I had posted on my last thoughts on a private list and got a reply from Francine Shapiro, the founder and steward of EMDR. It was a bit daunting for me. She’s smarter, more well-informed, and the inventor of what I do in much of my working hours. She has given me permission to post our discussion. Read the last entry to see what it refers to.

"Regarding a description of VR and EMDR, the actual explanation for the use of exposure therapy is that prolonged exposure is supposed to cause an extinction of the response.  Not a dissociation.  It is based upon animal models and has a long history in behavior therapy. 

Whatever other treatments achieve, I’d be careful about describing shared attributes.  That is, EMDR does not focus on increased affect, but rather the affect generated by the stored memory.  The dual attention is the attention to the manifestations of the elicited memory:image/thoughts/emotions/physical sensations/beliefs—which is an internal focus–and the bilateral stimulation which is external.  The here and now sensations are manifestations of the stored event.  So if that is what the other therapies are focusing on it is not dual attention. 

As we know in EMDR people can process with a primary attention on body OR thoughts Or images.  So none is mandatory as it is in other forms of therapy.  Nor do we coach a client to a coherent narrative as done in other therapies.  It merely evolves as a byproduct of the reprocessing.  As do the changes in affect, body sensation, thoughts, images, sense of self, etc."

My reply: I don’t mind you jumping in and I think your comments are absolutely relevant.  I’ve worked with several people who had had exposure therapy for PTSD, and the experience created dissociation in all of them, not extinction. Of course, they all could have had underlying dissociative processes, before the exposure therapy.
        I went to rat-running behavioral undergrad school: U of Iowa. and cognitive-behavioral graduate school, U Washington. I love how, since then, the neuro-research shows us how it all works. The dampening of affect, with exposure, showing up in the midbrain–I can’t remember if it was the amygdala or hippocampus in which the electrical response stops. With EMDR, the integrative process shows up in the left cortex, as more activity in the narrative part of the brain. All the trauma therapies that I like, especially EMDR, which is my "therapy of choice" appear to result in a coherent narrative. I think my language wasn’t precise. EMDR brings up "the affect generated by the stored memory." I have witnessed about 20 hours of tapes of Diane Fosha working. I think she does a similar thing. I sat in a 5 day class she did last year. The 6 EMDR therapists who were there, could see the Standard Protocol at work, in what she did. It’s all we talked about at lunch. She brings up the old state, the related cognition, the related affect, and the related body sensations. It appeared to us, that the switching of attention back and forth between internal states, related to the trauma, and the connection with the therapist worked much like EMDR. It had the same outcome. Or so it seemed to us.
        I like EMDR, better, because it’s easier to teach and easier to keep track of. It’s what I do. The Standard Protocol works, and it’s not fuzzy. It can be measured. I’ve taught some not-very-bright therapists the protocol. They were able to do ok, but not stellar, therapy. I don’t think they could do AEDP, because it’s not as structured.
Thanks for your input, it’s always welcome!
Warmly and with great respect, Robin

Her reply:  "It’s hard to know what outcomes really are, or are maintained, without follow up research.  I’d just say  that I’d be careful about the neuro research.  It’s all in it’s infancy.  There are various studies that show various things.  And you can’t link “left cortex” to “more coherent narrative.”  you can say that Broca’s area is off and then activated.  That has to do with language.  But things are a lot more complicated than that.  Exposure therapists claim the same thing (more coherent narrative) for their therapy."