Parietal cortical alpha/beta suppression during prospective memory retrieval.

Prospective memory (PM) impairment is among the most frequent memory complaints, yet little is known about the underlying neural mechanisms. PM for a planned intention may be achieved through strategic monitoring of the environment for cues, involving ongoing attentional processes, or through spontaneous retrieval. We hypothesized that parietal spectral power modulation accompanies prospectively encoded intention retrieval, irrespective of PM retrieval approach. A cognitively engaging arithmetic-based ongoing task (OGT) was employed to encourage spontaneous retrieval, with a focal, internally generated PM cue to eliminate OGT/PM trial differentiation based on perceptual or conceptual PM cue features. Two PM repetition frequencies were used to vary the extent of strategic monitoring. We observed a transient parietal alpha/beta spectral power reduction directly preceding the response, which was distinguishable on a single trial basis, as revealed by an OGT/PM trial classification rate exceeding 70% using linear discriminant analysis. The alpha/beta idling rhythm reflects cortical inhibition. A disengagement of task-relevant neural assemblies from this rhythm, reflected in alpha/beta power reduction, is deemed to increase information content, facilitate information integration, and enable engagement of neural assemblies in task-related cortical networks. The observed power reduction is consistent with the Dual Pathways model, where PM strategies converge at the PM retrieval stage.

Alterations in resting-state functional connectivity associated to the age-related decline in time-based prospective memory.

Time-based prospective memory (TBPM) is defined as the ability to remember to perform intended actions at a specific time in the future. TBPM is impaired in aging, and this decline has been associated with white-matter alterations within the superior fronto-occipital fasciculus. In the present study, we used resting-state functional magnetic resonance imaging from 22 healthy young (26 ± 5.2 years) and 23 older (63 ± 6.1 years) participants to investigate how age-related alterations in resting-state functional connectivity are related to TBPM performance, and whether these alterations are associated with the white-matter disruptions we have previously observed with diffusion tensor imaging. Whole-brain analyses revealed lower resting-state functional connectivity in older participants compared with younger ones, which in turn correlated with TBPM performance. These correlations were mainly located in the salience network and the parietal part of the frontoparietal network. Our findings suggest that resting-state functional connectivity alterations contribute to the age-related decline in TBPM.

"Do not take that medication": negative prospective memory in Korsakoff's syndrome.

BACKGROUND: While prospective memory (i.e., the ability to execute a future plan) has been extensively researched, little is known about negative prospective memory (i.e., the ability to remember not to execute a future plan) in Korsakoff's syndrome (KS). We thus evaluated both prospective memory and negative prospective memory in KS, as well as the relationship between both types of prospective memory and inhibition. METHODS: Patients with KS and control participants were invited to press a button on the keyboard (i.e., prospective memory) or not to press a button when a cue word (e.g., negative prospective memory) was encountered. RESULTS: The analysis demonstrated that patients with KS had more prospective memory errors (i.e., forgetting to click the keyboard when the instruction was to do so) than control participants. The analysis also demonstrated that patients with KS had more negative prospective memory errors (i.e., clicking the keyboard when the instruction was not to do so) than control participants. Similar levels of commissions and omissions were observed in patients with KS than in control participants. Interestingly, prospective and negative prospective performances were significantly correlated with performance on an inhibition assessment task. DISCUSSION: Our study demonstrates that KS is characterized by not only difficulty in remembering to execute a future intention but also by difficulty in remembering not to execute a future intention. A decline in negative prospective memory in KS can be associated with difficulty in inhibiting no longer appropriate previously learned intentions.

Prospective Memory Complaints Are Related to Objective Performance in People With Multiple Sclerosis.

