Retrospective Episodic Memory Research Articles

Experimental Effects of Acute Exercise on Episodic Memory Function: Considerations for the Timing of Exercise.

Our previous work employing a between-subject randomized controlled trial design suggests that exercising prior to memory encoding is more advantageous in enhancing retrospective episodic memory function when compared to exercise occurring during or after memory encoding. The present experiment evaluates this potential temporal effect of acute exercise on memory function while employing a within-subject, counterbalanced design. In a counterbalanced order (via Latin squares), 24 participants completed four visits including (1) exercising (moderate-intensity walking) prior to memory encoding, (2) exercising during memory encoding, (3) exercising after memory encoding, and (4) a control visit (no exercise). Retrospective memory function (short term and long term; 24-hour follow-up) was assessed from a multitrial word list. Prospective memory was assessed from a time-based task. Compared to all other visits, short-term memory was greater in the visit that involved exercising prior to memory encoding (F = 3.76; P = .01; η2 = .79). Similar results occurred for long-term memory, with no significant effects for prospective memory performance. We provide robust evidence demonstrating that acute moderate-intensity exercise prior to memory encoding is optimal in enhancing short-term and long-term memory function when compared to no exercise as well as exercising during and after memory encoding.

Experimental Effects of Acute Exercise on Prospective Memory and False Memory.

Research demonstrates that acute exercise can enhance retrospective episodic memory performance. However, limited research has examined the effects of acute exercise on prospective memory, and no studies have examined the effects of exercise on false memory performance. This study examined the potential effects of acute exercise on prospective memory and false memory performance. A between-group randomized controlled trial was employed, with participants (college students; Mage = 20 years) randomized into an exercise group (15-minute acute bout of treadmill walking; N = 25) or a control group (15 minutes of sitting; N = 26). Prospective memory was assessed from two laboratory and two naturalistic assessments outside the lab. False memory was assessed using a word-list trial. There were no statistically significant differences in prospective memory based on group allocation (FGroup×Time = 1.17; P = 0.32; η2 = 0.06). However, the control group recalled more false words and had a higher rate of false memory recognition (FGroup×Time = 3.15; P = 0.01; η2 = 0.26). These findings indicate that acute moderate-intensity aerobic exercise is not associated with prospective memory performance but provides some suggestive evidence that acute exercise may reduce the rate of false memories.

Prospective memory and subjective memory decline: A neuropsychological indicator of memory difficulties in community-dwelling older people

ABSTRACTIntroduction: Prospective memory difficulties are known to occur in Alzheimer’s disease, and may provide an early indicator of cognitive decline. Older people reporting high levels of subjective memory decline (SMD) but without evidence of cognitive decline on standard neuropsychological tests are increasingly considered at increased risk for Alzheimer’s disease. Therefore, the objective of this study was to investigate whether prospective memory performance is differentially impaired in older people reporting high levels of SMD as compared to a control group. Method: A total of 195 community-dwelling older adults (Mage = 73.48 years) were assessed for self-reported complaints of memory decline and allocated to either a group reporting high levels of SMD (SMD, n = 96) or a healthy control group (HC, n = 99). Groups were assessed on neuropsychological tests, an experimental prospective memory task (focal vs. nonfocal cue conditions), and a naturalistic prospective memory task. Results: The groups did not differ in performance on standard neuropsychological tests of working memory, executive attention, and episodic retrospective memory. Furthermore, on an experimental task of prospective memory (the Supermarket Shopping Trip task), although performance of both groups was better when cues for prospective memory were focal to the ongoing activity (η2 = .35), the SMD group were not impaired relative to the control group. On a naturalistic prospective memory task, however, there was a small but significant effect, with the SMD group performing more poorly than the HC group (η2 = .02). Conclusions: In older adults with high levels of SMD, naturalistic measures of prospective memory provide an approach to assessing memory performance that can offer a means of investigating the memory complaints of people with SMD. Identifying prospective memory difficulties in SMD also offers a focus for intervention.

Is binding decline the main source of the ageing effect on prospective memory? A ride in a virtual town.

ABSTRACT Objective: This study was designed to improve our understanding of prospective memory (PM) changes in ageing, and to identify the cognitive correlates of PM decline, using a virtual environment, to provide a more realistic assessment than traditional laboratory tasks. Design: Thirty-five young and 29 older individuals exposed to a virtual town were asked to recall three event-based intentions with a strong link between prospective and retrospective components, three event-based intentions with a weak link, and three time-based intentions. They also underwent retrospective episodic memory, executive functions, binding in working memory, processing speed, and time estimation assessments. Results: Older individuals recalled fewer intentions than young adults. While age-related PM decline affected the recall of both prospective and retrospective components, the recall of the latter seemed more challenging for older individuals when the link was weak. This PM decline was linked to an age-related decline in the binding process in working memory, as well as in processing speed, executive functioning, and episodic memory, depending on the nature of intentions. Conclusion: PM appears to be sensitive to ageing, even when the device is thought to be ecological. This decline is particularly pronounced when controlled processes are needed.

