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rewarding. For example, it may be a favourite movie where the picture is bright when measurement of the selected signals are moving in the right direction (towards the mean of the normative data base). That is, the client (and the brain) are rewarded for making the picture normal. It fades out when the targeted signals are moving in the wrong direction. For most, the process is unconscious. Others, however, can deliberately enter brain states that control powere and connectivity. This is the basis of the relatively new science of brain-computer interfacing. In the first case, where the process is unconscious, think of moving from a bright environment to a darker one. Do you deliberately instruct the pupils of your eyes to widen? No, the brain does that on its own. In fact, the brain can do many things that you are not conscious of in order to improve your environment.
In providing neurofeedback therapy, sensors are placed on the scalp as in the yellow illustration, above. Again, it is emphasized that the flow of electricity is from the brain to the sensors and never the other way around. We now know that the brain is plastic, which means that new connections develop as do new synapses (the small areas of the brain where neurons connect and talk to each other). Further, Dr. Eric Kandel received a Nobel Prize for demonstrating that the brain responds positively to reward by increasing these connections and synapses. Neurofeedback takes advantage of this.
The signals from the brain are processed as for qEEG except that moment by moment calculations of power and connectivity are made. These are fed back, often on a on a TV display and in a manner that is
As for the surface situation, described earlier, the computer also measures connectivity (hypercoherence and hypocoherence) between these internal Brodmann Areas.
To this point the focus of the discussion has been on the localization of abnormal power or connectivity. This does not mean there is something wrong. However, In fact, anomalies found in the qEEG may be related to:
Symptoms reported by the client, such as depression, anxiety, or impaired attention.
Compensatory mechanisms. If a brain is injured, other parts of the brain will compensate resulting in unusual readings in those areas.
High functioning. For example, a musician may have highly developed areas related to the processing of tone.
In examining these three possible causes for deviations from normal qEEG reading, and given that neurofeedback trains such values toward the values of the general population, it would be highly inappropriate to perform neurofeedback on those brain areas associated with 2 and 3, above. The message is, therefore, do not conduct neurofeedback without a qEEG to identify unusual values, and do not conduct neurofeedback without understanding the reasons for such deviations from the norm. That is, neurofeedback training should only address known symptoms and should target brain areas (Brodmann Areas) that process those symptoms. To do otherwise may cause harm.
With the above in mind, the next section will describe neurofeedback.
QEEG Based Neurofeedback
As for other forms of biofeedback, neurofeedback uses monitoring devices to provide moment-to-moment information to an individual on the state of their physiological functioning. The characteristic that distinguishes neurofeedback from other biofeedback, often termed peripheral biofeedback, is that it targets the brain. Neurofeedback training has its foundations in applied neuroscience and is supported by clinical evidence.
Just as power and coherence may be measured at the scalp, another important process allows for a three-dimensional localization of internal sources of electrical activity. These internal sources are the Brodmann Areas, mentioned above. Thus, functional brain components are localized for each frequency (1 to 30 Hz), and when there are deviations from the normqtive database, they are identified as indicated in the following Figure, which is set to examine power at 3Hz. Again blue shading identifies significantly low power and red shading (when present) abnormally high power. Although difficult to see in this small picture, the darkest area of blue is found at Brodmann Area 10, in the frontal lobes. A different map is generated for each of the 30 frequencies. This map leads to the most recently developed form of neurofeedback- Low Resolution Brain Electromagnetic Tomography (LORETA) Neurofeedback.
Another important parameter is termed connectivity. Think again of our household electrical supply. Typically the electricity comes from a network of power supplies and they all must be connected to provide appropriate balance. It is the same for the brain, and measures of connectivity indicate how effectively one part of the brain is communicating with another part.
In functional terms, the frontal regions of the brain are involved with processing new information; that is, information that is coming in through our senses, and the posterior regions contain a model of our perception of the world that has been built up over time and from experience. Thus, when walking along, if a small furry creature comes up and rubs against our legs, this image is compared to what we know about such experiences, and we will likely conclude that we have met a friendly cat. So, all is well unless we have an allergy to cats. On the other hand, if, when walking in a less populated region a small furry animal comes toward us, but this time it is 2 to 3 inches larger in stature, a comparison of this sensory input to past experience may not lead to such clear conclusions. Is it a variety of large domestic cat, or is it a wildcat? If the decision is that it is a wildcat then the "fight or flight" regions of the brain are activated and we deal with the situation accordingly. It is evident from this example that intact connectivity between the frontal and posterior regions of the brain is required for appropriate decision making.
Another example is that impaired connectivity can negatively affect personal relationships- a common occurrence following brain injury. For example, a couple may be arguing heatedly, but if one member of the partnership, while able to see the expression of fear on the other person's face is unable to interpret this sensory input, a change in communication style might be unlikely. There can be too much connectivity (hypercoherence) or too little (hypocoherence). Both are associated with reduced speed and efficiency of information processing. The following figure depicts coherence maps in each of the four frequency bands. Red lines between two sites depict hypercoherence and blue lines hypercoherence.