OBJECTIVES: To examine the association between subjective and objective prospective memory (PM) in people with multiple sclerosis (PwMS). DESIGN: Secondary analysis of a cross-sectional cohort study. SETTING: Community-based comprehensive multiple sclerosis center. PARTICIPANTS: PwMS (N=112) who completed a battery that included measures of PM, depression, and fatigue. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Objective PM was measured with the performance-based Memory for Intentions Test (MIST), whereas subjective PM was assessed with the self-report Perceived Deficits Questionnaire-Prospective Memory (PDQ-PM). RESULTS: PwMS had low scores on the PDDS (median=2) and HADS-D (median=5.29), with 26.8% scoring 1 standard deviation or lower (≤15th percentile) on the MIST. Objective PM was significantly associated with subjective PM in a multivariate model (ß=-0.18, P=.036), which accounted for demographics, physical disability, retrospective memory, and depressive and fatigue severity. Physical disability, depression, and fatigue were also significant contributors to subjective PM. Time-based PM performance emerged as the specific component that was associated with subjective PM. CONCLUSIONS: These findings suggest that among PwMS with relatively mild impairment and symptomatology, their objective PM performance was associated with their self-assessments, even when considering retrospective memory and factors that influence their cognitive perceptions. The results expand upon the subjective-objective cognition discrepancy literature in multiple sclerosis and highlights how the PDQ-PM could be used as a complementary measure to help identify difficulties with PM.

Self-reported strategy use and prospective memory: The roles of cue focality and task importance.

Interest in the metacognitive aspects of prospective memory (PM) is growing. Yet, the interplay between participants' metacognitive awareness of PM task demands and features that contribute to successful PM require further attention. To this aim, participants in the current study completed laboratory-based PM tasks of varying difficulty (cue focality: focal, nonfocal-category, or nonfocal-syllable) and reported their strategy use and perceptions of PM task importance. Most participants reported using a strategy regardless of cue focality. However, only under the most challenging condition (i.e., nonfocal-syllable) did participants who reported using a strategy exhibit better PM performance compared to those who did not use a strategy. Additionally, strategy use and cue focality were independently associated with greater costs to ongoing task performance: strategy users exhibited greater slowing relative to individuals who did not use a strategy, and the extent of slowing was greater as the task difficulty increased across cue focality. Finally, perceived task importance appeared to play an important role in the interactive link between cue focality and strategy use on PM performance for the more challenging, nonfocal PM tasks. Specifically, moderation analyses suggested that greater perceived task importance alone may improve the likelihood of PM success for moderately challenging PM tasks (i.e., nonfocal-category), but for the most challenging PM tasks (i.e., nonfocal-syllable), individuals' strategy use was still associated with better PM performance. The present study expands our understanding of metacognition's role in PM performance and has implications for everyday PM performance.

Isolating the effects of visual imagery on prospective memory.

Two experiments investigated the role of visual imagery in prospective memory (PM). In experiment 1, 140 participants completed a general knowledge quiz which included a PM task of writing a letter "X" next to any questions that referred to space. Participants either visualised themselves performing this task, verbalised an implementation intention about the task, did both, or did neither. Performance on the PM task was enhanced in both conditions involving visual imagery but not by implementation intentions alone. In experiment 2, 120 participants imagined themselves writing a letter "X" next to questions about space, or in a bizarre imagery condition imagined themselves drawing an alien next to those questions. Relative to the control condition, PM was significantly enhanced when participants imagined writing a letter "X" next to the target questions, but not by the bizarre imagery task. The findings indicate that the robust effects of imagery observed in retrospective memory also extend to PM.

Effects of delay and reminders on time-based prospective memory in a naturalistic task.

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.

Rumination, but not mood, predicts prospective memory performance: novel insights from a derived measure of trait rumination.

Prospective memory (PM) is the accurate execution of an intention in the future. PM may be negatively impacted by negative affect, but the underlying mechanisms remain unclear. Rumination may increase the frequency of task-irrelevant thoughts, which deplete attentional capacity and reduce performance. To date, no studies have examined state and trait rumination on an online measure of PM. The present study examined the effects of state and trait rumination on an event-based, focal PM task embedded within a one-back task over multiple sessions. 95 non-depressed adults (18-53 years) completed measures of state/trait rumination, mood, and PM on at least two occasions. Using multi-level modelling, we found that a derived measure of trait rumination, but not an established trait rumination survey, nor negative mood, predicted poorer PM accuracy. These novel findings demonstrate that trait rumination may partially underlie the association between negative affect & PM in a non-clinical sample, and highlight the potential of online methods to study PM.

Activity-Based Prospective Memory in Insomniacs.

