seconds of sniffing to smell the foulness of the following lengthy excretion of crap? Has anyone thought to ask what the prior characteristics of children who require repeated surgery might be? Might it be that they start out with brain damage as well as other forms of damage? I append some remarks by a chief anesthiologist working in a large American public hospital

Children who have had multiple surgeries under general anesthesia by the age of 4 may be at a higher risk of developing learning disabilities, according to a new study by scientists at the Mayo Clinic in Rochester, Minn. Dr. Robert Wilder, a Mayo Clinic anesthesiologist, says his study was motivated by recent research on baby rats and other young animals. Those studies, conducted in the last several years, show that exposure to anesthesia at a very young age can kill off brain cells. But results in rodents don't necessarily translate to humans.

"The initial reaction of the pediatric anesthesia community was, 'This must be wrong, we've been giving anesthetics to kids for years and we don't see a big problem,''' Wilder says. He, too, was skeptical.

The Mayo Clinic sits in Olmsted County. Both the research clinic and the county have kept precise records on the health care and hospitalization of its residents. Wilder sorted through the records of more than 5,000 children. About 600 of them had one or more surgeries with a general anesthesia, a class of drugs that enters the blood stream, reaches the brain and leaves a patient in a state of unconsciousness. Local anesthesia (like what's used by dentists when filling a cavity) and regional anesthesia (like an epidural that's common during childbirth) numb just a part of the body, but don't cause the patient to lose consciousness.

The surgeries ranged from those for serious problems, like open heart surgery, to more routine ones, like putting in ear tubes or removing adenoids and tonsils. Most of the kids in the study — about 80 percent — had surgeries for the small and common problems.

Wilder found that children who had undergone a single operation with a general anesthetic by the time they turned 4 were no more likely than other children to develop a learning disability. But kids who had had two surgeries were one and a half times more at risk. [In other words, it was only where kids had serious health problems that the learning problems were seen] And for children who had undergone three operations, the risk went up to two and a half times. Of the kids in Wilder's study who had had three or more operations, 50 percent of them later developed a learning disability.

Wilder speculates that anesthesia could cause learning problems in young children because it travels to the brain at a time when the brain is developing rapidly. "If you're exposed to these drugs at just the right time in your life," he says, "you have a lot more cell death than you otherwise would — and some of that is in the hippocampus, which is part of the brain that is involved in learning new things and it, therefore, does not work as well throughout the rest of your life."

That makes sense to Amanda Rathbun, who lives outside Salt Lake City. "I always thought that things like this ran in families, like if your dad has brown eyes, then you're more likely to have brown eyes. But there's not a history of this in our family," she says. Rathbun has three very smart kids. Her 11-year-old daughter has no learning disabilities. But another daughter, who's 8, and her son, who's 13, have both been diagnosed with attention deficit disorder. Both kids had several surgeries soon after birth. In addition, the son has struggled to write legibly. Fine motor skills are a problem for him, and Rathbun wonders if he could have gotten more attention for that sooner. "If general anesthesia early in life can really cause these sorts of problems," she says, "I think it would be good to know that, because maybe we could start more early intervention services for these kids and maybe prevent some of these later problems."

The new research is published in the current issue of Anesthesiology, the journal of the American Society of Anesthesiologists. The co-authors write that more studies are needed to be certain it's the anesthesia that's causing the problem. It might be the illness that requires the surgery — although the researchers took the sickest children out of the study.

Wilder says parents shouldn't avoid surgery when kids younger than 4 need it. "My advice is that if their child needs a surgical or diagnostic procedure that requires an anesthetic, then they should go ahead and have that surgical or diagnostic procedure with the anesthetic," he says.

Dr. Piyush Patel, who wrote an accompanying editorial in the same journal, agrees. He adds that parents can, however, ask their doctor if it's better to postpone a surgery until a child is older. "Based on these data, the parents of children have to be comfortable that the surgery is absolutely needed and they have to balance the risk of waiting for the surgery to be done versus the complication that may arise," says Patel, a professor of anesthesiology at the University of California, San Diego. "This is a decision that is best made by the surgeon and the anesthesiologist."

Wilder's study, and others, have created a sense of urgency to answer questions about the effects of anesthesia on the brain development of infants and young children. Earlier this month, the federal Food and Drug Administration announced a collaboration with Mayo and other clinics to support further research.



Trash from the start. And these guys are shameless - to get grant money - to raise stupid questions. And likely they will make a lot as expert witnesses to blame anesthesiologists for ADD etc..

