Return Home
It is currently Thu Oct 22, 2020 12:56 am

All times are UTC-06:00




Post new topic  Reply to topic  [ 6 posts ] 
Author Message
PostPosted: Wed Jun 10, 2020 3:25 pm 
Offline
Newbie
Newbie

Joined: Thu Nov 22, 2018 3:22 pm
Posts: 4
Hi, I used binaural beats like hemisync for years for various uses. Mostly I've used earphones and I recently was looking at the Wikipedia page for Bob Monroe and it said that research showed that the hemi sync effect seemed to be caused by the electromagnetic effect of the headphones more than the audio effect.
I am using better over ear headphones now and the effect does seem stronger than just with in ear phones. This I thought was worth investigating and might help others in the use of binaural audio. Here is the Wikipedia section ;

In 2002, a University of Virginia presentation at the Society for Psychophysiologial Research examined Monroe's claim. The presentation demonstrated that EEG changes did not occur when the standard electromagnetic headphones of Monroe's setup were replaced by air conduction headphones, which were connected to a remote transducer by rubber tubes. This suggests that the basis for the entrainment effects is electromagnetic rather than acoustical.[25]


Top
PostPosted: Sun Aug 16, 2020 6:54 pm 
Offline
Frequent Poster
Frequent Poster

Joined: Mon Jan 06, 2020 2:32 am
Posts: 56
Hey gssev,

Having just noticed this post, I find it interesting that no one has deemed it interesting enough to comment on it so far. Given its potential import, I'm frankly surprised that Tom hasn't responded to this, except for the fact that just finding the content of the presentation in question at all was an exercise in internet detective work.

Clearly, people can meditate deeply without the aid of binaural beat audio. This is a given. But BB technology is emphasized by Tom's program (as well as numerous others') as being of significant potential value for a lot of people, particularly with respect to exploring non-PMR data streams. So it seems prudent to examine this bit of research and anything that's been done along these lines, if only in the interests of trying to maximize the quality of experience people have when using this technology.

Unfortunately, it's not easy to find the actual content of the research presentation cited at WP. After a great deal of online searching, I ran across a comment in a post at TheDailyGrail.com from 2009. The tone of the comment renders the information a tad suspect (its author seems to be gloating a bit too ferociously for my taste which, in my experience, is frequently a red flag, especially when associated with hyphenated last names), but the content of the presentation - which the author has copied there in its purported entirety - seems reasonably serious as far as it goes. Further searching (i.e., on the email address provided) revealed that the comment was most likely posted by Dr. Dennis McClain PhD, who I'm guessing is the "McClain-Furmanski, D." referenced in the text included in the above-linked comment. "Drmcclainphd" edited the Hemi-Sync Wiki page back on 10/11/11. Note that (a) his contribution to the page on that date was much more expansive than the text that is there today and (b) he specifically mentioned Tom and Dennis. McClain's contribution was deleted in a subsequent revision the following month, with no explanation offered.

There's a reference to this presentation at the UVa site, as well as an entry for Volume 39, Issue S1 of Psychophysiology listed at wiley.com, but the content of that volume is locked behind a paywall. Cursory groping didn't reveal any way to locate the presentation at SPR's site. I've pasted the content of the presentation, as provided in the comment above, down below the content of this post, emphasis mine.

Please note: the present text on the Hemi-Sync Wiki page is not what McClain originally contributed and is, in fact, a misrepresentation of the research's conclusion, i.e., "[t]his suggests that the basis for the entrainment effects is electromagnetic rather than acoustical." This is not what the cited research concludes. Par for Wikipedia. Rather, the conclusion of McClain, et al's research is that there is no evidence of entrainment at all, and that the signals measured via EEG are artifactual. This sounds like a subtle difference but it's extremely important. The conclusion asserts that the EEG results are nothing more than an artifact of the EM energy from the speakers directly affecting the EEG electrodes. This is made clearer in the comment itself, i.e., "[t]o test whether the TMI work might be based on artifact I replicated some of their work, using a styrofoam wig stand shaped like a head as my subject. I got precisely the same results TMI got, with alpha and theta EEG signals recorded from binaural beats presented to a styrofoam head." This description hardly stands as scholarly research, but if true it's something that needs exploration, IMHO.

I went to the trouble of tracking all this down because Tom has repeatedly stressed that time is of the essence when it comes to the concept of general enlightenment in this PMR (I agree), and because ANY tool or technology that might be useful in assisting or accelerating the process ought to be made as widely available and as effective as possible. This is the very first time I've personally seen a reference to scholarly research concluding that brain entrainment via binaural audio - at least with respect to being measurable via EEG - is, in a word, 'bunk'. I've been using binaural beat audio files since the days when TMI's Gateway Program was shipped on cassettes, so let's just say that's why it caught my interest.

I'll just add, in reference to the presentation's final conclusion, I find it very difficult to believe that through all the decades during which binaural audio has been researched with respect to its effect on the brain, no one has ever thought to test this exact phenomenon. I'm just not sure how one would go about finding such information.

cheers,
r

--------------------------------------------------------------------

EEG Oscillations and Binaural Beat As Compared With Electromagnetic Headphones and Air-conduction Headphones

Presented at 42nd Society for Psychophysiological Research COnference, Oct 2-6 2002, Washington DC

Chandra Stone(1), Phyllis Thomas(1), Dennis McClain-Furmanski(2), April L. Collins(1), Barron Griffith(1), James E. Horton(1)

1-The University of Virginia’s College at Wise 2-National Institute of Deafness and Communication Disorders, NIH, Bethesda,MD

Introduction

Binaural beats occur when two separate tones of similar frequency range are presented, one to each ear, and the brain integrates the two tones into one perceived sound. The use of BB can be used in everyday life for relaxation and concentration (Atwater 1997), the study of Parkinson’s disease and detecting hearing loss (Oster 1973), vigilance and mood (Lane et all, 1998), as well as recovery and pain relief (Kliempt et al, 1999).

Prior research:

Atwater (1997) states that complex binaural beats that were brainwave-like were reported as more effective than binaural beats of single frequencies in producing hemispheric synchronization. Hemispheric synchronization occurs when the binaural beat is perceived and there are two electrochemical synaptic waves of equal amplitude and frequency present in each hemisphere. There is suggestion that binaural beats offer applications in many areas such as relaxation, improved sleep, and wellness.