OBJECTIVE: To investigate the activity-based prospective memory performance in patients with insomnia, divided, on the basis of actigraphic evaluation, into sleep onset, maintenance, mixed and negative misperception insomnia. METHODS: A total of 153 patients with insomnia (I, 83 females, mean age + SD = 41.37 + 16.19 years) and 121 healthy controls (HC, 78 females, mean age + SD = 36.99 + 14.91 years) wore an actigraph for one week. Insomnia was classified into sleep onset insomnia (SOI), maintenance insomnia (MaI), mixed insomnia (MixI) and negative misperception insomnia (NMI). To study their activity-based prospective memory performance, all the participants were required to push the actigraph event marker button twice, at bedtime (task 1) and at get-up time (task 2). RESULTS: Only patients with maintenance and mixed insomnia had a significantly lower accuracy in the activity-based prospective memory task at get-up time compared with the healthy controls. CONCLUSION: The results show that maintenance and mixed insomnia involve an impaired activity-based prospective memory performance, while sleep onset and negative misperception insomnia do not seem to be affected. This pattern of results suggests that the fragmentation of sleep may play a role in activity-based prospective memory efficiency at wake-up in the morning.

The role of cue salience in prospective memory commission errors in nonperformed nonfocal tasks.

Prospective memory (PM) refers to the ability to remember to execute an intention in the future without having a permanent reminder. These intentions can be performed when they are not relevant or become no-longer needed, the so-called "commission errors". The present study aims to understand the effect of cue salience on PM commission errors with unperformed intentions and on the ongoing task performance-associated costs. Through a between-subjects design, eighty-one participants were assigned to 3 conditions: the no-PM condition, which served as control, and the salient and nonsalient conditions, which were asked to perform a lexical decision task and an incomplete nonfocal prospective memory task (i.e. no PM cues were presented). Subsequently, participants were instructed to no longer execute the prospective intention. In the second phase, a lexical decision task occurred again, including irrelevant PM cues, which should not be answered as such. In the salient condition, cues were salient (i.e. presented in red or blue background). In contrast, in the nonsalient condition, PM cues appeared on a black background, as any other stimuli. In the no-PM control condition, participants only performed an LDT. A commission error occurred when the (irrelevant) intention was performed in this second phase. Results showed that more participants performed a commission error in the presence of salient cues, even when PM intentions became irrelevant. Additionally, when cues were not salient, participants took longer to answer the LDT, as reasoned by the spontaneous retrieval theory. These findings are discussed according to the dual-mechanism account.

Time-Based and Event-Based Prospective Memory in Mild Cognitive Impairment and Alzheimer's Disease Patients: A Systematic Review and Meta-analysis.

Prospective memory (PM) is the ability to remember to perform planned actions in a future moment and it is of fundamental importance for an independent and autonomous lifestyle from development to late adulthood. Deficits in episodic memory and executive functions, which are involved in PM are characteristic features of mild cognitive impairment (MCI) and Alzheimer's disease (AD). Considering that the number of older adults is drastically increasing over the next decades, it is of great interest to understand how PM decline in healthy older adults and patients with different degree of cognitive decline. The present meta-analysis included 46 studies investigating PM performance in AD patients (17 studies) and people with MCI (24 studies); 5 studies included both clinical conditions in the same article. The 46 studies contributed a total of 63 independent samples and 129 effect sizes from 4668 participants (2115 patients and 2553 controls). Unlike previous reviews of the literature, our results with a larger and updated sample of studies confirmed lower PM abilities in AD compared to MCI and controls, although we did not observe conclusive differences between event-based and time-based PM in patients. Surprisingly, PM deficits shown by MCI and AD patients have decreased across years, in parallel to a reduction of the evidence of publication bias and an increase in the number of observations per task. We propose the use of more reliable research designs as one plausible explanation for the reduction of PM impairments.

Prospective Memory Training in Older Adults: A Systematic Review and Meta-Analysis.

Prospective memory (PM), which enables one to remember to carry out delayed intentions, is crucial for everyday functioning. PM commonly deteriorates upon cognitive decline in older adults, but several studies have shown that PM in older adults can be improved by training. The current study aimed to summarise this evidence by conducting a qualitative systematic analysis and quantitative meta-analysis of the effects of PM training in older adults, for which systematic searches were conducted across seven databases (Cochrane Library, Embase, PubMed, PsycInfo, Web of Science, CINAHL and Scopus). Forty-eight studies were included in the qualitative analysis, and 43% of the assessed PM training interventions showed positive gains in enhancing PM. However, the methodological quality varied across the studies, with 41% of the non-randomised control trials (non-RCTs) rated as having either serious or critical risk of bias. Therefore, only 29 RCTs were included in the subsequent quantitative meta-analysis. We found a significant and moderate immediate efficacy (Hedges' g = 0.54) of PM training in enhancing PM performance in older adults, but no significant long-term efficacy (Hedges' g = 0.20). Two subgroup analyses also revealed a robust training efficacy across the study population (i.e., healthy and clinical population) and the number of training sessions (i.e., single session and programme-based). Overall, this study provided positive evidence to support PM training in older adults. Further studies are warranted to explore the mechanisms by which PM training exerts its effects, and better-quality RCTs are needed to provide more robust evidence supporting our findings.

