All About HEG

(THESE SHOULD ALL BE LINKED TO THE TEXT BELOW)

What HEG is and How it Works

Ease of Use

When to Use HEG

Duration of Training

Locations and Length of Training

Locating of Training Site

Sites to Train

Rotating One Site a Day

Exercise Analogy

Perfusion

Fast-Wave Frequencies and HEG

Responses to Training

Calibrating Device at Beginning of Session

Training Guidelines

Timing of Sessions

Percent Increase in Ratio

Attention Index

Baseline

HEG and Coherence

Safety

What’s the Difference Between nIR and pIR?

What HEG is and How it Works

Sometimes, especially when working the pre-frontal cortex, EEG neurofeedback is a challenge due to muscle artifact. HEG addresses that problem so that brain training can be efficient. This section covers what HEG is, how it works, and general theoretical questions. For technical questions such as how to operate the LIFE game, see (INSERT LINK HERE)/

HEG stands for HemoEncephaloGraphy and involves training to increase blood levels and blood oxygenation, which in turn improve the metabolic capacity of parts of the brain.  It is primarily done on the pre-frontal cortex, the area behind the forehead, which is the executive center of the brain.

One of the greatest benefits of HEG compared with EEG training is that it does not measure electrical signals, because the HEG signal isn’t an electrical signal at all. It’s a ratio of red to infrared light reflected by the surface of the brain. I use HEG with everyone, though I’m less likely to use it at Fpz if there is obsessiveness or compulsions. I’m more likely to go to F7 and F8 than Fp1 and Fp2 if there are impulse control, social or emotional regulation issues. I base that on the Client Report.

Training with EEG in the front of the head places the electrodes/sensors very close to the eye muscles, which produce large electrical signals when a client blinks or moves his/her eyes (muscles work with bio-electric signals just like the heart and brain).  The EEG amplifier and/or software can’t tell the difference between eye blink signals and brain signals, so it includes these eye blinks in the EEG we are training.  It is called “artifact” because it is not really from the brain.  It is difficult to avoid this eye blink artifact when electrodes are placed near the front of the head–and especially when they are on the forehead/prefrontal area.

HEG, since it measures blood perfusion or oxygen levels, is not affected by electrical activity, so you can blink as much as you wish and have no effect on the signal.  Hence, for the many people who seek brain training and have a lot of slowing in their prefrontal areas, and thus have difficulty with planning, organizing, attention, impulse control or other executive functions, HEG can be a very helpful training approach.  The more easily brain cells can get their blood supply, the more oxygen and glucose they have available to them, the faster they are able to fire when needed.

EEG has a fairly steep learning curve: there is a lot to learn about finding sites, placing electrodes to get a good signal, all the various different training options, performing assessments, etc.  HEG is pretty simple to get started with, and it’s hard to make many mistakes in working with it.  So it can be an excellent place for a new trainer to start–or an excellent addition for an experienced EEG trainer.

There are two HEG systems available:  pIR (stands for Passive InfraRed), developed by Jeff Carmen, and nIR (stands for near InfraRed), developed by Hershel Toomim.  pIR measures the infrared temperature changes on the forehead (higher infrared temperatures indicate more metabolic activity) and is almost always done at Fpz in the center of the forehead.  nIR measures the degree of red blood at the surface of the brain (indicating it is oxygenated) and it also measures infrared temperature changes.  It is often used in two or three different sites in a single training session.

The main thing to remember when you do HEG is that oftentimes less is more.  Over training–meaning training too long–can stress the prefrontal area and result in headaches, aggressive behavior, sleepiness, etc.  Usually trainers start with around 10 minutes in a session and work up to around 30 minutes.  There is some evidence that training once every 4 days is the optimum frequency for HEG.

HEG isn’t necessarily involved in building new circuits in the brain. Learning is what does that. It is designed to increase blood supply or blood oxygen levels. In a sense, EEG training does this as well, at least training which speeds up brain activity, since it requires metabolic increases. The real benefit of HEG from my point of view is that you work on this directly and, more importantly, you can do so directly on the frontal lobes. As you know, working on the frontals is complicated by eyeblink and eyeroll artifact when you use EEG systems. With HEG there is no muscle artifact, because you are not measuring electricity.

