QEEG Relevance

Research by leading scientists in the field found that this procedure yields, "... a level of specificity and sensitivity that is comparable to sonograms, blood tests, MRI and other diagnostic measures commonly used in clinical practice." Robert Thatcher, Ph.D., Norman Moore, MD, E.R. John, Ph.D., F. Duffy, MD, et. al. Clinical Electroencephalograph, 1999. The authors of this study include scientists responsible for the key databases used by the profession. They are preeminent researchers in their fields and conduct their research at Harvard University, New York University, Veterans' Administration Hospitals, and other leading institutions. Dr. Robert Thatcher, a current leader in the field of brain science, has published numerous prominent studies (e.g., 1989, 1999, 2000) using brain wave analysis in the diagnosis of head injury through analysis of brain wave patterns. Thatcher, in his chapter of an Academic Press text for brain wave professionals (Evan and Arabanel, 1999), sites numerous studies noting strong correlations between MRI (magnetic resonance imaging) biophysical measures of the brain and the
EEG (electroencephalography).

In the late 1980's, Dr. E. Roy John and his research team at the Brain Laboratories at New York University Medical Center, published what has proven to be the seminal work in computer-assisted differential diagnosis of brain dysfunctions (Science, 1988). Building on that work, researchers, using QEEG and powerful computer analysis, have created an objective evaluation that is highly sensitive and specific for assessment and interpretation of human electroencephalography. Frank H. Duffy, M.D. of Harvard Medical School is thought of as the father of QEEG. In 1994, Dr. Duffy and other prominent researchers and clinicians in QEEG prepared a position paper of the American Medical EEG Association (AMEEGA) presenting the current status of QEEG in clinical practice. Three broad uses of QEEG in clinical practice were reported, "the first often broadly termed 'organicity detection,' the second involving more specific diagnoses using discriminant functions, and the third epileptic source localization via Dipole Localization Method."

In 1999, two prominent QEEG scientists, John R. Hughes, MD, Ph.D. and E.
Roy John, Ph.D., published a comprehensive review of the scientific literature relating to the use of QEEG in psychiatry. The article (The Journal of Neuropsychiatry and Clinical Neurosciences) reviewed over 500 scholarly papers published during the 1990's, relating specific patterns of abnormality to particular diagnoses. The authors summarized their review of this voluminous body of literature, stating: "In view of the accumulation of positive findings surveyed in this article, more psychiatrists may wish to explore the utility of these methods for themselves and begin to apply them in their clinical practices."

QEEG Analysis

Quantitative EEG measures the minute electrical activity of the brain and then compares that unique electrical pattern to known databases of "normal" and "abnormal" patterns. This type of computer-driven statistical analysis is particularly useful in evaluating difficult or borderline cases. This cost-effective diagnostic tool provides an objective means--based on actual physiological characteristics--of assessing cognitive disorders. QEEG analysis is an assessment of the brain's functioning based on measurements of brain waves-the fluctuation, usually rhythmical, of electric impulses produced by the brain. Research has documented that these brain signals are related to many aspects of thinking, behavior and emotion. Brain waves occur at various frequencies, some fast, some quite slow and are identified according to their frequency, or wave speed. Generally it is agreed that brain waves should be grouped as follows: Delta brain waves are the slowest frequency with the highest amplitude, present primarily during sleep. Theta brain waves are present when daydreaming or fantasizing. Creativity and intuition are also associated with theta waves.

Alpha brain waves are associated with a state of relaxation and basically represent the brain shifting into idling gear, relaxed and disengaged, waiting to respond when needed. Beta brain waves are of low amplitude and faster frequency and are associated with a state of mental, intellectual activity and outwardly focused concentration.

It is essential to a healthy human to exhibit a range of brain wave patterns. Problems arise, however, when humans have the improper mix of frequencies for dealing with a task. For instance, individuals with AD/HD tend to have excess slow waves. When excess slow wave activity is present in the executive (frontal) part of the brain, it is difficult to control attention, behavior, and emotions. Such individuals may have serious problems with concentration, memory, controlling impulses and moods, or with hyperactivity.

QEEG and Other Technologies

There is a differentiation between QEEG brain wave analysis and other imaging techniques in medicine. For example, X-rays, CAT scans, and MRI, are all used to measure brain anatomy, or structure. The EEG, on the other hand, measures brain physiology, or function. The PET scan (Positron Emission Tomography) and SPECT (Single-Photon Computed Tomography) also evaluate brain function with accuracy. Unfortunately, however, these technologies are highly invasive with the need to inject radioactive tracers and can be very expensive procedures available only at regional medical centers. Radiation risk, cost prohibitive pricing, and limited availability are also true of other imaging techniques such as rCBF (which measures regional cerebral blood flow), MEG (which assesses brain electromagnetic activity), and MRS (magnetic resonance spectroscopy). In contrast to other tests, analysis of brain waves uses QEEG technology because it is safe, easy to administer, relatively inexpensive, and widely available. "Of all the imaging modalities, the greatest body of replicated evidence regarding pathophysiological concomitants of psychiatric and developmental disorders has been provided by EEG and QEEG studies." A comprehensive literature review in the Journal of Neuropsychiatry and Clinical Neurosciences, 1999.

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