Autism Therapy: EEG

www.neurofeedback.org

What is Neurofeedback? (taken with permission from http://www.thebrainlabs.com/neurofeedback.shtml)

Neurofeedback uses sophisticated computer technology to train the brain. While there are different forms of neurofeedback (as discussed below), the most traditional form is known as EEG Biofeedback. In EEG Biofeedback, a child plays video/computer games with his/her brainwaves. During a typical session, EEG electrodes are placed on the scalp and/or ear lobe(s). These sensors only measure a child's brainwaves; no electrical current enters the brain. The information/brainwaves that are read by these sensors are fed to a computer that converts this information into gamelike (pacman game) displays that include visual and auditory feedback. An example of a typical set up is displayed below in Figure 1.

Figure 1

As a child learns to control and improve upon their brainwave patterns, their game score increases and they progress. The only way to succeed at the games is for a child to improve their brain and how it functions. Further examples are included below, including the game computer that the client sees in Figure 2 and the therapist computer that monitors the clients brain wave patterns in Figure 3.

Figure 2
Figure 3

As this is done over various sessions, a child's brain improves and their symptoms or problems reduce. There is also every reason to believe that if this is done over a long enough period of time that the changes that occur will be enduring. In addition to its' long-lasting effects, the other major advantage is the lack of significant side effects.

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What can Neurofeedback help?

Given that this therapy helps people to control and change their brainwaves, EEG biofeedback can potentially help with any problems that can be influenced by brainwaves. This would include almost anything controlled by the brain including thinking abilities, motoric responses, behavioral, emotional, and social difficulties.

Table 1 shows the types of conditions/diagnoses for which Neurofeedback has been shown to be helpful. The number of research studies verifying its' impact is also presented.

Table 1

A simple review of the data in Table 1 shows that Neurofeedback is considered effective for some Seizure Disorders and Attention Deficit Hyperactivity Disorder. In fact, at least three research studies (Fuchs et al., 2003; Monastra et al., 2002; Rossiter & LaVaque, 1995) have now shown that EEG biofeedback is equivalent in its' effectiveness as compared to stimulant medications for the treatment of ADHD symptoms, but without the side effects and with a greater duration of lasting effects.

While Neurofeedback has also been shown to be effective for other conditions observed in children, such as Traumatic Brain Injury, there are clearly conditions in which much more work and research is needed. These would include Learning Disabilities, Stroke and especially Tourette's Syndrome and Autistic Disorders.

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What are the different types of Neurofeedback?

There are three major forms of Neurofeedback. These are:

1. EEG Biofeedback (monopolar, bipolar, coherence training)
2. Stimulation-Driven EEG Biofeedback (Roshi, LENS)
3. Hemoencephalography (nirHEG, pirHEG)

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What is EEG Biofeedback?

Clearly, the most well known and first form of Neurofeedback is EEG Biofeedback. It was first discovered in the late 1960's and early 1970's that individuals could learn to control their own brain waves when provided feedback about them and that this information could be used to minimize or control seizures. It was later found that EEG Biofeedback could be used to treat Attention Deficit Hyperactivity Disorder and other developmental conditions or problems.

The typical EEG Biofeedback session has been described and shown above. Typically, EEG Biofeedback is done with three electrodes arranged in a monopolar pattern. This means that one electrodes is placed on the scalp at a clinically significant location and the other two are placed at relatively neutral sites (e.g., earlobes). With these electrodes in place various EEG frequencies are rewarded and others inhibited. This occurs via the visual and/or auditory feedback received, often via a computer screen and image. For example, it is common to reward low beta frequencies (often associated with focused, calm thought processes) and inhibit lower frequency ranges (delta, theta), which are often associated with distraction, fatigue, etc. When these conditions are met, for example, the pacman will move rapidly through a maze. Following similar processes, brainwave patterns are shaped over time toward a client's therapeutic improvement.

EEG biofeedback can be performed in a monopolar fashion at any of at least 19 electrode sites. Alternatively, some therapists chose to use bipolar montage or arrangement. In such a pattern, there are now two electrodes placed on the scalp and one on one ear. Now, brainwave patterns are shaped between theses two electrode sites or so it is theorized. Possible electrode placements and sites are expansive given that there are at least 19 locations and two electrode pairing combinations.