Regularity effect in prospective memory during aging.

BackgroundRegularity effect can affect performance in prospective memory (PM), but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults.Objective and designOur study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30), 16 intermediate adults (40–55), and 25 older adults (65–80). The task, adapted from the Virtual Week, was designed to manipulate the regularity of the various activities of daily life that were to be recalled (regular repeated activities vs. irregular non-repeated activities). We examine the role of several cognitive functions including certain dimensions of executive functions (planning, inhibition, shifting, and binding), short-term memory, and retrospective episodic memory to identify those involved in PM, according to regularity and age.ResultsA mixed-design ANOVA showed a main effect of task regularity and an interaction between age and regularity: an age-related difference in PM performances was found for irregular activities (older < young), but not for regular activities. All participants recalled more regular activities than irregular ones with no age effect. It appeared that recalling of regular activities only involved planning for both intermediate and older adults, while recalling of irregular ones were linked to planning, inhibition, short-term memory, binding, and retrospective episodic memory.ConclusionTaken together, our data suggest that planning capacities seem to play a major role in remembering to perform intended actions with advancing age. Furthermore, the age-PM-paradox may be attenuated when the experimental design is adapted by implementing a familiar context through the use of activities of daily living. The clinical implications of regularity effect are discussed.

Handedness differences observed in episodic memory retrieval do not extend to the domain of prospective memory

A robust inconsistent handed advantage exists for episodic retrospective memory processes. The current study was undertaken to test whether this handedness difference extends to the domain of prospective memory (PM). Two studies, one based on a self-report measure (the Prospective and Retrospective Memory Questionnaire) and the second involving a performance-based test (Memory for Intentions Screening Test), were carried out. Handedness effects were absent for both measures of PM. The absence of a handedness effect strongly suggests that PM processes are primarily characterized by executing intentions that depend on semantic networks for retrieval and do not necessarily rely on recalling spatio-temporal context, as is the case with episodic retrospective memory.

Rule monitoring ability predicts event-based prospective memory performance in individuals with TBI.

Numerous studies have demonstrated that prospective memory (PM) abilities are impaired following traumatic brain injury (TBI). PM refers to the ability to remember to complete a planned action following a delay. PM post-TBI has been shown to be related to performance on neuropsychological tests of executive functioning and retrospective episodic memory (RM). However, the relative influence of impairments in RM versus executive functioning on PM performance post-TBI remains uninvestigated. In the current study, PM and neuropsychological test performance were examined in 45 persons with a history of moderate to severe TBI at least 1 year before enrollment. Regression analyses examined the relative contributions of RM and executive functioning in the prediction of PM performance on the Rivermead Behavioral Memory Test (RBMT). Results indicated that scores on tests of delayed RM and rule monitoring (i.e., ability to avoid making errors on executive measures) were the strongest predictors of PM. When the interaction between RM impairment and rule monitoring was examined, a positive relationship between PM and rule monitoring was found only in TBI participants with impaired RM. Results suggest that PM performance is dependent upon rule monitoring abilities only when RM is impaired following TBI.

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.

Ecological prospective memory assessment in patients with traumatic brain injury

Primary objective: Prospective memory (PM) impairments are often observed after traumatic brain injury (TBI). Although PM is crucial for daily functioning, few sensitive, valid and ecological clinical tests are available. To address these concerns, the authors developed a PM task, the TEMP, using naturalistic stimuli, in which each PM phase and component is evaluated independently in time- and event-based conditions.Main outcomes and results: The results show that moderate and severe TBI patients (n = 30), evaluated after spontaneous neurological recovery, experienced problems in learning the delayed intentions content and retrieving these intentions in the right context (prospective component), especially in the time-based condition. They also recalled fewer associated actions (retrospective component), but only in the time-based condition. Correlations revealed that the retrospective component was mainly supported by episodic retrospective memory processes, while the prospective component was supported by episodic retrospective memory processes, along with attentional and executive functions. Moreover, there was a significant correlation between performance on the TEMP and results on a questionnaire assessing PM functioning in daily living completed by participants’ relatives.Conclusions: The TEMP therefore appears to be a sensitive tool for assessing PM problems that combines internal and ecological validity.

Distinct and shared cognitive functions mediate event- and time-based prospective memory impairment in normal ageing

Prospective memory (PM) is the ability to remember to perform an action at a specific point in the future. Regarded as multidimensional, PM involves several cognitive functions that are known to be impaired in normal ageing. In the present study we set out to investigate the cognitive correlates of PM impairment in normal ageing. Manipulating cognitive load, we assessed event- and time-based PM, as well as several cognitive functions, including executive functions, working memory, and retrospective episodic memory, in healthy participants covering the entire adulthood. We found that normal ageing was characterised by PM decline in all conditions and that event-based PM was more sensitive to the effects of ageing than time-based PM. Whatever the conditions, PM was linked to inhibition and processing speed. However, while event-based PM was mainly mediated by binding and retrospective memory processes, time-based PM was mainly related to inhibition. The only distinction between high- and low-load PM cognitive correlates lies in an additional, but marginal, correlation between updating and the high-load PM condition. The association of distinct cognitive functions, as well as shared mechanisms with event- and time-based PM, confirm that each type of PM relies on a different set of processes.

