A Complicated Illness
I came across an article that is to appear in Epilepsy Research and wanted to upload it but the size was too big so the abstract appears below.
This was prompted by a question someone asked about Dr. Walker and how he could get such good results. The point of this article is that epilepsy is a complicated disease and cannot be solely understood by reading or observing the seizure. It notes that the connectivity between networks, different parts of the brain seems to influence the persistence of seizures and that there are different connectivity patterns in the front part and the back part of the brain and differences between the frequencies. By connectivity is meant the timing between pairs of sites and these pairs group into ROIs or regions of interest.
Walker and others such as myself, do a Quantified EEG which is the only way to measure connectivity (called coherence and phase) and use a database very much like a lab uses a database to match blood samples you give your doctor, to determine whether certain connectivity should be increased or decreased since you cannot tell solely from the symptoms or from the observation of the seizure. This individualization and targeted customized network approach based on matching against non seizure patients may account for Walker's success.
EEG functional connectivity of the intrahemispheric
cortico-cortical network of idiopathic generalized
B. Clemensa,∗, S. Puskásb, M. Bessenyeia, M. Emric, T. Spisákc, M. Koselákc, K. Hollódyd, A. Fogarasie, I. Kondákorf, K. Fülef, K. Benseg, I. Feketeb
a Kenézy Hospital Ltd., Department of Neurology, Bartók Béla út 3., 4031 Debrecen, Hungary
b University of Debrecen, Medical and Health Science Center, Department of Neurology, Debrecen, Hungary
c University of Debrecen, Institute of Nuclear Medicine, Debrecen, Hungary
d University of Pécs, Department of Pediatrics, Pécs, Hungary
e Epilepsy Center, Bethesda Children’s Hospital, Budapest, Hungary
f Teaching County Hospital of Bács-Kiskun, Department of Neurology, Kecskemét, Hungary
g Teaching County Hospital of Bács-Kiskun, Department of Child Neurology, Kecskemét, Hungary
Received 7 December 2010; received in revised form 22 March 2011; accepted 24 April 2011
generalized epilepsy; Network;
LORETA Source Correlation
Aims: Intrahemispheric, cortico-cortical EEG functional connectivity (fC) was investigated in untreated patients with idiopathic generalized epilepsy (IGE) in this explorative study. Patients and methods: Group comparison was carried out between 19, drug-naive IGE patients and 19, matched healthy persons. 90 × 2s of 19 channels waking, interictal background EEG signal (without epileptiform potentials) were processed to the LORETA (low resolution electro¬magnetic tomography) software to compute current source density for 2394 voxels representing parcels of the cerebral cortex for 25 very narrow bands of 1 Hz bandwidth (VNBs) from 1 to 25Hz. EEG fC was investigated among the already localized sources. Pearson correlation coefficients (R) were computed among the 33 regions of interest (ROI) within the left and within the right hemisphere, separately. Group differences were computed by means of t-statistics. Corrected p < 0.05 differences were accepted as statistically significant.
Main results: (1) The anatomical patterns of the fC differences showed great frequency-dependency. (2) Hemispheric asymmetry was prominent within most VNBs. (3) Decreased fC in the IGE group was found across all VNBs in the 1—6 Hz frequency range as compared to mixed patterns comprising both increased and decreased fC at >6Hz frequencies. (4) In the 5—25 Hz range, decreased fC dominated in the anterior, increased fC in the posterior parts of the cortex. (5) The results delineated an anterior and a posterior network.
∗ Corresponding author. Tel.: +36 52 511 777; fax: +36 51 511 729. E-mail address: ... (B. Clemens).
0920-1211/$ — see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.eplepsyres.2011.04.011
Last edited by Bernard; 06-12-2011 at 08:01 AM. Reason: remove email address per forum policy
I have a few questions about the QEEG and how it works. These are prompted by my own situation: I have IGE which is currently controlled by medication. I'm interested in trying neurofeedback with the hopes of potentially reducing my dosage or going med-free altogether.
1. Since my seizures are controlled, can the QEEG still provide data that would guide the nfb training?
2. If the QEEG can't provide the data, would it still be possible to use nfb to modify SCP and SMR, more-or-less on a prophylactic basis? Or would I need to reduce medication enough to allow additional info to show up on the QEEG before proceeding with the nfb?
Thanks for your help,
1. Yes it is still possible that the QEEG could supply information to guide the NFB training. Even though you are seizure free there may be events that will still show up on a digital EEG that can then be analyzed for sourcing using LORETA. Also coherence and Phase patterns and amplitude asymmetry patterns can be done and run against the database to see the weakest sites in the networks. With the use of the Laplacian montage, a montage to localize effects, it may be able to minimize the effect ofthe medication on the maps but you will not get coherence and phase information from that montage. Still even with meds the patterns would probably be there though subclinically. If the training is successful, and you slowly with the approval of your doctor titrate off or lower a medication it is possible that patterns that were masked by the meds might show up on a new QEEG and result in an adjustment of the training protocol. It is obviously a delicate and slow process. Thus the protocol may change both as a result of success and as a result of reducing the meds.
2. You can learn self regulation with skin conductance training and teach yourself relaxation that will approximate changes in SCP. SC training has been documented as helping control seizure, but that is peripheral not EEG biofeedback. I do not know off the top of my head if SC training was used with IGE or partial seizures or both.
Lastly, the evaluator should have the most recent and if possible as many of the EEG reports there are and if there are digital files they could be transmitted to him or her for comparison. If previous abnormal digital files are readable by the database then that could help as well.
The choice of database is very important. There are technical issues which I can apprise you of back channel if this becomes a reality for you,
I hope this is helpful.
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Thanks Jerry! The practitioner I have in mind is not specifically trained in seizure-related nfb, but has said he will work with a colleague who is. Your info is very helpful, I'll keep it in mind when I initiate the process later this year.
|connectivity, neurofeedback, research, walker|
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