Guest guest Posted April 5, 2004 Report Share Posted April 5, 2004 Spencer, I'm glad you are finding the assessment tools useful. There is a huge difference between these tools, which are designed to identify brain activation patterns, and QEEG's, which are designed to compare the client's brain against a "normal" brain (or at least a statistically-constructed set of brain probabilities derived from "normal" brains, however those happened to have been selected). The TLC files focus on relationships within the client's brain. We look at those in the light of the desired changes the client wants to make and then select the ones that are likely to have leverage on those changes. If you are going to perform a statistical comparison of one person's brain against a statistical database of a number of other brains, then yes, I guess it's pretty important to minimize any artifact and hope the same was done very well in the gathering of the normals. However, that becomes less critical if we are primarily looking at the relationships between, say, beta at F3 and F4 or Beta at F3 and P3, since we are comparing one brain against itself. When we teach the Level 2 (Assessment and Training Planning) or Trainer's Practicum workshops, there is a fair amount of emphasis placed on minimizing artifact from the most obvious sources (reducing eyeblinks, muscle tension and bracing, eye rolls, cable movement, etc.) during the gathering phase of the process. And when we look at the data, we are always ruling out the effect of artifact before deciding whether the brain has a trainable pattern or not. I suppose that, when Brainmaster or BioExplorer have the capacity to permit data artifacting (as does the Infiniti software for ProComp, on which we are performing final tests of the TLC Assess files) we'll have to open that can of worms. I learned to artifact data (at some level at least) when I was working with Dr. Lubar on the large multi-center study that got published in NeuroPsychology a few years back. There was a program available for the A620 which allowed us to select and keep or drop 2-second epochs. In 19 channels all arrayed on a page, it's not too hard to see a general excursion that happens in all or most of the traces, but in 2 channels it's not so easy. Even harder in one. Is that delta spike really delta, or just some kind of artifact? Should we drop it to keep the data clean, or are we removing valuable data by dropping something that is both there and significant? Fortunately, as you suggest, it has worked out that, with some care taken during the gathering of our one-minute epochs for the TLC Assess, we have been able to get very good information and folks who can actually read what's there and know what they are looking for can produce excellent training plans without the added complication of artifacting the data. Pete Van DeusenBrainTrainer ()16246 SW 92nd Ave, Miami, FL 33157305/321-1595 artifacting Dear Pete,I really like both the TLC assessment and the subjective assessment programs. They are very helpful in treatment planning. As I begin to learn more about QEEG however I wonder about the role that artifacting plays, or doesn't play, in the role of the data going into the TLC assessment. As I watch people artifacting the data for QEEGs before they are put into a standardized data base I realize there are huge and complex distortions that go beyond eye roll and gross movement artifact that is editted out by the BM. Do you have any recommendations for ways to artifact the BM data or do you feel this is even necessary? -Spencer Quote Link to comment Share on other sites More sharing options...
Guest guest Posted December 20, 2004 Report Share Posted December 20, 2004 Mike, You wrote about artifacting the assessment: So it sounds like I should throw out the data and do another assessment if the data has large jumps? My answer would be: Not necessarily. First of all, it's not uncommon for alpha and sometimes SMR to show large spindles, which really raise their amplitudes and overall amplitudes in the EEG. Those are not artifact--at least not any kind I'm aware of. The artifacting file looks at Delta and Theta spikes causing the total amplitude to rise and fall sharply (these would, of course, generally be eye-blinks) and at beta and high-beta spikes doing the same thing (generally muscle artifact). I run the TLC Assess Artifact report on a file and look at the graph. Where there are large spikes, there is usually one color line that drives the red (Total EEG) line up. Sometimes black and/or blue (delta and theta lines), sometimes yellow or magenta lines. Those would be probable artifacts. However it's not uncommon to see the light blue (alpha) line pushing the red line up. Probably not artifact. Sharp rises and falls with lower level activity between them are actually what the artifacting macro is designed to handle best. The ones I've seen that usually cause the problems are the ones where half or more of the points on one minute (or even more) are going up and down like a killer rollercoaster at Islands of Adventure. What I think happens there is that almost all the lines get thrown out by the macro, resulting in a " divide by zero " error. In those cases you should certainly be seeing it while you are gathering the assessment, and you have two choices: bag the assessment and start with some middle-frequency training, as I often suggest with young clients, autistic spectrum, etc.; or keep re-running it until the client gets the message and maintains enough control to reduce the spikes to 5-10 in 60 seconds, which you should be able to artifact. The other option, as someone stated very nicely earlier in this discussion, is simply not to artifact a file that can't make it through the process, run it through the standard TLC Assess report and bring it into the assessment without artifacting--making, of course, adjustments in you mind for what you know is there when you do the analysis. Pete Quote Link to comment Share on other sites More sharing options...
