The DESA is an EEG based neuroelectrical evaluation system developed at Harvard’s Children's Hospital Boston. The DESA currently is comprised of ten unique testing protocols. In its core is a combination of qEEG- (Quantitative Electroencephalogram), VER (Visual Evoked Responses/Potential), AER (Auditory Evoked Responses/Potential), FMAER (Frequency Modulated Auditory Evoked Responses/Potential), and P300 (Neural Evoked Responses/Potential). The DESA includes four additional protocols specifically designed for Irlen Syndrome (IS) and one Visual Color Recognition Evoked Response.[2]Protocols are recorded by a technologist and interpreted by a neurologist.[3]
In addition, The DESA provides 2D spectral analysis and Coherence maps as well as full motion comparative video where recorded segments can be viewed side by side with the normative database and then exported as an AVI or even directly in Flash format.[2]
Earlier versions of the DESA are various protocols/processes which are relevant to the explanation of the DESA. They are: 1)Digital EEG, 2)qEEG (Quantitative EEG), and 3)BEAM (Brain Electrical Activity Mapping).
The most recent, the Digital EEG "is the paperless aquisition and recording of the EEG via computer-based instrumentation, with waveform storage in a digital format on electronic media, and waveform display on an electronic monitor or other computer output device. The recording parameters and conduct of the test are governed by the applicable standards of the ACNS guidelines and are identical to or directly analagous to those for paper EEG recordings."--Nuwer.[4]The ACNS is the American Clinical Neurophysiology Society.
Then, the Quantitative Electroencephalograph (qEEG) is used as a segment of the DESA.[5] A patient's real-time electro-cortical activity is recorded and quantified thus allowing a neurologist to compare it to a normative database. In addition to comparing the acquired data to a normative database, the qEEG is able to display a comparative scale of deviations from the norm.[6][7]
To distinguish between the digital EEG and the qEEG, a qEEG is “the mathematical processing of digitally recorded EEG in order to highlight specific waveform components, transform the EEG in a format or domain that elucidates relevant information, or associate numerical results with the EEG data for subsequent review or comparison.” Thus, quantitative EEG analysis techniques provide additional measurements or displays of digital EEG data. Several "EEG brain mapping" techniques include topographic displays of voltage or frequency, statistical comparisons to normative values, and discriminant analysis.[4]
The BEAM is the acronym given to the computerized topographic mapping technology developed at Harvard’s Children's Hospital Boston. The BEAM (Brain Electrical Activity Mapping) is the predecessor to the DESA. [8][9]
As early as 1848, researchers reported the observation of electrical signals from the nervous system.[10]The presence of an electric current in the brain was discovered by Richard Caton in 1875. [11] In 1890, Beck found spontaneous electrical activity including rhythmic oscillations altered by light. In 1912, Vladimir Vladimirovich Pradich Neminsky found the first EEG and Evoked Potential. In 1914, Cybulsky and Jelenska-Macieszyna photographed EEG recordings of experimentally induced seizures.[12]
On July 6, 1924, Hans Berger made his first sucessful EEG employing rather crude instruments, such as the Edelman string galvanometer used to record electrocardiograms. [13]The so-called “alpha rhythm” was identified by Hans Berger in the late 1920s.[14] His 1929 article not only has shown that regular electrical current oscillations can be recorded from the scalp of humans, but also that these oscillations are not due to blood flow, electrical properties of the skin or any of several other possibilities. [13] Five years after Berger invented the EEG, Edgar Douglas Adrian and BCH Matthews confirmed electrical activity could be measured and thus verified Berger's conclusions.[15][13]
An early EEG recording obtained by Hans Berger in 1924.
The sources of the EEG are synaptic generators that are synchronously organized. The short distance local generators are connected by white matter axons to local generators many centimeters apart. The interplay and coordination of these are essential to the understanding of the genesis of the EEG.[16]
In 1933, Ralph Waldo Gerard describes the first use of experimental Evoked Potentials.[17] In 1934, Fisher and Lowenback, first demonstrated epileptiform spikes. In 1935, Gibbs, Davis and Lennox describe interical spike and 3 cycle/s pattern of clinical absence seizures which began the field of clinical electroencephalography. In 1936, Gibbs and Jasper reported the interical spike to be the focal signature of epilepsy.[18] Massachusetts General Hospital started the first EEG laboratory in 1936.[17]
In 1936, Walter Grey Walter invented EEG topography.[19] In that same year, he also demonstrated that the technology could find a brain tumor or lesions responsible for epilepsy.[15] He also was the first to determine by triangulation the location of alpha waves deep in the brain.[20]
American EEG Society
In 1946, representatives from several groups called, American Medical Association (AMA) , American Physiological Society (APS), and American Neurological Association (ANA) organized the American EEG Society. On this date, the first International EEG Congress was held. Among the officers were Herbert H. Jasper, President, and Frederic A. Gibbs, Vice President.[21][12]
In 1959, the American EEG Society assisted a group of EEG Technologists in establishing the American Society of EEG Technologists. One of its committees led a Colloquium on the Teaching Methods allowing wider adoption of standard procedures of the clinical EEG. Thus, usage of the clinical EEG was to become more prevalent. [21][22] Later, the American Medical EEG Association joined. The American EEG Society (AEEGS) continues to shape educational standards for EEG technologists.[21]
From the 1970s through the 1980s and onwards, there began decades of exploration and experimentation with the qEEG. The American Medical EEG Association (AMEEGA) Adhoc Committee on the qEEG stated, "[The] qEEG is of clinical value now and developments suggest it will be greater use in the future."[23]In 1986, the American Board of Clinical Electroencephalography or ABQEEG became known as the American Board of Clinical Neurophysiology, ABCN. Those certified by examination prepare to specialize in EEG and EP.[21]
The same standards were set by the American EEG Society [24]whose name changed to the American Clinical Neurophysiology Society in 1995.[21] From 1996 and on, the American Clinical Neurophysiology Society has continued to establish and maintain standards of professional excellence.[21]
In 1998, The AMEEGA and the American Psychiatric Electrophysiology Association (APEA) merged to form the EEG and Clinical Neuroscience Society, or the ECNS.Cite error: There are <ref> tags on this page without content in them (see the help page).