Oster (1973) provides historical data that defines and evaluates monaural and binaural beats that were produced through different methods of 440 and 434 hertz tone generation. These tones produced a 6 hertz binaural beat that is generated in the superior olivary nucleus and resulted in measurable evoked potential. Oster also demonstrated that age was not a factor in binaural beat detection.
Smith (1978) found that the complex binaurally presented tones consistently evoked a free-frequency response. A free-frequency response is a neuroelectric wave that relates to the frequency of auditory stimuli presented to the subject. Band-limited masking noises affected free-frequency response only with a pure tone, not with a complex tone. The tones were computer generated and were presented binaurally via the headset with two shielded headphones in an acoustic chamber.

Rationale and proposed research:

Most of the research investigated binaural beats in relation to effectiveness used electromagnetic headphones to deliver the binaural beat. However, it is possible that delivery using electromagnetic headphones interferes with the EEG recording by having electromagnetic activity around the area of the headphones during recording.

This research investigates the possible electromagnetic interference due to the use of electromagnetic headphones by comparing the EEG activity generated during binaural beat as compared to a rest condition with the binaural beat presented by electromagnetic headphones and by air-conduction that eliminates the possible electromagnetic interference of electromagnetic headphones.

It is hypothesized that the EEG from the air conduction delivery of the binaural beat tones will increase EEG frequencies matching the binaural beat but to a lesser amplitude than the electromagnetic headphone delivery method due to artifact from the electromagnetic headphones.

Participants

11 Healthy Adults
All male
Age (19 – 47)
No medical or psychiatric problems
Strongly right-handed

Apparatus

Stimulus preparation and presention
Pentium computer with Microsoft 98 OS
STIM Software with sound editor used to generate binaural beat tones
GENTASK used to present binaural beat tones
Standard EMHP (Sony MDR-CD 180)
Neuroscan Air Conduction System

EEG acquisition
Pentium computers with Microsoft 98 OS
Neuroscan 4.1 Software
Neuroscan SynAmp 32 channel bioamplifier
Quickcap Electrode Cap 32 channel silver chloride electrodes

Binaural Beat

Binaural beat tones were prepared to generate 6 hertz binaural beats and 16 hertz binaural beats. Each binaural beat was prepared with non-harmonic carrier tones as indicated in prior literature as well as with harmonic carrier tones for comparison purposes.
BB tones
Harmonic carrier tones
6 Hz generated by 42 and 48 Hz
16 Hz generated by 112 and 128 Hz
Lower Hz carrier tone always administered to the left ear
Non-harmonic carrier tones
6 Hz generated by 100 and 106 Hz
16 Hz generated by 100 and 116 Hz
Lower Hz carrier tone always administered to the left ear

Procedure

The research paradigm was explained to participant
Participants were instructed regarding procedure
Participants were prepared for EEG recording
Baseline EEG was established by recording in rest condition for 2 minutes
EEG was recorded for each tone presentation and conduction method
Two minutes of recording for each condition
Harmonic and Non-harmonic presentations were counterbalanced
6 Hz and 16 Hz were counterbalanced
Electromagnetic headphone and air-conduction delivery methods were counterbalanced

RESULTS

The amplitude of 6 hz and 16 hz frequency was measured and analyzed with ANOVAs for 20 electrode sites involving the frontal (F3, FZ, F4 , F7, F8), frontocentral (FC3, FCZ, FC4), central (C3, CZ, C4), centroparietal, (CP3, CPZ, CP4), frontotemporal (FT7, FT8), parietotemporal (TP7, TP8), and temporal (T3, T4) areas.
There was no significant difference in the 6hz or 16hz EEG frequency in any of the tone conditions as compared to the baseline EEG in the resting condition.
There was artifactual EEG in temporal and frontal electrode sites in some participants during the presentations using electromagnetic headsets.
Artifactual EEG appeared in electrode sites in close proximity to headphone ear pieces and wiring across headset band.
There was no artifactual EEG in electrode sites during tone presentations using air conduction.

CONCLUSIONS

This study did not support previous findings of EEG activity produced by binaural beat presentation
There was no statistically significant EEG activity due to binaural beat presentation
There was no statistically significant difference in presentation methods or carrier tones used
There was no statistically significant difference in either frequency of binaural beat
There was artifactual frequency generated in all frequencies with headset presentation in most, but not all participants
There was minimal artifactual frequency generated with air conduction presentation that was more evident with tones presented with a harmonic carrier tone and in only some participants
However, the tubes for air conduction presentation tended to pick up ECG artifact if placed in front of the participant proximal to the chest and had to be placed precisely and behind the participant’s back to eliminate the ECG artifact
The broad spectrum of increased frequency and artifact that is more evident in T3 and diminishes to CZ, as shown in the included example of one participant, may be indicative of bone conduction involvement in the increased 6hz activity
Therefore, it is strongly suspected that EEG frequencies attributed to binaural beat presentation is artifactual and generated primarily by the use of electromagnetic headphones as the presentation method
It is suggested that future research investigating binaural beat generation of EEG activity consider the artifactual influences of equipment and methodology used and design paradigms to eliminate the artifact.

REFERENCES

Atwater, F.H. (1997). Accessing Anomalous States of Consciousness with Binaural Beat Technology. Journal of Scientific Exploration, 11 (3), 263-274.

Kliempt, P., Ruta, D., Ogston, S., Landeck, A., and Martay, K. (1999). Hemispheric-Synchronization During Anathesia: A Double Blind Randomized Trail Using Audiotapes for Intra-Operative Nociception Control. Anathesia, 54 (8), 769-773.

Lane, J.D. Kasian, S.J., Owens, J.E., and Marsh, G.R. (1998). Binaural Auditory Beats Affect Vigilance and Mood. Physiology & Behavior, 63 (2), 249-252.

Oster, G. (1973). Auditory beats in the brain. Scientific American, 229, 94-102.

Smith, J.C., Marsh, J.T., Greenberg, S. & Brown, W.S. (1978). Human auditory frequency-following responses to a missing fundamental. Science, 201, 639-641.


Top
PostPosted: Mon Aug 17, 2020 8:08 am 
Offline
Site Admin
Site Admin
User avatar

Joined: Tue Jun 23, 2009 3:05 pm
Posts: 1219
Location: Copenhagen, Denmark
Hi gssev and renaldafeen, thanks for your posts.

Good internet detective work renaldafeen!

