Impact of inhibitory load on remembering delayed intentions in autism

Objective: Research on prospective memory (PM) in autism spectrum disorders (ASD) is scarce and inconsistent. Differences in results have been attributed to differences in executive control demands of the respective PM tasks. However, so far no study has systematically and experimentally manipulated executive control load. The present study set out to explore the impact of varying inhibitory control demands on PM performance in ASD. Method: Twenty-two adults with ASD and 22 age-, gender- and cognitive ability-matched controls were asked to work on a computerised word categorization task into which an event-based PM task was embedded. In addition, they were required to work on a task that put either low or high load on inhibitory resources. Results: With regards to the event-based PM task, no significant effects emerged. Controls outperformed individuals with ASD on the ongoing task performance and ongoing task performance varied with inhibition load. Similarly, inhibition load affected performance on the inhibition task; here, no group effects were found. Conclusion: Findings suggest spared event-based PM performance in ASD regardless of inhibition load. However, results might be limited by ceiling effects and future studies are needed to investigate to explore inhibition effects using more difficult tasks.