Fast Fourier Transform
The first qEEG study was conducted by Hans Berger in the 1930s. (Berger, 1931) He used the Fast Fourier Transform to spectrally analyze the EEG. Berger knew the significance of quantification and objectivity in evaluating the EEG.[22]
In 1965, the Fast Fourier Transformation (FFT) algorithm simplified computation of spectral coefficients. (Cooley & Tukey, 1965) (Dumermuth & Fluhler, 1967)[25] The FFT is an efficient algorithm to compute the discrete FT (DFT) and its inverse. [26]
EEG Rhythms and Cats
In 1949, Moruzzi and Magoun studied the origins of EEG rhythms using cats. They determined stimulating the reticular formation of the brainstem aroused the cats (subjects) behaviorally and any dispersed high amplitude EEG rhythms at the cortex. Their work led to physiological model of rhythmic activity. (Andersen & Andersson 1968) (Steriade et al 1990).[25]
Studies continued. Impressed by the possibilities of building bidimensional maps of EEG activity over the brain surface, Walter Grey Walter invented the toposcope in 1957. It consisted of 22 cathode ray tubes connected to a pair of electrodes on the skull. Each tube detected rhythms. The cathode ray tubes were photographed to show the rhythms present in a particular part of the brain.[19] It was called EEG topography and was never accepted by neurologists, but remains a research tool.[12]
Using the clinical EEG, during the 1960s, a study conducted by Barry Sterman of UCLA Medical School with EEG Biofeedback using SMR (sensorimotor rhythm) was successful on cats. It proved cats could be trained to produce EEG activity at 12 - 15 Hz frequencies using operant conditioning. This study is partly responsible for the launching of Neurofeedback.[27] Another study on cats by Sterman using SMR assisted with seizure activity.[14] He found he could reduce seizure activity significantly. [6]
Biofeedback
While Barry Sterman used EEG Biofeedback on cats using SMR, Joseph Kamiya succeeded in training people to increase their alpha activity, namely, EEG biofeedback training.[14] After a 1968 article in Psychology Today, the field exploded. A first meeting of biofeedback professionals opened in 1968 under the name International Brain and Behavior Conference. They later changed the name to Biofeedback Society of America, and then again to Association for Applied Psychophysiology and Biofeedback.[28]
Lubar, Tansey, and others found that Biofeedback assisted with the treatment of other disorders/conditions: hyperactive, learning disabled children, Traumatic Brain Injury, anxiety, depression, PMS, migranes, sleep disorders, Autism, cerebral palsy, chronic pain disorders, etc.[14] Lubar and Sterman found they could increase attentiveness and concentration among subjects.[6]
Cognition
The science of Cognition was advanced by the study of EEG and EP. Event Related Potentials have been in use since the 1960s. Many studies have attempted to associate particular features of Event Related Potential waveforms with specific cognitive processes.[29]Studies have reported reproducible changes in brain dynamics which are task dependent upon testing with EEG/EP. Active tasks are dependent on stimuli intensity, background noise, distance from stimuli, understanding of instructions, and subject motivation.[22]
Through the use of the normative database, neuroelectrical functioning is analyzed and interpreted. Cognitive Neuroscience "aims to understand how cognitive functions, and their manifestations in behavior and subjective experience, arise from the activity of the brain." (Rugg, 1997) The task-related EEG is sensitive to changes in cognitive state. Therefore, the EEG is used in assessing clinical changes in cognitive status/function, for example, working memory and psychomotor vigilance tasks.[30]
Normative Database
The qEEG is a valid test of brain function. Research indicates this highly reliable, precise test can be developed if brain waves of an individual are compared to well-constructed statistical databases. This diagnostic procedure yields:
" . . . a level of specificity and sensitivity that is comparable to sonograms, blood tests, MRIs and other diagnostic measures commonly used in clinical practice."--Robert Thatcher, PhD, Norman Moore, M.D., E. R. John, PhD, F. Duffy, M.D., et. al. [10]
In 1995, Duffy et al found that the standards of the normative database varied consistently in relation to age, gender, and neuropsychology when testing normal adults. Spectral Coherence was found to be similar in both hemispheres of the brain.[31]
In 1999, two prominent qEEG scientists, John R. Hughes, M.D., Ph.D. and E. Roy John, Ph.D., published a comprehensive review of the scientific literature referring to the use of the qEEG in psychiatry. The article reviewed over 500 scholarly papers published just in the last decade, relating specific patterns of abnormality to certain diagnoses.[10]
The John's indicate the clinical utility of the qEEG as a diagnostic tool in many mental illness categories. Among these categories, the literature documents EEG differences between ADHD and non-ADHD children. It shows qEEG discriminant analysis to be sensitive and specific to sub-types of ADHD, ADHD versus normal subjects, and ADHD versus specific developmental learning disorders (SDLD) individuals.