Lastly, there is an advanced form of EEG biofeedback referred to as coherence training. Coherence training is done with two separate channels of EEG (3 electrodes times 2 for a total of 6 electrodes). Each electrode grouping is arranged in a monopolar fashion. There are then two electrodes on each earlobe and two electrodes on the scalp. The purpose of coherence training is to facilitate "communication" between two specific brain regions.

EEG biofeedback conducted with either monopolar or bipolar setups seeks to focus on the amplitude or magnitude of various EEG frequencies, encouraging some and discouraging others. Monopolar arrangements seek such changes over one particular location, while bipolar setups seek changes between two sites (theoretically speaking). The training of specific locations and EEG frequencies then becomes of critical importance. EEG frequencies are described in cycles per second and reflect the speed of processing at a particular brain region. The following table is a representation of common frequency ranges, their names and associated features.

Typically, EEG biofeedback seeks to encourage some frequency ranges and discourage others. As a result, the neurofeedback therapist is left to choose the type of training, where on the brain to train and what frequency ranges to reward or inhibit. Discussed below are some issues related to these choices and approaches to neurofeedback.

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What is Stimulation-Driven EEG Biofeedback?

The two most popular forms of enhanced or stimulation-driven neurofeedback are LENS and the Roshi. LENS, or Low Energy Neurofeedback System, uses a very low power electromagnetic field to carry feedback to the person receiving it. This signal seeks to change this persons' brainwaves in subtle ways. The goal is often to alter to dominant brainwave frequency so as to make it more powerful. The result may be increased self-regulation and skills.

The Roshi is also an enhanced form of neurofeedback. In its' many incarnations, Roshi involved light stimulation that emulates a normally fluctuating EEG signal and its' many frequency variations. This tends to "push" the person more towards normalcy than they would be otherwise.

There is some evidence to suggest that these forms of enhanced neurofeedback can be helpful, especially in complex cases.

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What is Hemoencephalography?

Hemoencephalography or HEG refers to brain blood flow, its' measurement, and use as a neurofeedback application. This is a completely unique form of neurofeedback that is separate and different than EEG Biofeedback.

The originator of this technique, Hershel Toomim, developed a technology referred to as Near Infrared HEG or nirHEG. This measurement and biofeedback device is housed in a headband, which contains a light source and two optodes. Infrared lights are flickered alternating between 660 and 850 nm. The absorption of these lights, and a ratio of the same, received at the optodes is a calculation of cerebral oxygenation. This is used in the form of feedback to allow the client to enhance their brain's functions.

Another form of HEG has also been developed by Jeffrey Carmen. This form, entitled Passive Infrared HEG or pirHEG, uses an infrared lense that serves as a brain thermometer and measures temperature and inferred cerebral metabolism. This may also be used as a form of neurofeedback to aide in the enhancement and regulation of brain functions.

HEG is somewhat limited in that it doesn't see through hair. However, it has the advantage of being insensitive to artifacts such as muscle tension or eye blinks which may interfere with EEG biofeedback. As a result, HEG may be particularly useful of neurofeedback of frontal lobe or system dysfunction.

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What types of assessments can help Neurofeedback?

Now that we know there are various form of Neurofeedback that could be applied to many different problems and brain regions, how does one decide what to do and where? Believe it or not, there are some within the field that believe that all people can be treated the same way or with the same protocol. This is not our approach. In our clinical practice, we individually tailor and Neurofeedback protocol to an individual's particular problems or symptoms and, importantly, the identifiable regions of brain dysfunction that related to these symptoms.

The following is a possible list of ways in which Neurofeedback could be tailored for an individual:

1. Based on symptom presentation with an understanding of brain regions that mediate these functions or skills.
2. Protocols for particular problems or "tricks of the trade." For example, the most common protocol for ADHD is EEG biofeedback done over the top of brain (Cz, C4-C3) rewarding SMR and inhibiting theta and high beta activity.
3. Using psychological assessment information such as parent ratings scales and tests of attention such as TOVA or IVA.
4. Use of more complex neuropsychological tests to diagnose regions of brain dysfunction and treatment plan accordingly.
5. Use of direct neurophysiological measurement to determine brain dysfunction and treatment plan accordingly. This is often done with something called a QEEG or Quantitative Encephalogram or EEG.