Re: Scientific Jargon vs. reality

I agree we must be careful about our inferences. I personally have lost considerable interest in this particular debate, as it feels to me that people have made up their minds and no amount of rehashing old ground is going to change them. I include myself in that indictment: There is nothing that Ricky or Louise have said that has changed my mind about what I feel is the appropriate conclusion from the extant data on the role of eye movements in the efficacy of EMDR. To wit, my read on the data is that there are no convincing data to indicate that eye movements or any other form of laterally alternating stimuli or dual attention have any effect on treatment outcome for PTSD.

Please parse my conclusion carefully, as I put a lot of thought into how it was stated. I have not concluded that eye movements have no effect, because this would involve asserting the null hypothesis which is logically impossible. I have not concluded that eye movements have no effects at all. Rather, I have focused on the role of eye movements in the context of EMDR and specifically their effects on outcome measures (i.e., measures of symptoms). Finally, I have not claimed that I am considering all possible data or all possible domains. Rather, I am specifically limiting my conclusions to the realm of PTSD. With regard to the four studies mentioned by Louise in her 10/29/02 post (Andrade, Kavanagh, & Baddeley, 1997; Kavanagh, Freese, Andrade, & May, 2001; Sharpley, Montgomery, & Scalzo, 1996; van den Hout, Muris, Salemink, & Kindt, 2001), participants were non-clinical samples (i.e., not selected to have PTSD); the investigators evaluated the effects of eye movements on the vividness and emotionality of non-trauma images, thus they did not utilize EMDR per se and they did not measure PTSD symptoms.

Despite my waning interest in this debate at the present time, I will make one last attempt influence the dialogue on the topid of eye movements and EMDR.

My above stated conclusion rests on two pillers. The first piller is methodological: I have advanced the methodological position that the burden of proof rests with whoever wishes to make a positive claim (e.g., menehunes exist -- by the way Sandra, I still crack up at Tutu Nene). This methodological position translates to the following, if you want to assert that eye movements (or other bls/ds))have an effect on the efficacy of EMDR for PTSD, then you have to prove it. In legal terms, we might say "prove beyond a reasonable doubt" (p < .05, independently replicated, good clean study desing and execution, etc). And until you prove it, you can't claim it, you can only advance it as an hypothesis. My second piller is my summary of the extant emperical evidence, in which I conclude that the burden of proof has not yet been met.

My estimation of the discussion thus far is that:
1. No one has bothered to question my methodological position, therefore I assume that we are all in agreement as to who does (those who claim eye movements contribute to EMDR outcome for PTSD) and those who do not (i.e., me and those like me who do not yet believe that eye movements contribute to EMDR outcome for PTSD)have the burden of proof.

2. No one has provided convincing evidence that eye movements contribute to treatment outcome for PTSD.

Instead, what has been discussed are:
3. All of the methodological inadequcies of the extant dismantling studies that fail to find an effect of eye movements on treatment outcome. However, the fact that there exist poorly done studies that find null results does mean that properly done studies would have found positive results. For example, if a study that used only two sessions didn't find an effect of eye movements, we cannot conclude that a study that used 6 sessions (or 10 or 12 or whatever magical number you want to use) would have produced any different outcome. At best, this is an hypothesis to be tested, not a fact to be stated. Similarly with studies having small samples: Just because studies with small have obtained null results does not mean that they would have obtained significant results had they used a larger sample. Explaining away null results is not the same as providing positive evidence.

4. Recent results from studies investigating the role eye movements on emotive imagery in non-clinical samples. I do not deny that these studies can be informative. However, none of these studies actually show an effect of eye movements in the context of EMDR for the treatment of PTSD on measures of PTSD symptoms.

Replies:

Re: Scientific Jargon vs. reality, by Sandra Paulsen Inobe, PhD, 01/17/03 Re: Scientific Jargon vs. reality, by Barbara, 01/17/03 Sandra, by Cahill, 01/18/03 Re:Sandra, by Sandra Paulsen Inobe, PhD, 01/18/03

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