EEG

How EEG can Show an Epileptogenic Process

This is the first of a few posts with a variety of ways the EEG can show an epileptogenic process. The morphology of the underlying process are quite dramatically varied.

The two images below show the referential and sequential montage display of an active right temporal-parietal spike and slow wave focus, seen in a child clinically diagnosed with an attachment disorder. There was no history of convulsion, nor any suspicion of the actual underlying pathophysiological basis for the behavioral presentation.

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Epilepsy and EEG

Epilepsy and EEG have been inextricably linked since the 1930s, when Frederick and Erna Gibbs discovered that epileptic events were visible in the EEG.  The evolution of other medical imaging in the 1970s and 1980s provided a better way to localize tumors, and the clinical use tapered off in areas other than epilepsy and encephalopathies.  Even with the multiplicity of other methods, the EEG remains the gold standard for identification of epilepsy.

In modern neuroscience centers, the EEG is still the tool of choice in evaluation of convulsive epilepsy, as well as some other non-convulsive forms, such as staring episodes seen in “absence epilepsy” typically as a 3/second spike and wave dominant anteriorly, or temporal lobe epilepsy, which is seen as a “notched” slow wave discharge fronto-temporally.

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First Direct Evidence of Neuroplastic Changes Following Brainwave Training

The scientific and academic press is now considering Neurofeedback as one of the ways neural plasticity can be induced/enhanced. The paper below shows the NF training changing the brain’s plasticity measurably within a single feedback session.

This may not surprise too many old-time NF practitioners, except that it is now being proven with well done studies in the traditional neuroscience literature!  Neurofeedback can induce changes in brain plasticity!

Jay

First Direct Evidence of Neuroplastic Changes Following Brainwave Training

ScienceDaily (Mar. 12, 2010) — Significant changes in brain plasticity have been observed following alpha brainwave training.

A pioneering collaboration between two laboratories from the University of London has provided the first evidence of neuroplastic changes occurring directly after natural brainwave training. Researchers from Goldsmiths and the Institute of Neurology have demonstrated that half an hour of voluntary control of brain rhythms is sufficient to induce a lasting shift in cortical excitability and intracortical function.

Remarkably, these after-effects are comparable in magnitude to those observed following interventions with artificial forms of brain stimulation involving magnetic or electrical pulses. The novel finding may have important implications for future non-pharmacological therapies of the brain and calls for a serious re-examination and stronger backing of research on neurofeedback, a technique which may be promising tool to modulate cerebral plasticity in a safe, painless, and natural way.

Continued at http://www.sciencedaily.com/releases/2010/03/100310114936.htm

Drug exposure and EEG/qEEG findings

A technical guide by Jay Gunkelman, QEEG-D

General comments:

There is a generally reciprocal effect between alpha and beta, as brain stem stimulation desynchronizes the alpha generators, beta is seen.  During states of under-arousal, this relationship is not seen, as when the subject is alerted, when both alpha and beta increase.

The point is that the arousal level changes the EEG responses expected, as when a stimulant is given to an under-aroused subject, increasing alpha. In a normally aroused subject, stimulants decrease alpha, and in an anxious (low voltage fast EEG variant) subject alpha will not be seen as changed by a stimulant.

Though there is a response stereotype for each medication, there are also individual responses, which vary. Mixtures of medications become too complex to evaluate each individual medication’s contribution, not to speak of synergistic effects not seen with any single medication, which may be seen in polytherapy.

The following pages represent a summary of many articles, papers, reviews and books on medications and the CNS function, and finally nearly 30 years of experience in clinical and research EEG. The difficulty in this area is the definitions of bands varies, the methods of analysis range from visual inspection of the raw EEG to quantitative measures, not all of which are clearly defined… and thus the need for a brief summary which puts this into a concise form for reference.

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Neurofeedback and the Brain

Neurofeedback is an emerging neuroscience based clinical application, and understanding the underlying principles of neurofeedback allows the therapist to provide referrals or treatment, and provides clients with a framework for understanding the process. The brain’s electrical patterns are a form of behavior, modifiable through “operant conditioning,” with the excessive brain frequencies reduced, and those with a deficit are increased. The learning curve for EEG has been described (Hardt, 1975).

Neurotherapy using slow cortical potentials also shows promise in the treatment of epilepsy (Kotchoubey et al., 2001; Birbaumer et al., 1981; Sterman, 2000). Neurotherapy has also been used for ADD/ADHD (Monastra, Monastra, & George, 2002) depression (Rosenfeld, 1997), anxiety (Vanathy, Sharma, & Kumar, 1998), fibromyalgia (Donaldson, 2002), and for cognitive enhancement (Budzynski, 2000; Klimesch, et al.). Commonly reported success rates of 60 to 90% are reported  (Wright & Gunkelman, 1998).

Neurofeedback is an emerging neuroscience based clinical application based on the general principles of biofeedback or cybernetics. The Neurofeedback process involves training and learning self regulation of brain activity. Understanding the underlying principles of this process allows the therapist to provide referrals or treatment to their clients with some added understanding, and provides clients with  a framework for understanding the neurofeedback process. The following short paper will provide a quick review of the brain’s function, and the underlying process involved in neurofeedback, a technique  that will allow the client to better regulate and operate their brain.

The brain controls its own blood supply through the dilation and constriction of the blood vessels, and the blood flow is directed to areas that are more active through this self-regulation. The blood supply’s flow, along with the utilization of the oxygen and glucose the blood carries is measured as “perfusion,” a measure that is clearly seen in some of the modern imaging techniques, such as Positron Emission  Tomography (PET) and SPECT technology. Though these techniques are invasive, requiring the injection of small amounts of very short half-life radioactive materials, they do give good resolution of the perfusion due to the emission of the positrons, which are emitted from where the brain utilizes the oxygen and burns the glucose carried by the blood flow.