"Evidence has unequivocally established that 'mental illness' has definite correlates with brain dysfunction. . . qEEG promises to have greater expanded use as psychiatrists become more familiar with its many applications."[10] "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."[10]
The qEEG holds promise in answering a call for the more accurate diagnosis of childhood mental health disorders. Dr. Joel Lubar, a pioneer in the use of the qEEG in the diagnosis of ADHD, was the principal researcher in a landmark 1985 study. The study reported that EEG spectral analyses displays variations between children with and without learning disabilities.[10]
There are many examples of clinical content validity of qEEG and the normative databases and a wide number of clinical groupings of patients. [22]The John’s database can determine with close to 95% accuracy the following discriminants:
To detect subtleties of other conditions that need to be recognized, evaluated, and treated.[10]
Other versions of the normative database include the following three. Thatcher et al (1994), Thatcher (1995), and Hoechstetter et al (2004) used a dipole source solution for the normative database. Meaning, they used a scalp EEG with electrical potentials and coherence to find the correlation between the 3D current sources and changes relating to other tasks. [22] In 2001, Pascaul-Marqui et al used low-resolution electromagnetic tomography to find current sources, and then, used the Pearson Product to explore correlates between normal/ Schizophrenic patients.[22]Later, high statistical standards were applied to LORETA 3-D source correlations in a qEEG normative database. This, along with Thatcher et al (1994), Thatcher (1995), and Hoechstetter et al (2004), provide a deeper understanding of EEG dynamics.[22]
With relation to EEG dynamics, the findings from studies on ADHD children tested with the EEG show abnormalities. Some researchers interpret the EEG abnormalities of ADHD as evidence of developmental delay. Findings suggested reduced beta activity in ADHD children and adolescents changes with age. A 2002 study conducted by Bresnahan et al examined the EEG profile specific to adults with ADHD. The resulting data displayed that the qEEG was able to differentiate between adults with ADHD, normal adults, and those that display some symptoms of ADHD, but fail to meet diagnostic criteria of ADHD.[32]
Guidelines of the Normative Database
Another method, pharmacological intervention at its beginnings, Julius Axelrod, Bernard Katz, and Ulf Svante Von Euler share the Nobel Prize in 1970 for their work on neurotransmitters.[17]Neurotransmitters activate receptors. The effect the neurotransmitters have on the system depends on the connection of the neuron that uses that transmitter.[33]From this, medication was used for neurotransmitter activation/deactivation among those subjects with an imbalance of neurotransmitter function.
Because of the varied use of EEG/EP, the first series of guidelines were published on the EEG in 1970. They defined technical/professional competencies in applications of EEG/Evoked potentials. They now cover 13 topics. The latest revisions are available at the American EEG Society's Executive Office.[21]
Guidelines were also needed for the normative database. During the 1970s, the normative database sample size became known as “adequate”, as measured by the extent to which samples were Gaussian and their degree of cross validation accuracy.[22] A Gaussian distribution is a nonlinear function which looks like an ideal bell shaped curve and provides distribution that is symmetrical about its mean. Two ways to cross validate are: 1) obtaining independent samples; and 2) computing Z scores for individual subjects.[34]
In 1973, the first peer-reviewed normative database was used by Matousek and Petersen. Then, two years later, in 1975, the cultural validity/reliability of the 1973 database was shown when E. Roy John replicated by independent cross-validation, a study with the EEG sampling of a group of Harlem black children from the ages of 9-11. None of the participants in the study had previously been diagnosed with a neurological disorder.[22]
Regarding the normative database, the definition of content validity is the extent to which empirical measurements reflect on a specific area/domain of content. (Nunally, 1978). Examples of clinical content validity in the qEEG and the normative database(s) are: ADD/ADHD, Schizophrenia, compulsive disorder, depression, epilepsy, Traumatic Brain Injury, etc. Linking the subjects' symptoms and complaints is important when using a normative database. It is useful to link the symptoms with the appropriate brain region to derive a proper clinical diagnosis from the testing results.[22]
Patient safety being a priority, standards were established for the clinical EEG in 1984. A program was started for Laboratory Accreditation for maintaining minimum standards of clinical EEG laboratories, including: qualifications for lab personnel; equipment; quality of EEG records; patient safety; an internal program for infectious disease control; and provisions for continuing education.[21]
The clinical sensitivity and specificity of the qEEG is directly related to the reliability and stability of the test upon repeat testing. In a 1991 study, Salinsky et al concluded the reliability and stability of the qEEG.[22]Reliability concerns the measure of the same results on repeated trials. Stability concerns the measure of the same results over a period of time.[35]
The qEEG became admissible in court by virtue of the Daubert criteria of the scientific method, in a 1993 Supreme Court decision. It replaced the Frye standards of “general acceptance” in establishing the standards for admissibility of evidence in federal court. Since 1923, the Frye test had held that expert testimony that is based upon a scientific testimony is inadmissible unless the technique is “generally accepted in the scientific community”. The scientific and technical aspects of the qEEG match the Supreme Court standards of “technical” and “Other specialized” knowledge. [36]
The Daubert guidelines for scientific validity are: 1) hypothesis testing; 2) estimate of error rates; 3) peer-reviewed publication; and 4) general acceptability in the scientific community. The peer-reviewed literature of the qEEG meets all of the Daubert standards of scientific knowledge.