If the EEG effects where purely artefacts of electrical interference, that would certainly be something one should know.

I think the research in question have some possible limitations, for example they only recorded 2 minutes of stimulation.. The problem with that if there indeed is an artefact, but ALSO a real effect that takes more time to set in (2 minutes seem low for most people to get into a meditating state), then it would only reveal the artefact and no potential additional effect. While 2 minutes seems to be enough to determine whether there are artefacts or not, it really limits their possible conclusions. As such, their result that "There was no significant difference in the 6hz or 16hz EEG frequency in any of the tone conditions as compared to the baseline EEG in the resting condition." could be misleading.. though after reading some more about duration, it seems like the binaural beat should be apparent within seconds, according to other research (I quote something later in this post), and people have stimulated up to 4 hours before with no significant EEG results.

I really wish they had a paper that were more detailed, because the "article" is just some content for a poster it seems. They are no details about their data analysis and no discussion.. For example, they need to give a possible explanation for "There was artifactual frequency generated in all frequencies with headset presentation in most, but not all participants"... how can the artefactual frequency be participant dependent? Their methodology can also be flawed, and it appears the author's ego is quite involved with the results, which is never a good thing in science.

The research is however very useful if indeed no one doing the binaural beat studies had considered how electrical headphones can affect the EEG's measurements.. I find it difficult to imagine that this is the case, but stranger things have happened.

Some cursory reading: https://www.researchgate.net/post/Do_co ... in_the_EEG
Quote:
"Do commercially available in-ear headphones create artifacts in the EEG?
I am planning to conduct an auditory EEG study in which I present spoken sentences. I currently do not have headphones available that are optimized for our recording system (Brain Products actiCAPs), so I am wondering if I would be better off using normal speakers or in-ear headphones.
Does anyone have experience testing with commercially available in-ear headphones?"

"Not if you are looking at 0.5 - 20Hz activity (don't know about higher frequencies)"

"As Michael has suggested I don't think it should matter if you are looking at low frequencies. This is because the sound frequency range you are presenting is unlikely to be below 100Hz, so should not interefere too much. However, if you were using high frrequency ERPs such as auditory brainstem reponses you would need to consider the possibility."

"I use airtube earphones because the digital converters in the conventional earphones interfere with the EEG. I hope that helps!"

"I'm not 100% but one of my supervisors (who is an engineer) is very avid about this. I would say they are detrimental to ERPs as a signal is created at each sound presentation.
Air tube earphones are really good because they are noise cancelling. Participants can barely hear me when I talk to them! :)"
From Methods to eliminate stimulus transduction artifact from insert earphones during electroencephalography
Quote:
Stimulus transduction artifacts occur when stimulus-producing current in the headphone wire or transducer, proximal to the body or electrode components, contaminates the EEG measurement. The acoustical waveform mirrors aspects of the stimulus-producing current. Clinical systems use several common ways of avoiding the artifact. One is to present very brief stimuli (clicks) so the artifact ends before the ABR is evident (<1-msec). However, this does not work for realistic stimuli, which overlap in time with their cABRs (Skoe & Kraus, 2010). Another method is to deliver stimuli pneumatically via plastic tubes, where the transducer is situated at a distance of up to 20 feet from the patient (Killion 1984); e.g., the Etymotic ER-3A (Henry et al. 2001, Hall 2006:pg.71). Stimulus transduction artifact has been shown to be eliminated by grounded shielding of the electrical apparatus from such a system (Akhoun, Moulin, Jeanvoine, et al. 2008; Riazi & Ferraro 2008), even when that apparatus was close to the volunteer. However, such earphones are costly and have an inferior frequency response for sounds above 6–7 kHz (Henry et al. 2001), an important range for spatial localization and speech cues (consonant stops). For instance, high frequency cues contribute to the perception of sibilants and fricative sounds by children during middle childhood (Stelmachowicz et al., 2001; 2008). An additional shortfall of tubing is that of acoustic dispersion, whereby the low frequency components of sounds travel faster than high frequency components within a tube, such that the phase relations of different frequency components becomes distorted: e.g., a click can become smeared into a frequency-modulated sweep or “chirp” (Kinsler et al. 1982). The frequency response and fidelity of the pneumatic approach thus has limitations for those interested in the responses to everyday complex stimuli such as speech or music sounds, but the problem is also relevant for click stimuli (Kinsler et al. 1982). The tubing approach does offer a … solution to the problem of stimulus transduction artifact should: i) the investigation not require high fidelity reproduction of sound and, ii) should the investigation not need the reproduction of high frequency information such as speech or location cues.

Typical lower cost solutions to the stimulus transduction artifact include “counter-phasing”, where EEG responses to two versions of the same stimulus with opposing polarity cancel out the artifact (Hall 2006: pg.248, Aiken & Picton 2008, Skoe & Kraus 2010), and referencing, where the EEG signal is compared to an equally contaminated electrode so the artifact is Common-Mode Rejected (Fisch & Spehlmann, 1999). A third approach that we explore here is electrically-shielding the headphone wire with a grounded Faraday cage of conducting mesh.

With a view to the high-fidelity reproduction of speech cues as is ideal for cABRs to speech sounds, here we used the Etymotic ER-4B earphones (Henry et al. 2001). ER-4Bs are of a very different construction from the ER-3As that are the current state-of-the-art in clinical evaluations. The ER-4B could in theory induce greater artifact, having wires right up to the ear and the transducer in the ear canal. To determine whether auditory responses to click and /dɑ/ speech stimuli during the first 60-msec can be measured with an ordinary digital EEG system (Fisch & Spehlmann, 1999; Swartz, 1998) and personal computer, here we test the effectiveness of three low cost approaches – counter-phasing, referencing and shielding – to the eliminate stimulus transduction artifact from ER4-B earphones.
Interestingly, it seems like air conduction method have some limitations due to this acoustic dispersion.. again a possible thing the University of Virginia’s College researchers also overlooked.

