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- 1 Merge Electroencephalography and Electroencephalogram?
- 2 Voltages
- 3 Voltages again
- 4 Is it really useful for Astral Projection?
- 5 References
- 6 research on EEG training
- 7 Note 12
- 8 Check your notes!
- 9 Image
- 10 Monroe Institute Critique
- 11 Bias regarding neurofeedback
- 12 POV and Clean-Up
- 13 Ideas for future work
- 14 Other Brainwaves?
- 15 Brain wave and sex
- 16 Requested move
- 17 Silver electrodes
- 18 Gamma and Schizophrenics
- 19 Four types of waves?
- 20 Construction of electroencephelograph
- 21 Corticography
- 22 First human EEG record published in America.
- 23 Electrode placement diagram
- 24 forensic method?
- 25 Merge Kappa rhythm into Electroencephalography
- 26 Removed opinion on electrode placement
- 27 Removed EEG-marketing-spam
- 28 qEEG?
- 29 Did You Know
- 30 Event Related Potentials
- 31 Sound Cancellation
- 32 the amount of brain wave (Hertz) the brain generates
- 33 Dense Array EEG (daEEG)
- 34 EEG/Brainwave Of Ego Death
- 35 underlying theory of EEG missing?
- 36 Confusing section
- 37 Lack of references/verifiability
- 38 What do you mean by brainwave?
- 39 EEG at home
- 40 My Son Has Had What They Think Is A Seizure, My Brother Had Convulsions As A Child - Could This Be A Gene Thing
- 41 Voltage falls of as the fourth power of radius?
- 42 External links
- 43 QEEG
- 44 an EEG STORY - 1984 - Electronic system prearranged to replace in the electronic games the existing manual controls with equivalent controls directly commanded by the brain. 1984
- 45 "Clinical Use" needs more about long-term EEG
- 46 DC
- 47 Which articles are referred to?
- 48 History
- 49 Brainwave Hacking
- 50 How Real Is this
- 51 Adding NIRS and EROS
- 52 Add MUSE? (http://www.indiegogo.com/interaxonmuse)?
- 53 Ion Flow vs Electromagnetic Conduction
Merge Electroencephalography and Electroencephalogram?
Done 14:46, Sep 15, 2004 (UTC)
Yes. There's no difference. electroencephalography is the technique of making EEG recordings; an electroencephalogram is one such recording. I don't have a handle yet. email@example.com 10/26/04 10:17 PDT
- Yeah, but like photography and photograph deserve separate articles. I think the merge is good, though. - Omegatron 19:15, Dec 17, 2004 (UTC)
I know that the electrodes are measuring voltages at the scalp, but what is the reference? Is the voltage measured between pairs of electrodes? What is the electrical model of the scalp as related to the brain? - Omegatron 19:15, Dec 17, 2004 (UTC)
- Differential amplification is more complex than the explanation offered above. Take for example an EEG channel called C3-A1 (C3 as active, A1 as reference).
- To produce a single EEG signal (the wavy line or "trace" showing values over time), requires not one but three differential amplifiers. In the example of C3-A1, the first amplifier receives values from C3 and Ground, amplifying the difference. The second receives A1 and ground, amplifying that defference. Finally the third receives the output of amp 1 and amp 2, amplifying that difference and producing the EEG trace. Thus there are no less than three wires attached to the head to define one EEG channel of data: the active, the reference and the ground sites must be measured.
- There is an international convention called the "10-20 System" that specifies the locations of active and reference sites in a fully replicable manner. It also is conventional to regard the specific location of ground as immaterial so long as it is on the skin. (I expect that this convention will prove to be wrong.)
- The three differential amplifiers produce common-mode rejection, the very important effect of removing most artifact, or non-brain sources of voltage variation. We live in a sea of electromagnetic flux from outside the body, and parts of the body outside the brain produce voltages as well. For example muscle contractions, heart activity, eye-movements, and swallowing are common sources of artifact voltage changes in EEG. Simply, common-mode rejection occurs when an electromagnetic fluctuation is detected by both first-stage amps simultaneously, and the fluctuation is removed when only the difference between those values is passed on by the second stage amp.Psydoc 07:25, Apr 8, 2005 (UTC)
- So one amplifier produces C3-ground, and the second produces A1-ground, and the third produces (C3-ground)-(A1-ground) = C3-A1. So it's still a differential amplifier amplifying the difference between C3 and A1 (regardless of how many op-amps and transistors are actually involved). It sounds like there's some practical common-mode rejection aspect to measuring relative to ground? I'm not really sure how this would work, though.
- I am not an expert (and you seem like you are), but every "Common reference derivation" schematic I have seen uses:
- 1 reference/common electrode - all signals are measured relative to this
- 1 DRL (driven right leg) amplifier - an active output that is connected to the patient
- As many signal electrodes as desired
- This schematic http://circuitos.tripod.cl/schem/r24.gif shows the DRL driving the average of the ("signal" and "reference") electrodes back into the person.
- So by "ground" do you mean the active DRL output? - Omegatron 16:25, Apr 8, 2005 (UTC)
I really appreciate this interchange. Your expertise apparently is electronics. My experience includes comprehending the EEG, but I particularly focus on clinical applications of operant conditioning of EEG - commonly called "Neurofeedback" - based on quantitative analysis of EEG and database comparisons. So I'm a clinician, but I have been interested in the electronics too, the better to comprehend the EEG.
I agree with your first paragraph summarizing the differential amplifier. To better answer your puzzlement about the benifits of common mode rejection I have referred to "Spehlmann's EEG Primer 2nd Ed.", B.E.Fisch, 1991. (Ouch that is old!) That common textbook describes the following rationale. Potentials from brain tissue distributed across the brain seldom are precisely the same in amplitude and timing. In contrast, potential changes arising from the environment strike the electrods essentially simultaneously and are cancelled by the amplification scheme. That effect requires low impedances and relatively equal impedances for each electrode. Technicians are tought to assure that condition, and the very high front-end impedances of modern EEGs (10 plus gigohm) make the problem less critical.