Standards imply courtroom judges must determine whether images and expert testimony can be admitted as evidence. Guidance is needed for judges who must make evidentiary determinations from the medical profession, in conjunction with scientific societies, concerning the proper use of the images and testimony in the courtroom. Further, national oversight bodies are needed to guide research on the science itself, the use of these technologies in the field of medicine and in fields outside of medicine. Also, these national oversight bodies must provide an educational forum for professionals and the public on the status of the science.[37]
Dr Frank H Duffy of Harvard Medical School is thought of as the father of the qEEG.[10] In 1994, Dr. F H Duffy and others along with the American EEG Association produced a position paper where the statistical standards of replication, reliability, cross-validation, and Gaussian approximation were said to be acceptable basic standards for any normative qEEG database. (Duffy, 1994)[38]
Concurrently, another paper was presented by the AMEEGA, Dr. Frank H Duffy, and other prominent researchers providing the current status on the qEEG in clinical practice. The paper reported three uses of qEEG in clinical practice, "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]."[10]
Music and the EEG
The EEG, when used in association with music, shows varied processing interpretations. Two studies are presented: Lerdhal & Jackendoff’s (2003) two component model predicts a dissociation of left (rhythm) and right (meter) hemispheric processing; and that of Kuck et al (2003) shows uniform right temporofrontal predominance reflecting auditory working memory and pattern recognition using both rhythm and meter. Kuck et al has demonstrated the most reliable interpretation of processing of rhythm and meter and interpretation. [39]
A 2006 study with music therapy (Loewy et al) found that music is a cost effective, risk-free alternative to pharmacological sedation. The study was conducted on toddlers using the EEG and mild sedation. The effects of chloral hydrate and music therapy were evaluated and compared. Results indicated that music therapy is an alternative. [40]
When studied in association with music, Coherence increases learning and memory. Peterson et al, in 2007, found music can enhance learning and memory. Increased Coherence within and between left and right frontal areas in theta, alpha and gammafrequency bands was associated with musical verbal learning. The results are verbal learning with a musical template strengthens coherent oscillations in frontal cortical networks involved in verbal coding.[41]
In 2008, a study by Steinbeis et al was conducted on the processing of music and its similarity to language. The meaning of music is represented in comparable fashion to language meaning. Both music and language meaning are very similar. Single chords varying in harmonic roughness are perceived as similar to the processing of affective target words. This provides an important piece of evidence in support of music meaning being represented in a similar, but distinct, fashion to language meaning.[42]
Other recent uses of the EEG
When paired with HRV, the EEG can explore human thermal comfort. A study conducted by Yao et al (2008) exhibited two factors: (HRV) Heart rate variation and EEG. They were explored for research on human thermal comfort. Findings suggested physiological factors responded to the environmental temperatures. They also indicated HRV and EEG related to thermal comfort and that they are useful in understanding the mechanism of thermal comfort. Thermal comfort is closely related to the mental and physical health of indoor occupants. The study managed to identify two physiological variables that may have potential relationship with human’s thermal comfort: HRV and EEG. They may help us better understand thermal comfort in the future.[43]
When the EEG and Coherence were used on children with Autism, abnormalities of an Autistic nature were found. In 2009, the largest integrated study of EEG power and Coherence during a resting state in children suffering Autism Spectrum Disorder was completed. The findings were consistent with other EEG, MRI and fMRI research suggesting that neural connectivity anomalies are a major deficit leading to Autistic symptomatology.[44]
The latest uses of the EEG consist of improvements made in manufacturing and other applications. In manufacturing, components of the EEG have become smaller, more portable, less expensive, and more desirable to consumers. Improvements may have been made in applications to Alzheimers, Paraplegics, and consumers who may benefit by being able to control devices such as; household lights, computers, and appliances. There are some instances whereby the use of the appliances/computers are able to be controlled just by thinking.[15]
The use of the qEEG/EEG, governmentally, began as early as 1950. The earliest reference of the use of the qEEG normative database was in the 1950s at UCLA as a tool for NASA's study and selection process for the purposes of space travel.[22] Regarding military and governmental use of the EEG, the Air Force utilizes the EEG for pilots in the cockpit. They utilize an evoked potential-based system that attempts to record the pilot's gaze and whether or not they are rapidly detecting and reacting to quick changes of the cockpit's display items. It is also used to observe the pilot's level of attention.[45]
In 2010, the future in EEG technology will include one of the Pentagon's DARPA (Defense Advanced Research Projects Agency) Projects. One such project utilizes the EEG to read brain waves to devise mind-reading binoculars in a project with potential for computer-mediated telepathy. This technology will alert soldiers to threats faster than the conscious mind can process them. It will be used to communicate on the battlefield without the use of vocalized speech through analysis of neural signals. The Project, called Silent Talk, will be conducted by the Pentagon's DARPA Division.[46]
Event Related Potentials have helped to distinguish psychiatric and neurological conditions such as Schizophrenia and ADHD. (Ford et al, 1999) (Van der Stelt et al, 2001) An Evoked Potential is a quantified electrodiagnostic test used to evaluate the peripheral/central nervous system. There are four primary types of Evoked Potentials, including: 1) visual, 2) cognitive, 3) auditory, and 4) somatosensory.[47]
The DESA is considered clinically useful by many medical professionals.[48][49]
The DESA aids clinicians by providing a normative database for comparison. Unlike other procedures, the DESA is non-invasive. It can also provide dynamic real-time colored brain mapping that is useful in Neurofeedback applications. The DESA can provide a basis to distinguish functional and/or organic disorders.[23]
Several other applications of the data arising from the DESA include validating diagnostic hypotheses; identifying undetected brain abnormalities; cross-validating learning disabilities, e.g. ADHD; and cross-validating auditory and/or visual processing deficits. [3]
As an EEG can assist in the choice of medication for treatment, the DESA helps the clinician diagnose, identify, and find the appropriate therapy to use. [50]
Speech and language therapists can provide better treatment for their patients by being able to identify and/or confirm problems. If the treatment is started early in young children, it allows time for “rewiring”. [51]
Educational therapists are given precise information on the causes of a patient’s learning disabilities. [51]
Occupational therapists may observe the transmission of information invaluable in forming treatment plans. [51]
Psychotherapists may use the test as a basis for intervention because it can identify a patient’s processing strengths and weaknesses. [3][51] These therapists are given information on the causes of patient difficulties, thereby, making the course of treatment more effective and efficient.[2]
The DESA may also be used: to establish a baseline for future comparative analyses; following a subsequent trauma; after therapy; for titration of pharmacological intervention; or, for treatment of addictions. [52]
Further Clinical Use: Diagnosis-Based
TBI (Traumatic Brain Injury)
Proper assessment would reduce incidence of missed or incomplete TBI diagnoses and provide a better basis for treatment. One example explains: [53]
A case involving an individual in an automobile accident with a head injury was dismissed from the ER as normal.
His behavior subsequently became inadequate. He was tested with CT, and EEG scans, and was incorrectly
diagnosed shortly thereafter with Schizophrenia and confined to a mental hospital.
After a long hospital stay, he was tested with the BEAM and diagnosed with a head injury. Because of the irritable
nature of the electrophysiological abnormality, he was given psychotropic medication, and
hallucinations ceased.
