Thursday, March 26, 2009

Brain scan may reveal risk for Alzheimer's disease

  • Key structural changes seen in brain scans of some patients with memory loss
  • One year later, many patients with brain changes had developed Alzheimer's
  • Memory-loss patients without these changes were mostly stable one year later
  • Brain scans could identify who gets Alzheimer's, help with drug testing

The bottom line: The average person can't run out and get an MRI that shows if they're on the road to Alzheimer's just yet. But these findings could help drugmakers as well as patients in the future.


Brain scans may identify which patients suffering from mild cognitive impairment, or MCI, are likely to progress to Alzheimer's disease, and who will probably not develop the disease, according to a new study. The findings, published in April 2009 issue of the journal Radiology, could help in developing new drugs for Alzheimer's. More than 5 million Americans have Alzheimer's disease, about 3.5 million have mild cognitive impairment.
Questions and answers

What did the brain scans show?

Dr. Sanjay Gupta, CNN chief medical correspondent: This was a small but significant study in the fact that it may lead researchers to determine who will develop Alzheimer's disease and who may not. I had a chance to view the brain scans used in this study and they were truly fascinating. The images of patients with Alzheimer's showed many areas throughout the brain where the cells and tissue have begun to deteriorate or have already died. We know Alzheimer's is a neurodegenerative disease and when the cells die, patients begin to experience loss of cognitive function. Although all the patients with MCI experienced mild memory problems, not affecting their daily life, inside their brains looked very different. One group looked very similar to the brain of the Alzheimer's patients. The other MCI group showed very little cell damage.

What does this mean for patients with MCI?

Gupta: What this tells us is no two patients with MCI are the same. And some may progress to an Alzheimer's diagnosis in less that a year. These researchers looked at follow-up imaging a year later and found 30 percent of the group whose brains showed signs of cell loss were now Alzheimer's patients. This is a potential clue in trying to figure out who is most likely to develop Alzheimer's later on in life. Not ready for prime time yet, in terms of patients having access to these scan results, but it could be available a few years from now.

Is there anything people can do as they age to keep their brain strong?

Gupta: Yes, various cognitive exercises and memory activities can help keep your brain healthy and maintain cell production. But there isn't a lot of evidence showing that it can somehow reverse the effects of cell loss after getting an Alzheimer's diagnosis. What I found even more interesting, is something I started to incorporate into my own life: simple physical exercise. I am not talking about necessarily strenuous exercise, but simple, regular daily activity. Studies show it has a way of fueling your brain and even ward off Alzheimer's. I would say cognitive and physical activity is your best bet for now.


CNN interviewed Bill Thies, the chief medical and scientific officer at the Alzheimer's Association, about this study. Here are some of his observations:

"This is an interesting study. Right now, we make an MCI diagnosis from talking to people; it requires symptoms to be there to make a diagnosis. And now people are looking at all sort of high-tech tools and imaging to track the signs inside their brain. MCI is often a very sporadic condition, a person might have symptoms of MCI one day and the next day might be normal. Part of the reason is different things can cause MCI -- depression, anxiety, its not always Alzheimer's disease."

"At the ultimate extent, based on this research, you'd be able to take any individual and take a picture of their brain structure and get a decision one way or another if they will develop Alzheimer's disease. It would be extremely valuable, especially for a MCI patient."

"Everybody wants better medication for Alzheimer's disease, even the people who already make the drugs want to develop something better. We all recognize, as we look to the next 40 or 50 years, that the number of cases are going to increase. And it is a very expensive disease for society. If we don't have a better way to treat it, it will have disastrous effects on society."

Suicidal behavior may run in families

By Elizabeth Landau

The poet Sylvia Plath, who made a name for herself through prose and poetry that conveyed a sense of depression and suicidal tendencies, famously died by asphyxiating herself in an oven in 1963.

The recent reported suicide of her son, marine biologist Nicholas Hughes, brings to light a known psychiatric phenomenon: the heredity of suicidal behavior.