Episodic and prospective memory difficulties in 13-year-old children born very preterm.

OBJECTIVES: Children born very preterm (VP) are susceptible to a range of cognitive impairments, yet the effects of VP birth on long-term, episodic, and prospective memory remains unclear. This study examined episodic and prospective memory functioning in children born VP compared with their term-born counterparts at 13 years. METHOD: VP (n = 81: born <30 weeks' gestation) and term (n = 26) groups were aged between 12 and 14 years. Children completed: (i) standardized verbal and visuospatial episodic memory tests; and (ii) an experimental time- and event-based prospective memory test that included short-term (within assessment session) and long-term (up to 1-week post-session) tasks. Parents completed a questionnaire assessing memory functions in everyday life. RESULTS: The VP group performed worse on all measures of verbal and visuospatial episodic memory than the term group. While there were no group differences in event-based or long-term prospective memory, the VP group performed worse on time-based and short-term prospective memory tasks than term-born counterparts. Parents of children born VP reported more everyday memory difficulties than parents of children born at term, with parent-ratings indicating significantly elevated rates of everyday memory challenges in children born VP. CONCLUSIONS: Children born VP warrant long-term surveillance, as challenges associated with VP birth include memory difficulties at 13 years. This study highlights the need for greater research and clinical attention into childhood functional memory outcomes.

The effect of loss incentives on prospective memory in healthy older adults: study protocol of a randomized controlled trial using ultra-high field fMRI.

BACKGROUND: Prospective memory is important for our health and independence but declines with age. Hence, interventions to enhance prospective memory, for example by providing an incentive, may promote healthy ageing. The neuroanatomical correlates of prospective memory and the processing of incentive-related prospective memory changes in older adults are not fully understood. In an fMRI study, we will therefore test whether incentives improve prospective memory in older adults and how prospective memory is processed in the brain in general, and when incentives are provided. Since goals and interests change across adulthood, avoiding losses is becoming more important for older adults than achieving gains. We therefore posit that loss-related incentives will enhance prospective memory, which will be subserved by increased prefrontal and midbrain activity. METHODS: We will include n = 60 healthy older adults (60-75 years of age) in a randomized, single-blind, and parallel-group study. We will acquire 7T fMRI data in an incentive group and a control group (n = 30 each, stratified by education, age, and sex). Before and after fMRI, all participants will complete questionnaires and cognitive tests to assess possible confounders (e.g., income, personality traits, sensitivity to reward or punishment). DISCUSSION: The results of this study will clarify whether loss-related incentives can enhance prospective memory and how any enhancement is processed in the brain. In addition, we will determine how prospective memory is processed in the brain in general. The results of our study will be an important step towards a better understanding of how prospective memory changes when we get older and for developing interventions to counteract cognitive decline.

Daily Affect and Daily Prospective Memory in People after Stroke and Their Partners: The Moderating Role of Resting Heart Rate.