Prospective memory in amnestic mild cognitive impairment

Individuals with amnestic mild cognitive impairment (aMCI) often complain of difficulty remembering to carry out intended actions, consistent with findings of impaired prospective memory (PM) in this population. In this study, individuals with aMCI (N = 27) performed worse than healthy controls (N = 27) on the Memory for Intentions Screening Test (Raskin, 2004), including on time- and event-based subscales, and recognition of the intentions. The aMCI participants made more errors overall, but the proportion of the various error types did not differ between the two groups. Across all error types, both groups made more retrospective than prospective errors, especially on event-based PM tasks. Overall, the findings suggest that PM impairment in aMCI is associated with deficient cue detection involving both automatic (as in event-based tasks) and more strategic detection (as in time-based tasks) processes. These difficulties are likely due to a combination of problematic retrospective episodic memory (e.g., reduced encoding and/or consolidation of cue-intention pairings) and executive functions (e.g., decreased self-initiation, attention switching, and/or inhibition on memory tasks). Formal assessment of PM may help characterize the nature of the memory impairment among individuals with aMCI in clinical neuropsychological evaluations.

Frequency and predictors of self-reported prospective memory complaints in individuals infected with HIV

Failures of episodic retrospective memory (RetM) are among the most frequently reported cognitive complaints endorsed by individuals living with HIV infection. The present study sought to examine the nature, frequency, and determinants of self-reported complaints of prospective memory (ProM) in HIV, which is a singly dissociable and ecologically relevant aspect of episodic memory involving the execution of future intentions. Seventy-five HIV seropositive individuals and 60 seronegative volunteers were administered the Prospective and Retrospective Memory Questionnaire (PMRQ) as part of extensive neuropsychological, psychiatric, and medical research assessments. The HIV sample endorsed more frequent ProM complaints in daily life than the seronegative group, particularly on items requiring self-initiated cue detection and retrieval. Within both study groups, ProM complaints were significantly more frequent than RetM complaints. Although the HIV sample was impaired relative to the seronegative group on an objective, performance-based ProM test, self-reported ProM complaints did not correspond to actual ProM abilities. However, greater frequency of self-reported ProM complaints was moderately associated with increased fatigue, as well as with symptoms of anxiety and depression. Consistent with prior research on RetM in HIV, results indicate that affective distress contributes to a metamemory deficit for HIV-associated ProM impairment, which highlights the potential importance of assessing both self-reported and performance-based ProM in clinical and research neuroAIDS evaluations.

The Rise and Decline of Prospective Memory Performance across the Lifespan

In the present study, the trajectory of prospective memory across the lifespan was investigated in a total of 200 participants from five age groups (4- to 6-year-old children, 13- to 14-year-old adolescents, 19- to 26-year-old adults, 55- to 65-year-old adults, and 65- to 75-year-old adults). In an event-based prospective memory task the prospective and the retrospective components were assessed separately. For the prospective component, the results showed better performance for adolescents and young adults than for children and 65- to 75-year-old adults. In addition, participants belonging to the latter group were more likely to forget the retrospective component after having noticed the prospective memory targets. Overall, these results indicate that across the lifespan prospective memory performance follows a similar inverted u-shape function as is well known for retrospective episodic memory.

Early Experiences of Visual Memory Prosthesis for Supporting Episodic Memory

This article describes the use, experiences, and inferred design issues of an audio-visual content recorder that supports retrospective episodic memory (i.e., memory of personal events). In addition, some further user interface issues are discussed. The concept was explored by collecting mostly images and some audio over a period of more than a year (every now and then) using a body-worn camera and DAT-recorder. Special browser was built to be used in wearable and desktop computers. We also consider the use of thumbnail reductions of images. We empirically determined that image and audio data could help episodic memory to recall other facts related to the recorded episode. This kind of technology could be utilized in both personal and professional applications.

Failure of Prospective Memory after Acquired Brain Damage: Preliminary Investigation and Suggestions for Future Directions

This paper investigates the premise that the greater frequency of errors after acquired brain damage will facilitate identification of essential components of successful prospective memory. It examines performance by patients with recent acquired non-progressive brain damage and age-matched control subjects on two experimental measures of prospective memory. A significant different between patients and control subjects arises mainly from performance on a time-based prospective memory task. Results from patients on tests of time- and event-based prospective memory are compared with scores on tests of episodic memory and executive skills. A relationship is identified between event-based prospective memory and retrospective episodic memory but not between time-based prospective memory and executive skills. Premorbid intelligence and current mood state are identified as variables that should be considered when investigating prospective memory under experimental conditions.