Ten days later, he was released from a mental hospital, as stable for the first time in four years. (Duffy, 1986)
Studies have been made using the DESA and patients with ADHD/Depression. Results show upon using a pre/post DESA, a diagnosis can be made, and the method of treatment can be altered; thereby, providing a more stable environment for the patient than before testing. Intervention may or may not include using medication with treatment.[52][55]
Tumors/Lesions
A DESA can locate tumors in patients with normal EEG’s; add additional information to what is seen on a computerized axial tomography; and show electrophysiological abnormalities with functional lesions, and abnormalities not identifiable with normal CT scans.[56]
There are five basic segments (elements) to the DESA: qEEG, AER, VER, FMAER,P300. There are five extended segments: TNTR, RDTR, RDCR, VTR, and VCRR. Each is a stand-alone protocol, however, the DESA incorporates all ten protocols with Coherence to gather more relevant data on neuroelectrical functioning. The extended segments (elements) are four Irlen Syndrome (IS) protocols designed for those with eye deficits and reading deficiencies and one Visual Color Recognition Evoked Response protocol.
These elements are measured by recording the frequency and amplitude of electrical signals. The signals are recorded from electrodes on the scalp in 60 segments of 2 seconds each. 10-20 of the 60 segments are usually usable and/or reliable for analysis.[16]
20 second sample of EEG = 82% reliable
40 second sample of EEG = 90% reliable
According to Gasser et al (1985), 20 seconds of activity is sufficient to reduce adequacy of variability inherent in the EEG.[16] Other recommendations regarding samples are: larger sample sizes are more favorable; 60 seconds of artifact free EEG is better; and, a 2-5 minute sample is preferred for clinical evaluation. (Duffy et al, 1994) (Hughes & John, 1999).
qEEG (Quantitative Electroencephalogram)
The qEEG is a recording of electric currents developed in the brain. [47] The qEEG is composed of two protocols:
1) EOPR (Eyes Open State), and 2) ECLR (Eyes Closed State). The qEEG measures amplitude (height) and frequency (times per second) of the waves of interest. These waves are Delta, Theta, Alpha, Beta waves and Gamma waves.[57] A comparison can be made from the patient’s presentation to a normative reference database.[58]
THE WAVE PATTERNS
Each wavelength has a frequency and amplitude. Below are the frequencies per waveform:
Delta is the frequency range up to 3 Hz. It tends to be the highest in amplitude and the slowest waves. It is seen normally in adults in slow wave sleep.
Theta is the frequency range from 4 Hz to 7 Hz. Theta is seen normally in young children. It may be seen in drowsiness or arousal in older children and adults; it can also be seen in meditation.[59] Excess theta for age represents abnormal activity.
Alpha is the frequency range from 8 Hz to 12 Hz. Hans Berger named the first rhythmic EEG activity he saw, the "alpha wave." This is activity in the 8–12 Hz range seen in the posterior regions of the head on both sides, being higher in amplitude on the dominant side. It is brought out by closing the eyes and by relaxation.
Mu rhythm is alpha-range activity that is seen over the sensorimotor cortex. It characteristically attenuates with movement of the contralateral arm (or mental imagery of movement of the contralateral arm).
Beta is the frequency range from 12 Hz to about 30 Hz. It is seen usually on both sides in symmetrical distribution and is most evident frontally. Low amplitude beta with multiple and varying frequencies is often associated with active, busy or anxious thinking and active concentration. Rhythmic beta with a dominant set of frequencies is associated with various pathologies and drug effects.
Gamma is the frequency range approximately 26–100 Hz. Because of the filtering properties of the skull and scalp, gamma rhythms can only be recorded from electrocorticography or possibly with magnetoencephalography. Gamma rhythms are thought to represent binding of different populations of neurons together into a network for the purpose of carrying out a certain cognitive or motor function.
AER (Auditory Evoked Potential)
The AER assesses the functional pathways as sound travels and is processed from the ear to the temporal cortex of the brain. [2] Auditory abnormalities of a receptive nature can be clearly identified. The AER is a measurement of the brain’s processing of auditory stimuli.[60]
VER (Visual Evoked Potential)
The VER allows an objective look at the data found as a light stimulus flows from the retina to the visual cortex of the brain.[61]The proper identification of visual processing abnormalities is critical for a thorough diagnosis of problems. [2] Abnormalities in visual processing from the normative database are recorded and scored as standard deviations. The VER is a measurement of the brain’s processing of visual stimuli. [61]
The FMAER is a specific auditory wavelength that “warbles” in pitch creating sound the brain recognizes as language. It can identify language difficulties before they actually surface. In young children, this is extremely important. In the context of recent findings, that the brain can “rewire” itself when problems are identified at an early age.[2]The FMAER is a measurement of the brain’s processing of language frequency stimuli.[3]
P300 (Neural Evoked Potential)
The P300 evaluates the brain’s ability to identify random occurrences of different sounds. Its value is in identifying parameters of attention, auditorally, [47] in different parts of the brain. [62] The P300 is a measurement of the brain’s processing of auditory working memory, e.g. the brain’s recognition of sound change.[62]
Coherence
Coherence is the synchronicity of brain region functioning.[63] Coherence measures how the inner self-talk is performed: how our brain connects and disconnects to accomplish various tasks. Coherence between two electrodes over time is called "coupling" and measures activity between two brain regions.[64] Excessive Coherence shows the brain’s ability to stay “overly connected or locked together.” [63] In other words, the brain is not efficient in processing or executing multiple tasks. Deficient Coherence shows that the brain cannot connect to certain cortical areas to perform a task. [63]
When there is a learning disability, the Coherence is either excessive and/or deficient. While, when there is a sign of TBI (Traumatic Brain Injury), Coherence becomes excessive. [63]
