Abstract
Eye Movement Desensitization and Reprocessing (EMDR) was developed by Shapiro (1989a, 2001) and was designed to facilitate the processing of distressing memories. It has since evolved into a standardised intervention for post-traumatic stress disorder (PTSD) that utilises elements from many different treatment approaches. EMDR has generated considerable debate, perhaps due to a lack of understanding of how it works. One aspect of EMDR procedure that has remained particularly controversial is the use of eye movements. Over the past twenty years there have been a number of studies investigating whether eye movements contribute to outcome in EMDR. Much of the research suffered from methodological flaws and therefore was inconclusive. More recently, researchers have begun to investigate why eye movements may be useful in EMDR by looking into possible psychological and neurophysiological mechanisms. This review provides an overview of research so far, including a description of two prominent theories of how eye movements might contribute to outcome in EMDR: the interhemispheric interaction account and the working memory account. Implications for clinical practice and future research are discussed.