From their discussion:
Quote:
Grounded shielding proved effective here, and this is probably due to the containment of the electromagnetic field produced by earphone wire currents. Without shielding, this field is thought to have induced a stimulus transduction artifact in the volunteer’s body that reached the electrodes via volume conduction. The transducer itself remained unshielded throughout, yet the transduction artifact was basically eliminated by shielding the wires alone. The primary origin of stimulus transduction artifact is thus the current in the earphone wire, rather than the balanced-armature transducer of the ER-4B. As noted in the Introduction, grounded shielding of the electrical apparatus has proved successful in eliminating transduction artifact with systems that deliver stimuli via pneumatic tubes (Akhoun et al. 2008; Riazi & Ferraro 2008). Grounded shielding approaches could have considerable potential in the investigation of the cochlear microphonic and ABRs in early life, as they could improve approaches to the early diagnosis of auditory neuropathy (Riazi & Ferraro 2008). However, earphones that deliver stimuli via pneumatic tubes suffer from acoustic dispersion (Kinsler et al. 1983) and offer an inferior representation of high frequencies (Henry et al. 2001); information that is important for speech recognition and spatial localization. A distinct approach, shielding the wiring yet not the transducer, was shown here to eliminate transduction artifact from lower cost ER4-B headphones that are viable for presentation of speech content for ABR and cABR investigations, and the presentation of high frequency auditory localization cues.
It is quite clear that artefacts must be taken into account when doing these studies, and grounded shielding of the wire seems to be a good solution.

Here is some more recent research about binaural beats in general:
Binaural Beat: A Failure to Enhance EEG Power and Emotional Arousal

The introduction is very useful here, as it goes over the literature and controversies about binaural beats, and they write:
Quote:
From the studies reviewed above, regarding the effects of binaural beats on electrophysiological, cognitive and affective measures, no conclusions can be drawn. The different experimental protocols in these studies, including stimulus duration, the specific beat frequencies used within the same range, the participant’s attention to the stimuli (Schwarz and Taylor, 2005), as well as individual differences (Reedijk et al., 2015) may account for the observed contradictory results. In addition, in several of the studies, the lack of proper control conditions, the lack of details about the experimental protocols, as well as the fact that binaural-beat effects on cognitive processes were assessed without monitoring brain oscillatory activity, result in methodological limitations that leave the issue controversial. In fact, electrophysiological research comparing the effects of beat stimulation under different conditions is still rare (Chaieb et al., 2015). On the other hand, from the reviewed literature it is also under debate the role of binaural beat stimulation in modulating autonomic functions. Disentangling such role may help to prove the potential clinical effectiveness of binaural beats.
and
Quote:
The goal of the present study was therefore to elucidate whether binaural-beat stimulation at different beat frequencies would affect EEG oscillatory activity at the particular frequency of the beat stimulation, to test the potential usefulness of binaural beats as a brainwave entrainment tool. Particularly, we addressed this question by using a paradigm that allowed us to disentangle the specific and differential contribution of binaural beats over that of acoustic beats. Despite the exploratory nature of the present study and the inconclusive evidence on the topic, our theoretical prediction was that binaural beat stimulation would induce an enhancement of EEG power at the specific frequency of the beat. A secondary goal was to explore the effects of binaural-beat at different frequencies on psychophysiological measurements traditionally related to emotional arousal, such as heart rate and skin conductance, to test their suggested potential effect on autonomic function (McConnell et al., 2014) and thus further understand their potential clinical usefulness.
Their didn't find any EEG effects due to the binaural beats:
Quote:
After normalization, as summarized in Table ​Table1,1, no significant effects whatsoever were found in the EEG spectral power within the theta, alpha, beta or gamma frequency ranges analyzed. Specifically, ANOVA analyses yielded no effect for the Session factor, indicating no differences in the normalized spectral power values, within the EEG bands analyzed, between the noise and beat epochs of the block. No significant effects were found for the Treatment factor neither, indicating no overall differences between binaural-beat and acoustic-beat stimulation. Furthermore, no interaction between Session and Treatment factors were found. According to these results, no enhancement of EEG spectral power would be induced neither with binaural or with acoustic beats of the reported frequencies. With binaural beats in the upper gamma frequency, which cannot be perceived (Licklider et al., 1950), EEG spectral power in the upper gamma frequency range analyzed showed no significant increase in relation to acoustic beats.
About duration in these studies:
Quote:
Previous studies on event-related potential modulation and auditory steady-state responses suggest that entrainment effects occur within seconds of the binaural beat stimulation (Karino et al., 2006; Kasprzak, 2011). Additionally, as mentioned, in previous studies testing the same hypothesis binaural beats were presented for a longer duration obtaining similar negative results (Wahbeh et al., 2007; Goodin et al., 2012; Gao et al., 2014). Therefore, we consider unlikely that the lack of increased EEG spectral power within specific bands in the present study is related with the short duration of 3 min used here for beat stimulation. In this regard, as suggested by some authors (Becher et al., 2015), another important factor to consider when trying to induce changes in EEG oscillatory activity at a particular frequency is the use of continuous tones or short repetitive bursts of stimulation
They don't discuss anything about shielding, and they do use electrical based "insert earphones", but they do perform 'artefact removals', and since they don't get any EEG enchantments it would seem that their artefact removal would have removed any potential EEG artefacts based on the electrical interference.. It would be interesting though to see if their raw data also showed these artefacts introduced by the audio equipment.

Their final conclusion:
Quote:
This study has provided a thorough research on the potential effects of binaural-beat stimulation on enhancing EEG activity on specific frequency bands. Our aim was to verify the theoretical assumption on the effects of binaural beats in both EEG rhythms and psychophysiological responses. The literature on the field was inconclusive: we reviewed studies on the effects of binaural beats in EEG oscillatory activity, as well as on the effects of binaural beats in measures related with autonomic responses. We performed an experimental design using rigorous methodological controls, with baseline-treatment-washout sessions and treatment vs. “placebo” condition (a beat with the same frequency, but generated acoustically).

No effects of binaural-beat stimulation on EEG spectral power occurred with beat frequencies belonging to theta, alpha, beta, or gamma EEG ranges, as well as with those belonging to upper gamma band. On the other hand, our measures of heart rate and skin conductance did not support the effect of binaural beats on emotional arousal. Thus, our results altogether do not support binaural beats as a potential brainwave entrainment tool, nor they suggest any beneficial effect on clinically relevant dimensions.
I wonder if the lack of shielding or otherwise taking into account of the possible electrical interference can explain difference of positive and negative results. It would appear that the electrical interference can produce enhanced EEG readings, but what if electrical interference could actually prohibit EEG readings at the specific ranges? A bit like you can have constructive interference and destructive interference in waves (light, sound etc.). It could explain these very divergent results, as the results would be very setup specific in such a case.