What you are trying to do is to draw oxygenated blood into the area trained–to stress the distribution system to its limit so it is motivated to expand the capillary beds it uses to deliver oxygen and glucose to the neurons in various areas.

The most demanding task for the PFC is single-pointed focus (the OPPOSITE of open focus, which is more of a back-of-the-head phenomenon). It requires that the PFC neurons block all other functions to focus the attention on an external point.

When you think, visualize, try, talk to yourself, etc. you are moving inside your head and, at least in my experience, the graph of the red/infrared ratio begins to fall. When I am blank in my mind, with the intention of seeing the graph rise, focusing intently on the place where it “comes out” of the right wall of the graph window, it goes up quickly and steadily. As soon as a thought enters my mind, it starts to fall.

Ease of Use

I used to think Hershel Toomim, creator of nIR HEG, was bragging when he said he taught people to do HEG in one session, but I’ve found (in my own work and in that of the trainers I’m supervising) that it’s pretty rare to find a kid who doesn’t figure it out in one session.  Adults can be a different story.

When to Use HEG

Anytime I have someone with lots of slow frontal activity, or any time I see significant executive function issues in the subjective assessment, I would use HEG.  Because I do HEG generally once every 4 days, and usually I start with up to 10 minutes per session (adding perhaps a minute each 2-3 sessions as the client tolerates it), and because there is no prep or cleanup, I will often do it at the beginning of the session, then go ahead with EEG based on the assessment

Problems with impulse control, emotional regulation, social regulation and (almost certainly, though they didn’t mention it) distractibility are related to prefrontal function.   With ANY child or adult who shows executive function problems, HEG is the approach of choice for me.

Duration of Training

According to Hershel Toomin, creator of nIR training, 300 minutes of nIR HEG training (without significant breaks) resulted in lasting changes.

Locations and Length of Training

HEG is generally limited to training the forehead area where there is no hair, though it reputedly can be used in other areas if there is no hair or the hair is light-colored, not too dense and is parted.  I’ve never been too clear on how the headbands would actually work outside the forehead area.  It is reported that HEG can be trained optimally only once every 4 days. It is also important that it not be over trained, especially in terms of length of training in a given session.  Most suggestions are that it begin with about 10 minutes per session early in training and slowly work up to 30 minutes per session as the client can sustain it.

The software shows you what the brain is doing. When someone who has raised his levels effectively begins to show drops that don’t turn around, that probably means the brain is tired–it has done all it can do in response to the challenge–and it’s time to stop training that spot. Overtraining is a bigger problem with HEG than under training.

Locating Training Site

The white dot on the outside of the band should be placed over the spot you wish to train.

Sites to Train

Over the first few years we returned to recommending nIR over pIR, I did suggest it was better to train at the edges of the forehead, before going “around the corner” onto the temples. The potential for over training–especially at F8–didn’t seem worth the potential downsides. Training on the edges of the forehead and training at F7 and F8 end up training very nearly the same spots.

When LIFE was released, the issue of over-training became much less of a concern, since most trainings ended by “withdrawing” blood from the PFC, so people rarely experienced the sense of tiredness.

F7 is an area strongly related to language output, regulation of physical and verbal impulses. F8 seems to be related to social inhibition and control of emotional impulses, so they seem useful spots to train.

I usually start with F7/Fpz/F8, though I have no problem with switching F7 and F8 for the edges of the forehead. For issues of motivation and emotional regulation, I sometimes train up near the top of the forehead in the center, closer to AFz than to Fpz. After I have a client training 8 or 10 minutes per site, I tend to shift to training 2 sites–above the left eye and above the right eye. It that way I can keep most sessions to about 20 minutes training time.

Rotating One Site a Day

My preference would be to work both sites (or 3 sites, working the edges of the forehead and the middle) in each session and train shorter periods rather than training one site one day and another the next.   You might even try the idea I’ve written about recently of training up for 1-2 minutes, then seeing if you can learn to produce a steady downward movement of the graph. Learning to produce an open focus state which allows the PFC to rest and de-perfuse is very interesting and seems to help some of the folks I’ve tried it with to increase as well.

