HEG stands for HemoEncephaloGraphy–training to increase blood levels and blood oxygenation, which 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. 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 hear 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 infrard temperature changes. It is often used in 2 or 3 different sites in a single training session.
The main thing to remember when you do HEG is that oftentimes less is more. Over training–training too long–can stress the prefrontal area and result in headaches, agressive 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.
What is the Difference Between nIR and pIR?
pIR is training temperature in a roughly 5-square-inch area across the center of your forehead. When I did a session at Jeff Carmen’s and he was able to do the pre and post IR photos of my forehead. 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.
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, but not necessarily in outcome.
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.
nIR (per Coben), being very specific in site, tends to break up hypercoherence (if it exists) in the prefrontal, while the more general pIR tends to improve hypocoherence.
nIR (in my experience) is more demanding of pure attention and tends to be more variable a signal (feedback goes on and off more), where pIR is more related to executive function over the broader area and tends to be more stable. pIR is perhaps better for those who have migraines.
nIR trains a spot around 3/4 inch in diameter (obviously affecting a larger circle around it). 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.
Ease of Use
I used to think Hershel Toomim 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.
Which HEG to Use
I usually use them interchangeably depending on which I like better at the moment. At present I’m using the nIR much more.
For ease of use, pIR would win, since you always put it in the same place and leave it there for the whole session.
For flexibility, nIR would win, since you could train various different areas if you had specific reasons to do so.
pIR tends to be a more “stable” signal (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.
HEG and Coherence
According to Rob Coben, who’s probably the guy who looked at this most carefully, pIR tends to increase coherence in the PFC (it trains over a broad area), while nIR tends to decrease it (it trains very locally). Since it would be a winning bet in many cases that an obsessive or compulsive person’s frontal fastwave coherence would already be high, you might argue that pIR wouldn’t be a good idea.
If you are getting positive results, the fact that one guy (even if it IS Rob Coben!) says that pIR tends to be better for hypo-coherence shouldn’t stop you from continuing to build on the good results. Besides, if I recall correctly, Rob didn’t find that pIR caused high coherence to increase; it might help low coherences to increase. It makes sense, since pIR trains a large area at the same time, and nIR trains small areas at a time.
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.
Duration of Training
According to Hershel, 300 minutes of training (without significant breaks) resulted in lasting changes with nIR HEG.
In the program we are getting ready to implement in a public school here, we used 3 sites for the first 12 sessions, starting at 3 minutes/ each and going up a minute after 3 sessions. From session 12-20 we train 2 sites and increase a minute every 2 sessions, ending up with 10 minute segments, 20 minute sessions. That gets us 297 minutes.
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. So 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.
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.
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.
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.
Here are a few interesting facts about the cardiovascular system I learned from a physician at one of my recent 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.
The first few times I do HEG with a client, using the graph page I prefer for nIR training, I use those sessions to show the client how good the distribution system is in his PFC. Some people spike up 8-10% almost immediately and then crash just as fast, stumble along a little, then spike and crash again. Others run up more slowly and are able to sustain a level for a minute or two before starting to see their ratios fall. Those patterns in the ratio tend to be pretty good analogs of their attention capabilities.
But 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.
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.
Signs of Over Training
Irritability is a good indicator of over-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 this.
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.
I don’t know that results are necessarily faster or more lasting. That may be a client-by-client thing. I do know there are an increasing number of trainers who are using HEG to “set up” an EEG session, since it is generally recommended that you stay with fairly short trainings of HEG for some time. With a device that can do freestanding HEG (Pocket Wireless for example), I teach clients to hook up and run a few 3-minute segments in the waiting room before starting EEG. But, Hershel’s claims to the side, I don’t think that either of these technologies effectively replaces the other. Certainly there are clients who have very active frontal lobes already, and I would not train HEG with them.