Cognitive performance is described as a network of brain cortical regions (Hogan et al., 2003) in communication with each other. In relation to memory processes, studies on healthy humans have generally reported an increase of synchronization between two different brain regions involved in the respective task. Moreover, the patterns of high Coherence between EEG signals recorded at different scalp sites have functional significance and can be correlated with different kinds of cognitive information processing, such as memory, language, concept retrieval and music processing. (Hogan et al., 2003)
Because the DESA evaluates cognitive brain activity, it can can analyze cortical Coherence patterns to locate pathologic processes relative to critical cortical areas to identify, modify, and treat TBI (Traumatic Brain Injury). [65]
The DESA also performs the Irlen/ Visual Evoked Response protocols when the patient is in need of the additional testing protocols:
Irlen Syndrome (IS) can be diagnosed with the DESA. A patient with IS (Irlen Syndrome) must wear Irlen filters which filter out natural light. Those who have IS (Irlen Syndrome) see with the tinted Irlen filters as if they are seeing with natural light.[66]
• Irlen Syndrome (IS) protocols are defined as follows:
TNTR: (Tinted Irlen filters Eyes Open Response): a variation of the standard qEEG Eyes Open Protocol in which the patient wears tinted Irlen filters. RDTR: (Reading with Tinted Irlen filters Eyes Open Response): a variation of the standard qEEG Eyes Open Protocol in which the patient wears tinted Irlen filters while reading. RDCR: (Reading with Clear Irlen filters Eyes Open Response): a variation of the standard qEEG Eyes Open Protocol in which the patient wears clear Irlen filters while reading. VTR: (Visual with Tinted Irlen filters Evoked Response): a variation of the standard VER Evoked Response Protocol in which the patient wears tinted Irlen filters.[2]
• The Visual Evoked Response color protocol is defined as follows:
VCRR: Visual Color Recognition Evoked Response: a variation of the standard VER Evoked Response Protocol in which the identification and recognition is the primary objective as a white light stimulus is transmitted from the retina to the visual cortex of the brain. (VCRR is the recognition of color during VER.)[2]
The DESA uses state of the art FDA approved medical electronics.[67]The FDA provides production recommendations adapted by the industry and recommendations made by various medical and governmental organizations. Some of these are standardized input signal ranges, the accuracy of calibration signals, frequency responses, and recording duration.[15]
The DESA is a non-invasive, low risk testing procedure for the following reasons. [23]
There are no sedatives required. As with other methods of scanning that require people to stay still for 15-25 minutes of scan time, the DESA only requires 2 minutes time per test. This means that tests can be performed on most individuals 5 years on up. Having no need for sedatives, the DESA testing has no ancillary risk factors that increase a facilities' liability.[68]
The DESA testing does not cause pain. [23]Some testing methods that employ radioisotopes require them to be injected into the body. Other methods cause patients to feel dizzy, ringing of the ears, and sickness in their stomach. [69]Additionally, burning or other unusual sensations of the skin may be felt. When using other invasive testing procedures that require injections, the injection point could bleed, become red, swollen, painful, or even infected. Some individuals may develop a rash, facial redness, swelling, fever, transient increase in blood pressure or have an allergic reaction to the injection of the radioisotopes (Tracer Medication as it is called).[70] Anyone can take a DESA test, as there are no Radioisotopes involved. Unlike tests involving the injection of radioisotopes, the DESA is safe for everyone including pregnant or soon to be pregnant women.[71]
In the DESA, there is no exposure to high magnetic gauss, x-rays, or gamma rays. There are no dyes used in the DESA .[72][73]High magnetic gauss is used in MRI testing, a test which diagnoses internal structures. X-rays diagnose bony problems. Gamma rays have a tissue penetrating property, thus used in CT scans. Contrast injections (dyes) help to visualize blood flow and help to see other internal structures in an MRI.[74][75]
Any individuals who are taking anti-depressants or other medications are not at risk for any contraindications, toxicity, or fatality due to serotonin syndrome. Also, there is no risk of chemically induced depression.[76]
The DESA test has no proximity effect for patients. Individuals are not exposed to any radioactive isotopes or ionizing radiation and are therefore able to interact and be in the vicinity of their loved ones immediately without the need for completion of a waiting period. Other testing methods require patients to refrain from immediate close proximity to family members and others, especially children.[72][71]
The DESA test does not interfere with travel through airport security. No additional papers will be required to prove a patient is not a terrorist.[77]Given heightened concerns about terrorism, sensitive radiation detectors are used in major cities and public transportation facilities. Individuals who receive nuclear medicine procedures may trigger detector alarms and be stopped by security personnel.[78]
Physicians are often required to help avoid any security problems by providing a letter containing the following information: the patient’s name, name and date of the nuclear medicine procedure, the related radionuclide, its half life, the administered activity and 24-hour contact information. This letter should provide specific details about who should be contacted. Outside of normal working hours, the contact person should have access to an appropriate source of information so the information in the letter can be independently confirmed.[79]
Common radioisotopes that are used in many nuclear medicine studies that could set off radiation monitors, each with varying half lives or decay time, includes technetium-99m, fluorine-18 (FDG) and thallium-201. Most recent problems with radiation monitors have been with the use of iodine-131, which is used to treat hyperthyroidism, thyroid cancer and lymphoma.[80]
A clinical evaluation is performed within a neuroelectrical laboratory, and then later, interpreted by a neurophysiologist.
Successful clinical application of neurophysiologic cartography requires three critical elements:
Adequate equipment is essential. The term "adequate equipment" requires the ability to form, visualize, and manipulate topographic images with reasonable speed, provide control groups for comparative database, and ability to provide control of artifact.
A skilled technologist is essential. The term "skilled technologist" requires that one must be able to place electrodes with accuracy and quality, be able to reduce artifact, and monitor state.
