Emotional prospective memory in traumatic brain injury: task characteristics matter

Whilst the deleterious effects of alcohol on retrospective remembering have been widely documented, no study has yet objectively determined alcohol's effects on prospective memory (PM)--remembering to do something in the future. With this aim, the present study determined the acute effects of alcohol upon PM using a laboratory measure that simulates the PM tasks in everyday life--'Virtual Week'--both (a) in its standard form with regular, irregular, event-based and time-based PM tasks; and (b) an adapted version which enabled exploration of how future event simulation at encoding impacted upon subsequent PM. Forty healthy volunteers were administered 0.6 g/kg ethanol or a matched placebo in a double-blind fashion and completed the two versions of Virtual Week along with prose recall (to tap retrospective memory) and an executive function task. Alcohol acutely produced global impairments across all (regular, irregular, event-based and time-based) PM tasks. It also produced impairments of episodic memory which positively correlated with PM performance of irregular tasks. Future-event simulation tended to enhance PM in the placebo but not in the alcohol group. These findings on an objective measure of PM suggest that 4-5 units of alcohol will compromise PM abilities in everyday life.

The overall aim of the current thesis was to explore three key components of future-oriented thinking, namely episodic future thinking (EFT), episodic foresight, and prospective memory (PM), in middle childhood. The developmental literature examining each of these future-oriented abilities has generally focused on their emergence in the preschool years, with less known about how these abilities present in middle childhood. In addition, research investigating what cognitive mechanisms may drive these abilities in this age band is limited and findings of those studies that have been conducted are inconsistent. Lastly, the literature has predominantly examined EFT, episodic foresight, and PM in isolation, and research has only just begun to explore interrelations between these future-oriented constructs. The first empirical study therefore aimed to investigate whether EFT ability was associated with age and to examine what cognitive mechanisms may contribute to this skill. The second empirical study aimed to examine, for the first time, whether episodic foresight was associated with age across middle childhood. A second aim of this study was to provide the first investigation of the cognitive mechanisms that may contribute to episodic foresight in this age group, with the particular interest in whether EFT contributed to episodic foresight. The final empirical study aimed to explore whether age was associated with children’s PM performance across event-based and time-based PM tasks. An additional aim of this study was to explore the cognitive abilities that contribute to children’s performance on both event-based and time-based PM tasks, with a particular interest in the contribution of EFT. A single sample of 80 children aged 8 to 12 years were recruited for this research project. Study 1 indicated greater EFT ability was associated with age, consistent with some of the limited studies previously conducted with this age group. Study 1 also demonstrated strong evidence regarding the contribution from episodic memory to children’s EFT and a lack of contribution from executive functions. Study 2 was the first study to examine episodic foresight beyond the preschool years. Results of this study provided the first evidence of an association between age and better episodic foresight performance across the ages of 8 to 12 years. In addition, Study 2 identified age and IQ as significant contributors to successful episodic foresight performance, while retrospective memory, executive functions, and EFT were not found to contribute. The lack of contribution from EFT may have been due to the specific form of episodic foresight task used in this study, which did not require a specific scenario to be envisaged. Further research is now required to investigate whether EFT contributes to other types of episodic foresight task that involve clear scenarios that can be envisaged. The results of Study 3 indicated age was significantly correlated with performance on both event-based and time-based PM tasks. The findings also clearly revealed age, retrospective memory, and EFT were significant contributors to event-based PM performance, while retrospective memory was the only significant contributor to time-based PM performance. Furthermore, the results clearly demonstrated a lack of contribution from executive functions to performance on both task types. Importantly, Study 3 demonstrated that EFT selectively contributed to children’s event-based PM performance. This finding is consistent with the only other study in this age band and used a more comprehensive set of predictors than this previous study. The current research provided novel insights into the profile of children’s future-oriented thinking across the middle childhood period. The findings regarding age-related improvements in EFT, episodic foresight, and PM help to bridge the gap in understanding of the development of these abilities between their emergence in the preschool years and their presentation later in development. Longitudinal research that extends from early childhood to adulthood is now needed to provide a thorough understanding of the developmental trajectory of these abilities across the lifespan. In addition, the current research revealed a clear pattern of results regarding the cognitive mechanisms that contribute to each of these abilities, providing some clarity to the previously mixed findings in the children’s future oriented-thinking literature. Results regarding the inter-relationships between the future-oriented constructs also provided an important extension to current understanding of future-oriented thinking as a broader taxonomy. Furthermore, the current findings bring attention to the need for further theoretical distinction between different forms of episodic foresight and the cognitive processes that contribute to this skill. Overall, the findings from the current thesis have important implications for children’s daily living. In particular, greater understanding of future-oriented thinking in the middle childhood period gained from this thesis may assist in fostering the development of these abilities early in life. This in turn will enable parents and teachers to create reasonable expectations regarding children’s capacity to use these skills in their everyday functioning, thereby maximising success and minimising failure.