A first-degree relative -- a parent, sibling or child -- of a person who has committed suicide is four to six times more likely to attempt or complete a suicide, said Dr. David Brent, psychiatrist at the University of Pittsburgh Medical Center.

Studies on twins have shown that suicidal behavior is between 30 and 50 percent due to heritable factors, he said. Suicide victims' biological relatives who were adopted away also show an increased risk of suicide, he said.

The rate of suicide in America is 10.9 suicide deaths per 100,000 people, according to the latest information from the National Institute of Mental Health. That means, although the likelihood of suicidal behavior increases in families, a completed suicide is still a rare event, Brent said.

"Genetics is not destiny," he said. "The odds are still very much against you having this happening to another relative."

Family history of suicide and family history of mental disorder are two risk factors that the National Institute of Mental Health lists.

More than 90 percent of people who die by suicide have depression or another mental disorder, or a substance abuse disorder in combination with another mental problem, according to the National Institute of Mental Health. Learn about the link between depression and creativity

Research shows that depression runs in families. A new study in the Proceedings of the National Academy of Sciences shows biological markers for the inherited condition. The researchers found, in a sample of 131 people, that the biological offspring of depressed people had structural differences in their brain. Some of these people had been followed for more than 25 years. Learn more about mood disorders »

People at high risk of developing depression had a 28 percent thinning of the right cortex, the brain's outermost surface, the study found. Those with an extra thinning abnormality in the left cortex were most likely to develop depression or anxiety.

The data set shows that this brain surface thinning was present before these people developed mental problems, and was found in both children and grandchildren of depressed people, said Dr. Bradley Peterson, psychiatrist at Columbia University Medical Center and co-author of the study.

The new study may point toward more individualized medicine -- one day people may be screened for these brain abnormalities that indicate high depression risk, and receive treatment based on that, he said.

Researchers believe the cortical thinning causes depression by interfering with the processing of emotional stimuli, he said. A person with these brain abnormalities may benefit from therapy targeted at responding to social stimuli more appropriately, he said.

With both depression and suicide, research suggests that causal factors are a combination of genetics and environment, Peterson said.

The best way to prevent suicide is to treat the underlying psychiatric disorder, Brent said.

Besides Hughes and Plath, famous examples of two or more close relatives committing suicide include Ernest Hemingway's family -- Hemingway's father, brother, sister and granddaughter, in addition to the famous novelist himself, killed themselves.

The poet John Berryman jumped off a Minneapolis bridge in 1972; his father had committed suicide when the poet was a child. More recently, the playwright Spalding Gray apparently killed himself in 2004; his mother had taken her own life many years earlier.

Do relatives of people who killed themselves imitate suicide? This is possible, but hard to prove or disprove, Brent said. In fact, there is more evidence of copycat suicides among people who did not know the victim well, but merely learned about him or her through the news.

If you've actually lost a relative to suicide and go through the bereavement process, you may be more likely to understand the aftermath of suicide, Brent said.

Suicide "can also represent the learned or transmitted way of coping with unbearable stress," Peterson said.

What exactly gets transmitted in families with suicide? One theory is that it's a difficulty in emotional regulation.

"Not necessarily depression per se, but it's the ability to restrain yourself from acting on suicidal thoughts," Brent said.

The American Association of Suicidology is one place for online information if you or someone you know is contemplating suicide.

For immediate assistance, contact the National Suicide Prevention Lifeline at 1-800-273-TALK (8255).

All AboutDepression • Suicide

Head injury: Do you need to go to the ER?

By Elizabeth Cohen
CNN Senior Medical Correspondent

(CNN) -- Connie and Donald McCracken were watching CNN one evening last week when they learned of the tragic death of actress Natasha Richardson from a head injury. Immediately, their minds turned to their 7-year-old daughter, Morgan, who was upstairs getting ready for bed.