Under each of the 19 sites are found functional areas of the brain from which the surface electricity arises. Von Brodmann identified the functional brain structures in his text Localization in the Cerebral Cortex, 1909 by assigning numbers (Brodmann Areas), a classification system that has stood the test of time, the latest edition of the text being published in 2006. For example, when we look at site Cz (right in the middle of the head) we can look up the Brodmann Areas associated with this site. They are Areas 1, 2, 3, 4, 5, 6, and 24, and each has an anatomical name. For example, sites 1, 2, and 3 identify the somatosensory cortex which runs laterally across the center of the head with Cz being positioned squarely in the middle. So it may be predicted that the person associated with the above Figure has anomalies associated with the reception of sensory information. Also, F7 is in the red zone, and Brodmann Areas 38, 44, 45, 46, and 47 are associated with this region. These areas are concerned with language and memory.
under different circumstances. Delta waves are the slowest and are predominant when we sleep or are drowsy, theta wave are present when we are awake but not focussed, alpha waves occur when we are relaxed but focused, and the faster beta waves are seen when our brains are cognitively active. At each of the 19 sites, all of these waves forms combine into a single trace and it is the computer which separates them. Think of a slow delta wave with a much higher frequency beta wave superimposed on it as it rises and falls, much like the swell of the sea with ripples on top. It is not difficult to understand that we can measure the frequencies of the roller and the ripples as they pass by a buoy in the ocean. Further the height of the ripple from the roller and the height of the roller from a flat sea are equivalent to the power of each, respectively.
In the qEEG, the microvolts (power) are measured for each of the 30 frequencies. Then the difference between these power values from a normative data base is calculated. A normative data base was developed from the general population. This is the same process as in a medical blood test, where the physician tells us that we have a low or high red blood cell count. How does the physician know this? Because our count is compared to what has been found to be the average or mean (normal) in the general population. These EEG powere differences are then displayed in a map format.The next figure provides an example of surface maps. Green depicts normal values, red high values, and blue low values. It can be seen that there is high powere at 7 and 8 Hz. The units of the colour scales are termed standard deviations from the mean of the general populations, and values greater than +2 or less than -2 are only found in about 5% of the population and therefore become a focus of the assessment.
Our brains are somewhat similar. The thalamus and other brain structures create the rhythmic activity that underlies EEG signals- the frequency, and the number of neurons in the loop creates the voltage or power, in the case microvoltage (millions of a volt). For the purposes of qEEG, the frequencies of most interest ranges from 1 to 30 Hz, and we measure the voltages at 19 sites on the scalp- see adjacent Figure. Neurofeedback does not send electricity into the brain; it just measures what is already there. Also, frequencies may be divided into bands, and the bands of interest are Delta (1-4 Hz), Theta (4-8 Hz), Alpha (8-12 Hz), Beta (13-30 Hz). These waves each have somewhat different shapes and are seen
If you are considering neurofeedback therapy for your child or for yourself it is suggested that you read this page. After reading it, you are welcome to call us to arrange for a free 20 minute discussion on whether it is appropriate to your situation. At this time a short demonstration may be provided.
This page is designed to help you understand what EEG biofeedback, popularly known as neurofeedback, is and what it can do to help you meet your therapeutic goals. It will address the importance of the neurofeedback practitioner to be independently certified because, more and more, unqualified practitioners are entering the field. It will also indicate why we only use quantitative EEG (qEEG) based neurofeedback, by describing the qEEG process.
Qualified Practitioners and General Cautions in Seeking a Neurofeedback Practitioner
In seeking neurofeedback services, always ask for the qualifications of the pratitioner.
You would not want to be treated medically by someone who was not certified as a physician. Likewise, in seeking neurofeedback therapy you should always ask whether the person providing such treatment has specific training is certified. Just because a therapist is a psychologist or counsellor does not mean they are qualified to practice neurofeedback. There is only one body in North America overseeing standards for such training and certification. That is the Biofeedback Certification International Alliance (BCIA). Likewise, presently, there is only one body providing certification in the practice of Quantitative EEG.
A further caution related to the need for "independent" certification is that some suppliers of neurofeedback equipment provide their own certification, but this is problematic because such "certification" is not from an independent body, and there is a conflict of interest becasue their goal is to sell their equipment and their franchises.
Finally, psychologists must adhere to the College of Psychologists of British Columbia Code of Conduct which states in Article 10.8, "A registrant must not solicit or utilize testimonials from clients or former clients." Thus, have some concern if you find a psychologist providing neurofeedback services in a manner that is inconsistent with this code.
Registered Clinical Counsellors Counsellors (RCCs) are registered with the British Columbia Association of Clincial Counsellors and also adhere to stringent ethic standards as dectated by their Association. This practice has an Associate who is an RCCs. She is also independently certified with the BCIA.
To summarize, in seeking neurofeedback services, (1) always ensure that the therapist is Board Certification in Neurofeedback (BCN) from the Biofeedback Certification International Alliance; (2) beware of certification claims where the certification is provided by the supplier of equipment; and, (3) determine whether the practitioner is a Registered Psychologist or Registered Clinical Counsellor.
The International Society for Neurofeedback and Research (ISNR), to which this practice belongs, published a set of guidelines (ISNR Guidelines). We adhere to these guidelines, and encourage other neurofeedback practitioners to do likewise.
The purpose of this section is to provide a basic understanding of qEEG assessments, and the next section will relate the importance of qEEG to providing neurofeedback therapy.
Electroencephalography (EEG) refers to the recording of electrical activity that is produced by the firing of neurons in the brain. Traditionally, EEG is displayed on a paper trace or on a computer screen, just like an electrocardiogram for the heart, where interpretation is limited to the eye of the interpreter. The EEG provides much valuable information to the qualified neurologist in identifying phenomena such as seizure activity and sleep disorders. However, contained within the EEG is a rich source of addition information which, until approximately 30 years, was not readily accessible. With the advent of powerful personal computers, however, this additional data is now easily accessed by trained professionals. This detailed, objective, quantitative process is known as qEEG.
In order to provide an understanding of this process a familiar analogy will be used. We are all aware that the electricity coming to our homes is defined in terms of frequency (cycles per second or Hertz (Hz), and voltage. Specifically, electricity is provided in North America at a frequency of 60 Hz and 110 volts. These parameters are monitored by engineers and if they vary too much our refrigerator motors run slowly and our food melts.