Exercise Analogy

Everyone understands aerobic exercise.  You do something to make your heart and lungs work harder, you measure the pulse rate to make sure you are in the training range.  You don’t think about it, and you don’t try, you just walk or jog or do the exercise.  If you do it with a good intensity, do it regularly and do it for a while, your body changes its ability to produce and sustain energy, and many things in your life change as a result.

The prefrontal cortex is the heart and lungs of the brain. It helps to screen incoming sensory information so you can focus in busy places, receives the information from your senses, emotions and memory and figures out moment-by-moment what it means and what to do about it. It sends messages to the frontal lobe to produce actions and speech, and then it screens those before they are implemented. It organizes, plans, creates, controls emotions and behavior. It is the center of motivation and is the seat of your personality.

With HEG you do something to make your prefrontal cortex–the executive center of your brain–work harder. You measure the infrared temperature to tell when you are training and when you are overtraining.  You don’t think about it and you don’t try. You just focus on the training screen.  If you do it with a good intensity, do it regularly, and do it for a while, your brain changes its ability to produce and sustain more energy in the control center–which should be the most active part of the brain–and many things in your life change.

Perfusion

Here are a few interesting facts about the cardiovascular system I learned from a physician at one of my workshops:  the average human body has around 60,000 MILES of arteries/capillaries and veins, enough to circle the earth 2.5 times!  Yet, there are only up to10 pints–about 5 quarts–of blood in your body. It’s not hard to see that, at any given time, a large percentage of the blood vessels aren’t carrying much if any blood.

Think of the cardiovascular system like a highway system:   There are superhighways, other large roads, small roads and little neighborhood block-or-two-long streets.   Even with all the cars in the US, it’s probably fair to estimate that, at any given point in time, most of the square feet of streets/roads/highways DON’T have any cars on them.   But there are times when most of those square feet of paving ARE needed to carry traffic.

Now let’s imagine a little beach town called PFCity.  It has some large highways capable of delivering traffic to it, but because it’s a sleepy little town, there are only a few roads leading from the highways to the town–and even fewer streets and drives for getting around within the town.   That’s not a problem except maybe 2-3 times a year when people from large cities decide to go to the beach, and they all arrive on the same day on the highways.   Traffic backs up because once cars get off the highway, the roads quickly jam (they’re just simple two-laners), and when you actually reach the town itself, to get to the beach or any of the bed-and-breakfasts where people stay is a nightmare.

If this only happens one or two times a year, people grumble and maybe change their plans, but no big deal.

But what happens if a new mayor is elected who decides to really promote the town as a gorgeous tourist haven to pump up the local economy?   Now nearly every weekend there are traffic jams.   The state could get involved (if it had any money) widening the roads that lead from the highways to the town (more revenue for the town, more taxes for the state).  And the mayor could get the town to build a much more complete grid of streets and parking, etc.

Still, during large parts of the year, this will be overkill.  But when the traffic needs/wants to come to PFCity, it can get there and move around more effectively.

Yet each time we train–as long as we are doing so 2-3 times a week–the brain calls on the body for more blood, and the body tries to increase the traffic.  After a while, the body says, “you know, I’m over it with these emergency demands for blood in the PFC; let’s just build some new capillary beds–or make the ones we have denser–so we can get the blood out into the tissue faster and more efficiently.”  And that’s what happens (exactly the same thing that happens in your heart and lungs when you do aerobic exercise).  You stress the system, then give the highway department some time to work on improvements.  Then you stress it again, and further improvements are made.  Eventually I look for a client able to raise her ratio by7-12% (more or less) within 30 seconds to a minute.  The PFC becomes much quicker kicking into a higher gear.  And then I look for the plateau to hold (perhaps with some additional rises as it goes along) for another 9 minutes.  When the client can do that, he/she has optimized the distribution system, so these neurons, which should be the most active in the brain, have all the oxygen and glucose they need, and a great trash service, to work at their peak.