When it comes to reading electronic diagrams I am a novice, but those you provide do not look familiar or similar to the simplified versions in my texts. I have not seen one that shows an output driven into the person, other than those you provided (was it really an EEG?) I do see your reasoning, and as far as it goes I see why you think the "ground" is a DRL. The biomed engineer who tought me EEG emphacised that no signal is driven into the person, so I wonder. The "ground" is clearly described by Fisch as destinct from the amplifier ground, and as the basis for inverting the phase of the signal from the second electode in the pair. I think I will pose the question to a manufactuter (I do know several) and get back to you on that.Psydoc 05:14, Apr 12, 2005 (UTC)
- Excellent. Well I'm just starting to learn about it, helping out with the OpenEEG project. I haven't really gotten into the actual EEG part of the circuitry; focusing on the signal parts of the circuit first. Their circuits are based around this paper, which uses a design with DRL amplifiers. - Omegatron 13:19, Apr 12, 2005 (UTC)
The electrical model of the scalp as related to the brain has been worked out in very extensive medical research. To simplify, voltages at the scalp are most influenced by voltage changes in large groups of pirimidal neurons at the brain surface directly beneath the electrode. Voltages are attenuated about 100-fold by the skull and other interveining tissue. In addition to that local signal source, there is "volume conduction" to the electrode from across the brain. Three-dimensional mathmatic procedures exist that identify major signal sources deeper within the brain.Psydoc 07:25, Apr 8, 2005 (UTC)
- Is there a circuit model (with capacitance/resistance, etc.)? - Omegatron 16:25, Apr 8, 2005 (UTC)
Not that I have seen. The research I have seen has focussed on the level of individual neurons, postsynaptic potentials, and summated fields. I do expect that others have modeled it in detail, given the sophistication of the industry worldwide. Remember that very high-density-array brain-surface EEG is used to guide brain tissue ablation to treat severe intractable epelepsy. They model the seizure focus in 3D using EEG, then incert micro devices with precision. When I did a brief search I found only a discussion of the need for the EEG in that process, but it is informative.
Psydoc 05:14, Apr 12, 2005 (UTC)
- Aha! "Active DC suppression is superior because it biases the output stage towards zero, allowing for higher gains." It's used to prevent premature clipping in the amplifiers?
- "First, Huhta and Webster assumed that the subject was connected to earth ground. This simplification reduces the number of variables in the calculations, but it is no longer appropriate. Grounding the subject is unsafe because it increases the risk of electric shock. Modern safety regulations require that the subject must be isolated from ground so that contact with an electric source would not result in the subject creating a path to ground. Furthermore, grounding also allows more 60 Hz noise to enter the measurements. Modern amplifiers use an “isolated common” electrode which is electrically isolated from the ground of the power supply. In this configuration, the potential of both measurement and reference leads are measured relative to this common electrode and only their difference is amplified. Since the subject is only capacitively coupled to ground, the 60 Hz noise due to electric fields is greatly reduced." - Omegatron 14:31, Apr 15, 2005 (UTC)
- Regarding the scalp-brain connection, here is the very wonderful way that Bruce Fisch puts it in his "EEG Primer," which I recommend to anyone interested in EEG: He points out that there are two questions that people interested in the scalp voltages may ask. The first question is, if the electric fields of the brain are in a certain state, what will the fields be at the scalp? He calls this the forward problem, and he points out that there is only one answer to this question for any state of the brain. The other question is what EEGers would like to know the answer to: if the electric fields at the scalp are thus-and-so, what is the underlying state of the electric fields in the brain? This is the reverse problem and there are an infinite number of possible answers to it. The computer programs that Psydoc refers to use mathematical modeling to propose plausible answers to the reverse problem; they benefit from their programmers' physiologic understanding of the cortical generators, as well as the knowledge of the general average size and permissivity/permittivity of the skull, scalp, and so on. (For instance, IPSPs hyperpolarize in the millivolt range; there are no volt, or megavolt generators in the brain and so the computer can quickly rule out solutions that would require them.) - Ikkyu2 09:39, 28 August 2005 (UTC)
The EEG is a collection of biopotential measurements. The EEG measures potential (voltages, SI unit Volt) between two sites on the scalp. Since the signal is very small compared to other massive sources of noise, one uses a differential amplifier system. There is one reference electrode (often erroneously called ground) (Ref), and two active electrodes (e.g. A1, A2). The biopotential amplifier measures the difference between A1 and Ref, and between A2 and Ref. The biopotential amplifier has a high common mode rejection ratio, which means that signals (e.g. noise) that are common to A1-Ref and A2-Ref are cancelled. You need three electrodes and one amplifier to get one useful raw EEG signal.
The raw EEG thus consist of a collection of potential measurements (voltages) of Fp1,Fp2,T3,T4 etc., all versus the reference. This is different from the montages.
What is usually analyzed in clinical EEG is at one further level of abstraction. Conventional EEG looks at bipolar montages, where Fp1 is compared to another electrode such as F3 - the Fp1-F3 lead, or an average reference where Fp1 is compared to the average all the other electrodes. One can also link to a "neutral site", which is just a bipolar montage but with a fixed comparison electrode such as A1, A2 or an average of A1+A2. Thus, you need four electrodes and two amplifiers (each of which takes input from three electrodes), to get a conventional EEG signal.
Hope this clears things up. Janbrogger 08:35, 22 March 2007 (UTC)
Is it really useful for Astral Projection?
The article states, "Altering the brain's electrical activity can be useful for ... astral projection ..." Is that an NPOV statement? Or is it instead someone's belief that it can be useful for astral projection? If so, shouldn't Wikipedia instead report that someone (preferably identified) believes it to be the case?
Given that the Astral projection article states, "Neither this technique, nor OBEs in general, are accepted by the overwhelming majority of scientists," I would think that something needs to be modified about this statement in the Electroencephalography article. 126.96.36.199 15:36, 17 Jan 2005 (UTC)
- changed to astral projection experiments. :-) - Omegatron 21:13, Jan 17, 2005 (UTC)
I have noticed there are claims made about such things. Part of the interest in brainwaves is the speculation about what is possible. It may be absolute nonsense according to my reasoning, but it still makes interesting and encyclopedic reading. It would be right to document what people claim, and what has been found by various forms of investigation. I'll have a good scout around for more of the same. There's so much stuff out there, but I'll try to keep it balanced and concise. Regs D.Right 11:25, 30 Mar 2005 (UTC)
Of the several hundred practitioners of neurofeedback I have met, I think probably there are only a few who comfortably makes such statements, the author of the article prominent among them. For more common uses, see the professional sites devoted to this field.Psydoc 05:21, Apr 12, 2005 (UTC)
Hi everybody. With interest I read scientific articles on novel brain readout techniques (like doi:10.1038/nature06713), which I wanted you to read to tell me your opinion about it.
