Prospective memory (PM) refers to an ability to remember carrying out previously formed intentions in the future. The demand for performing PM tasks in everyday increases as children enter schools. The key cognitive processing to complete PM tasks successfully involves voluntary retrieval and execution of PM intentions when PM cues occur. There are three types of PM cues, namely time, event, and activity-based PM cues.
Compared with typically developing children, children with Attention Deficit Hyperactivity Disorder (ADHD) are more forgetful and show inattention in daily activities, suggesting potential impairment in PM function. However, few studies have investigated PM in children with ADHD. Moreover, no study has directly compared performance in three types of PM cue conditions and characteristics of the cognitive processing.
In order to address this issue, Dr. Raymond Chan's team from the Institute of Psychology of the Chinese Academy of Sciences, together with Dr. QIAN Ying from Peking University Sixth Hospital, and Prof. WANG Yanyu from Weifang Medical University, have investigated time, event, and activity-based PM in 28 children with ADHD and 28 typically developing children using the Fishing Game.
The Fishing Game adopts the classical dual-task paradigm, and the primary/ongoing task requires children to fish. At the same time, they need to pay attention to PM cues while fishing, and stop fishing to execute PM tasks when the PM cues appear.
In this study, researchers also measured the children's intelligence, sustained attention and switch attention functions.
The findings show that despite lower intelligence quotient and attentional deficits, children with ADHD exhibited similar level of PM performance as typically developing children, suggesting no signs of impairment in PM.
Subsequent analysis indicated that type of PM cues had a significant impact on PM performance, and the patterns were similar in children with ADHD and typically developing children. Specifically, children in both groups showed the best performances in the activity-based PM task, followed by the event-based PM task, and the time-based PM task.
This finding suggests that children have more attentional resources for PM cues when an activity ends, and thus they are more likely to detect cues and retrieve intentions. However, both event and time-based cues may need voluntary monitoring during the process of ongoing task. Since temporal cues are often more difficult to detect, they tend to demand higher level of monitoring, leading to worse performance.
It is worth noting that in the event-based PM condition, children with ADHD exhibited worse ongoing task performance compared with typically developing children. When children with ADHD spend more attentional resources monitoring PM cues and completing PM tasks, they tend to pay larger cost on ongoing task performance compared with typically developing children.
Taken together, these findings suggest that children with ADHD have limited attention and experience difficulty in attending to both PM and ongoing task.
Because children with ADHD showed best performance in activity-based PM cue conditions, parents and teachers may try to arrange PM tasks at the end of activities when they assign PM tasks. Under such circumstances, the ongoing task is over and children do not need to pay attention to it and are thus more likely to retrieve the PM intentions. Similarly, as children have difficulty completing time-based PM tasks, parents and teachers should consider replace temporal cues with event or activity-based cues.
The study has been published online in Developmental Neuropsychology entitled "Event-, Time- and Activity-Based Prospective Memory in Children with ADHD".
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