A specially trained neurophysiologist is essential. The term "specially trained neurophysiologist" requires that one must be skilled at recognizing artifact and be able to read classic EEG and Evoked Potential data. [29]
Routine testing is as follows. The technician explains to the patient the procedure. Then, the patient sits in a recliner.[2] The technician places a specially designed cap containing thirty-two electrodes on the patient's head. The electrodes are used to record electric currents developed in the brain. [81] Electrogel, a clear pasty substance, is used to ensure proper contact with the predetermined points on the scalp, ears, neck, and cheek. [23]
Equipment is calibrated by the technologist and the patient information is entered to create a patient record. The test results of this first visit can then be compared to future visits.[22]
The basic protocols are applicable for all patients. The extended protocols are reserved for those patients who are suspected to have Irlen Syndrome.
The collection of data begins. The patient need not do anything more than sit quietly. [23] First EEG segments are taken, then Evoked Responses are recorded to visual and auditory stimuli. This data is either merged or averaged depending on the protocols. Once the technician determines that all pertinent information has been collected, the patient's cap is removed.[23]
A neurophysiologist is then handed the results of testing. Interpretation of the results then begins.
Interpreting event related brain potentials (Event Related Potential's), or, small changes in the electrical activity of the brain that are recorded from the scalp and that are brought about by some external or internal event, (Coles & Rugg, 1995) (Kutas & Dale, 1997), has been around since the 1960s. Attempts have been made to associate Event Related Potential waveforms with specific cognitive processes.[29]Cognitive processes like auditory, visual, language, and Coherence based functioning processes have been studied in depth in relation to Event Related Potentials.
Highly skilled medical professionals select and interpret the data very carefully. To analyze only the most important EEG data, the technologist manually removes the artifact (medical imaging) to “clean” the data.[82] However, the advanced system of the DESA removes artifact from Evoked Potential segments automatically based on threshold levels initially set by the technologist. The analysis of data includes a comparison to a normative database. [58]Harvard's Children's Hospital Boston compiled this database over many years.[2] When a report is generated, it is divided into sections covering both EEG and Evoked Potentials. [83]These reports explain the function/dysfunction of the brain. When dysfunction is identified, many methods of intervention are possible.[83] The neurophysiologist or other medical practitioner can work with the patient knowing their dysfunction and the chosen method of treatment.
The DESA and its auxiliary components of Evoked Potentials differ in many significant ways from an ordinary EEG.[51]
EEG
The accuracy of the data stems from the use of thirty-two channels as opposed to the eight, sixteen, or twenty channels of other EEG instrumentation.[50][57] The EEG segment is Quantified, and therefore, a qEEG.
Evoked Potentials/Coherence
The utilization of the Visual Evoked Responses/Potentials, the Auditory Evoked Responses/Potentials, the FMAER and the P300 studies helps to gather precise information with which to design a course of treatment with medication intervention, when deemed necessary.[84] Coherence is also studied and analyzed to identify, modify and treat dysfunction.
Irlen Syndrome/Other Evoked Potentials
Detecting the visual/color responses associated with Irlen Syndrome (IS) /Evoked Potentials (VCRR) which assists with locating and treating eye deficits and reading deficiencies.
Normative Database
As with all qEEG type systems, the results are compared to a normative database of patients. Developed and established at Harvard’s Children's Hospital Boston, the advanced technology of the DESA allows on-screen comparisons and quantifiable, objectified data with which to assess, diagnose, and treat patients with greater effectiveness and efficiency than any other system.
Clinical Use
With brain mapping data and correlation analysis, clinicians have advanced information revealing the inner workings of the brain. Depending on what is found, the information can then be utilized by neurologists, psychiatrists, pediatricians, family practitioners, psychologists, psychotherapists, speech and language therapists, educational therapists, occupational therapists, and other disciplines to more effectively treat patients.[49]
REAL WORLD BENEFITS
TBI (Traumatic Brain Injury) detection
Some symptoms of TBI include anxiety, memory loss, depression, loss of concentration, and loss of balance. [85]The qEEG segment of the DESA reads patient's real-time electro-cortical activity and compares it to the normative database to detect dysfunctions like minute changes in brain activity that other methods are not able to detect. The qEEG is able to discriminate between mechanical injury and diffuse axonal injury.[6]
Autism & Learning Disability Analysis
Some of the symptoms of Autism and learning disabilities are auditory processing, auditory attention, and many other difficulties associated with language. [2] The DESA is read and the activity in segments such as AER, FMAER, and Coherence, etc. are then compared to the normative database. Detection of dysfunction in activity otherwise unable to detect is then possible.
The DESA tracks visual and auditory input from start to finish. We are able to provide a blueprint for the course of therapy by using the DESA to determine the precise nature of an individual’s disorder.[2]
Drug Addiction Treatment
The DESA has been used to identify brain functioning before and after detoxification. Comparative analysis shows undeniable differences between a brain on drugs and a brain after detoxification. The Los Angeles County Psychological Association highlighted its use in their publication dated January-February 2009. [86]
Pharmacological Intervention
The DESA can assist doctors in the choices and titration of medications. As an example, because there are different components of attention, each with its own location in the brain, it is often difficult to know which area of the brain’s attentional area to address and what the prescribed dosage should be. The DESA can pinpoint the source of brain electrical abnormalities, and the medication and proper dosage can be targeted for that region.[86]
^ abcdYellen A. “Wired for Learning, Wired for Life: Understanding the Brain’s Electrical Activity by Means of the DESA.” 13 Feb 2009. Online PowerPoint. YA.com. 13 Feb 2009. <http://www.yellenandassociates.com/pdf-downloads.php>
^ abNuwer, PhD. “Assessment of digital EEG, quantitative EEG, and EEG brain mapping: Report of the American Academy of Neurology and the American Clinical Neurophysiology Society.” Neurology. 49 (1997)277-292. American Academy of Neurology. Department of Clinical Neurophysiology, UCLA Medical Center, Reed Neurological Research Center, Los Angeles, CA. 22 May 2009. <http://www.neurology.org/cgi/content/full/49/1/277>
^A qEEG is a stand-alone protocol, however, it is used in the DESA. BEAM is a predecessor to the DESA.