An artifical neural net (multilayer preceptron) could be used as visual encoder to reconstruct the images seen or imagined by an individual from its brain currents (electro-encephalography) or from its biomagnetic fields, alternatively.
Thereby, the images seen or imagined by an volunteer could be reconstructed to a good extent (1 to 5 images per second, black/white, but dentoted as "almost youtube-quality").
Another part of the work was the recording of the brain activity of dying persons. More than one hundred volunteers of an elderly hospital were examined in advance and questionnaired for their religious beliefs also. When they were up to die, their brain activity was recorded and the concerning images were reconstructed, finding characteristic sequences, like that reported by near-death-experiencers. There was almost always a tunnel experience, followed by some kind of judgement tribunal chaired by an old man, some kind of life film and afterwards a sequence showing a paradiese garden, or alternatively hellfire, or a "black hole" before brain flatline. Interestingly, hellfire and black hole sequences seemed to be significantly increased for atheist volunteers, whereas the paradiese garden sequences were found more frequently for persons with strong religious believes.
This technique could also be used as lie detector, or at the airport, as detector against terrorism, the inventors of this technique think. —Preceding unsigned comment added by 188.8.131.52 (talk) 13:34, 5 August 2008 (UTC)
All the above talk about brain activity of dying persons and astral projection, as well as lie detection, is entirely unsupported by the current neuroscienfitic literature. No one who scientifically or academically uses EEG methods would support any of these statements. The people who wrote about those topics above have not provided any evidence for their claims, and the claims they make are unsupportable. For example, you cannot use EEG to simply "reconstruct" images that people are seeing, as mentioned above. If this were possible, we neuroscientists would be using this technology to study innumerable important questions! It is not possible. Sorry. This is all nonscientific, untrue, speculation. 2607:F470:6:400B:E598:8B94:A1AF:6B59 (talk) 15:10, 28 July 2014 (UTC)Lorna
"Computer programs such as Noromaa Solutions Oy's Brainwave Generator (http://www.bwgen.com) are able to stimulate the brain and alter the brain's frequency via an audio stimulus."
Have there been any article's in peer-reviewed journals that support this statement? If so we should probably note them. If not we probably shouldn't make it sound like it is necessarily a fact. — Asbestos | Talk 14:56, 24 Feb 2005 (UTC)
- Hmmm, doing some search myself, I guess there is some peer-reviewed research out there. An article in Psychology and Behavior is the only peer-reviewed source I could find. Outside of that there are various other articles,  , but they are connected to the Monroe Institute which I'm not certain would be a neutral source. Anyway, I'm putting up the first link.
- My only remaining question is putting up the name and link for Noromaa Solutions Oy's Brainwave Generator. Looks like advertising. Should we just say that binaural sound generators exist, and maybe link in External Links? — Asbestos | Talk 17:37, 24 Feb 2005 (UTC)
I read the psych and behaviour paper in full. I'm afraid it really only says that the experiment effected mood, and they cannot conclude that it balances the brain in any way. Similar effects can be achieved with cheaper alternatives. Research on brain training really is mostly manufacturer's hyperbole. JuneD 22:48, 23 Mar 2005 (UTC)
research on EEG training
There is a growing collection of peer reviewed articles on EEG operant conditioning, AKA neurofeedback, if one knows where to look. The overall implication is of robust efficacy. Try these for a start: they are profesional organization sites. www.isnr.org www.aapb.org www.ecnsweb.com
184.108.40.206 19:46, 27 Mar 2005 (UTC)tvm firstname.lastname@example.org
The research is there alright. But I can't seem to find any findings that neurofeedback leads to any lasting beneficial changes. The research seems to me to be focussed on measuring what happens in the brains of various people with injuries vs normal etc. I cannot find anything that concludes brain entrainment will improve performance. Perhaps we could have some more specific references? Cheers EBlack 09:28, 29 Mar 2005 (UTC)
The "Training the brain to a desired state" section has become a mismash of claims and counterclaims. I've tried to reorganize this section to give a clearer veiw of the debate. This is a rather difficult area to wade into, since there is some degree of pseudoscience along with some legitimate research. The best bet is to stick with PubMed-referenced articles, but there isn't yet a clear picture on what works and what is baseless, as far as I can tell. Sayeth 21:34, Mar 28, 2005 (UTC)
It does look better. I will continue looking for references to clarify any myths. Regs EBlack 09:28, 29 Mar 2005 (UTC)
Sorry I conributed to the "mismash of claims and counterclaims" in my first forey into Wikiland. Psydoc 07:28, Apr 8, 2005 (UTC)
I am concerned that the caracterization of the neurofeedback research as "this research is still at the earliest pilot stage" is technically incorrect. A pilot study is a well-defined and very limited form of research. Few if any of the studies referenced at the ISNR site are pilot study designs. There are well-honored scientific methods and criteria for peer-review and adequacy of research design, including statistical tesing of hypotheses. Those criteria are being followed by the scientists in the societies to which the readers were directed. I will try later to provide you with speciffic citations on longer term efficacy for neurofeedback. But please be thoughtful in this matter.Psydoc 07:28, Apr 8, 2005 (UTC)
The term "brain entrainment" does not actualy apply to neurofeedback, but is speciffic to the "following' response found when a person is stimulated with light, sound or tactile activity at a given frequency. I find the section is a mishmash of neurofeedback and light-sound stimulation. Would it be better to discuss the efficacy of each at its own section? There is markedly more research on neurofeedback than on stimulation/ entrainment. Also whereas stimulation devices are sold to the public, neurofeedback devices are FDA controlled devices used by licensed professionals. The area for EEG would in my opinion be better if it included the medical uses more prominently too.Psydoc 07:26, Apr 8, 2005 (UTC)
Some studies: After looking back at the ISNR bibliography, there are a number of case studies included. I will begin here to point to a few of the more solid studies.