Guest guest Posted August 14, 2005 Report Share Posted August 14, 2005 J & J, My suggestion would be to use the manual artifacting or at least to go back and manually adjust the selections if you use the auto. To the best of my knowledge, the auto system simply removes any signal with total EEG amplitude above a certain level. Obviously individual brains could be variant enough in their base amplitude to require defferent cut points. More importantly, and the reason I went to the self-selection model with the new TLC artifacting that works with bioExplorer, is that it is possible to have significant surges in EEG amplitudes due to strong synchronous alpha activity (which is definitely NOT artifact) or even significant beta or SMR spindles, which you would not want to remove. I focus on Delta, low theta and high-beta, which are the frequencies most likely to be affected by eye (slow frequencies) or muscle (fast frequencies) activities. Francois Dupont was going to see if it would be possible to simply output a text file in the right format from Infiniti to allow you to simply run the TLC Artifact file on it, but that did not look like it would be simple. It would just require that one-second epochs (180 total per site-pair) be produced, but at present Infiniti doesn't have that capability. Pete > > From: " jamesandjulieahrick " <advancedbiofeedback@...> > Date: 2005/08/13 Sat PM 06:34:13 EDT > > Subject: Artifacting > > We are wondering if anyone could comment on the best way to artifact TLC Assess recordings using Infinity software. at Thought Technology suggested using a value of 25 or 30 for automatic artifacting. That value works much of the time, but at times we have had to artifact much higher in order to get the data to show up in the printouts. We realize some seizure, or other high voltage activity can cause a great deal of amplitude changes, and we do not want to eliminate pertinent data from the analysis, so where do we draw the line?, 50? Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 7, 2006 Report Share Posted February 7, 2006 Pete, Sue, I believe the problem Sue is having is that sometimes the macros do not load when she opens the Assessment. Then there are no macros to Run. I have had this problem also, more in the past, but just yesterday also. When the macros load, the macro file appears in the task bar at the bottom of the screen, "TLC with optional sites . . ." etc. If the macros don't load, I don't see that. What fixes it for me every time is to leave the Assessment file open, but before doing anything else, go to the XLStart folder and double-click on the macro file to open it directly. (Sue, this is what I suggested to you on Friday.) I wonder if the programmer will have thoughts on whether this is a known problem with Excel or whether it can be fixed within TLC Assess. Foxx artifacting> > I am having difficulty with the artifacting program, i.e. when I push CTRL, Shift, S, nothing happens. It doesnt' happen all the time, but it surely is tonight and I am stuck.Can anyone tell me how to correct this?> thanks, Sue> Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 7, 2006 Report Share Posted February 7, 2006 You're not supposed to see the macro file. It opens in the background, so the sheet can access it, but you have to go to Window: Unhide to get it to show up (and you should only do that if you plan to make changes to the macros--hopefully not something you are planning to do. So close the file and don't re-open it. Someone in doing that you have gotten it not to open automatically but to require you to open in manually. Pete > > From: " Foxx " <foxx@...> > Date: 2006/02/07 Tue PM 11:36:51 EST > < > > Subject: RE: artifacting > > Pete, Sue, > > I believe the problem Sue is having is that sometimes the macros do not > load when she opens the Assessment. Then there are no macros to Run. I > have had this problem also, more in the past, but just yesterday also. > > When the macros load, the macro file appears in the task bar at the > bottom of the screen, " TLC with optional sites . . . " etc. If the > macros don't load, I don't see that. > > What fixes it for me every time is to leave the Assessment file open, > but before doing anything else, go to the XLStart folder and > double-click on the macro file to open it directly. (Sue, this is what I > suggested to you on Friday.) > > I wonder if the programmer will have thoughts on whether this is a known > problem with Excel or whether it can be fixed within TLC Assess. > > Foxx > > > > artifacting > > > > I am having difficulty with the artifacting program, i.e. when I push > CTRL, Shift, S, nothing happens. It doesnt' happen all the time, but it > surely is tonight and I am stuck.Can anyone tell me how to correct this? > > thanks, Sue > > > > > > > Quote Link to comment Share on other sites More sharing options...
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