Eye movement desensitization and reprocessing (EMDR) is a form of psychotherapy developed by Francine Shapiro starting in 1988 in which the person being treated is asked to recall distressing images; the therapist then directs the patient in one type of bilateral stimulation, such as side-to-side eye movements or hand tapping. According to the 2013 World Health Organization practice guideline: "This therapy is based on the idea that negative thoughts, feelings and behaviours are the result of unprocessed memories. The treatment involves standardized procedures that include focusing simultaneously on (a) spontaneous associations of traumatic images, thoughts, emotions and bodily sensations and (b) bilateral stimulation that is most commonly in the form of repeated eye movements."