Event-based prospective memory following adult traumatic brain injury




Patry, Brigitte N.

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Objectives: The ability to remember to carry out future intentions (prospective memory or ProM) has been shown to be impaired in individuals with severe traumatic brain injury (TBI). However, it is not known whether such deficits extend to people with milder TBI. This study sought to investigate the status of event-based ProM in a sample with a wide range of TBI severity. Furthermore, it proposed to determine whether perceptually salient cues and the formation of implementation intentions, shown to be beneficial in other populations, are also helpful for people with TBI. A detailed error analysis was performed, and the relationship of objective ProM performance to subjective ProM and to scores on other cognitive tests was investigated in an attempt to clarify the mechanisms underlying ProM performance post-TBI. Method: The sample consisted of 20 individuals who sustained a mild (n=10) or severe (n=10) TBI at least 6 months earlier and 20 age-, gender-, and education-matched healthy adults below the age of 55. The groups did not differ in terms of level of pain or substance abuse; however, the TBI group endorsed more symptoms on the Beck Depression Inventory-lI (BDI-II) and on the Beck Anxiety Inventory. They completed two event-based ProM tasks, a game entitled Navigating Your Week (NYW) and the Prospective Remembering of Actions and Sentences (PROAS). Each measure was designed to create intentions that would prompt different actions in response to various cues. They also completed the Prospective and Retrospective Memory Questionnaire (PRMQ) to assess subjective evaluation of memory, the Rey Auditory Verbal Learning Test (RAVLT) and cued recall tasks to assess retrospective memory, and Digit Span Backward to measure working memory. Results: Participants with TBI scored significantly below controls on the NYW game, even after controlling for BDI-II scores, and the two TBI subgroups performed similarly. Participants with TBI made more ProM failures and loss of content errors than controls on the NYW game. The groups performed similarly on the PROAS when it was the second ProM task administered. Although salient cues increased the frequency of responding upon cue presentation, they did not increase response accuracy and thus, did not result in greater fulfillment of intentions. The formation of implementation intentions (lid not enhance the ability to carry out previously formed intentions. The TBI group's performance on the NYW and on the PROAS was associated with their scores on Digit Span Backward and on cued recall measures. The PROAS was also related to delayed recall on the RAVLT; the association between the NYW and the RAVLT did not reach statistical significance. The TBI group endorsed more prospective and retrospective memory problems on the PRMQ as compared to the control group, but their self-ratings were not significantly related to their ProM performance. Conclusions: Individuals with TBI fulfilled fewer of their intentions than controls, particularly on the NYW game, because they failed to respond to cues and had more difficulty remembering the content of their intentions. Their reduced ProM was not fully attributable to depressive symptomatology and was not related to their subjective ProM complaints, despite their greater ProM concerns as compared to controls. Deficits may be attenuated when ProM situations emphasize more automatic retrieval as compared to strategic monitoring processes. Working memory and retrospective memory may both contribute to ProM status after TBI. Cue saliency did not help TBI participants to carry out more intentions; however, it reduced the frequency of ProM failures. The lack of implementation intention effects may be related to study design characteristics. The NYW game appears to he a sensitive, valid, and reliable tool that could he useful in a rehabilitation setting.



prospective memory, brain, injuries