It is also quite possible that there are no real correlation between binaural beats and its effects on our brain waves (EEG), but that it still helps with going into specific meditation states, beyond just being placebo.

A good starting point into such an investigation would probably be to read all the literature referenced in the paper I quote above. I don't have the time presently, but maybe you do renaldafeen?


Top
PostPosted: Mon Aug 17, 2020 8:23 am 
Offline
Site Admin
Site Admin
User avatar

Joined: Tue Jun 23, 2009 3:05 pm
Posts: 1219
Location: Copenhagen, Denmark
Just for preservation, I will copy the relevant comments on https://www.dailygrail.com/2009/11/rons ... ment-36656 , as it would be a shame to lose them if the website went down.

-------------------------------------------------
DynaSoar Tuesday, November 10th 2009

Atwater’s Brains vs. Ronson’s Goats
Feel free to reproduce this in any forum or medium as long as the references (authors and referenced works) are included.

The following is one of my favorite activities, poking holes in over-inflated claims, statements and “science”. This is what true skepticism should lead to, rather than ad hominem attacks devoid of any proof (You hear that, Plait? Real science. Try some.). This does not directly address the specific claims and actions from The Monroe Institute and/or Fred Atwater with respect to “Goats”, Ronson or anything Atwater did following the initial TMI development. Rather this goes directly to the original work on which Atwater built TMI. Whether or not that should impact his standing and veracity in subsequent topics in which he became involved based on TMI remains a decision for the reader to make. I’ve made mine: Atwater is incompetent. The only alternative I can see is that he knew he was wrong and has based his entire career since then on a scientific fraud. I can’t rule that in or out based on this work; my conclusion is a subjective opinion with a generous helping of benefit of the doubt. My money says any subsequent activities he participated in should be examined thoroughly in a manner such as this (ie. independently, externally and objectively as a replication of techniques) before any conclusions drawn from such works an be accepted. If any such works are mentioned but not stated clearly enough for replication to be done, the body of work should be rejected as inadequately presented material unworthy of being called science. Still, read along, read the references and find others, and make your own decision.

I first read about TMI in OMNI. The essentials of the technology of binaural beat and “hemisync” EEG entrainment were covered there, and are summarized below. When I started training in neuroscience, I learned EEG research techniques. A standard was to keep the subject in an electrically isolated ‘cage’ to prevent electrical noise from getting into the recording. An EEG is a microvolt meter and picks up everything electrical around it if not so isolated.

I reviewed the TMI literature and saw their entire premise was based on EEG recordings conducted with electrical stereo headphones on the subject’s head and on top of the EEG electrode cap. That goes against the concept of preventing artifact from electrical devices and noise. To test whether the TMI work might be based on artifact I replicated some of their work, using a styrofoam wig stand shaped like a head as my subject. I got precisely the same results TMI got, with alpha and theta EEG signals recorded from binaural beats presented to a styrofoam head.*

Later, while training one of U.Va. Professor Horton’s students (Phyllis Thomas) in advanced EEG analyses, I suggested she follow up on my initial work by testing human subject using an audio presentation system that would not introduce electrical interference. Our EEG system had an audio presentation system with the transducer 10 feet away from the subject and the sound transmitted from there to the subject through air tubes, no chance for electrical noise. She picked it up and ran with it. I was right, she proved it, and we’ve presented it publicly. As a result, some researchers who worked in their field have since had their work rescinded from the journals it was published in.

I always enjoy it when I can bust someone’s bubble. I’m even more proud of the fact that except for Professor Horton and myself, whose contributions were strictly theoretical background or in training in technique on the equipment, all the authors listed were undergraduates. That should add to the sting.

Follow along now in a reproduction of real science conducted specifically to test the initial work and claims of TMI and Atwater. Please excuse the fortmatting — this was cut and pasted directly from the presentation poster .ppt file. I’ll email that as an attachment to requests sent to threesigma@rocketmail.com

=========================================

EEG Oscillations and Binaural Beat As Compared With Electromagnetic Headphones and Air-conduction Headphones

Presented at 42nd Society for Psychophysiological Research COnference, Oct 2-6 2002, Washington DC

Chandra Stone(1), Phyllis Thomas(1), Dennis McClain-Furmanski(2), April L. Collins(1), Barron Griffith(1), James E. Horton(1)

1-The University of Virginia’s College at Wise 2-National Institute of Deafness and Communication Disorders, NIH, Bethesda,MD

Introduction

Binaural beats occur when two separate tones of similar frequency range are presented, one to each ear, and the brain integrates the two tones into one perceived sound. The use of BB can be used in everyday life for relaxation and concentration (Atwater 1997), the study of Parkinson’s disease and detecting hearing loss (Oster 1973), vigilance and mood (Lane et all, 1998), as well as recovery and pain relief (Kliempt et al, 1999).

Prior research:

Atwater (1997) states that complex binaural beats that were brainwave-like were reported as more effective than binaural beats of single frequencies in producing hemispheric synchronization. Hemispheric synchronization occurs when the binaural beat is perceived and there are two electrochemical synaptic waves of equal amplitude and frequency present in each hemisphere. There is suggestion that binaural beats offer applications in many areas such as relaxation, improved sleep, and wellness.
Oster (1973) provides historical data that defines and evaluates monaural and binaural beats that were produced through different methods of 440 and 434 hertz tone generation. These tones produced a 6 hertz binaural beat that is generated in the superior olivary nucleus and resulted in measurable evoked potential. Oster also demonstrated that age was not a factor in binaural beat detection.
Smith (1978) found that the complex binaurally presented tones consistently evoked a free-frequency response. A free-frequency response is a neuroelectric wave that relates to the frequency of auditory stimuli presented to the subject. Band-limited masking noises affected free-frequency response only with a pure tone, not with a complex tone. The tones were computer generated and were presented binaurally via the headset with two shielded headphones in an acoustic chamber.

Rationale and proposed research:

Most of the research investigated binaural beats in relation to effectiveness used electromagnetic headphones to deliver the binaural beat. However, it is possible that delivery using electromagnetic headphones interferes with the EEG recording by having electromagnetic activity around the area of the headphones during recording.
This research investigates the possible electromagnetic interference due to the use of electromagnetic headphones by comparing the EEG activity generated during binaural beat as compared to a rest condition with the binaural beat presented by electromagnetic headphones and by air-conduction that eliminates the possible electromagnetic interference of electromagnetic headphones.

