19.10.2018

Do eye movements contribute to outcome in EMDR?

Much confusion tends to result when the outcomes of the three types of component studies (see What has research determined about EMDR’s eye movement component) are combined. Because these studies differ substantially in design, purpose, participants, and outcome measures, they have produced a wide range of results:

In dismantling studies with analogue participants, EMs do not contribute to outcome, possibly because of a floor effect.
In clinical dismantling studies with diagnosed participants, there has been a consistent nonsignificant trend for a treatment effect.
In the component action studies a consistent significant effect for EMs in isolation was found in reducing the vividness of, and affect associated with, autobiographical memories; it is possible that such effects may contribute to treatment outcome.

In the Davidson and Parker (2001) meta-analysis, no effects were found for EMDR-with-EMs compared to EMDR-without-EMS, when all types of studies were included. However, when the results of the clinical dismantling studies were examined, EMDR-with-EMs was significantly superior to EMDR-without-EMs.Various reviews of the related EM research have provided a range of conclusions. Some reviewers (e.g., Lohr, Lilienfeld, Tolin, & Herbert, 1999; Lohr, Tolin, & Lilienfeld, 1998) stated that there is no compelling evidence that eye movements contribute to outcome in EMDR treatment and the lack of unequivocal findings has led some reviewers to dismiss EMs altogether (e.g., McNally, 1999). Other reviewers (e.g., Chemtob et al., 2000; Feske, 1998; Perkins & Rouanzoin, 2002) identified methodological failings (e.g., lack of statistical power, floor effects) and called for more rigorous study.Numerous controlled studies have also indicated that eye movements cause a decrease in imagery vividness and distress, as well as increased memory access.

Andrade, J., Kavanagh, D., & Baddeley, A. (1997). Eye-movement and visual imagery: a working memory approach to the treatment of post-traumatic stress disorder. British Journal of Clinical Psychology, 36, 209-223.
Barrowcliff, A.L., Gray, N.S., MacCulloch, S. Freeman, T.C.A., & MacCulloch, M.J. (in press). Horizontal rhythmical eye-movements consistently diminish the arousal provoked by auditory stimuli. British Journal of Clinical Psychology.
Christman, S.D., Garvey, K.J., Propper, R.E. & Phaneuf, K.A. (in press). Bilateral eye movements enhance the retrieval of episodic memories. British Journal of Clinical Psychology, 40, 267-280.
Kavanaugh, D.J., Freese, S., Andrade, J., & May, J. (2001). Effects of visuospatial tasks on desensitization to emotive memories. British Journal of Clinical Psychology, 40, 267-280.
Kuiken, D., Bears, M., Miall, D., & Smith, L. (2002-2002). Eye movement desensitization reprocessing facilitates attentional orienting. Imagination, Cognition and Personality, 21, (1), 3-30.
Sharpley, C.F., Montgomery, I.M., & Scalzo, L.A. (1996). Comparative efficacy of EMDR and alternative procedures in reducing the vividness of mental images. Scandinavian Journal of Behaviour Therapy, 25, 37-42.
van den Hout, M., Muris, P., Salemink, E., & Kindt, M. (2001). Autobiographical memories become less vivid and emotional after eye movements. British Journal of Clinical Psychology, 40, 121-130.

Suggested research.
Research is needed to answer questions about the role of EMs and other dual attention stimuli. It is recommended that clinical dismantling studies use a large sample of participants with PTSD (from a single trauma) to investigate whether EMDR-with-EMs is more effective than EMDR-without-dual attention stimuli. To date, no study like this has been conducted. (See Shapiro, 2001, for specific recommendations for research designs.)