Different types of memory and epilepsy

This article discusses different types of brainwaves, and how they relate to epilepsy.

Our long-term memory is consolidated when we sleep. Short-term memory traces in the hippocampus, an area deep in the brain, are then relocated to more outer parts of the brain. An international team of neuroscientists, among who Mathilde Bonnefond and Til Ole Bergmann from the Donders Institute at Radboud Universiy, now shows how a three-step brain oscillation plays an important part in that process. Nature Neurosciences publishes the results on September 21st.

Bonnefond and Bergmann specialize in research on oscillations: waves of brain activity. 'Non-rapid eye movement (NREM) sleep is responsible for the memory consolidation during our sleep', Bonnefond explains. 'NREM is known for its very slow oscillations (SOs). Other types of oscillations are hidden inside these SOs. We discovered that three types of oscillations are nested inside each other in the hippocampus and have a joint function.'

Slow waves, spindles and ripples

Slow oscillations only happen about once per second (~0.75 Hz). In a specific time frame within these SOs, Bergmann, Bonnefond and their colleagues found clusters of oscillations of an intermediate speed: the so called spindles which happen about 15 times per second (12 -- 16 Hz). And within these spindles, they found clusters of superfast oscillations called ripples, which happen about 90 times per second (80 -- 100 Hz), and which reflect the local reactivation of the memory trace to be shuttled to the cortex.

To summarize: SOs contain spindles, which in their turn contain ripples. 'Earlier studies only coupled these oscillation types in pairs', Bonnefond explains. 'But now, we see that SOs, spindles and ripples are functionally coupled in the hippocampus. And we hypothesize that they provide fine-tuned temporal frames for the transfer of memory traces to the neocortex.'

Epilepsy

The group of researchers investigated the process in human epilepsy patients during natural sleep. Doctors were looking for the brain areas responsible for their epilepsy, and the current research was done at the same time: with special electrodes, the researchers recorded oscillations from inside the brain. Bonnefond: 'This was a great opportunity to investigate the hippocampus, since it's difficult to measure deep brain regions with classical electrophysiological techniques.'

The patients did not have to remember any specific information. 'You're consolidating memories every night, so we investigated the process in general. The next step would be to link these clustered oscillations to specific memories.'

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Study: Brain waves may help to determine autism severity

A recent study shows that the severity of autism may  be determined by brainwaves. This is a small study and not ready for prime-time.
JR

Measuring how quickly a child's brain processes sounds might help identify the severity of autism, according to a new study.

Observing children's brainwaves may also allow identification of autism earlier than is currently possible, the study authors reported.

"The finding that the brain's response to certain types of information is associated with autism severity is hugely promising," said senior researcher Sophie Molholm, an associate professor of pediatrics and neuroscience at Albert Einstein College of Medicine in New York City.

"A major goal of autism research is to develop measurements to diagnose the disorder as early as possible, and that can help to identify areas of weakness, and strength, so that treatments can be optimized," Molholm said. "Our work shows that measuring brain activity is a viable approach to achieving these goals."

The findings were published in the Sept. 22 online edition of the Journal of Autism and Developmental Disabilities.

Approximately one in 68 children has been diagnosed with an autism spectrum disorder, according to the U.S. Centers for Disease Control and Prevention. But the experience of autism for these children differs significantly in terms of their symptoms and impairments.

Molholm's past research found that among children with autism, the brain takes slightly longer -- measured only in milliseconds -- to process sounds, sights and other sensory information.

In this study, Molholm and her colleagues measured this processing speed in 43 children with autism, aged 6 to 17, using electroencephalograms, or EEG (brain wave) recordings. When the children were shown an image, played a tone or provided a tone and image at the same time, they pressed a button while the EEG recorded how quickly their brains registered the stimulus.

Then Molholm's team compared the children's visual, audio and audiovisual processing speeds to the severity of their symptoms. The researchers based their assessment of autism symptom severity on how great the children's social-communication difficulties were, how severe their repetitive behaviors were and how restricted their interests were.

The more severe the children's symptoms were, the study found, the slower the children processed sounds. There was also a connection between how slow children processed combined audiovisual stimuli and the severity of symptoms, but there was no difference in how quickly they processed the images by themselves, according to the study.

"As we develop EEG probes that measure areas of dysfunction, or even areas that individuals with autism are unusually good at, we should be able to use them as tools to help diagnose autism," Molholm said.

This study's particular finding on audio and audiovisual processing, however, would only apply to those with slower sensory processing. That may not necessarily include all individuals with autism spectrum disorders, she said.

In addition, the association seen in the study does not prove a cause-and-effect relationship.

One autism expert expressed optimism about the study, but noted it has some significant limitations.

"The finding is intriguing and may well open new areas of researching the problems those with autism spectrum disorders have in interacting with their environment," said Dr. Glen Elliott. He is a clinical professor of psychiatry at Stanford School of Medicine and chief psychiatrist and medical director of the Children's Health Council.