Fast-Wave Frequencies and HEG

The fact that a person has a brain dominated by high frequencies doesn’t necessarily mean that she is in good shape in terms of perfusion–the supply system for getting blood out into the neighborhoods where neurons work and live.  In fact, since the PFC is the center of a good deal of the inhibitory control systems in the brain, and one could argue fairly effectively that any brain that is producing lots of beta and high-beta for no functional reason is lacking in control. Improving prefrontal function could actually reduce excess fast activity.

Responses to Training

Headaches (often described as feeling a kind of pressure in the head which fades after training) can be a natural response early in training, just like pumping up muscles is a result of weight training.   It’s an indication that the client was working hard. Headaches that last for hours, or irritability/obsessiveness–or a loss of executive function for a period after training–are often a sign of over-training. Since I’ve begun using LIFE to do my nIR, combining uptraining with downtraining–HEG with an analogue for HRV (the Dive), I’ve had no one experience over-training.

Irritability is also a sign of over-training.

Calibrating Device at Beginning of Session

The software needs to fill registers to calculate the values and “calibrate” the unit to the brain that day.  That’s why there is a baseline process. When the signal stabilizes, usually in about 30 seconds, you should set the baseline and you are ready to train.

Training Guidelines

In general, I tend to think about HEG as I would about aerobic exercise. With nIR I would say the following guides me:

1. nIR trains specific areas (though they tend to have a more global effect when you combine a few of them), so train on the left (anywhere from the edge of the forehead to above the left eye), train on the right (ditto) and train in the center in each session.

2.   Rotate the order of training sites. The prefrontal cortex (PFC) is not like an ice cube tray, so when you train at Fp1 on the left, it will have an effect at Fp2 on the right as well. The first site is usually easiest to change, then the second and the third may be difficult to produce much change. What I have found is that almost everyone does pretty well raising the ratio at the first site–regardless of which of the three I use. They then have a harder time at the second and very difficult time at the third.   From that I infer that improving perfusion in one small area probably raises it throughout the structure, at least collaterally. I rotate the order of the sites, so I may start on the right one time, on the left the next session and in the middle for the third. HEG doesn’t necessarily change activation patterns, as EEG can do. It can change activation capability.

3.   Training too little is better than training too long (training “just right” is, of course, best).  You wouldn’t take a new exerciser out on a five-mile jog in his first session, so don’t try training 10 minutes at each site in the beginning. Train till the brain shows it is tired, then stop. Train 2 (maybe 3 in the beginning, when sessions are short) times a week.

4. I like to start training with our HEG AI design which has a nice graph for the client to watch.   I ask them to watch the line and figure out what makes it go up (usually single-pointed focus). Most clients can get it to rise a little (maybe 30 seconds to a minute or more), then they can hold a plateau (these are trend lines I’m talking about: they rise and fall, but the tops and bottoms of each successive step are higher–or about level–or they begin to fall). Finally, the trend turns down, indicating that the brain is nicely toasted at that site–like finally working up a little sweat and breathing more deeply when you are walking or jogging. That’s a good time to stop. If you don’t want to look at what the brain is doing, you can start with something like 4 minutes per site, then raise it a minute ever 2-3 sessions.

5. I tell the client, don’t think; don’t try. Just pay attention to the screen (or a task if you choose to use one). If you do not use the LIFE game, you can watch a DVD or play solitaire or read a book if you wish. Thinking and trying are inside your head. I find that focusing out and staying focused outside your thoughts is much harder for most people and activates the PFC better.

6. Increase a little at a time until you can do 10 minutes at each of three sites once every 4 days.

7. If you can’t tell it’s working, it’s not working. Can the client focus better in real life? Is he getting more organized?   Is she able to regulate her emotions better? Whatever the client started training to change…should change.

Diving/Open Focus Training

When you train with an open focus—diving in the LIFE game—you aren’t thinking and doing, you are being. You aren’t acting, you are just conscious, so the processes to be controlled are significantly fewer, and the PFC gets to rest. The whole brain gets to rest. If you are thinking or trying or judging, if you are aware of being in your head, you are NOT in the state that will allow the blood supply to fall. That may very well not be a state your brain knows how to do very well or often–and certainly not to sustain. So practice it. Getting very good at open focus doesn’t reduce your ability to activate–it may actually improve it since the range between resting and active increases.