Frontal lobe involvement in a task of time-based prospective memory

The current study examined the effect of a delay on naturalistic time-based prospective memory (PM) tasks. Two experiments were performed to compare PM performance on a texting task with delays of 1 to 6 days after an initial session. In the first experiment, half of the participants were asked to repeat their response with the same delay to test whether requiring a second response (i.e., a repeated PM task, such as taking medication at the same time each day) would affect time-based PM performance. In the second experiment, participants were given an implicit or an explicit reminder several hours before their time to respond to examine the effect of type of reminder on this PM task. The results of both experiments showed a significant decline in PM performance between the 1-day and multi-day delays. Repeating responses (Experiment 1) had no effect on accuracy of the PM task, but in Experiment 2, explicit experimenter-initiated reminders significantly increased time-based PM performance compared with implicit reminders. These results are discussed in the context of previous studies that have tested delay effects on time-based PM and current theoretical descriptions of time-based PM.

ABSTRACTWe examined prospective memory (PM) function in children with attention deficit hyperactivity disorder (ADHD). A group of 28 children with ADHD and 28 typically developing children completed event-, time- and activity-based PM tasks and attention tests. ADHD children had impaired attention but intact PM performance. Both groups performed best in activity-based PM tasks, followed by event-based PM tasks, and performed worst in time-based PM tasks. ADHD children had lower ongoing task performance in the event-based PM task. The findings indicate that children with ADHD may have an intact PM, but this may be at the cost of ongoing task performance.

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.

This study investigates prospective memory (PM) deficits as well as the interplay between performance in executive functions (EFs), speed of processing, episodic memory and PM in traumatic brain injury (TBI), differentiating between time based and event based tasks. The Memory for Intentions Screening Test was administrated to a sample of 19 participants with TBI and 50 healthy controls. Tasks probing different EFs (i.e., shifting, updating/working memory, inhibition, and access to long term memory), speed of processing, and episodic memory were also administrated to the TBI group. PM deficits were found in participants with TBI compared to controls. In the role of EFs in PM, only tasks probing updating/working memory and access to the long-term memory showed to play a specific role in PM performance in TBI. However, while updating/working memory was related to both time and event based PM, access to the long term memory was associated to performance on time based PM task only. Speed of processing and retrospective memory abilities do not seem to play a specific role in PM deficit in TBI. Our results provide a better understanding of the PM deficit in TBI, which may contribute to improve existing rehabilitation programs for individuals with TBI.

The aim of the present study was to deepen knowledge about the effect of a lowered vigilance state on time-based prospective memory (TBPM) performance. For this purpose 2 TBPM tasks (primary and interpolated), which shared a portion of the retention interval, and 3 reasoning tasks, as ongoing activities, were administered after total sleep deprivation and in a regular sleep condition. The results showed a detrimental effect of sleep deprivation on prospective memory performance and a partial dissociation between clock-checking behavior and time estimation for prospective compliance. This study clearly indicates that total sleep deprivation im- pairs the ability to complete multiple prospective task assignments in a timely fashion. Results are discussed suggesting the existence of different mechanisms involved in time monitoring and other cognitive functions underlying TBPM performance.

Enhancing cue salience improves aspects of naturalistic time-based prospective memory in older adults with HIV disease.

