Archive for 'ADD / ADHD'

What Gamma Can Do For You

For a long time neuroscientists have shown work from poor unsuspecting birds and cats that there are specific critical periods in development important for a functional visual system or a species-appropriate bird song. In humans there have been a few unfortunate cases of horrific neglect of children (i.e. Genie) that have likely been responsible for profound intellectual deficits, which have been informative to scientists interested in the consequences of depravation during the early years. But scientists have not been able to conduct a formal and yet ethical scientific experiment to measure the relationship between a critical period and its function in humans until now, thanks to the ability to measure gamma.

On Oct 21st, the Science Daily featured an article on the exploration of the critical period for language development and other skills in toddlers by measuring their gamma waves on the EEG. The time period between 16 to 36 months is a time of tremendous language growth in humans, where their vocabulary typically expands from about 100 to 1000 words. Dr. April Benasich from Rutgers University in Newark, measured gamma activity in the frontal cortex of toddlers (16, 24 and 36 months) while they sat on a parent’s lap and quietly played. Gamma power (which is determined by the amount of synchronous gamma firing) was associated with language development, cognitive skills, behavior and impulse control. The more advanced a child’s language or cognitive skills, the more gamma power that child showed. And as expected, children who’s parents had a history of language impairments showed lower gamma power.

This new finding is consistent with what is already known about gamma in adults and from work in animals. Gamma heightens during the processing of linguistic information, during the formation of ideas and memories and during other abilities. Furthermore, gamma fires between 2 regions of the brain during associative learning, when a new concept is linked to one already known.

Low gamma coherence within different hemispheres is associated with ADD and learning disabilities. In fact Dr. C. Njiokiktjien from the Amsterdam, Netherlands compared intrahemispheric coherences of various frequencies (including gamma) of children with non-verbal vs. verbal learning disabilities(1). Their results suggested that children with non-verbal learning disabilities had less connectivity in the right hemisphere, which is consistent with the idea that it’s the right hemisphere that manages spatial skills, as well as other non-verbal tasks.

Dr. Hermann from Magdeburg University in Germany presents a model of gamma based on its power under various psychiatric conditions(2). Too much gamma firing is associated with ADHD, positive associations in Schizophrenia (i.e. hallucinations) and epilepsy, and Alzheimer’s disease, negative symptoms of Schizophrenia (i.e. blunt or flat affects) are associated with too little gamma.

So can we benefit from using brainwave entrainment to help us enter gamma states? Or are there risks associated with having more gamma power?

Dr. R. Olmstead, a clinical psychologist from Sunrise, FL, found benefits with gamma training in children with non-verbal learning disabilities, ages 6-16(3). She exposed them to 35 min brainwave entrainment sessions twice a week for 6 weeks. The sessions alternated between excitatory sessions (increasing from 14 (beta) to 40 (gamma) Hz), and inhibitory sessions (decreasing from 40 to 14 Hz). She found that her training enhanced various non-verbal cognitive abilities such as processing speed, freedom from distractibility, arithmetic and coding.

But what about the rest of us?

I think there is good reason to hypothesize that gamma training might also benefit many with other learning disabilities as well. But I am concerned about the fact that ADHD is associated with too much gamma firing. Thus if you have a learning disability and ADHD, or just ADHD alone, or even if you didn’t have any signs of ADHD, would gamma training enhance your distractibility or impulsiveness? 

Unfortunately, there hasn’t been enough research done to answer these questions at this point. However, there is good news. Brainwave entrainment for most of the population is a very gentle stimulus, and it takes time for cognitive benefits to take effect. Thus training with gamma (or any other stimulus) is done slowly. All such training should be conducted mindfully, and if you start to develop any unwanted symptoms, you can simply stop your training, and the effects will likely to go away. The higher the gamma power, the more severe the symptoms, so ignoring milder unwanted side effects could be dangerous.

The study by Olmstead might also be a good example as to how to safely train gamma. She trained students to progress into gamma with the excitatory protocol, and to leave gamma and return to beta in the inhibitory protocol. I would imagine that such training is good for leading our brains in and out of gamma as needed. And thus it might be teaching our brains to self regulate.

Nevertheless, there is an element of adventure in using gamma to potentially enhance your cognitive skills, and if the idea makes you queasy, I’d stand back and wait for more research to be done.

References:
1 Njiokiktjien C, de Rijke W, Jonkman EJ. Children with non-verbal learning disabilities (NLD): coherence values in the resting state may reflect hypofunctional long distance connections in the right hemisphere. Fiziologiia cheloveka. 2001; 27: 17-22.
2 Herrmann CS, Demiralp T. Human EEG gamma oscillations in neuropsychiatric disorders. Clin Neurophysiol. 2005; 116: 2719-33.
3 Olmstead R. Use of Auditory and Visual Stimulation to Improve Cognitive Abilities in Learning-Disabled Children. Journal of Neurotherapy. 2005; 9: 49-61.

