criteria / efficacy of alpha-theta to show someone in or not in anxiety?

Comments

• wjcroft Mount Shasta, CA

  June 2015

  Anfeng, hi.
  
  That's a landmark paper you cite. Has been very influential in the neurofeedback field. In this case they are using alpha-theta protocol to facilitate healing and integration of unconscious patterns. Patterns and beliefs which possibly contributed to the substance abuse. Alpha-theta has wide application.
  
  The idea of the protocol is to help the client enter "altered states" of consciousness, where some of this unconscious programming material comes up to the surface and is processed, integrated. While the protocol is running, both alpha and theta are "rewarded", possibly with different thresholds. The goal is to achieve what are called alpha theta cross-overs, where the two band amplitudes cross. Meanwhile delta is usually inhibited or signaled, as you don't want the client to fall asleep. The idea is to inhabit that 'twilight' area between awake state and sleep state, so that dream and hypnogogic material can surface.
  
  So no, alpha theta ratio is not the idea, it's the crossovers.
  
  Independent of the actual training session, a baseline is usually run where all band amplitudes are recorded before the reward / inhibit signals start. In this case one might be able to watch general beta amplitudes decrease from session to session. Or high beta, 20-30 hz, which is more associated with anxiety and hypervigilence. But this is a long term trend that might show up after a series of sessions.
  
  Administering alpha-theta is considered somewhat of an art, and is recommended to accompany some counciling or coaching to aid in integration of the material surfacing.
  
  William
  
  
• afliu Beijing, China

  July 2015

  William, hi
  
  Really appreciated for your comments.
  
  In a training session, can we make quantitative analysis and use this quantitative value to show someone current anxiety degree? Take high beta, 20-30 hz as example, if we can, wihch amplitude value can be used, minimun value, maximum value, mean value or other algorithm to caculate this value?
  
  I have this idea because it will be easier for those people, who has no any idea about the EEG diagram, but can understand his/her current status.
  
  Very appreciated for any advices and comments,
  
  -Anfeng
  
• wjcroft Mount Shasta, CA

  July 2015

  Anfeng, thanks.

  
  

  In most neurofeedback situations, you don't generally see that much shift within one session. That is why 'trend' graphs and pre post baselines are taken so you can track changes in amplitude over a series of sessions. For example a typical course of neurofeedback might be sessions twice a week for 10 or 20 weeks. Very very gradual changes. Not likely something you can measure as simply as an "in session" anxiety indicator.

  
  

  There is a whole field called QEEG, quantitative EEG, and those systems typically compare 19 channel brain maps, taken say at the beginning of the series and every month or so. Then again at the end. These maps (which record per band amplitudes, coherence, phase) -- are compared to "normative databases", and colored by their Z-score values, that is, how many standard deviations from the norm.

  
  

  This page is perhaps not the best, but shows some examples of the maps.

  
  

  http://www.qeeg.com/qeegfact.html
  

  
  

  In the typical course of neurofeedback, various reward / inhibit protocols are used (again monitoring trends), to try to get the client into a more normative range. The alpha-theta is a special case protocol (used only occasionally), and the goal is not to shift the QEEG; but to help the client enter altered states that will facilitate healing and insights. That kind of effect cannot be measured, even with QEEG, although the end result is that people get more stability, resilience, ability to face challenges, etc.

  
  

  
  
• Chintutritya

  April 2020

  @William Do you happen to have a BioExplorer design for the same that you can please share?