An orienting response model of eye movement desensitization.

Dyck's (Journal of Behavior Therapy and Experimental Psychiatry, 1993) conditioning model of EMD provides a useful description of failure of habituation in post-traumatic stress disorder, but may not account for some common EMD phenomena. An alternative model proposes that the therapist's waving hand--in the presence of a trauma-related cortical set--triggers an intense orienting response (OR). Intrinsic effects of the OR facilitate continuing attention to the memory without avoidance, and provide for effective input of new trauma-related information. The person's neuronal model of the trauma alters to reflect his survival and current safety--as true outcome of the trauma--and associated conditioned responses extinguish. Proposals for experimental evaluation of the model are described.