New study on Brainwave Entrainment (By Dr. Huang)

I’m pleased to announce the publication of “A Comprehensive Review of the Psychological Effects of Brainwave Entrainment” in Alternative Therapies in Health and Medicine this month. This paper is the most comprehensive review of peer reviewed research in the subject, and was written in order to inform those within and the beyond the field of brainwave entrainment (BWE), and to provide sufficient background for future research.

Most of the research known to date has been summarized by David Siever in two unpublished manuscripts that he sells and distributes. They contain much valuable information about the history of BWE, both published and unpublished studies and proposed mechanisms of action. However, despite their length, they do not provide a complete listing of the peer reviewed literature, nor have his manuscripts faced the scientific scrutiny that comes with publishing in a peer reviewed journal. In fact, in our comprehensive search, we found articles that have never before been mentioned by those in the brainwave entrainment development and scientific community. Why? Believe it or not, the problem is in the inconsistency in terminology used to describe BWE. The term, BWE, until today, cannot be found in the scientific literature. Instead it is referred to as audiovisual stimulation, photic stimulation, photic driving, auditory entrainment, etc, etc. In all I did a search using 31 different terms to look for articles on brainwave entrainment, which returned 27,830 articles using Ovid (1 out of the 4 databases I used to do the search). Only a very small handful of these turned out to be articles on BWE. Thus much of the credit needs to go to my bosses at Transparent Corporation, who gave me the time to do this exhaustive, time consuming, and yet important work.

I looked for papers with psychological terms that described outcomes that I’d seen associated with BWE on the web, in conferences and in the published and unpublished literature. After combining the two searches, and screening for those that were indeed articles addressing psychological outcomes of BWE, and those that passed some basic scientific criteria, we ended up with just 20 articles.

The psychological effects that had been examined in relation to BWE included cognitive functioning (we divided it into verbal, non-verbal, memory, attention and overall intelligence), stress (long and short-term), pain, headache/migraines, mood, behavior and pre-menstrual syndrome (PMS). When two or more studies had examined similar outcomes, we placed them into tables for greater comparability. Thus we had five tables divided by cognitive functioning, stress, pain, headaches/migraines and mood. Studies used a variety of different frequency protocols and stimulation methods which are outlined in the tables.

Out of the 20 studies, 17 were actually developed to support or confirm a hypothesis, and of these, all found a positive effect in at least one outcome. And in each outcome mentioned, at least one study had a positive finding. What was remarkable was that for some outcomes, only one of several protocols had a positive effect, while others were improved by a variety of different protocols. The most consistent positive findings were found in attention (4/4 studies), pain (3/3 studies) and headache/migraines (3/3). While positive effects were found in all other outcomes examined except for mood, either fewer studies had been conducted or a smaller percentage of the protocols examined were effective. Mood was examined in the 3 studies where the effects of theta were examined on a variety of outcomes. So we believe that the ability of brainwave entrainment to positively effect mood has not been properly tested in the peer reviewed literature.

Overall, we conclude that brainwave entrainment shows real potential to positively affect psychological outcomes. However, more and bigger studies need to be done, using additional outcomes and outcomes already examined. We hope that we’ve provided the necessary background to inspire future research and collaboration, so that the field of brainwave entrainment can gain recognition and momentum in the scientific literature.

To view a copy of this article, visit:

http://www.transparentcorp.com/research/

Tina L. Huang, Ph.D.
Director of Research
Transparent Corporation

The effect of belief on intelligence

A unique and fascinating new study was released this year by Carol Dweck, a psychologist at Stanford University, researching the effects of belief on cognitive performance.

The results: children who believed that intelligence was malleable and could be improved were much more likely to perform well in school. Children who believed intelligence was something set in stone – a genetic gift from birth that never changes – did not perform as well.

To test this, Dweck separated one hundred 7th grade students into 2 equal groups. All students had suffering math scores. One group was taught good studying habits, the other was taught about the plasticity of the brain, and how the brain can change; new neural connections can be formed and intelligence can actually be increased.

At the end of the semester, the children who had the crash course in neuroscience ended up performing better than those who were taught study skills! This is because their beliefs about intelligence had changed.

Here’s some excerpts from an article on this:

“Some students start thinking of their intelligence as something fixed, as carved in stone,” Dweck says. “They worry about, ‘Do I have enough? Don’t I have enough?'”

Dweck calls this a “fixed mindset” of intelligence.

“Other children think intelligence is something you can develop your whole life,” she says. “You can learn. You can stretch. You can keep mastering new things.”

She calls this a “growth mindset” of intelligence.  

“When they studied, they thought about those neurons forming new connections,” Dweck says. “When they worked hard in school, they actually visualized how their brain was growing.”