Lubar et al, 1995. www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7786929&dopt=Abstract
Monastra et al, 2002. www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12557451&dopt=Abstract
Psydoc 06:34, Apr 12, 2005 (UTC)
I did an overall edit on the "training the brain" section. Hope it seems ballanced.Psydoc 06:59, Apr 12, 2005 (UTC)
I adjusted the Dr Berkley critique. Of course he is wedded to something that works. I'm sure brain training companies don't like him saying that brain training doesn't work for attention deficit disorder. I wonder about some of those links to "professional" brain training cert people. Its starting to look a bit like wikispam. EBlack 04:36, 27 Apr 2005 (UTC)
I think thats right. The whole section on "training the brain" could be relabeled "Mind Machines and Snake Oil". The "institutes" that are involved in electroencephalography are generally only measuring the brain, not actually trying to alter it. The results that show inconclusive or negative effects of brain training, vastly outweigh the studies showing positive results. BTW, the positive ones are generally assessed to be sloppy. As far as I can see, some party with a vested interest is on the soapbox. D.Right 07:03, 29 Apr 2005 (UTC)
I tidied it up a bit, removing the redundant para on "following", and put some of the minor references as links in the link section. I have a database of references which counters the research entailed in those small references and minor brain machine conventions. However, if I place them in the same paragraphs as the moved links, the page will become ridiculously large. So I suggest we stick with conclusive reviews or meta-analyses in the main body, rather than argumentative or speculative little conference papers. As much of brain training it related to quackery, I think the section should include more claims of brain training companies (balancing left and right, development of psychic abilities, photographic memory, and hypnosis machines etc) I am putting a brief para together, if anyone else has some interesting additions, that'd be great. Regards D.Right 05:07, 4 May 2005 (UTC)
This note does not have source. There is no link: ref|12 "See for example this commercial site reporting university research"
Check your notes!
Folks, check you own notes (11-15) please!--Shooravi 17:40, 5 May 2005 (UTC)
In the chart, delta is shown as "up to four", underneath it, as "up to three". Inconsistency is not reassuring.
User:A.Warner's only contributions were uploading and posting Image:Neurofeedback_and_Remote_Seduction.JPG to this article. The image didn't make much sense, so I removed it until a better image can be found. Sayeth 21:28, May 4, 2005 (UTC)
Well, I was working on it! The image makes a great deal of sense when you read the additional references about brain training claims, remote seduction, hypnosis, esteem etc. If you can find a better image that has copyright permission, then feel free to replace it. Regards A.Warner 04:18, 5 May 2005 (UTC)
May I humbly suggest this picture I just contributed
Monroe Institute Critique
Perhaps it doesn't belong in this article, but an article on the Monroe Institute would be appropriate, I think. I've used their products and personally think they work, but I've not found any studies other than TMI's own in which to form an objective opinion.
Bias regarding neurofeedback
It appears a proponent of neurofeedback, someone who sells this stuff, has come on here and is now trying to insert POV information. There are others who also appear interested in inserted the exact opposite POV. Please try to remove the bias and rewrite the neurofeedback section in a clean and NPOV manner. This includes avoiding putting in links to commercial vendors, this is not supposed to be an advertisement. Please also see neurofeedback as it is suffering from POV problems as well.
And regarding the section title "training the brain": this seems like a very odd, POV and unprofessional choice for a section. It should be changed to something more acceptable for an encyclopedia.
-Nathan J. Yoder 17:01, 11 May 2005 (UTC)
- I think there are several different people doing both, actually. It will settle out eventually. Maybe we should break it up into "for" and "against" sections thuogh. Really that stuff should be in neurofeedback, though. - Omegatron 19:48, May 11, 2005 (UTC)
- And, um... WTF is this: Image:Neurofeedback and Remote Seduction.JPG? "How to zap the walking peanuts with only your mind"? - Omegatron 12:47, May 12, 2005 (UTC)
- Agreed. The picture is silly and badly drawn. I removed it once (see talk section "Image" above), but someone apparently replaced it. Sayeth 14:10, May 12, 2005 (UTC)
- Well, if you really think so! I thought it was kind of colourful. I think the peanuts were there to illustrate a pun that the article it was taken from included (nuts and brains etc). And there was a passage about increasing penis size (hence the banana), that I could clarify in the wikipage. I still think it does a good job of representing brain training/neurofeedback's state in the world. But I will leave it up to another neutral and aesthetically aware individual to post it back up in the future:) A.Warner 19:46, 13 May 2005 (UTC)
- Well this isn't the article it was drawn for, so it really makes no sense here.
- Also, I assume you have the right to reproduce it under the GFDL license? - Omegatron 21:49, May 13, 2005 (UTC)
- Would you prefer some kind of monochrome? A.Warner 17:16, 14 May 2005 (UTC)
POV and Clean-Up
This seems easy to resolve: The main field of Electroencephalography is medical diagnosis. So this article should primary talk about this, pointing to neurofeedback and brain computer interface for other, and maybe emerging, fields. --Pjacobi 23:48, 2005 May 14 (UTC)
- Done. --Pjacobi 00:21, 2005 May 15 (UTC)
- Good. - Omegatron 00:52, May 15, 2005 (UTC)
- Nice work,Pjacobi. Sayeth 03:00, May 16, 2005 (UTC)
Ideas for future work
- The roles of the IPSP and EPSP as the primary generators of the recorded potentials should be described, in addition to the currently-present statement that the action potential is not a generator of same.
- The History section is very wonderful, and would be more so with a brief discussion of, or at least a pointer to, the contributions of Herbert Jasper and Wilder Penfield.
-Ikkyu2 23:14, 27 August 2005 (UTC)
- There appears to be nothing on the point at which a fetus's brainwaves begin to differentiate from the mother's. This seems to be relevant information for this article. I can't think (other than "fetus") where else in wiki one might find such information.
I'm going to add in a bit about Epsilon brainwaves and site a link. Reference to 'EEG Today',the thermodynamic monitor + EEG could be named:The Thermodynamic EEG,and we can take the EEG and thermomap of brain;the white air bubble during yawning is thinkless. H.H.Li October 22,2013
Brain wave and sex
What brain wave would be most likely to be active during sex? Beta is what I think.