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New research shows: Neurofeedback is an ‘Evidence-Based’ treatment for ADHD.

Nijmegen, July 16th 2009 – Neurofeedback – also called EEG Biofeedback – is a method used to train brain activity in order to normalize Brain function and treat psychiatric disorders. This treatment method has gained interest over the last 10 years, however the question whether this treatment should be regarded as an Evidence-Based treatment was unanswered until now. Tomorrow a study will be published in the scientific journal ‘EEG and Clinical Neuroscience’ demonstrating that Neurofeedback can indeed be regarded as an evidence-based treatment for Attention Deficit- / Hyperactivity Disorder (ADHD).

Neurofeedback is a treatment where real-time feedback is provided for specific brain activity (most often EEG) in order to learn the brain to suppress or produce specific brain activity. This method was initially discovered for the treatment of Epilepsy and from 1976 investigated further for the treatment of ADHD. This technique has become more popular by clinicians worldwide, and is currently provided for the treatment of several disorders. Critics have often questioned the efficacy of Neurofeedback and whether it can be considered an Evidence Based treatment or not.

In collaboration with researchers from Tübingen University (Germany), Radboud University (Nijmegen, the Netherlands), Brainclinics and EEG Resource Institute a so-called meta-analysis was conducted on all published research about Neurofeedback treatment in ADHD. This meta-analysis included 15 studies and 1194 ADHD patients. Based on this study – which will be published in the July issue of EEG and Clinical Neuroscience – it could be concluded that Neurofeedback can indeed be considered an Evidence-Based treatment for ADHD. The results show that neurofeedback treatment has large and clinically significant effects on Impulsivity and Inattention and a modest improvement of Hyperactivity.

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Thalamic Involvement in the Generation of the Alpha Rhythms

Alpha… it’s not a simple idling rhythm… let’s look at alpha generators:

The thalamic involvement in the generation of the alpha rhythm is being under-valued when looking at the LORETA images of alpha current source generators. The alpha power may come from the sources that LORETA identifies, but the thalamus is intimately involved in alpha rhythm generation, and this is not part of the LORETA image of the sources.

The polarization within the thalamus sets the base frequency of the alpha, but the cortical rhythm requires a complex multi-layer feedback loop from the thalamus to the cortex, and back to the thalamus. Without the cortex, there is a total disruption of the normal spatio-temporal distribution of the alpha wave’s spike trains within the thalamus, and cortical damage often disturbs coherence due to this mechanism.

The thalamus distributes the alpha posteriorly via specific sensory relays, which have a simple return circuit. Like the white matter relay from the lateral geniculate of the thalamus to the occipital lobe’s primary visual areas, and directly back. This thalamo-cortical-thalamic loop is relatively faster than the loop seen frontally. The frontal return circuitry is not simple, but the descending routes are complex and somewhat circuitous, taking more time, and thus it is common for the frontal lobe’s alpha to be at the slower end of the individual’s alpha frequency range. The frontal lobe has a return path through the striatum.

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Dementia and Alzheimer’s Disease: LORETA findings

Thanks to Jay Gunkelman who made a very informative post on January 27 on this forum entitled Dementia and Alzheimer’s Disease. There he described the EEG patterns that we should expect and detect when evaluating for AD or other dementias.

I’d like to just throw out there a few other findings that were discovered in a few exploratory investigations while working on some studies with our colleague Alicia Townsend, at the time at Univ. of North Texas. Lexicor funded these projects and now the arrangements are such that I can’t disclose more than was published in the abstracts from our talks at ISNR and AAPB.  I did at least want to point to these very preliminary findings because theoretically they are in concert with your explanations.

First, we explored 10 participants between the ages of 65 and 85 were recruited at the University of North Texas Health Science Center.  Each was diagnosed by the Alzheimer’s Disease Assessment Scale and a medical interview.  The aim of the study was to identify current source density markers in AD.  EEG recording of the eyes closed condition of an AD group was compared to an age-sex matched control group using within-subject multiple t-test procedures. sLORETA difference maps in nine frequency bands were investigated. Interestingly the results showed that there was a significant increase in current source density in the delta and theta bands in the Brodmann Area (BA) 39 of the right temporal lobe and BA 31, the cingulate gyrus respectively.  Additionally there were decreases in alpha in the BA 21 of the right temporal lobe and right inferior parietal lobule (Sherlin, Townsend & Hall, 2006).

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Neurofeedback Foundation Award 2009

In his role as the Managing Director of the Foundation for Neurofeedback and
Applied Neuroscience John Fisher recently announced the Foundation’s selection of a recipient of the Neurofeedback Foundation Award.

The Foundation gives an award to the author(s) of the publication which has
“contributed the most to furthering the field of neurofeedback” during the
past year. Past recipients have included Drs Rob Coben, John Gruzelier, as
well as Johan Levesque and Mario Beauregard.

This year the Foundation has chosen Professor Dr. Juri Kropotov as recipient
of this years award, based on his book and the body of work Juri has
contributed over the years.

This award selection was announced recently at the EEG Spectrum Clinical
Interchange Conference in Los Angeles.  The award includes a gorgeous plaque
as well as an honorarium.

We salute both the Foundation for helping promote the fiend of NF, as well
as all the award recipients for their publications and the substantial
contributions they all have given to our field.