....

"An objective measure of autism severity would, indeed, be a boon -- for example, allowing regional centers to set a cut-off of who does and does not qualify for services, even if they meet criteria for autism spectrum disorder," Elliott said.

Molholm said she plans to continue looking at ways that EEGs can be used to assess individuals with autism spectrum disorders.

The more precise these tools can become, then the more information they might be able to provide long before it's currently possible to diagnose autism based on behavior.

"We imagine that once developed, these will be used in conjunction with clinically based diagnostics, at least for the foreseeable future," Molholm said. "However, the hope is to get to the point where they can be used for very early diagnosis."

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Brain wave test to diagnose ADHD approved by FDA

The FDA approved a brain wave test to diagnose ADHD, one of the only objective tests for this purpose.

The first brain wave test that could help diagnose children and teens with attention-deficit/hyperactivity disorder (ADHD) has been approved by the U.S. Food and Drug Administration.

The device can be used in patients between the ages of 6 and 17 as part of a complete psychological examination to either help confirm an ADHD diagnosis or bolster a doctor's decision that more testing for ADHD or other disorders is needed, the FDA said in a news release Monday.

Called the NEBA system, the 20-minute noninvasive test uses an electroencephalogram (EEG) to calculate the ratio of two brain wave frequencies, called theta and beta, which studies have shown is higher in children and teens with ADHD.

One expert offered a word of caution about the device.

"For clinicians and researchers interested in ADHD, an objective diagnostic test that is accurate, sensitive and specific has been one of the 'holy grails' which has long been sought," said Dr. Andrew Adesman, chief of developmental & behavioral pediatrics at Steven & Alexandra Cohen Children's Medical Center of New York, in New Hyde Park, N.Y.

However, he added, "it is doubtful that this EEG test newly approved by the FDA will be as accurate and reliable as clinicians and families would ideally want.

"Given concerns among the public and some professionals about the steady increase in the number of children and adolescents being diagnosed with ADHD, it would be wonderful if clinicians had an objective test to assist in the diagnostic process," Adesman said. "Although this new EEG test may prove helpful to clinicians, neither parents nor professionals will be able to rely upon it as a standalone 'litmus test' for whether a child has ADHD."

Adesman also noted that the FDA has approved other "objective" diagnostic tests for ADHD that have not become a common part of diagnosing the disorder, and the fate of the NEBA system remains to be seen.

The device, made by NEBA Health of Augusta, Ga., is already used to assess sleep issues, measure unconsciousness, diagnose side effects from head injuries and monitor the brain during surgery, according to CBS News.

The FDA's approval of the device was based on a company-funded study of 275 children and teens with attention or behavioral problems. The study showed that the test, when used with standard diagnostic criteria, helped doctors more accurately diagnose the disorder when compared to a doctor's exam alone, the agency said in its statement.

"Diagnosing ADHD is a multistep process based on a complete medical and psychiatric exam," Christy Foreman, director of the Office of Device Evaluation at the FDA's Center for Devices and Radiological Health, said in the news release. "The NEBA System along with other clinical information may help health care providers more accurately determine if ADHD is the cause of a behavioral problem."

ADHD is a common childhood disorder. Nine percent of American teens have ADHD and the average age of diagnosis is 7, according to the American Psychiatric Association. Symptoms of ADHD include inattention, hyperactivity, impulsivity and behavioral problems. Treatments for ADHD include medication, behavioral modifications and therapy.

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10 Reasons Babies Wake Up At Night

Most babies wake up at night, and this article discusses 10 common reasons why they do.

Most babies wake up at night. And although some superhero babies sleep 10-12 hours straight starting around 3-4 months of age, most infants wake up during the night and cry out for their parents. There are scientific reasons and some developmental and behavioral explanations for these awakenings. I spoke with my friend Dr. Maida Chen, a pediatric pulmonologist, mother to three and director of the Pediatric Sleep Disorders Center in Seattle. I put this list together regarding why babies wake up at night. I'll author a follow-up blog on ways you can help your baby when they wake up, too.

10 Reasons Babies Wake Up At Night:

1. Sleep Cycle: Babies wake up during the night primarily because their brain waves shift and change cycles as they move from REM (rapid eye movement) sleep to other stages of non-REM sleep. The different wave patterns our brains make during certain periods define these sleep cycles or "stages" of sleep. As babies move from one stage of sleep to another during the night, they transition. In that transition, many babies will awaken. Sometimes they call out or cry. Sometimes they wake hungry. It's normal for babies (and adults) to wake 4-5 times a night during these times of transition. However, most adults wake up and then fall back to sleep so rapidly that we rarely remember awakening. At 4 months of age, many parents notice awakenings after a first chunk of deeper sleep. This is normal, and often due to development of delta wave sleep (deep sleep). The trick for parents is to do less and less as each month of infancy unfolds during these awakenings; we want to help our babies self-soothe more and more independently (without our help) during these awakenings so that sleeping through the night becomes a reality.