Timing of Sessions

The idea of spreading out the sessions is to avoid over-exercising. If you are doing 4 minutes per site, and he is able to sustain the blood flow and not get tired or irritable or obsessive or anxious afterwards, you can go up a minute per site. It’s also acceptable to do it more frequently. The once-in-4-days is a guideline from Hershel, stating that according to his calculations that was the optimum in terms of return in response per time spent. If you want to do it every other day–or more specifically if your son does–then try it out.

When I’m training a client with HEG and EEG together, I try to keep the HEG part of the session to around 20 minutes, so there’s time for the EEG. If you are only training HEG, you can train 4 sites (F7 / Fp1 / Fp2 / F8) or 3 or 2. You can train at 3 sites until you are doing 10 minutes at each.

I usually start people with 3 minutes per site and, when they can sustain a rise for the whole period, we work up to 4 minutes, etc.

Percent Increase in Ratio

The ratio is a ratio of red light reflected back from the surface of the brain (more reflection, more red/oxygenated blood) divided by the infrared value. Infrared being a fairly stable measure over short periods of time forms a kind of stable base against which the red light values can rise or fall when O2-rich blood availability increases or decreases

The percent increase in the ratio indicates the ability of the client to activate the area being trained.  The Max% Gain can be tracked over sessions. The more effectively the client is able to produce a single-pointed focus state (no think/no try/no judge)–which demands a great deal of the PFC in terms of braking all other processes, and thus demands that blood be shunted into that area–the higher this percent will go.   I also look at HOW the increase is taking place. Early in training, the client will probably produce rises with bursts upward and then drops, then a higher burst and another drop.  These suggest that the distribution system for blood in the PFC area being trained–the real target of the training in my opinion–is able to squirt blood into the area but the supply lines stretch and break very easily, so there is a period where it must recoup before making another squirt. Eventually you should be able to raise the graph in a steep, steady climb (I’ve done 25-30% in 90 seconds when I was practicing regularly) almost without any “pauses” or drops. That suggests that the distribution system of capillaries is dense and well broad.

Attention Index

The Attention Index is calculated from 1-100% essentially, and it is a measure of the maintenance of the increase.  For half a second (if I recall correctly from a conversation with Hershel several years ago), if each sample of the red/infrared ratio is equal to or greater than the previous sample, the AI will reach 100%.  Any sample that drops will result in a drop in the index. Once you reach 100%, the design starts timing, and every time you hold it at 100% for 1 second you get an AI point.  The value reported on the screen is the average number of AI points per minute that you achieved. If the Max% measures ability to activate, the Average AI points measures the ability to sustain. Running up in the middle 20’s is about as well as I’ve done, suggesting that 25 seconds out of every minute I was keeping the level stable or rising without a slip.

So I may see a person who produces a small rise in percentage terms, but maintains a flat or slightly rising line who has a very high AI points value. Someone else may produce a larger percent increase but does it all with choppy up-and-down activity, and their AI will be quite low. Ideally, as a person trains, both the AI points and the percent increase grow steadily.

Baseline

The baseline is a measure of the starting point (if done properly) BEFORE the client starts to really focus. It can be affected by a number of things, but I look at as the person’s ability to “idle” the PFC. If a person who is in what should be “idle” mode is producing ratios of 120-140 or so–well, that’s not very restful. I still haven’t decided it it’s better not to train in that area or to train for decreases. I usually tell the client to focus intently on a single point (obviously the point can move or you can shift what you focus on). Some people with very high ratios at baseline, once they start focusing will go down quite steadily for some time before flattening out or starting to rise. This is equivalent to what one often sees in EEG where the Eyes-Closed and Eyes-Open resting values of, say, high-beta in the temporals are very high and drop at task, because the temporal lobes have something to do and they can stop freaking out (excuse the technical terminology…). Other people with fairly high baselines (especially in the center) are able to raise the ratio quite well. My rule of thumb is, if it doesn’t cause problems for the client, go ahead.

LIFE Baseline setting: One trick I use before starting to climb or dive is to get myself into the opposite state first. While I’m waiting for the yellow light to stop blinking I go into a focus state before I’m going to dive.