It is hypothesized that the EEG from the air conduction delivery of the binaural beat tones will increase EEG frequencies matching the binaural beat but to a lesser amplitude than the electromagnetic headphone delivery method due to artifact from the electromagnetic headphones.

Participants

11 Healthy Adults
All male
Age (19 – 47)
No medical or psychiatric problems
Strongly right-handed

Apparatus

Stimulus preparation and presention
Pentium computer with Microsoft 98 OS
STIM Software with sound editor used to generate binaural beat tones
GENTASK used to present binaural beat tones
Standard EMHP (Sony MDR-CD 180)
Neuroscan Air Conduction System

EEG acquisition
Pentium computers with Microsoft 98 OS
Neuroscan 4.1 Software
Neuroscan SynAmp 32 channel bioamplifier
Quickcap Electrode Cap 32 channel silver chloride electrodes

Binaural Beat

Binaural beat tones were prepared to generate 6 hertz binaural beats and 16 hertz binaural beats. Each binaural beat was prepared with non-harmonic carrier tones as indicated in prior literature as well as with harmonic carrier tones for comparison purposes.
BB tones
Harmonic carrier tones
6 Hz generated by 42 and 48 Hz
16 Hz generated by 112 and 128 Hz
Lower Hz carrier tone always administered to the left ear
Non-harmonic carrier tones
6 Hz generated by 100 and 106 Hz
16 Hz generated by 100 and 116 Hz
Lower Hz carrier tone always administered to the left ear

Procedure

The research paradigm was explained to participant
Participants were instructed regarding procedure
Participants were prepared for EEG recording
Baseline EEG was established by recording in rest condition for 2 minutes
EEG was recorded for each tone presentation and conduction method
Two minutes of recording for each condition
Harmonic and Non-harmonic presentations were counterbalanced
6 Hz and 16 Hz were counterbalanced
Electromagnetic headphone and air-conduction delivery methods were counterbalanced

RESULTS

The amplitude of 6 hz and 16 hz frequency was measured and analyzed with ANOVAs for 20 electrode sites involving the frontal (F3, FZ, F4 , F7, F8), frontocentral (FC3, FCZ, FC4), central (C3, CZ, C4), centroparietal, (CP3, CPZ, CP4), frontotemporal (FT7, FT8), parietotemporal (TP7, TP8), and temporal (T3, T4) areas.
There was no significant difference in the 6hz or 16hz EEG frequency in any of the tone conditions as compared to the baseline EEG in the resting condition.
There was artifactual EEG in temporal and frontal electrode sites in some participants during the presentations using electromagnetic headsets.
Artifactual EEG appeared in electrode sites in close proximity to headphone ear pieces and wiring across headset band.
There was no artifactual EEG in electrode sites during tone presentations using air conduction.

CONCLUSIONS

This study did not support previous findings of EEG activity produced by binaural beat presentation
There was no statistically significant EEG activity due to binaural beat presentation
There was no statistically significant difference in presentation methods or carrier tones used
There was no statistically significant difference in either frequency of binaural beat
There was artifactual frequency generated in all frequencies with headset presentation in most, but not all participants
There was minimal artifactual frequency generated with air conduction presentation that was more evident with tones presented with a harmonic carrier tone and in only some participants
However, the tubes for air conduction presentation tended to pick up ECG artifact if placed in front of the participant proximal to the chest and had to be placed precisely and behind the participant’s back to eliminate the ECG artifact
The broad spectrum of increased frequency and artifact that is more evident in T3 and diminishes to CZ, as shown in the included example of one participant, may be indicative of bone conduction involvement in the increased 6hz activity
Therefore, it is strongly suspected that EEG frequencies attributed to binaural beat presentation is artifactual and generated primarily by the use of electromagnetic headphones as the presentation method
It is suggested that future research investigating binaural beat generation of EEG activity consider the artifactual influences of equipment and methodology used and design paradigms to eliminate the artifact.

REFERENCES

Atwater, F.H. (1997). Accessing Anomalous States of Consciousness with Binaural Beat Technology. Journal of Scientific Exploration, 11 (3), 263-274.

Kliempt, P., Ruta, D., Ogston, S., Landeck, A., and Martay, K. (1999). Hemispheric-Synchronization During Anathesia: A Double Blind Randomized Trail Using Audiotapes for Intra-Operative Nociception Control. Anathesia, 54 (8), 769-773.

Lane, J.D. Kasian, S.J., Owens, J.E., and Marsh, G.R. (1998). Binaural Auditory Beats Affect Vigilance and Mood. Physiology & Behavior, 63 (2), 249-252.

Oster, G. (1973). Auditory beats in the brain. Scientific American, 229, 94-102.

Smith, J.C., Marsh, J.T., Greenberg, S. & Brown, W.S. (1978). Human auditory frequency-following responses to a missing fundamental. Science, 201, 639-641.

======

* Apropo of nothing except a shared enjoyment with deflating the overblown, Karl Pribram accepted my results with relish, and shared one of his own. It seems that if you embed EEG electrodes in lime Jell-o and shake it, you will get alpha EEG signals. No signals are forthcoming if you don’t shake it. When questioned regarding lime vs. other flavors, Karl reported that he didn’t try any others, and did this with lime flavor because he can’t stand the flavor to eat it. He also reported that when his Jell-o results were shared with researchers in (the then) USSR, they responded with results showing alpha EEG produced by electrodes sitting in a glass of vodka while being shaken.


Greg November 11th 2009

Hi DynaSoar,

Thanks for posting all this, fascinating. Some questions below (not meant as criticisms, just questions that came to me as I read it):
Quote:
this was cut and pasted directly from the presentation poster .ppt file. I’ll email that as an attachment to requests sent to threesigma@rocketmail.com
Is there a PDF of the entire published article available, or is it only in .ppt?
Quote:
Strongly right-handed
Is there a particular reasoning behind this choice? My thinking here is that it seems that it is left-handed people who report more ‘paranormal’ and OBE occurrences (perhaps due to less influence by the ‘rational’ brain?).
Quote:
Two minutes of recording for each condition
Is this the standard measuring time (and used by Atwater and others in earlier papers) for experiments in this area? My question derives from a sense that this is a very short time compared to the usual Monroe ‘practical’ sessions.
Quote:
It is suggested that future research investigating binaural beat generation of EEG activity consider the artifactual influences of equipment and methodology used and design paradigms to eliminate the artifact.
Is there subsequent research literature available confirming/extending this?