Prospective Memory (PM) refers to remembering an intention to be acted upon in the future. Such a memory may be triggered by an event (i.e., Event-based PM) where a specific cue reminds one of the previously encoded intention. PM can be assessed in a lab-setting by having subjects learn a baseline task, subsequently receiving a PM instruction, completing a distractor task, and then going through a test phase where the PM task (i.e., responding to PM cues) is embedded within the ongoing task. The multiprocess view (McDaniel & Einstein, 2000) posits that PM can be retrieved primarily using two different strategies: one can strategically monitor for the PM cue to keep the intention in mind or spontaneously retrieve the intention by coming across the cue. The multiprocess view suggests that monitoring or spontaneous retrieval strategies are chosen based on whether one’s current task is focal or non-focal to the nature of the PM task. When processing of the ongoing task stimuli and PM stimuli overlap (i.e., focal), spontaneous retrieval of the encoded intention is thought to occur more often. On the other hand, when processing of the PM stimuli is peripheral (i.e., non-focal) to the ongoing task, one may have to consistently monitor for the PM cue for successful task performance. Manipulation of PM task focality has shown a PM performance advantage in focal conditions (Einstein & McDaniel, 2005), confirming the focality effect posited by the Multiprocess view. Past studies (e.g., Schnitzspahn, Stahl, Zeintl, Kaller, & Kliegel, 2013) have suggested that some aspects of executive function (EF) are involved in non-focal PM performance. However, according to the multiprocess view, spontaneous retrieval of the PM cue can occur when the ongoing task is focal to the PM task. Because subjects may not need to appropriate as many cognitive resources toward the PM task, EF might be unrelated to PM performance in focal tasks. The current study tested this idea by examining a sample of college-aged subjects on two event-based PM (category and syllable judgments) and two EF (inhibition and task-switching) tasks. Subjects were assigned to focal or non-focal conditions for the PM tasks. The prediction of a focal condition advantage was found for PM performance measures, particularly in the syllables task. No relationships were found between PM performance and EF measures for the focal condition, as predicted. However, most of the predicted relationships between PM performance and EF measures for the

Prospective memory (PM) refers to remembering to perform a previously planned action at the appropriate time or in the appropriate context. The present study investigated the effects of individual differences in age and trait anxiety on PM performance in 3–5- and 5–7-year-olds. Two types of PM measures were used: an event-based task, requiring ongoing activity interruption across two conditions (with/without memory aid), and an activity-based task, requiring PM action implementation after the main activity was finalized. On the event-based PM task, we found that: all children benefited from the external memory aid; the 5–7-year-old group outperformed the 3–5-year-olds; and higher levels of anxiety negatively affected only the younger age group. On the activity-based PM task, we found no significant age-group differences, while higher anxiety negatively predicted children’s PM performance. Findings support and extend the literature on early PM development, revealing the benefits of external cueing and the potential detrimental effects of anxiety.

Prospective memory (PM) is defined as remembering to remember or remembering to perform an intended action, which requires to form and later realize intentions that must be delayed for minutes, hours, or days, such as remembering to take medication with a meal, or to turn off the stove after cooking. Prospective memory is important in our everyday life, especially to those old people with declined (i.e., less efficient) cognitive functions. Better prospective memory performance can help old people maintain their independent lives and improve their quality of life. So the present study focused on the age difference in an event-based prospective memory task. Regarding the internal mechanism of age differences in PM, two contradictive perspectives were proposed: the age deficits exist in prospective component VS in retrospective component. Noticing-search model (Einstein McDaniel, 1996) suggested that the PM deficit in old people came from the searching process. On the other hand, Smith and Bayen (2006) applied a formal multinomial processing tree model of PM and indicated that the deficit existed in the process of recognizing target cues, which was resource-demanding. The present study evaluated the two perspectives and further investigated the related cognitive mechanism using a classic paradigm where the prospective memory task was embedded in a semantic categorization task. 60 young (29 females) and 60 old adults (26 females) participated experiment 1 voluntarily. The experiment compared the effect of age on the prospective component and the retrospective component of PM, manipulating semantic relatedness between cue and intention, and the distinctiveness of the cue. Young adults performed better than old adults in both the prospective component and retrospective component, but the effect size of age was larger in prospective component. When the relatedness was high or the cue was distinctive, old adults performed as well as young adults, however, it showed age deficits when the relatedness was low or the cue was indistinguishable.These findings suggest that both data-driven and conceptually driven processes can improve old people's memory for intentions greatly.Another 68 young (37 females) and 68 old adults (46 females) participated in Experiment 2. The experiment examined the effect of prospective component on the age difference in prospective memory by reducing the demand of retrospective component and manipulating the cognitive resources of prospective memory. Main effect of age, the distractive level of divided attention and the distinctiveness of the target cue were all found in the accuracy of prospective memory. Both the response time of ongoing and PM tasks had a significant decline in the older adults compared to the young ones. Significant age deficits were found when the target was indistinguishable. And the high distractive level task made old adults’ performance even worse. To be summarized, the aging of PM is modulated both by data-driven and conceptually driven processes. Compared to retrospective component, the age effect in PM is greater on the prospective component. The cognitive load in the task influences the age effect in PM since the prospective component is resource-demanding. The age effect is more obvious when the PM task needs more strategic control than automatically processed. These results further reveal the cause of the reasons for age differences in prospective memory.

