Traumatic Brain Injury and Prospective Memory in a Virtual Shopping Trip Task: Does It Matter Who Generates the Prospective Memory Target?

Prospective memory functions in traumatic brain injury: The role of neuropsychological deficits, metamemory and impaired self-awareness

A large body of evidence suggests that individuals with traumatic brain injury (TBI) have significant difficulties with prospective memory (PM), the memory for future intentions. However, the processes underlying this cognitive deficit remain unclear. This study aimed to gather further evidence regarding PM functions in TBI and clarify the role of neuropsychological deficits, metamemory, and mood disorders. We used a laboratory-based clinical measure, the Virtual Week, to examine PM function in 18 patients with TBI and 18 healthy control subjects. Measures of attention, processing speed, executive functions, episodic memory, and self-report questionnaires were also administered. In line with prior literature, our findings indicate that individuals with TBI had a consistent deficit compared to controls across all PM tasks. In previous studies, TBI patients had more severe impairment on time-based tasks; nevertheless, our results show that across all participants event-based tasks were easier to perform compared to time-based only when the retrospective memory demand was high. The patients were not only impaired on the prospective component of PM but also failed to recognise the content of their task (the retrospective component). Interestingly, the TBI group did not report higher levels of everyday memory problems, anxiety and depression compared to the control group. These measures also failed to correlate with PM and recognition memory performance. This study found that besides the neuropsychological deficits, a global impairment in PM functioning is present in individuals with TBI across various task types, tasks low and high in retrospective demands, and event versus time-based.

Cognitive performance in older adults at three months following mild traumatic brain injury

Introduction: In the context of limited research assessing outcomes following mild traumatic brain injury (mTBI) in older adults, this study evaluated cognitive outcomes through prospective memory, and expected that performance of an older mTBI group (≥65 years) would be lower compared to orthopedic and community controls. The study also explored whether cognitive resources (retrospective memory, executive function) moderated any association between presenting Glasgow Coma Scale (GCS) and prospective memory.Method: At three-months post-injury, a mTBI group (n = 39), an orthopedic control group (n = 63), and a community control group (n = 46) completed a neuropsychological assessment, including (i) prospective memory, using a standardized paper-and-pencil task (Cambridge Prospective Memory Test), an augmented reality task and a naturalistic task, and (ii) standardized measures of retrospective memory (Hopkins Verbal Learning Test) and executive function (Trail Making Test). Group performances were compared, and bootstrapped moderation analyses evaluated the role of cognitive resources in the relationship between GCS and prospective memory outcome.Results: The mTBI group, as compared to community controls, performed significantly lower on the augmented reality task (d = -0.64 to d = -0.79), and there was a small-moderate but non-significant effect (d = -0.45) on the naturalistic task. There were no differences between the mTBI group and orthopedic controls. Retrospective memory was a unique predictor of the augmented reality task (B = 1.83) and moderated the relationship between presenting GCS and the naturalistic task (B = -5.60). Executive function moderated the association between presenting GCS and augmented reality (B = -1.13) and naturalistic task (B = -1.57).Conclusions: At three-months post-mTBI, older adults are at risk of poor cognitive performance; and the relationship between GCS and prospective memory can be moderated by cognitive resources. Further follow-up is indicated to determine whether impairments resolve or persist over time.

A meta-analysis of task-related influences in prospective memory in traumatic brain injury

Prospective memory is the ability to remember to do something in the future and it is essential to every-day functional independence. Traumatic brain injury is associated with frequent and persistent prospective memory deficits. This study presents a review and meta-analysis investigating the effects of task parameters on prospective memory performance of individuals with TBI. Individual studies using continuous behavioural measures of prospective memory with a sample of adults with TBI and matched controls were included. Consistent with previous research, a random effects meta-analysis indicated that TBI groups demonstrated lower prospective memory performance than control groups (d = 1.10, SE = 0.12, 95% CI = 0.86-1.34). In addition, we found that type of prospective memory cue, saliency of cues, and complexity of the ongoing task significantly moderated the difference in prospective memory performance between TBI and control groups. These findings suggest that prospective memory task parameters should be considered in the assessment of prospective memory in individuals with cognitive impairment. In addition, considering the influence of these task parameters would be useful to develop effective compensatory strategies to reduce prospective memory failures.