2. Brain Waves: The majority of babies are really capable of sleeping for a prolonged 6+ hour period of time 1/2 way through infancy, around 6 months. As Dr. Chen explains, "When doing sleep studies we follow brain wave activity." After 6 months of age she says, "We see brain waves at 6 months of age and up that are similar in pattern to that of adults." Now that doesn't mean that babies that wake throughout the night have abnormal brain waves, but it does mean as they progress through infancy, they get more and more mature when it comes to sleep. Dr Chen says, "If you look at sleep studies on newborns and infants, they will look very different compared to older children. But by 6 months of age, the baby's brain wave patterns will look much like an 18-year-olds." That being said, unlike an 18-year-old, once some babies are awakened during transitions, they may call out for your help!

3. "Good Sleepers" Versus "Bad Sleepers": Some babies are just better sleepers right out of the gate. Dr Chen reminded me, "There are good sleepers and there are bad sleepers. Part of that is organically hard-wired. But there are also good sleepers with bad habits." Our job as parents is to do the best we can in creating good sleep habits. Most of that has to do with consistency from one night to the next. Some babies make habitual associations like always nursing to sleep, always being rocked to sleep or always being held to fall asleep. Then, when they have awakenings at night, they may cry out to have those associations (bottle, nursing or rocking to sleep) to get back to sleep. These associations can cause a good sleeper to have bad sleep, because of the habit.

4. Crying Is Part Of Being A Baby: There is a pretty serious ongoing debate and national dialogue between parents, psychologists, pediatricians, lactation consultants and scientists about letting babies cry-it-out versus not cry-it out. I'll not delve into much of the debate here, but if you're worried that letting your baby cry-it-out will damage them, try to relax. Dr Chen says, "We don't think that some crying is bad for a baby. The evidence to support long-term damage from crying at night is nil." Many pediatricians recommend letting your baby gradually learn to self-soothe or cry-it-out once they have self-soothing skills (turning over, sucking on fingers or hand, and more mobility) starting somewhere around 4-6 months of age.

5. Mom or Dad's Role At Night: Studies have evaluated how parents can change an infant's sleep. Studies have found that infant sleep disorders are affected by how many times a parent comforts them at night. The more parents camp out (remain in the room until baby is asleep), the more parents transfer the baby into the crib after asleep and the more they picked the baby up at night, the more likely the baby has sleep challenges. And although most studies have evaluated a mother's role in overnight awakenings, a2010 Tel Aviv study found that when fathers were more involved in infant care (day and night), in addition to mothers, their babies had fewer overnight awakenings. Take turns!

6. Development: Developmental milestones shift and change sleep. As described in the video, after 4 months of age, most babies have a prolonged period of sleep and then wake up every couple of hours because of sleep cycle changes. Sometimes they will wake up and roll over and then freak out and cry when they get stuck or move into a new position. The rolling milestone may translate into awakenings. At 6 months of age, babies are exploring the world, putting all sorts of objects and germs in their mouths, and subject to more infection. They're also learning to sit at 6 months of age and this milestones often triggers awakenings. At 9 months of age, babies learn how to pull themselves up in the crib and stand-up -- don't be surprised if they are awake more. Most parents are unpleasantly surprised to find their 9-month-old up and awake in the middle of the night standing up, ready to rock and roll.

7. Teething: There's no question that teething wakes children at night and disrupts sleep. Teething typically commences around 6 months of age but I hear about teething waking babies all the way through their toddlerhood. Acetaminophen is the only medication I recommend for teething.

8. Behavioral Changes: Many babies will have more frequent awakenings around 6 or 9 months of age due to advancing sense of independence and self-awareness. At 6 months of age, I often hear from parents their babies will wake up in the middle of the night and start talking, just go through their different sounds. No need to go to them if they are not fussing! When babies develop separation anxiety around 9 months of age, they will often change their sleep patterns. Often during those times of behavior change they will wake and scream out when they realize you're not at their side.

9. Infection: Infants and children typically have an upswing in infections after 6 months of age. This occurs primarily because once a baby reaches 6 months, they are capable of putting lots of new objects (including their hands) in their mouths, so their exposure to germs increases dramatically. Many babies who have colds or upper respiratory infections will wake due to congestion or coughing. Fever, vomiting and diarrhea will awaken babies at night, too. Hang on and support your baby with a little TLC. Sleep schedules typically go back to normal within a few weeks after the illness began, especially if you can keep up good sleep routines.

10. Pacifiers/Bottle: Many babies are conditioned to fall asleep (or fall back to sleep) while sucking on something. This starts just after birth, when newborns instantly fall asleep with breastfeeding or a bottle in their mouth. Many infants who use a pacifier will wake up between 6-12 months of age when the pacifier falls out. The easiest solution is to get rid of it all together! But remember, big habits die hard, if a baby learns to fall asleep sucking and does so for 6+ months, it can take awhile to unlearn the habit.

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