Effect of type of cue, type of response, time delay and two different ongoing tasks on prospective memory functioning after acquired brain injury

Abstract

Failures of prospective memory (PM) are one of the most frequent, and least studied, sequelae of brain injury. PM, also referred to as memory for intentions, is the ability to remember to carry out a future task. Successful completion of a PM task requires the ability to monitor time, keep the action to be performed periodically in awareness, remember the task to be performed, and initiate the action. Although PM has been shown to be a common difficulty after brain injury, it remains unknown which aspects of performance are impaired. In this study, the performance of 25 individuals with brain injury and that of 25 healthy participants were measured separately on the following variables: time until completion of the task, difficulty of the ongoing task being performed while waiting, whether the task to be performed is an action or is verbal, and whether the cue to perform the task is the passing of a particular amount of time (e.g., 10 minutes) or is an external cue (e.g., an alarm sounding). Individuals with brain injury demonstrated impairment compared to healthy adults on virtually all variables. PM performance was also compared to a battery of standard neuropsychological measures of attention, memory, and executive functions, and to self-report measures of PM functioning, in order to determine the underlying cognitive deficits responsible for poor PM performance, if any. PM performance was correlated with measures of executive functioning but not to self-report measures of PM functioning. Implications are discussed in terms of cognitive rehabilitation recommendations.

Keywords:

• Prospective memory
• Memory for intentions
• Acquired brain injury

Acknowledgments

This research was supported, in part, by a grant from the James S. McDonnell Foundation and the Trinity College Faculty Research Committee. We would like to thank all of the individuals who served as participants and all of the Trinity College students who helped to collect data, including Brian Harel, Chloe Zaug, Sara Levy and Laura O'Sullivan. We also thank two anonymous reviewers for their very helpful comments.