Thanks for the informative post.

DynaSoar November 11th 2009

Greg, thanks for the questions. I’ll just answer them rather than add quoting upon quoting.

It’s in .ppt because it’s a poster, full size 3 x 4 feet. Not an article, thus no PDF. I could convert it with OpenOffice but then it’d be too big to send. There’s a free .ppt viewer available if you don’t have Office or OpenOffice (but the latter is free too, so what the hey).

Right handed are typically used in EEG research because they represent the single largest subgroup of the population and thus can be most generalized from, statistically speaking. So they say. I don’t. They also have the most differentiated brains with the most apparently localized activity, but even they have widespread and overlapping activities, contradicting the premise. Still, this is what the old farts at the journals expect, so what you gonna do?

The recording time is based on the statistical testing to be done. The Monroe system tapes use a longer time frame for creating their effects (so they say) but the EEG activity itself can be measured and tested plenty fine with 2 minutes. This is supported by getting the Monroe ‘results’ with the same amount of recording time with the headphones over the cap. In fact 2 minutes is more than enough the see the effect. I got results from 15 second recordings (including on the styrofoam head). But to do statistics you want to decrease the variance in the measurements, and that means more or longer samples. As a comparison, when we do research on stimulus locked responses (same as nerve conduction tests done by neurologists) we do as few as a couple dozen and average them together, each of them being less than a second. But in these cases we use more subjects and/or conditions (pesky statistical sampling stuff again).

As for replicability, I did it myself prior to presentation, just to be able to say it passed retest reliability. There have been no independent replications that I know of, certainly none published. But then that’s increasingly rare these days, especially when the premise and testing are so clearly stated in terms of theory. I mean come on, Atwater’s sample collection violated a basic tenent of EEG recording. It was just so blatant that nobody thought to question it, especially since they could easily replicate it (in all its erroneous glory). I am happy to report that while there are articles still appearing that use binaural beats and EEG, they are using a well known auditory illusion (used by all good piano tuners and other musicians) that does do specific things to the brain (very specific early activity in the olivary nucleus) the results of which can lend themselves to other investigations (like magnetic potentials, rather than EEG). But since this was presented, I can find exactly one article testing the concept in a different way (not a replication but a parallel test) and they got no Monroe-type results either.

There’s also one article from someone prior to this presentation that got the results which they compared to hypnotizability, then another article from the same group after this presentation that essentially backed off their claims. But then this was probably due as much to the fact that my supervisor was several times president of the experimental hypnosis group/society/whatever and had been high up in hypnosis research ever since helping Ernest Hilgard update and reverify the Stanford Hypnotic Susceptibility Scale as a grad student. I’m pretty sure they looked up my work, saw I’d done hypnosis research with her (Helen Crawford, now emeritus from Virginia Tech), and decided self-criticism is the better part of scientific valor.

A note on the subjective effects, since you asked. I underwent both auditory and visual beat stimuli, the latter with a pair of sunglasses with LEDs glued inside the lens. I can tell you for a fact, as someone with experience in all manner of substances both natural and manufactured, many with alphabet-soup names, all of which are intended to produce altered perceptions, cognitions and behaviors, that 3 minutes under the combined audio-visual beat stimulus (other external stimuli being blocked out) seemed like a full 30 minute DMT exploration in both intensity of experience and vividness of perceptions. My mouth fell open, and I drooled. They unplugged me when I didn’t move at all after 3 minutes. There’s no doubt in my mind that the stimuli they use produce subjective results.

When I started this research it was an open question whether there would be some sort of EEG effect that could be worked out. But it was strictly my point that they way they did things early on was a mistake and that could be proven. We did that. There may still be measureable EEG differences associated with the very profound perceptual stuff, and should be. But the testing needs to be done right. When done right, the EEG changes that Atwater and others claim correspond to the many changes they claim they can effect with their stimuli just do not happen, except as a matter of electrical artifact.

--------

Rick MG November 11th 2009

Gloating goats
Quote:
I always enjoy it when I can bust someone’s bubble. I’m even more proud of the fact that except for Professor Horton and myself… all the authors listed were undergraduates. That should add to the sting.
That’s a bit harsh, DynaSoar. Why not just let your data speak for itself? As my old man would say, “don’t gloat or else it’ll come back and bite you on your arse.” 😉

Have you presented your data to Atwater and allowed him to respond?


DynaSoar November 11th 2009

Gloatidity
Quote:
Quote:
I always enjoy it when I can bust someone’s bubble. I’m even more proud of the fact that except for Professor Horton and myself… all the authors listed were undergraduates. That should add to the sting.
That’s a bit harsh, DynaSoar. Why not just let your data speak for itself? As my old man would say, “don’t gloat or else it’ll come back and bite you on your arse.” 😉

Have you presented your data to Atwater and allowed him to respond?
Hi Rick, good questions.

We’ve presented it in public in a professional venue, the same one that some researchers using his technique presented their work in previous years. He noticed theirs, he had the chance to notice ours. It’s poor form to confront someone directly with contrary research. All such correspondence is kept public because the interaction itself may produce valuable information. This is why many journals will print letters from one researcher “to” another, and the other respond. In short, if he wanted to, he could. In less short, he’s already taken his idea and turned it into a commercial venture. He’s not about to risk that to engage in a confrontation regarding the validity of what he’s selling successfully.

Yeah, you’re probably right about the gloating stuff, at least as far as my own enjoyment in seeing an old fart’s accepted theory overturned. I don’t do it at them, but I do engage in the happy dance in public otherwise. I’m not after the ‘perfect person’ job. That job’s taken. The last guy that got hired for it got nailed to a tree 2000 years ago, and still has the job as far as I know. If not, I don;t want it anyway. I enjoy the happy dance too much. But the part about my students producing international class science, and they all undergrads, that gloat is perfectly justified, and I do gloat right at them over it. I’ve had four such projects in which undergrads proved an old fart wrong and presented it at a conference, and each time the gloat gets bigger and better because those young people deserve it.


Rick MG November 12th 2009
Quote:
But the part about my students producing international class science, and they all undergrads, that gloat is perfectly justified… because those young people deserve it.
I agree, when kids — and older folk! — perform above and beyond what’s expected of them, they deserve a pat on the back. As long as it’s a respectful and courteous competitiveness, then all’s fair in love and science. However, the Bad Astronomer, Shermer, Myers, et al… Heghlu’meH QaQ jajvam! 😉

And I just wanted to rhyme gloat with goat.