Why are skin-surface electrodes made of silver (silver chloride) or gold? Do these make a better connection? Do they prevent galvanic DC voltages when the metals mix with skin fluids? It seems like every professional electrode for EEG and EKG is silver/silver chloride, but I can't find an explanation why. — Omegatron 18:24, 15 March 2006 (UTC)
- Au and AgCl don't interact with scalp electrolytes. This avoids creating a salt bridge between electrodes that would totally screw up the voltage recordings, so yeah, you're pretty much dead on with your guess. Sn and Pt can also be used, but are pretty rare in EEG from what I've seen. Semiconscious • talk 21:02, 30 March 2006 (UTC)
- Don't interact with the scalp electrodes? I'm talking about scalp electrodes made from these metals. — Omegatron 05:42, 31 March 2006 (UTC)
Gamma and Schizophrenics
here's an Interesting question. I recall one of my psychology teachers in college referring to the gamma state often being seen in schizophrenics. If anyone knows anything about this I would suggest they add it under the gamma section. —The preceding unsigned comment was added by Malicide (talk • contribs) 08:14, 10 August 2006 (UTC)
Four types of waves?
The article states that historically, there are four types of brain wave patterns, and then proceeds to list 6 patterns. Minor issue, but maybe it should be changed? Good article overall though.
- Delta, theta, alpha, and beta are the traditional Berger bands. Mu rhythm is an alpha rhythm; it is generally considered to be a "normal variant." Gamma is a frequency-defined rhythm like D/T/A/B, but it is not generally seen on the scalp EEG (because of the properties of the skull/scalp). Most gamma research is done with intracranial electrodes. 220.127.116.11 11:17, 24 July 2007 (UTC)
Construction of electroencephelograph
What is the construction and working of electroencephelograph?
The electrical activity recorded from inside the skull (intracranial electrophysiology) yields information that is radically different from EEG. This is because EEG provides a big picture of brain dynamics, while elecrodes on the cortex, for example, provide detailed local information. The latter technique should therefore be reffered to as corticography.
First human EEG record published in America.
This image may be useful in the article. Figure 2: First human EEG record published in America. Upper line shows alpha waves waxing and waning; bottom two lines show blocking of the alpha waves with visual stimulation (Jasper and Carmichael, 1935). Taken from the article Herbert Henri Jasper (1906-1999): An Appreciation
Electrode placement diagram
A most useful addition would be an electrode site diagram, something of the type found here:  It could be accompanied by a list describing electrode sites for typical montages, something one would think would be essential to the article. Can anyone provide? Robert K S 17:08, 16 August 2006 (UTC)
- Just what the doctor ordered. Robert K S 02:04, 11 February 2007 (UTC)
could it be considered a forensic method?
Merge Kappa rhythm into Electroencephalography
I'm not seeing how Kappa rhythm can become more than a stub; even the original author thinks it should be merged into this. If someone can expand it, please do, otherwise it probably shouldn't be more than a paragraph in electroencephalography. Kathy A. 18:24, 3 December 2006 (UTC)
Merged.--Poorman1 23:08, 6 December 2006 (UTC)
Removed opinion on electrode placement
An anonymous user (using a computer at the University Library in Groningen, the Netherlands) added the following under methods, regarding localization:
- "... This involved a complicated systyem of adding electrodes in specific locations known as localization and polarity. This is of limited utility in todays atmosphere of MRI and CT scans and is rarely used in the field except in specialized research applications. It follows then if placement is accomplished without measuring and marking but with attention to equal spacing to avoid asymetries, this time consuming part of the testing proceedure may be safely omitted as it has no relevance. In fact in clinical practice in many hospitals measuring and marking is not done on portable patients such as in the various ICUs but may be done in the lab with primarily out patients. If in fact the use of the 10-20 system was of importance it would be mandated for all patients. The fact is the patients where measuring and marking is not used in ICUs are the sickest and would need the most accurate recordings possible. However the de facto reduction of the 10-20 system in such cases would seem to demphasise the importance of the proceedure and would beg the question why does such a out moded procedure still occupy such a position of emphasis. "
This seems to be a little opinionated, without any references. Accurate placement of electrodes is still very important for many focal non-tumor pathologies and especially for focal epileptic seizure activity. Many patients with epilepsy have refractory epilepsy (approx 1/3 depending on your cutoff), and current guidelines indicate that within a scope of a few years they should be considered for epilepsy surgery. Localizing the site of the lesion over the history of the patient then becomes quite important. It is perhaps outmoded as a general brain health test and for tumor localization, but not at all for epilepsy syndrome diagnosis and monitoring. Janbrogger 09:30, 19 December 2006 (UTC)
Removed commercial spam regarding EEG and marketing (user originating from U.S.-based DCI Marketing according to arin.net/whois). As far as I can see, some effort has been put into correlations between EEG and advertising in controlled experiments. But the reference given is commercial spam. Janbrogger 08:57, 22 December 2006 (UTC)
- "+ In recent years there has been increased interest in electroencephalographic (EEG) measurement of brain activity as a way to measure advertising effects.  "
Quantitative Electroencephalography is apparently, from what I can tell, just normal EEG with use of computers over simple analog means (paper). I was thinking we might want to include it into this article since it just seems to just be a minor branch from normal EEG, and probably couldn't make a whole article on it's own. Does anyone know more about qEEG so as to either write a whole article or place it within this one coherently? Tonerman 20:27, 27 February 2007 (UTC)
- qEEG is not only computerized/digital EEG. I'm going to add a section to it. "qEEG provide new ways to view to view data that are different from traditional visual analysis...Digital analysis techniques, however, are accompanied by considerable difficulty in routine use". Janbrogger