Two days earlier, Morgan, her father, and brother had been playing baseball in the yard of their Mentor, Ohio, home when her father hit a line drive that landed just above Morgan's left temple. A lump formed, but the McCrackens iced it down and the swelling subsided within an hour.

"For the next two days, she was perfectly fine," Donald McCracken says. "She had no symptoms. She went to school both days and got an A on her spelling test as usual. There were no issues whatsoever."

But after hearing about Richardson's death, the McCrackens wondered if Morgan was really as OK as she seemed. After all, Richardson had been talking and lucid immediately after her fatal injury.

When they went upstairs to kiss Morgan good night, she complained of a headache. "Because of Natasha, we called the pediatrician immediately. And by the time I got off the phone with him, Morgan was sobbing, her head hurt so much," McCracken says.

The McCrackens took Morgan to the emergency room at LakeWest Hospital in neighboring Willoughby, where doctors ordered a CT scan and immediately put Morgan on a helicopter to Rainbow Babies and Children's Hospital in Cleveland, with her father by her side.

"I knew it was bad when she had to get there by helicopter in six minutes, instead of the 30 minutes it would have taken to get to Cleveland in an ambulance," McCracken said.

When the helicopter arrived at Rainbow, the McCrackens were greeted by Dr. Alan Cohen, the hospital's chief of pediatric neurosurgery. He whisked Morgan into the operating room, pausing for a moment to tell McCracken that his daughter had the same injury as Richardson: an epidural hematoma.

McCracken remembers standing in the emergency room, feeling like the life had just been sucked out of him. "My heart sank," he says. "It just sank."

Unlike Richardson's, Morgan's story has a happy ending. After surgery and five days in the hospital, she's at home and doing fine. "Dr. Cohen told us that if we hadn't brought her in Thursday night, she never would have woken up," McCracken says.

Now the McCrackens sometimes wonder if they waited too long to get Morgan to a doctor. After hearing about Richardson's death, many people are asking themselves the same question: Do all head injuries need attention, even ones that seem minor?

"Sometimes there's a gray zone, and there's no right answer," Cohen says.

In most cases, it's pretty clear when someone needs medical attention after a head injury, says Greg Ayotte, a spokesperson for the Brain Injury Association of America and a cognitive rehabilitation therapist. "They're confused, they're agitated, or they might be dizzy or unresponsive," he says.

But then there's what doctors call the "talk and die" scenario, where someone seems fine, only to die hours, or sometimes even days later.

"Talk and die" can happen with several different kinds of brain injuries. In the case of epidural hematomas, the injury Richardson and Morgan had, blood pools in the area between the lining of the brain and the skull. "Fluid is building up in a contained space, creating pressure. Something's got to give, and that something is the brain," Ayotte says. If you don't get to the hospital to have surgery to drain the fluid, "the deterioration can happen very quickly."

Here, from Ayotte and other experts, is a list of what to do after someone has suffered a head injury.

1. Be vigilant

Keep an eye on someone who has hit his head, even if the person never lost consciousness. "A lot of folks are still under the assumption that as long as you're not knocked out, you're OK, and that's not true," Ayotte says.

2. Look for dizziness, vomiting, headache and confusion

If the injured person has these signs, take him or her to an emergency room, says Dr. Jam Ghajar, clinical professor of neurological surgery at Weill Cornell Medical College in New York, and president of the Brain Trauma Foundation.

3. Look for changes in symptoms and behavior

Any sudden change, such as Morgan's headache going from mild to severe in minutes, means the person needs medical attention. For example, Ghajar says, if a person gets suddenly sleepy in the first 12 hours after a hit, it may mean the parts of the brain responsible for staying awake are experiencing pressure from a bleed.

4. Be especially wary if someone has been drinking alcohol or is on blood thinners

It's tough to distinguish brain-injured behavior from drunken behavior, so when in doubt, take the person to the hospital, Ghajar says. Also, blood thinners can turn a mild bleed into a major bleed, so be especially vigilant if the injured person is taking blood thinners such as warfarin.