DynaSoar November 13th 2009

Then To Glare Fat Gloats
Quote:
I agree, when kids — and older folk! — perform above and beyond what’s expected of them, they deserve a pat on the back. As long as it’s a respectful and courteous competitiveness, then all’s fair in love and science. However, the Bad Astronomer, Shermer, Myers, et al… Heghlu’meH QaQ jajvam! 😉

And I just wanted to rhyme gloat with goat.
I don’t think I mentioned that in every case, these undergrads performed all the work and writing within a single semester, in a 1 credit hour lab course. Few pros produce at a rate like that. That’s why I prefer my students to my colleagues.

As for the other sort (watch your thlIngan Hol, there may be puqpu’ present) keep in mind they are entertainers, not scientists, when they are acting in the role that tends to displease many, much like Rush Limbaugh with respect to politics. And like him, the bad publicity is as welcome to them as the good, because it’s about being noticed rather than right. If it were about being right, I wouldn’t catch Plait trying to pass off points he was trying to make with anti-facts that’d get marked wrong on my students’ exams, or at least an acknowledgement for the ‘mistake’ once it was pointed out.

And now that you’ve got them to rhyme, let’s try it in harmony.
-------------------------------------------------


Top
PostPosted: Mon Aug 17, 2020 12:24 pm 
Offline
Frequent Poster
Frequent Poster

Joined: Mon Jan 06, 2020 2:32 am
Posts: 56
Quote:
A good starting point into such an investigation would probably be to read all the literature referenced in the paper I quote above. I don't have the time presently, but maybe you do renaldafeen?
Agreed - at least to a point (see below). And thanks for doing so much more digging! I kind of ran out of gas (and time) or I'd have looked further. As time permits I'll definitely be reading more about this, at least casually.

Having worked for years at Plantronics in automated audio testing, specifically aimed at in-ear and over-the-ear headphone technology, the very first thing that occurred to me while reading this is the same one you've pointed out: the questions of proper shielding, acoustic isolation, proper grounding and all the other issues one encounters while struggling with the Black Art of Electronics (aka "the main reason I switched from that field to Software Engineering fairly early on in my professional career" ;-). When building the production test equipment for Plantronics' various products, we spent as much time dealing with those issues as anything else, and we weren't even close to dealing with the microvolt levels of potential measured by an EEG system.

A lot of the folks doing these research projects are social scientists or neuroscientists with a modicum of technical experience, and who may be relying on an EEG Tech to administer the test. For reference, my ex-wife's first job after we married was as an EEG tech, doing tests solo with almost no training, which is simply to say that there's clearly wide variability in the expertise available there. Someone with very strong experience in research-grade EEG functionality would need to closely examine every single element of every setup across the published literature in order to make any reliable assessments relative to McClain, et al's conclusions. Per my 'see below' up above, I'm not sure that's feasible at this point.

For a couple of reasons, even if it had received proper treatment as part of the presentation's research, I think the 'wig stand' experiment can be handily dismissed regardless of what it demonstrated. It would be a trivial exercise to tweak such a setup so that EM from a set of magnetic-coil headphones would create EEG artifacts. The easiest approach would be to simply increase the speaker coil energy (via audio amplitude) until one starts seeing an effect. I have no reason to believe this isn't precisely what happened. This is why it's dangerous to gloat about something like this, IMHO: it's not something one does if one wants to be taken seriously. An attitude like this makes it easy to believe the researcher is being driven by Ego to actively DIS-prove something, rather than trying to examine a phenomenon objectively. In such a case, one might rely on questionable practices to do so.

McClain clearly has a solid understanding of speaker coil function, and whether consciously or not, that understanding and his self-proclaimed glee from, basically, making others look bad, could easily have driven his approach during this test. Finally, 'proving' that one can create EEG artifacts without a human subject doesn't demonstrate anything with respect to brain entrainment. It only shows that there are alternative methods one can use to generate EEG waveforms, to which my response is, "well... duh!"

Regarding the absence (or drastic reduction in amplitude) of FFR (Frequency-Following Response) measured via EEG using acoustic as opposed to electronic headphones, I'd want to see the equipment used. Specifically, I'd want to see if they used the same sort of audio gear they used to hand out on airline flights, where you'd plug the ends of two pliable rubber tubes into a receptacle in the armrest, acoustically (as opposed to electronically) coupling the sound source to your ears. In such a scenario, or any other suffering from related issues, it seems likely that a beat frequency could be generated in the acoustic piping along its mechanically-coupled length which, once it reached the listener's ears, would be hardly different from listening to the same audio via desktop speakers. The perceived audio effect is VERY pronounced in such a case (for me, at a given amplitude, it's MUCH louder than when heard binaurally), but the beat is not actually being created in the brain's auditory center, so one would hardly expect to see any FFR on the EEG in such a case. My response, if this is the case is, again, "well... duh!" If this IS the case, maybe it's an indication regarding why you don't just let undergrad students run open-loop on a research project.

Again, I'm not sure it's practical to go back and review the existing literature; it's just not clear one could ascertain the specifics of the various setups used with enough detail to make an assessment reliable. Rather, I think these things, specifically, ought to be tested and verified with the same rigor currently being used to perform Tom's CUSAC experiments. I strongly believe such tests should be performed, and their results openly published, by anyone asking for money in return for a product that is purported to aid in achieving some desired state of consciousness. And I think it's only fair that this ought to include MBT Events' audio files.


Top
PostPosted: Mon Aug 17, 2020 4:24 pm 
Offline
Frequent Poster
Frequent Poster

Joined: Mon Jan 06, 2020 2:32 am
Posts: 56
FWIW, I did run across another research paper (not a presentation, but a full paper).

The reference can be found here: "Analysis of EEG activity in response to binaural beats with different frequencies".

As before, without the full text of the paper it's impossible to know how their methodology may have impacted their result. I used the ResearchGate request widget to ask for the text. If it's sent to me I'll provide the info here. In the meantime, one of the key findings in their published abstract was that "no clear brainwave entrainment effect was identified."

I'm well-satisfied, looking at the lists of additional works attributed to each of the paper's various authors, that this research wasn't conducted by a team of undergrads working under a professor with gloat fetish. ;-)


Top
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 6 posts ] 

All times are UTC-06:00


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Limited