- "Digital EEG" refers to EEG recorded on computer, rather than on paper. "Quantitative EEG" refers to signal processing that quantifies features of the EEG (rather than the typical way of reading an EEG, which is by ("qualitative") visual inspection of the waveform. It is the same idea as an EKG monitor that gives a numerical heart rate from the EKG tracing. I look forward to your review and would be happy to share ideas. I would caution that there is a major dichotomy in the EEG world when it comes to qEEG. I am new to Wikipedia, so I apologize if any of my comments are inappropriate to this forum, but let me share my experience so that the ultimate article is actually as factual as possible. There are some with a good grounding in basic neurophysiology, clinical neurophysiology, engineering and physics who work to quantify the EEG--which is read with much "art"--and relate the findings to broader research into brain function. This is very much a research situation. There are limited ways in which qEEG has been used in a a way that is generally agreed upon scientifically--like anesthesia measurements (though I don't know much about that topic), spike detection (always as a "pointer"--need to be reviewed by an EEGer, and some new developments in critical care neuromonitoring. The group from Australia (Johnstone, Barry, Clarke) has a number of publications on qEEG/ERP in ADHD, but it hasn't caught on as a clinical test for some reason (see their review in Clinical Neurophysiology, 2003). On the other hand, there are a number of companies who sell equipment for quantitative EEG equipment which uses proprietary databases to discriminate between "normal" and certain conditions (like mild traumatic brain injury, depression or learning disabilities). As far as the scientific process is concerned, it is problematic that the research is done commercially and not generally as peer-reviewed work. (Much of what is published is in journals specific to "Neurotherapy"--so there is a good chance that the reviewers are already convinced that there is something to the whole proces--and much less so in broader neurology/psychiatry/neuroscience publications.) Also, there are a lot of difficulties in doing research on conditions that are "mild" (not for the people suffering from them, but what I mean is that there are not as many objective signs as in other neurological conditions). I recently read a qEEG "clinical report," and the conclusions that were made were far from what can possibly concluded from the data at hand. I am also looking at the websites of these companies (and the clinics that employ them) for a talk I am writing, and my general impression is that they have lots of neuroscience language, but the content of their statements is not supported by current knowledge. Let me recommend also Nuwer's statement on behalf of the American Academy of Neurology and the American Clinical Neurophysiology Society. Shwmtpf 02:13, 24 July 2007 (UTC)
Did You Know
Not to take up too much space, but did you know that a plate of Jell-o registers similarly to an adult's brain on an eeg? User:Planes&Mustangs510
- I find that very unlikely. It may be that there is a constant DC electrochemical potential in a plate of Jell-o but it is extremely unlikely that there are rhytmical generators of sufficient amplitude to remotely resemble a human EEG. Janbrogger 08:35, 22 March 2007 (UTC)
- Maybe if the Jell-o it self is vibrating at an alpha rythm it could be possible. Anyways, what are your sources Planes ? XApple 22:11, 19 July 2007 (UTC)
- I find that very unlikely. It may be that there is a constant DC electrochemical potential in a plate of Jell-o but it is extremely unlikely that there are rhytmical generators of sufficient amplitude to remotely resemble a human EEG. Janbrogger 08:35, 22 March 2007 (UTC)
I'd readily believe that some adults' brains have similar neural activity to that of a plate of jello. Most of them are posting comments on youtube at the time. 18.104.22.168 (talk) 06:22, 31 August 2009 (UTC)
Event Related Potentials
The ERP page should be merged into the EEG page. EEG is not just used as a clinical tool. The majority of EEG based Cognitive Neuroscience rsearch involves Evoked Potentials. Terry Toweling 14:00, 12 August 2007 (UTC)
- I respectfully disagree about merging ERP and EEG. Although it is true that the majority of cognitive neurophysiology is done with event-related potentials rather than spontaneouns EEG, I think there is more than enough to be said about ERPs that would clutter the EEG page. The ERP page needs work (though I don't have the time at the moment to work on it)....perhaps once it is a little more fleshed-out, it would be apparent that there is enough to warrant 2 separate pages. Shwmtpf 18:31, 14 August 2007 (UTC)
You're probably right, but there is currently no mention on the EEG page of its cognitive research applications.Terry Toweling 21:24, 14 August 2007 (UTC)
- Since cognitive EEG research is what I do for a living, I should probably add something... 22.214.171.124 21:59, 17 August 2007 (UTC)
Question, is there a way to cancel sound waves out with brain wave transfers? Also - along with feeling, and the rest of the senses? I have a feeling sound waves can be cancelled out, but how about sight stored in the mind after seeing? Or other interactions like that? —The preceding unsigned comment was added by 126.96.36.199 (talk • contribs) 00:20, 15 August 2007 (UTC)
- As far as I know, these are not possible. Do not make speculative edits to articles, the way you did to this article. The talk page is the place for speculation. Hu 06:55, 15 August 2007 (UTC)
the amount of brain wave (Hertz) the brain generates
Should there be a list of the amounts of hertz the brain generates as well as how much the brain can generate? - RVDDP2501 13:12, 23 August 2007 (UTC)
Dense Array EEG (daEEG)
Should Dense Array EEG be added to the EEG page or should it have it's own page?
Dense Array EEG is an improvement on standard approaches to EEG, as it uses a much larger number of “electrodes” (small saline soaked sponges that are able to record the electrical activity of the brain) so that there is better accuracy and localization of the source of any abnormal electrical activity.
Dense Array EEG applies a large number of electrodes (128 or 256) by using a “net” that can apply the electrodes in minutes. The application is painless, reduces patient anxiety about the test and, therefore, increases compliance. Additionally, the net application does not require the need for sedation, and since there is no abrasion of the scalp as is used with standard EEG, there is a reduced risk of infection.
Just as Magnetic Resonance Imagining (MRI) and Computed Tomography (CT) allow a structural image of the brain, Dense Array EEG is a way to electrically “image” the brain, as the electrical information that is gathered is run through a powerful computer that allows the location of the electrical activity to be determined with great accuracy. Recent software advances in this technology now provides for the electrical source to be mapped right on to a MRI.
Dense Array EEG has been used for many years for research applications investigating aspects of brain function and mind control, and has been featured on the cover of National Geographic and Newsweek. Dense Array EEG is a useful clinical tool for the detection of electrical abnormalities associated with seizure activity (i.e. Epilepsy,) but also for “subclinical” electrical activity that might be interfering with attention or learning, sleep disorders and more.
Goodspace 22:40, 2 October 2007 (UTC)
- Could add something on high-density EEG to this page... Even though there is a qualitative improvement in validity of the topographical data provided by high-density EEG arrays, the fundamental issues associated with the inverse problem of localizing cerebral sources of scalp EEG data are still present.
High density systems are rarely used for long-term EEG monitoring; they are however sometimes used to "localize" seizure foci by determining where inter-ictal discharges are coming from (and inter-ictal discharges are less reliable than ictal onsets). Jean Gottman presented some work with inter-ictal localization using high density EEG at the American Epilepsy Society 1-2 years ago.
High density EEG is no more accepted by the neurological community as a clinical tool in ADHD/learning disabilities, sleep disorders, etc., than "standard" EEG is, though it is a helpful research tool.