He also warns people to be extra vigilant when an elderly person hits his or her head. The Centers for Disease Control and Prevention has information on traumatic brain injury and senior citizens.

5. Go to a certified trauma center if you can

The American College of Surgeons has a list of certified trauma facilities; a hospital that's not a trauma center may not have a neurosurgeon on call.

The McCrackens say they look back and still can't believe Morgan suffered such a severe injury and didn't show any signs for 48 hours. "She didn't black out, her speech wasn't slurred, she wasn't dizzy, she wasn't any of the things you'd expect," McCracken says. "And you don't want to be one of those panicky parents who takes their child to the emergency room all the time."

Cohen's advice after a head injury: When in doubt, go. "It's always better to err on the side of being conservative," he says.

Tuesday, March 24, 2009

Brain Images Reveal the Secret to Higher IQ

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

By Emily Singer

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 Phillip 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."

Thursday, March 19, 2009

Consciousness signature' discovered spanning the brain

Brain scans have long been used to try to find the "seat of consciousness" in the brain.

17 March 2009 by Anil Ananthaswamy

Electrodes implanted in the brains of people with epilepsy might have resolved an ancient question about consciousness.

Signals from the electrodes seem to show that consciousness arises from the coordinated activity of the entire brain. The signals also take us closer to finding an objective "consciousness signature" that could be used to probe the process in animals and people with brain damage without inserting electrodes.

Previously it wasn't clear whether a dedicated brain area, or "seat of consciousness", was responsible for guiding our subjective view of the world, or whether consciousness was the result of concerted activity across the whole brain.

Probing the process has been a challenge, as non-invasive techniques such as magnetic resonance imaging and EEG give either spatial or temporal information but not both. The best way to get both simultaneously is to implant electrodes deep inside the skull, but it is difficult to justify this in healthy people for ethical reasons.
Brainy opportunity

Now neuroscientist Raphaƫl Gaillard of INSERM in Gif sur Yvette, France, and colleagues have taken advantage of a unique opportunity. They have probed consciousness in 10 people who had intercranial electrodes implanted for treating drug-resistant epilepsy.

While monitoring signals from these electrodes, Gaillard's team flashed words in front of the volunteers for just 29 milliseconds. The words were either threatening (kill, anger) or emotionally neutral (cousin, see).

The words were preceded and followed by visual "masks", which block the words from being consciously processed, or the masks following the words weren't used, meaning the words could be consciously processed. The volunteers had to press a button to indicate the nature of the word, allowing the researchers to confirm whether the volunteer was conscious of it or not.

Between the 10 volunteers, the researchers received information from a total of 176 electrodes, which covered almost the whole brain. During the first 300 milliseconds of the experiment, brain activity during both the non-conscious and conscious tasks was very similar, indicating that the process of consciousness had not kicked in. But after that, there were several types of brain activity that only occurred in the individuals who were aware of the words.
Lost seat

First, there was an increase in the voltage levels of the signals in their brains. Second, the frequency and phase of neurons firing in different parts of the brain seemed to synchronise. Then some of these synchronised signals appeared to be triggering others. For example, activity in the occipital lobe seemed to cause activity in the frontal lobe.

Because this activity only occurred in volunteers when they were aware of the words, Gaillard's team argue that it constitutes a consciousness signature. As much of this activity was spread across the brain, they say that consciousness has no single "seat". "Consciousness is more a question of dynamics, than of a local activity," says Gaillard.

Bernard Baars of the Neuroscience Institute in San Diego, California, who proposed a "global access" theory of consciousness in 1983 agrees: "I'm thrilled by these results."

He says they provide the "first really solid, direct evidence" for his own theory. He also says that having such a signature will make it easier to look for signs of consciousness in people with brain damage, infants and animals with the help of non-invasive techniques such as EEG.