^Duffy experimented with the qEEG in order to arrive at the DESA protocol.
^Baran JA, Long RR, Musiek FE, Ommaya A. “Topographic mapping of brain electrical activity in the assessment of central auditory nervous system pathology.” Am J Otol. 12.9 (1998) 72-6. PubMed Online. 5 Feb 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
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^ abcdefghAmerican Clinical Neurophysiology Society. “A Brief History of the Activities of the American Clinical Neurophysiology Society.” 2009. History of AEEGS Committee and Society Staff. 04/28/2009. <https://www.acns.org/history.html>
^ abcdefghijklmThatcher, RW Lubar, JF. “History of the Scientific Standards of qEEG Normative Databases.” St. Petersburg, Florida: NeuroImaging Laboratory Applied Neuroscience, Inc.: 2008.
^ American Electroencephalographic Society. “American Electroencephalographic Society statement on the clinical use of Quantitative EEG.” J Clin Neurophysiol. 4 (1987) 197.
^Neurofeedback Solutions. “A Brief History – How did science and cats discover SMR EEG training?” 2006. Learn Neurofeedback. 06/23/2009. <http://aboutneurofeedback.com/science and cats.php>
^Duffy et al. “Spectral coherence in normal adults:unrestricted principal components analysis; relation of factors to age, gender, and neuropsychologic data.” Clin Electroencephalogr. 26.1 (1995) 30-46. PubMedOnline. National Institute of Health. 3 Feb 2009. <http://www.ncbi.nlm.nih.gov/ >
^Thatcher et al. “Sensitivity and Specificity of an EEG Normative Database: Validation and Clinical Correlation” J. Neurotherapy. 7 (3/4):87-121, 2003.
^ Thatcher et al. “Quantitative qEEG and the Frye and Daubert Sandards of Admissibility.” Clin Electroencephalogr. NeuroImaging Laboratory, VA. and Dept of Neurology, FL: 34.2 (2003) 1-15.
^Tramontano, G. “qEEG Testing Can Discern Reason for Cognitive Disorder: Digital EEG Recordings of Brainwaves Can Determine TBI Etiology.” Connecticut Lawyer. 3 (2006) 14-16. Ctbar.org. 30 May 2009. <http://www.ctbar.org/filemanager/download/713>
^Duffy et al. “Status of Quantitative EEG (qEEG) in clinical practice.” 1994. Clin Electroencephalogr. 25 (1994) 6-22.
^Kuck et al. “Brain processing of meter and rhythm in music. Electrophysiological evidence of a common network.” Ann N Y Acad Sci. 999 (2003) 244-53. PubMedOnline. National Institute for Health. 23 May 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
^Loewy et al. “Sleep/sedation in children undergoing EEG testing: a comparison of chloral hydrate and music therapy.” Am J Electroneurodiagnostic Technol. 46.4 (2006) 343-55. PubMedOnline. National Institute for Health. 23 May 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
^Peterson et al. “Music increases frontal EEG coherence during verbal learning.” Neurosci Lett. 412.3 (2007) 217-21. PubMedOnline. National Institute for Health. 23 May 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
^Steinbeis et al. “Comparing the processing of music and language meaning using EEG and FMRI provides evidence for similar and distinct neural representations.” PLoS ONE. 3.5 (2008) e2226. PubMedOnline. National Institute for Health. 23 May 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
^R. Coben, A. Clarke, W. Hudspeth, R. Barry. “EEG power and coherence in autistic spectrum disorder.” Clinical Neurophysiology. 119. 5 ( 2008 ) 1002-1009.
^ abGarber et al. “Clinical use of topographic brain electrical activity mapping in psychiatry.” J Clin Psychiatry. 50.6 (1989) 205-11. PubMed Online. National Institute of Health. 2 Mar 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
^ abcdeYellen A. "DESA®: Digital EEG Spectral Analysis." Northridge, CA: Yellen & Associates: 2006.>
^ abYellen A, Schweller T. “The Use of Brain Imaging in Clinical Practice: Two Case Studies.” The LA Psychologist. (2009) 12-13.
^Thatcher et al. “An EEG Severity Index of Traumatic Brain Injury.” J Neuropsychiatry Clin Neurosci. 13.1 (2001) 77-87. QEEG References. Kuhn Center: Integrative NeuroPsychiatric Services of New York. 03/19/2009. <http://www.kuhncenter.com/forensic/qeeg-references.shtml>
^Duffy, Frank H."Topographic Mapping of Brain Electrical Activity." Butterworths. 25 (1986) 409.
^ A head injury causes brain damage, causing pain. This is revealed on the DESA map.
^Duffy FH, Burchfiel JL, Lombroso CT. “Brain electrical activity mapping (BEAM): a method for extending the clinical utility of EEG and evoked potential data.” Ann Neurol. 5.4 (1979) 309-21. PubMed Online. 3 Feb 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
^ abBehavioral Medicine Associates, Inc. “Quantitative EEG and Neurotherapy Fact Sheet.” 2009. Education Pages. 03/06/2009. <http://www.qeeg.com/qeegfact.html>
^Towle et al. “Identification of the sensory/motor area and pathologic regions using ECoG coherence.” Electroencephalogr Clin Neurophysiol. 106.1(1998) 30-9. PubMedOnline. National Institute for Health. 5 Feb 2009. <http://www.ncbi.nlm.nih.gov/pubmed/>
^The University of Mississippi Medical Center. “Magnetic Resonance Imaging (MRI) and the Pediatric Patient.” Pediatric Dept. Division of Child Development. 2002. University of Mississippi. 16 July 2009.<http://www.dhss.delaware.gov/dhss/dph/files/radisotopmed.pdf>
^Layeeque, Rakhshanda et al. “Intraoperative subareolar Radioisotopes Injection for Immediate Sentinel Lymph Node Biopsy.” Annals of Surgery. 239.6 (2004) : 841-848.
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