Re: movements

The sample size (n=17) of the Pitman et al. study is inadequate for the purposes of a component analysis. This is a fact which has been publicly acknowledged by Roger Pitman at last year's ISTSS conference.

That is, given that the standard EMDR protocol contains aspects and effective ingredients from many different types of psychotherapy, EMDR without bilateral stimulation is likely to be an effective treatment.

Thus, the real question is how much does bilateral stimulation adds above and beyond what is just good psychotherapy. None of the studies conducted so far have really addressed this question.

That is, the effect size of bilateral stimulation is one which needs to be an additive effect beyond beyond that of good psychotherapy. Most psychotherapy studies show that the latter has a moderate effect size (in statistical terms). To discern the relative effect sizes between different components of psychotherapies, one needs a large sample size indeed.

An alternative way of answering the same question is the use of imaging research. While there is support that EMDR is effective, from a research point of view, alternative explanations at this point in time, due to the lack of experimental controls, cannot be ruled out.

Most clinicians who use EMDR feel that bilateral stimulation adds to the treatment effect. Given reports that EMDR "breaks through" dissociation, and thus recommendations regarding its cautious use in dissociative disorders, is some support that bilateral stimulation is not innocuous, at least in some populations.

Further, there is some yet unpublished research with pain which shows changes in brain activity secondary to EMDR in a specific population which has historically not responded to other treatments, including other psychotherapies.

Similarly, there is imaging research which has demonstrated an activating effect of eye movements, as well as focussed attention, on brain activity. Thus, it appears that a fixed gaze condition, as used in at least one dismantling study, is not an appropriate control.

The majority of clients' reports seem to corroberate clinicians' impressions. That is, many report that bilateral stimulation aids in working through traumatic material. Thus, while there is no definitive large scale controlled study supporting bilateral stimulation as an effective ingredient 'per se' EMDR's effectiveness in the treatment of PTSD is beyond a reasonable doubt.

EMDR is a relatively novel treatment. While many studies have been published ascertaining EMDR's effectiveness, at the same time a lot of the information is not in yet. It is important, however, that scepticism in parts of the research and therapeutic community towards the effectiveness of bilateral stimulation will not stand in the way of further research on what its potential effects might be.

Given that there is fairly good consensus by both clinicians and clients alike that bilateral stimulation adds to the treatment effect, both as a client and a clinician, I am inclined to make use of bilateral stimulation, even if definitve empirical support for one of the latter is still outstanding.

Replies:

Re: movements, by Robert P. O'Brien, Ph.D., 5/3/00

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