“We saw among those with the growth mindset steadily increasing math grades over the two years,” she says. But that wasn’t the case for those with the so-called “fixed mindset.” They showed a decrease in their math grades.

“If you think about a child who’s coping with an especially challenging task, I don’t think there’s anything better in the world than that child hearing from a parent or from a teacher the words, ‘You’ll get there.’ And that, I think, is the spirit of what this is about.”

In the articles on our website, we’ve been talking for years about how beliefs can work for or against your cognitive performance. Many people who approach us with cognitive issues want to focus only on the neurological or physiological aspect of that. Often, after a few months of work, it becomes apparent that a psychological approach is needed – the physiology is right for peak performance, but the belief system keeps the brain stuck in first gear. Negative beliefs about one’s intelligence can often be very hard to counteract. This study is useful in that it shows that merely learning more about the brain can help give your brain the boost it needs to make real progress.

NPR has a nice broadcast of this new research online: http://www.npr.org/templates/story/story.php?storyId=7406521

Meditation sharpens the mind, attention, and the distribution of neural resources

Lots and lots of meditation“You can imagine that life is a series of attentional blinks, and we might be missing an awful lot of what’s going on.” 




This has been all over the news recently, so you might have already heard of it, but since it so relates to what we do I thought I would mention it here anyway.

A group of researchers from the University of Wisconsin have studied the effects of meditation on the brain’s ability to manage its attentional resources. Specifically, they studied the phenomenon known as “attentional blink”, or the inability of most people to discriminate between closely spaced visual targets.

Neuroscientist Richard Davidson explains:

Paying attention to facts requires time and effort, and since everyone only has a limited amount of brainpower to go around, details can get overlooked. For instance, when two pictures are flashed on a video screen a half-second apart, people often miss the second image.“Your attention gets stuck on the first target, then you miss the second one,” Davidson said. This is called “attentional blink,” an effect akin to how you might overlook something when you blink your eyes.

However, meditation appears to decrease this effect, sharpening the ability of the brain to focus attention and recognize targets rapidly.

Davidson studied volunteers before and after training in meditation. Specifically, they were trained in Vipassana meditation (which is often mentioned on our forums by the way).

They found that after meditation training, subjects required less time to spot details than before. Subjects were asked to discriminate between numbers flashed rapidly along with letters on a computer screen. To many people’s surprise, their ability to detect the second number improved within the “attentional blink” time frame.

In recent years, scientists have found meditation affects brain functions. For instance, research into Tibetan monks trained in focusing their attention on a single object or thought revealed they could concentrate on one image significantly longer than normal when shown two different images at each eye. Another study of people who on average meditated 40 minutes daily found that areas of their brains linked with attention and sensory processing became thicker.



I have read similar findings before. One example would be Habituation, or the tendency of the mind to give progressively weaker responses to sensory stimuli. Have you ever noticed how quickly you can become accustomed to sounds in your environment, to the point where you no longer even notice them? That is an example of habituation. It happens with the vast majority of people, but not as much with experienced meditators.

Here is a quote from Professor Shantha Ratnayake:

“To understand these phenomena let us imagine that a person who is reading quietly is suddenly disturbed by a loud noise. If the same sound is then repeated with a few seconds later his attention will again be diverted, only not as strongly nor for as long a time. If the sound is then repeated at regular intervals, the person will continue reading and become oblivious to the sound. A normal subject with closed eyes produces alpha waves on an EEG tracing. An auditory stimulation, such as a loud noise normally obliterates alpha waves for seven seconds or more; this is termed alpha blocking. In a Zen master the alpha blocking produced by the first noise lasts only two seconds. If the noise is repeated at 15 second intervals, we find that in the normal subject there is virtually no alpha blocking remaining by the fifth successive noise. This diminution of alpha blocking is termed habituation and persists in normal subjects for as long as the noise continues at regular and frequent intervals. In the Zen master, however, no habituation is seen. His alpha blocking lasts two seconds with the first sound, two seconds with the fifth sound, and two seconds with the twentieth sound. This implies that the Zen master has a greater awareness of his environment as the paradoxical result of meditative concentration.”




Here’s an article on the topic: http://www.livescience.com/health/070507_mental_training.html

Here’s a link to the University of Wisconsin study: http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371/journal.pbio.0050138

Also mentioned in the article is what this research could mean for people with ADD/ADHD. Perhaps meditation will be part of a recommended regimen for people with ADD in the future.

Here is another interesting excerpt:

“One of the fundamental mysteries that is now becoming better understood as we go along but which is still a breakthrough area of research is neuroplasticity, the idea that we can literally change our brains through mental training,” Davidson told LiveScience. “Certain kinds of mental characteristics such as attention or certain emotions such as happiness can best be regarded as skills that can be trained.”

Happiness as a skill? What an amazing paradigm shift that would be for most people. :)