Links to Additional Information on QEEG
Quantitative Electroencephalograph (QEEG) is the measurement, using digital technology, of electrical patterns at the surface of the scalp which primarily reflect cortical activity or "brainwaves." A multi-electrode recording of brain wave activity is recorded and converted into numbers by a computer. These numbers are then statistically analyzed and can be converted into a color map of brain functioning. A patient's/client's performance can be statistically compared to that of a large population data base. Such comparisons allow the clinician to determine whether or not brain functioning is abnormal, to what degree, in what locations and in which frequency bands. This information can then be used to plan the best form of Neurofeedback training.
The following table is an example of the utility of QEEG assessment. When one compares the diagnostic accuracy of various rating scales to QEEG assessment in the diagnosis of ADHD, QEEG is obviously the most accurate test available with a prediction rate of approximately 92%.
The type of data provided by a QEEG may be seen below. This is a display for relative power (amount of EEG activity in one location reflected as a portion compared to the whole brain) across 4 frequencies ranges and the total of all frequencies. These data are graphically displayed onto what are referred to as "brain maps" that reflect relative power in terms of statistical comparisons to a normative database.
What is clear from this image is that there is excessive theta activity over the prefrontal cortex including Fp1, Fp2 and F4. Neurofeedback would then seek to decrease this activity and improve upon the person's symptoms or problems. The next image is another example of a brain map for a person with severe ADHD and symptoms of anxiety.
This shows considerable excesses of Alpha over the entire front portion of the brain. As Neurofeedback decreases frontal alpha activity, his symptoms of anxiety, attention problems, distractibility and impulsivity will decrease.
The next series of brain maps now show a different way at looking at the information contained within someone's EEG. These are what are called measures of connectivity or coherence. Coherence is a measurement of the degree to which different brain regions and their associated brain waves are similar, have similar shape or are in the same frequency band. Coherence is related to connectivity which is a reflection of how well brain regions can communicate or "work together."
These images and connectivity brain maps show a disconnection (hypoconnectivity or low connectivity) between the left side of the brain and the center. There is also an apparent hyperconnectivity present over right hemisphere brain structures. These connectivity problems can be treated with Neurofeedback and their reduction is associated with clinical improvement.
These same QEEG measurements can then be used to track progress in Neurofeedback. For example, if one does a second QEEG following some treatment the change in the images would reflect the improvement in brain functioning as a results of the NF therapy performed. Below is an example of such a case. This is a 15 year old female diagnosed with Asperger's Syndrome. She presented with severe problems in attention, judgment/problem solving, social skills, pragmatic language and communication and poor emotional control and regulation. Her intial QEEG is presented in Figure 8 below.
Her initial QEEG shows clear evidence of excessive delta to theta (1-4 hz.) activity over the right frontal and temporal regions of the brain. This clearly corresponds to what might be expected in such cases. Figure 9 is her followup QEEG brain maps following a course of NF therapy.
The post NF QEEG shows significant reduction in the brain dysfunction shown in Figure 8. There has been a near resolution of these right frontal and temporal problems. Clinical and therapeutic improvements were clearly associated with these brain-related changes. Her family now describes her as "a completely different person." She now does quite well in school, has developed a good network of friends, is emotionally stable and cares about the feelings of others.
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