Most high-density EEG systems use a cap with the same metalic electrodes and electrode paste as used with standard EEG. The system that uses saline-soaked sponges is produced by Electric Geodesics, Inc. It is a little different in that it uses a high-input-impedance amplifier.Shwmtpf 20:41, 17 October 2007 (UTC)
EEG/Brainwave Of Ego Death
Does anyone know the brainwave pattern of psychedelic (LSD, shrooms, mesc, DMT, ect.) ego death? Has there been a specific studies on the brainwave pattern of ego death? Ken Wilber did some experiments some time ago on different meditative states of mind and he managed to stop his brain waves completely and according to him this is a state of pure non-dual awareness with no feeling of the mind-body limitations on perception. This description seems similar to ego death so is ego death brought upon by having no brain waves? Zachorious 18:15, 29 October 2007 (UTC)
underlying theory of EEG missing?
Why is there no discussion regarding the underlying neuronal activity which generates the EEG wave? Is that on a different page? I would add some of it, but I figure that if this article has lasted so long without it being there, maybe there's a reason. -- eykanal talk 17:33, 2 December 2007 (UTC)
The section titled "Source of EEG Activity" makes use of a bucket load of jargon without explaining any of it. I learned absolutely nothing from that section, it should probably be re written so mere mortals can comprehend it. --188.8.131.52 (talk) 06:16, 20 January 2008 (UTC)
Lack of references/verifiability
I'm not an expert in this subject, just a reader, and I find that the article lacks verifiability. I've tagged it as such and hope the community can improve it.
What do you mean by brainwave?
Brainwave as a term is misleading. What is a brainwave? How do you measure one? Any evidence for a brainwave spreading over the surface of a brain? Brainwaves seem appropriate in the context of brain dynamics in a quantum theory of the mind, but what would we mean by brainwave if we thought the brain to be equivalent to a computer? It is a natural word for English speakers to use to describe EEG data, but it suggests more about the brain than we currently know. 184.108.40.206 (talk) 21:24, 6 January 2009 (UTC)
EEG at home
There are some notable projects like OpenEEG and PCEEG which seek to make EEG available for home use, and presumably there may be commercial products affordable for home use too. In the spirit of amateur science I think the article should mention these. —Preceding unsigned comment added by Dranorter (talk • contribs) 16:00, 16 June 2009 (UTC)
My Son Has Had What They Think Is A Seizure, My Brother Had Convulsions As A Child - Could This Be A Gene Thing
My son who is 46 has been in doctor's care for about 2 years for a nervous breakdown. He has been doing very well with the meds he is on, has gained weight and doing well in his job. Last night out of the blue he passed out at a restaurant. He was looked after by 2 nurses before 911 was called. He was not unconsious when 911 arrived. Because he lost his cognitive ability they have summized that he had a seizure. He will go to see a neurogolist as soon as he can. My question is that my brother had many episodes of convulsions as a child, but has not had any episodes in over 50 years. Could this be a gene that my son could have inherited.
Ms. Thompson, your son is fortunate to have you caring for him. You may find helpful answers to your questions at epilepsy.com, which is a better place for discussion than wikipedia. If you want to send me private questions, will you please click on the word (talk) below, which will take you to my own talk page? You can leave your question there the same way you did here. Katharine908 (talk) 09:23, 22 March 2010 (UTC)
Voltage falls of as the fourth power of radius?
The article currently says that voltages fall off as the fourth power of radius. This is certainly not a generally true statement in physics. Does anyone know if it happens to be true for the brain? I expect it is probably not true since the article also mentions that the electric dipole moment is reconstructed from the EEG. The voltage due to an electric dipole falls off as the radius squared. At large radii, the electric dipole contribution should dominate and thus the voltage should fall off as radius squared. I hope someone who knows for sure can comment on this. —Preceding unsigned comment added by StevenGW (talk • contribs) 09:12, 29 September 2009 (UTC)
The article has a large number of external links, some of which seem to have commercial ends. This has already been tagged in June 2009. Today another link was added. How should these be assessed to get a shorter list?
Links normally to be avoided:
- 14. Lists of links to manufacturers, suppliers or customers.
- 19. Links to websites of organizations mentioned in an article
- But in line with Wikipedia policies, you should avoid linking to a site that you own, maintain, or represent.
- I removed all external references except to scholarpedia. The references don't add any information to the article.TjeerdB (talk) 00:34, 31 December 2009 (UTC)
If anyone has got time I'd sure welcome some help with the QEEG article
an EEG STORY - 1984 - Electronic system prearranged to replace in the electronic games the existing manual controls with equivalent controls directly commanded by the brain. 1984
sorry I'm Italian and I do not speak good English.
I'm looking for help to put this news in English Wikipedia
If we turn that Wikipedia is an encyclopedia actually decent would be the case that someone read who are the inventors of Principles of the decoding of brain waves, two scientists, one of which is dead is invalid and the other be right that their names are placed in the history of EEG.
The names of two inventors are Vinicio de Bortoli and Ugo Licinio. Vinicio de Bortoli is paraplegic and Ugo Licino died.
in 1984 years they have discovered how to transform an analog signal into digital allowing you to be able to use this decoding system all you need to control mouse, computers, airplanes etc. ..
- Mr De Bortoli didn't invent anything. The first research on BCI were placed in the '70. Mr De Bortoli claims is totally invalid (100%) but as you can see on his video on YouTube he's not. He claims is an Engineer and a Theoretical Physicist but on his website he says he's not graduated. Moreover, he says the aliens gave him the BCI technology. —Preceding unsigned comment added by 220.127.116.11 (talk) 21:52, 14 May 2010 (UTC)
"Clinical Use" needs more about long-term EEG
The "clinical use" section needs more info about the use of long-term EEG. At the moment it only says this: At times, a routine EEG is not sufficient, particularly when it is necessary to record a patient while he/she is having a seizure. In this case, the patient may be admitted to the hospital for days or even weeks, while EEG is constantly being recorded (along with time-synchronized video and audio recording). Katharine908 (talk) 09:38, 22 March 2010 (UTC)
In the same section, I also find this confusing,
Routine EEG is typically used in the following clinical circumstances:
to distinguish epileptic seizures from other types of spells, such as psychogenic non-epileptic seizures, syncope (fainting), sub-cortical movement disorders and migraine variants.....
Epilepsy monitoring is typically done:
to distinguish epileptic seizures from other types of spells, such as psychogenic non-epileptic seizures, syncope (fainting), sub-cortical movement disorders and migraine variants.