Differing Baselines at Different Locations

The ratio value you use for a baseline really has not much to do with anything. Nearly everyone is significantly higher at the midline than on the sides. I’ve heard several anatomical reasons for that which sounded fairly plausible, but I just accept that in most cases that’s the way the brain is.

HEG and Coherence

According to Rob Coben, who’s probably the guy who looked at this most carefully, pIR tends to improve hypocoherence in the PFC (it trains over a broad area), while nIR tends to break up hypercoherence.  

For quite a while I was of the opinion that I didn’t train HEG with people who had lots of beta or high-beta.  The underlying assumption there was that increasing blood perfusion meant increasing blood supply and/or beta levels.   What I think I understand now is that (as infrared cameras show) PFC’s may have cold spots and hot spots–areas of too little or too much concentration of metabolic activity.  The idea of HEG is to optimize perfusion–basically to make available to all areas the necessary blood supply.  It makes sense that if a town has a few good roads and a bunch of poorly paved older ones that run a block or two then die, traffic on the good roads will be excessive.   Whether that’s a cause or an effect or neither of OC symptoms doesn’t really matter to me.   Optimizing the flow means improving the streets and connecting them more effectively in the weak areas–and that allows traffic to clear off the previously over-crowded “good” ones.

Safety

HEG is often resisted by people who are training post-stroke or with high BP or aneurysm, so as not to increase the pressure by sending a lot more blood to the area. In fact it’s the opposite. Training HEG increases the efficiency of the distribution system, generally REDUCING pressure. Assuming you do an assessment and find some good things to train with EEG, I don’t see how that would affect the aneurysm either.

What is the Difference Between nIR and pIR?

Brain-Trainer focuses exclusively on the use of nIR. nIR, in my experience, is more demanding of pure attention and tends to be more variable of a signal, meaning that the feedback goes on and off more). nIR trains a spot around 3/4 inch in diameter, though it obviously affects a larger circle around it.  With nIR, we are measuring the degree of oxygenated hemoglobin in the area beneath the sensor.   The training I prefer is single-pointed focus.   Think of wind-sprints as a means of conditioning–running flat out for 100 yards, then jogging 300, then sprinting again, etc.   Each push takes you to a limit in the distribution system (perfusion system).   Without a supply of oxygenated blood, the neurons have to slow down and can’t perform their functions as well.  Then you push again.  In the nights between one session and the next, capillary beds are expanded, so the next time you train, there is greater ability to deliver blood quickly and to store enough to sustain activity longer.  New limits are reached. Because you train (or can) around to F7 and F8, or to stay on the front of the forehead, you can really stress all parts of the system and get them all growing at the same time.

There is another type of HEG, called pIR, or passive infra-red HEG. Rob Coben, perhaps the person who has most carefully used both options, as part of a study he did with autistic spectrum children, compared responses to the two approaches and found no significant differences. That’s been my experience with clients I’ve worked with using either or both options. There are some differences in usage, but not necessarily in outcome.

pIR tends to be a more “stable” signal, meaning that it doesn’t move as much, since it measures a large area and may be involved in some cases in moving blood around from hot areas to cool areas in the same real estate.  That may be good, though it frustrates some trainers and clients because it doesn’t seem to respond.  nIR is more likely to show an uptrend, stable plateau then downtrend.

pIR is training temperature in a roughly 5-square-inch area across the center of your forehead.  When I once did a session at Jeff Carmen’s, he was able to do pre- and post-IR photos of my forehead using a specialized camera.   After 10 minutes there had been some significant lightening of several dark areas and some reduction of brightness in several hot spots. It appeared that blood went from some areas to some others within that space.  It makes sense to me that pIR is reputed to increase prefrontal coherence.

nIR measures an area around 3/4 in2, where pIR measures about 4 in2.   Hence nIR is usually moved around during a session to 2 or 3 sites, while pIR is always used centered on Fpz and covering pretty much the whole width of the forehead.

pIR is more related to executive function over the broader area and tends to be more stable, meaning that feedback does not go on and off as often. pIR is perhaps better for those who have migraines.