Evaluation of a virtual reality prospective memory task for use with individuals with severe traumatic brain injury

The current study aimed to evaluate the sensitivity, convergent validity and ecological validity of a newly developed virtual reality prospective memory (PM) task (i.e., the Virtual Reality Shopping Task; VRST) for use with individuals with traumatic brain injury (TBI). Thirty individuals with severe TBI and 24 uninjured adults matched on age, gender and education level were administered the VRST, a lexical decision PM task (LDPMT), an index of task-friendliness and a cognitive assessment battery. Significant others rated disruptions in the TBI participants' occupational activities, interpersonal relationships and independent living skills. The performance of the TBI group was significantly poorer than that of controls on event-based PM as measured by the LDPMT, and on time- and event-based PM as measured by the VRST. Performance on the VRST significantly predicted significant others' ratings of patients' occupational activities and independent living skills. The VRST was rated as significantly more reflective of an everyday activity, interesting and was afforded a higher recommendation than the LDPMT. For the TBI group, event and total PM performance on the VRST significantly correlated with performance on measures of mental flexibility and verbal fluency, and total PM performance correlated with verbal memory. These results provide preliminary but promising evidence of the sensitivity, as well as the convergent and ecological validity of the VRST.

Everyday Memory for Everyday Tasks: Prospective Memory as an Outcome Measure Following TBI in Older Adults

Traumatic brain injury in older adults is an increasing problem in our aging community. Traditional functional outcome measures, such as return to work or academic achievement, as used with younger samples following traumatic brain injury are of limited use for older people. Although challenging to assess reliably, evaluation of prospective memory is gradually being included in outcome assessments following traumatic brain injury in younger samples and may be a useful index of cognitive competence in everyday life when assessing older adults following traumatic brain injury.

Event-based prospective remembering in a virtual world

Most laboratory-based prospective memory (PM) paradigms pose problems that are very different from those encountered in the real world. Several PM studies have reported conflicting results when comparing laboratory- with naturalistic-based studies (e.g., Bailey, Henry, Rendell, Phillips, & Kliegel, 2010 ). One key contrast is that for the former, how and when the PM cue is encountered typically is determined by the experimenter, whereas in the latter case, cue availability is determined by participant actions. However, participant-driven access to the cue has not been examined in laboratory studies focused on healthy young adults, and its relationship with planned intentions is poorly understood. Here we report a study of PM performance in a controlled, laboratory setting, but with participant-driven actions leading to the availability of the PM cue. This uses a novel PM methodology based upon analysis of participant movements as they attempted a series of errands in a large virtual building on the computer screen. A PM failure was identified as a situation in which a participant entered and exited the "cue" area outside an errand related room without performing the required errand whilst still successfully remembering that errand post test. Additional individual difference measures assessed retrospective and working memory capacity, planning ability and PM. Multiple regression analysis showed that the independent measures of verbal working memory span, planning ability, and PM were significant predictors of PM failure. Correlational analyses with measures of planning suggest that sticking with an original plan (good or bad) is related to better overall PM performance.

The contribution of retrospective memory, attention and executive functions to the prospective and retrospective components of prospective memory following TBI

PRIMARY OBJECTIVE

Despite the prevalence of prospective memory (PM) problems, relatively little is known about the processes underlying impairment following TBI. This study sought to examine PM performance, using a multiple-task, multiple-response video-based paradigm in which initial encoding of the cue-action associations was ensured (Video-Assessment of Prospective Memory; VAPM).

RESEARCH DESIGN

VAPM was designed to allow easy identification of reasons for failure (i.e. cue detection and/or specific action retrieval). Patients with moderate/severe TBI (n = 32) and matched controls (n = 16) also completed standardized neuropsychological assessment including evaluation of episodic retrospective memory (RM), attention, information processing, executive functions and mood.

MAIN OUTCOMES AND RESULTS

As a group, those with TBI were impaired on PM tasks with 50% failing to complete at least 2/6 required tasks despite near perfect performance by controls. Individual profile analyses revealed different reasons for impairment, with RM contributing significantly to both the prospective and retrospective components. This was supported by correlational analyses illustrating a significant relationship between cue detection and RM measures, in addition to measures of executive functions and attention.

CONCLUSIONS

The contribution of RM to both components of PM, along with the finding of heterogeneity in performance among participants have important implications for theoretical understanding and clinical practice.

Prospective memory in patients with closed head injury: a review

This paper aimed to review the limited, but growing literature on prospective memory (PM) following closed head injury (CHI). Search of two commonly used databases yielded studies that could be classified as: self- or other-report of PM deficits; behavioral PM measures in adults with CHI, behavioral PM measures in children and adolescents with CHI, and treatment of PM in adults with CHI. The methodology and findings of these studies were critically reviewed and discussed. Because of the small number of studies, meta-analysis was only conducted for studies that used behavioral PM measures in adults to integrate findings. PM deficits were found to be commonly reported by patients with CHI and their significant others and they could be identified using behavioral measures in adults, children and adolescents with CHI. However, more work is needed to clarify the nature and mechanisms of these deficits. Although some promising results have been reported by studies that evaluated PM treatment, most studies lack tight experimental control and used only a small number of participants. The paper concluded with some suggestions for future research.