Assessing the 24-hour effect of EMDR: An analogue study


Eye movement desensitization and reprocessing (EMDR) is an efficacious treatment for PTSD. The intervention involves patients recalling traumatic memories while making horizontal eye movements (EM). To date, the long term effects of eye movements are not well known and so are the effects of emotions on the outcome measures.

This study aimed to test four hypotheses. 1) Subjective units of distress (SUD), vividness and emotionality of the image decrease significantly more in the EM condition than in the RO condition from pre-test to post-test 2) and from pre-test to follow up 3) EMDR maintains the effects it initially achieved after a 24-hour follow up. 4) A higher score on the primary emotions has a positive effect on the results of EM and results in a greater decrease of vividness, emotionality and SUD.

Undergraduates recalled two emotional memories and rated these on vividness, emotionality and SUD. They scored the emotions fear, anger, sadness, helplessness, guilt, shame and surprise on visual analogue scales (VAS). After this they were assigned to the EM or RO condition. The intervention consisted of eight sessions of 4 x 24s each and had a pre-test, post-test and 24h follow up.

The scores on vividness, emotionality and SUD decreased in the same amount for EM and RO. For ‘recall+EM’ the scores increased more after 24h than the ‘recall only’ scores. Both conditions remained effective, since the follow up scores were significantly lower than the pretest scores. Emotions had a negative effect on the decrease of emotionality, but not on the other outcome measures.

This study found support for the 24h effect of both EM and RO. The study did not find an additive effect of EM in comparison to RO. Emotionality in general seems to reduce the effects of recall.






T. E. Mekes

Original Work Citation

Mekes, T. E. (2106). Assessing the 24-hour effect of EMDR: An analogue study. (Master's thesis, Utrecht University)



“Assessing the 24-hour effect of EMDR: An analogue study,” Francine Shapiro Library, accessed October 22, 2020,

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