You see that the same bullet point appears in each passage. I believe that the bullet point belongs in the upper passage, with routine EEGs distinguishing epileptic from non-epileptic seizures. It doesn't belong in the "Epilepsy monitoring" passage because you have already diagnosed people there with epilepsy. Every time I look at this recurrence it looks wronger to me. Am I overlooking some subtle clinical distinction? —Preceding unsigned comment added by Katharine908 (talk • contribs) 00:05, 3 April 2010 (UTC)
What means DC in:
- "Ultra-slow" or "near-DC" activity is recorded using DC amplifiers in some research contexts. It is not typically recorded in a clinical context because the signal at these frequencies is susceptible to a number of artifacts.
Direct current? Keysanger 08:47, 27 June 2011 (UTC)
- Yes -- a current that is sustained for a long time with minimal change is often referred to as DC, as opposed to AC which oscillates rhythmically; maybe this should be clarified in the article. Looie496 (talk) 23:37, 27 June 2011 (UTC)
Which articles are referred to?
Some of the references in the comparison table of EEG bands are terribly unspecific and lacking external links to referred studies. I've tried to find which ones are referred to, but I couldn't find what are the specific articles for the following ones, which I just moved to here until this can be sorted out:
- Klimesch, Sauseng, & Hanslmayr 2007
- Coan & Allen 2008
- Nieuwenhuis, Yeung, & Cohen 2004
- Herrmann, Frund, & Lenz 2009
- Moretti et al. 2009
I thought this article is interesting (8/29/2012): 1
How Real Is this
How real is the research on this stuff and should it be added? T bought a white noise machine by this guy and it sounds somewhat flakey but I don't knows: Anyway don't answer my questions, just add what should be added if anything. Or maybe there should be a NEW WIKIPEIDA page which I don't know how to make on speculative and unknown brainwave patterns where this goes anlong with other stuff; that would be an awesome interesting page.
See: http://www.neuroacoustic.com/epsilon.html http://musicmefree.com/page_brainwave_classification_chart.php — Preceding unsigned comment added by 18.104.22.168 (talk) 15:15, 5 January 2013 (UTC)
Adding NIRS and EROS
I just added some stuff to the part comparing EEG to other techniques. NIRS and EROS were not on the list, which led to some false statements, such as that only EEG and MEG get this millisecond temporal resolution (EROS is also capable of that temporal resolution), or that EEG is the only imaging modality resistant to movement artifacts (NIRS and EROS are resistant to movement, which is why they're being recommended highly for infant imaging lately).
Seeing as this article is about EEG, I'm guessing detailed explanations and citations of why EROS gets good temporal resolution, for example, are neither necessary nor welcome, so I just linked to the wiki articles on those two modalities and changed some of the language to reflect that EEG is not alone in certain advantages it provides.
Also, EEG can be combined with either NIRS or EROS for multi-modal imaging, so it might be nice to add some articles about that to that section. I'm doing a study right now combining EROS and EEG, in a lab where it's been done before, so there are definitely papers out there on it.
Finally, there's this weird section about EEG compared to fMRI, fNIRS, and PET, which states fNIRS measures metabolic activity like PET. fNIRS measures the hemodynamic response like fMRI, not at all like PET. I'm actually not even sure why this section exists. It seems that between the explanation of how EEG works and the section comparing it to other methods this is all covered elsewhere. Maybe this section should be deleted and a statement could be added to the comparison section saying that EEG, MEG and EROS are direct measures of brain activity, versus indirect measures like the hemodynamic response and metabolic activity like most other methods.
Add MUSE? (http://www.indiegogo.com/interaxonmuse)?
- Not to this article. It already appears in the Comparison of consumer brain–computer interfaces article, which is the right place. Looie496 (talk) 19:50, 25 February 2013 (UTC)
Ion Flow vs Electromagnetic Conduction
I'd like to question the description of the "source of EEG activity". The current first paragraph of that section reads, " Ions of similar charge repel each other, and when many ions are pushed out of many neurons at the same time, they can push their neighbors, who push their neighbors, and so on, in a wave. This process is known as volume conduction. When the wave of ions reaches the electrodes on the scalp, they can push or pull electrons on the metal on the electrodes. "
I'm not sure that's quite precise -- I think it may be that while ion flow in and out of neurons is the mechanism of the action potential, it is not an actual ion (charged molecule, as opposed to just electron) flow that reaches the scalp but rather an electromagnetic field caused by the ion flow. I don't have access to the source cited for this paragraph, and I'm not an expert, although I'm rather well educated on chemistry and physics and have a basic understanding of neuroscience. I am hoping someone with more information can weigh in. It seems like this may hinge on what the precise meaning of "volume conduction" is. — Preceding unsigned comment added by 22.214.171.124 (talk) 14:00, 28 April 2013 (UTC)
- It seems almost impossible to explain this stuff in a way that is both precise and understandable. In any case, it is impossible in an electrically conductive medium such as brain tissue to have electric fields without having ion movement, so I don't think that part is too inaccurate. Looie496 (talk) 15:38, 28 April 2013 (UTC)
The piece with which I take issue is the last step - the ions reaching the electrodes, because that simply does not happen. (Also because there is already a great deal of confusion in the general public about the difference between ion flow and more general electron flow in the functioning of the brain, it seems important to me that this be resolved to avoid adding to that confusion.) Why be slightly inaccurate instead of accurate? That is a pretty detailed description and not really necessary. The section could simply read,
- "... This process is known as volume conduction. The movement of ions is a type of electric current, which generates an electromagnetic field that can be read by the electrodes on the scalp."
Any further explanation of HOW metal can be used to read an EM field is really the purview of EM, not EEG. It might be worth adding more detail about the reading actually being on the voltage between two electrodes, and not the activity of one electrode -- although I am not really well enough educated to formulate this detail. — Preceding unsigned comment added by 126.96.36.199 (talk) 12:01, 30 April 2013 (UTC)
- Well, in an ordinary EEG setup there actually is a flow of ions (or at least electrons, if you count those as ions) into the electrodes. In an ordinary setup the electrodes are glued to the scalp using conductive paste. The ions that move into the electrodes are not the same ions that move inside the brain, but there is movement of electrons or other ions all along the path. Looie496 (talk) 15:54, 30 April 2013 (UTC)