Memory for past events: movement and action chains in high-functioning autism spectrum disorders

In the present study, we assessed whether individuals with autism spectrum disorders (ASD) show memory impairments for previously performed actions, as previously suggested for people suffering from obsessive-compulsive disorder (OCD) (Ecker and Engelkamp in Behav Cogn Psychother 23:349-371, 1995; Merckelbach and Wessel in J Nerv Ment Dis 188(12):846-848, 2000). To test this possibility, we explored verbal memory for actions in individuals with a diagnosis of ASD, with and without co-morbidity for OCD, and in controls matched for age and gender. Participants observed or observed and enacted a number of actions while listening to the corresponding phrases being spoken. After a suitable delay, they were submitted to an old/new recognition task. Results showed that ASD individuals with OCD were less accurate and slower in responding compared to ASD individuals without OCD and controls, particularly when dealing with phrases describing simple movements. In contrast, ASD participants without OCD were more impaired when phrases described complex actions that involved pantomiming object use or coordinating movements of multiple body parts. These findings are discussed in terms of differential organization of the motor trace for simple versus complex actions in ASD individuals according to the concurrent presence of OCD.