And they admit that they excluded the worst cases. TRASH - how can you exclude children with serious defects requiring multiple surgeries? I speak as an expert. A routine anesthetic in a healthy patient is HARMLESS. In a sick patient, it is also HARMLESS -


These shameless anesthesiologists are pandering to the Obama Care lobby - to declare anesthesia as a risk factor, and use 'more caution' to limit the number of operations. Fits in just right to reduce budget. And to make parents hysteric so they avoid needed surgery in their children.


PS - In private practice, I did a lot of anesthesia on "healthy children" and NONE were more stupid after anesthesia than before, that I could see.

The integrity of neural wiring is a big factor in determining intelligence. It's also inheritable

I have mentioned this before but the article below gives more detail

New research suggests that the layer of insulation coating neural wiring in the brain plays a critical role in determining intelligence. In addition, the quality of this insulation appears to be largely genetically determined, providing further support for the idea that IQ is partly inherited.

The findings, which result from a detailed study of twins' brains, hint at how ever-improving brain-imaging technology could shed light on some of our most basic characteristics. "The study answers some very fundamental questions about how the brain expresses intelligence," says Philip Shaw, a child psychiatrist at the National Institute of Mental Health, in Bethesda, MD, who was not involved in the research.

The neural wires that transmit electrical messages from cell to cell in the brain are coated with a fatty layer called myelin. Much like the insulation on an electrical wire, myelin stops current from leaking out of the wire and boosts the speed with which messages travel through the brain--the higher quality the myelin, the faster the messages travel. These myelin-coated tracts make up the brain's white matter, while the bodies of neural cells are called grey matter.

White matter is invisible on most brain scans, but a recently developed variation of magnetic resonance imaging, called diffusion-tensor imaging (DTI), allows scientists to map the complex neural wiring in our brains by measuring the diffusion of water molecules through tissue. Thanks to the fatty myelin coating, water diffuses along the length of neural wires, while in other types of brain tissue it moves in all different directions. Researchers can calculate the direction of fastest diffusion at each point in the brain and then construct a picture of the brain's fiber tracts. A well-organized brain has well-functioning myelin, in which water can be seen clearly moving along specific paths. "Diffusion imaging gives a picture of how intact your brain connections are," says Paul Thompson, a neuroscientist at the University of California, Los Angeles, who lead the study.

Thompson and his colleagues took DTI scans of 92 pairs of fraternal and identical twins. They found a strong correlation between the integrity of the white matter and performance on a standard IQ test. "Going forward, we are certainly going to think of white matter structure as an important contributor of intelligence," says Van Wedeen, a neuroscientist at Massachusetts General Hospital in Boston, who was also not involved in the research. "It also changes how you think about what IQ is measuring," says Wedeen. The research was published last month in the Journal of Neuroscience.

If white matter is linked to both processing speed and IQ, this raises the question: is intelligence merely a function of how fast your brain works? Previous research has linked processing speed to IQ, but the tests used in the study are measures of general intelligence, including verbal skills, math, and logic. "Processing speed plays a big part in how intelligent you are, but it's not the only factor," says Shaw.

The new study is among the first to link a specific neural architecture to IQ in healthy individuals. "Most people have focused on grey matter," says Shaw. "This is good evidence we should be looking at white matter as well." Previous studies using DTI have linked white matter damage to Alzheimer's disease, chronic alcoholism, and traumatic brain injury.

The UCLA researchers took the study a step further by comparing the white matter architecture of identical twins, who share almost all their DNA, and fraternal twins, who share only half. Results showed that the quality of the white matter is highly genetically determined, although the influence of genetics varies by brain area. According to the findings, about 85 percent of the variation in white matter in the parietal lobe, which is involved in mathematics, logic, and visual-spatial skills, can be attributed to genetics. But only about 45 percent of the variation in the temporal lobe, which plays a central role in learning and memory, appears to be inherited.

Thompson and his collaborators also analyzed the twins' DNA, and they are now looking for specific genetic variations that are linked to the quality of the brain's white matter. The researchers have already found a candidate--the gene for a protein called BDNF, which promotes cell growth. "People with one variation have more intact fibers," says Thompson.

The search for the genetic and neuroanatomical basis of intelligence has been controversial, largely because opponents fear it will spawn a deterministic view of abilities and education. "People worry that if something is genetic, they have no power to influence it," says Thompson. "But that's not true at all." For example, both an average runner and a genetically gifted one can benefit from training.

But the debate may be moot since, as Wedeen points out, it is unlikely that an individual brain scan could predict a person's IQ. "The report described aggregate data over number of individuals," he says. "That's not the same as saying we can do a scan and determine a person's intelligence. That may be in the offing, but we don't know that yet."


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