ObjectivePatients with Korsakoff’s syndrome (KS) have difficulty carrying out tasks which rely on prospective memory (PM). Since remembering to carry out an action in the future is crucial for living independently, it is of primary interest to develop strategies that improve PM performance in KS patients.DesignThe study employed a computer categorization task as an ongoing activity into which a PM task was embedded. We included episodic future thinking (EFT) and observational learning (Experiment 2) to boost PM.MethodsExperiment 1 evaluated the efficacy of EFT following written PM task instructions in ten KS patients. Due to floor‐level PM performance in Experiment 1, Experiment 2 included an instructional video demonstrating the PM intention. In Experiment 2, twenty‐six KS patients performed both conditions (EFT and no‐EFT) at least 1 week apart, while twelve controls with alcohol use disorder without KS performed the no‐EFT condition. In Experiment 2, the PM instructions were also shown through video (observational learning component). Mild cognitive impairment was assessed in a short test battery.ResultsExperiment 1 showed overall floor performance in both conditions. Experiment 2 showed that KS patients performed PM tasks less accurately than the control group in the no‐EFT condition. In Experiment 2, where the observational learning component was included, EFT improved PM performance in KS patients. This effect was driven by a sub‐group of high‐functioning KS patients.ConclusionsThis study showed the value of an observational learning component together with EFT in improving PM performance, in relatively high‐functioning KS patients.Practitioner points KS patients performed the PM task less accurately than non‐KS controls with alcohol use disorder, confirming PM impairment in this patient population.Controls with alcohol use disorder performed the PM task at ceiling level.Showing an instructional video demonstrating the PM intention improved PM performance and later recall of PM task instructions in KS patients.Episodic future thinking strategy improved PM performance in KS patients with relatively intact cognitive functioning.

Time-based prospective memory in children and adolescents with traumatic brain injury: Impact of working memory demands.

Prospective memory (PM) impairment in recreational drug users has been documented in recent years. However, most studies on the effects of drugs on PM contain several methodological challenges, such as small sample size (< 100 participants), unrepresentative sample type (e.g., student or patient), short abstinence period (< 7days), and lack of control of potential confounds (e.g., sleep and IQ). The present study investigated the possible consequences of recreational drug use on prospective memory, using self-report and lab-based prospective memory measures while overcoming the methodological challenges. The sample was composed of 47 non-users (27 females, age range from 18 to 50 +) and 53 drug users (21 females, age range from 18 to 50 +). Recreational drug users reported significantly more deficits in the long-term episodic, short-term habitual, and internally cued PM failures subscales of the Prospective Memory Questionnaire. However, these deficits were eliminated after controlling for covariates (e.g., age, sleep quality, general health, alcohol usage). Recreational drug users also performed worse than non-users in the short-term, long-term, event-based, and time-based PM subscales of the Royal Prince Alfred Prospective Memory Test. These results remained significant after controlling for the covariates. Drug users demonstrated greater impairments on time-based and long-term PM tasks thought to be linked with executive functioning. Taken together, the present study provides further support for recreational drug-related deficits in PM and highlights a dissociation between self-report and lab-based PM measures.