INTRODUCTION: Experimental research suggests that affect may influence prospective memory performance, but real-life evidence on affect-prospective memory associations is limited. Moreover, most studies have examined the valence dimension of affect in understanding the influence of affect on cognitive performance in daily life, with insufficient consideration of the arousal dimension. To maximize ecological validity, the current study examined the relationships between daily affect and daily prospective memory using repeated daily assessments and the role of resting heart rate on these relationships. We examined both valence and arousal of daily affect by categorizing affect into four dimensions: high-arousal positive affect, low-arousal positive affect, high-arousal negative affect, and low-arousal negative affect. METHOD: We examined existing data collected from community-dwelling couples, of which at least one partner had a stroke history. The analytic sample included 111 adults (Mage = 67.46 years, SD = 9.64; 50% women) who provided 1,274 days of data. Among the participants, 58 were living with the effects of a stroke and 53 were partners. Participants completed daily event-based prospective memory tasks (in morning and/or evening questionnaires), reported daily affect in the evening, and wore a wrist-based Fitbit device to monitor resting heart rate over 14 consecutive days. RESULTS: Results from multilevel models show that, within persons, elevated high-arousal negative affect was associated with worse daily prospective memory performance. In addition, lower resting heart rate attenuated the inverse association between high-arousal negative affect and lowered prospective memory performance. We did not find significant associations of high- or low-arousal positive affect and low-arousal negative affect with daily prospective memory. DISCUSSION: Our findings are in line with the resource allocation model and the cue-utilization hypothesis in that high-arousal negative affect is detrimental to daily prospective memory performance. Lower resting heart rate may buffer individuals' prospective memory performance from the influence of high-arousal negative affect. These findings are consistent with the neurovisceral integration model on heart-brain connections, highlighting the possibility that cardiovascular fitness may help maintain prospective memory into older adulthood.

I forgot that I forgot: PTSD symptom severity in a general population correlates with everyday diary-recorded prospective memory failures.

Extant research suggests a complex relationship between prospective memory (PM) and post-traumatic stress disorder (PTSD) symptom severity. In a general population, this relationship exists for self-report assessment but not objective, in-lab PM performance (e.g., pressing a certain key at a particular time, or when particular words appear). However, both these measurement methods have limitations. Objective, in-lab PM tasks might not represent typical everyday performance, while self-report measurement might be biased by metacognitive beliefs. Thus, we used a naturalistic diary paradigm to answer the overarching question: are PTSD symptoms associated with PM failures in everyday life? We found a small positive correlation between diary-recorded PM errors and PTSD symptom severity (r = .21). Time-based tasks (i.e., intentions completed at a particular time, or after a specified time has elapsed; r = .29), but not event-based tasks (i.e., intentions completed in response to an environmental cue; r = .08), correlated with PTSD symptoms. Moreover, although diary-recorded and self-report PM correlated, we did not replicate the finding that metacognitive beliefs underpin the PM-PTSD relationship. These results suggest that metacognitive beliefs might be particularly important for self-report PM only.

Prospective memories in the wild: Predicting memory for intentions in natural environments.

Prospective memory, the ability to remember an intention at the appropriate future moment, is often investigated in the laboratory to maximize experimental control. However, demands of laboratory prospective memory tasks only partly map onto everyday demands. Therefore, it is an open question whether factors which predict prospective memory in the laboratory also predict prospective memory in the real world. We combined diary and ecological momentary assessment methods to investigate which factors, that have been repeatedly shown to predict prospective memory performance in laboratory tasks, are related to the fulfillment of everyday intentions. Results showed that substantial portions of variance in real-world prospective memory performance could be explained with the factors found to be significant in laboratory. The most powerful predictors were perceived intention importance, the use of external memory aids, delay interval, and conscientiousness. However, some meaningful laboratory predictors (e.g., working memory) played only a minor role in natural environments and a large portion of the variance in everyday intention fulfillment remained unexplained. The results substantially extend the understanding of conditions and personality variables most conducive to remembering intentions, but they also suggest that additional factors influencing real-world prospective memory remain to be discovered.

A thorough examination of cue specificity and task-appropriateness in defining focal and nonfocal prospective memory tasks.

Prospective memory (PM) - memory for future intentions - has a core term called focality which describes how closely a PM task relates to an ongoing task. When a close relationship exists between an ongoing and PM task, the task is classified as focal (loose relationships are classified as nonfocal). Competing PM theories differ primarily in explanations for how focality changes participants' approaches. Researchers classify PM intentions as focal or nonfocal in two ways: (1) task appropriateness, congruency (TAP) or incongruency (TIP) of processing to complete both tasks, and (2) cue specificity, specific or general task cues. Independently manipulating this ambiguity in defining "focality" was our current focus. Participants were randomly assigned to a control group, a focal PM condition, or one of three nonfocal conditions. Their ongoing task involved a semantic judgment (Experiment 1) or an orthographic judgment (Experiment 2). Cue specificity impacted PM accuracy consistently, favouring specific cues. Task-appropriateness impacted PM accuracy in Experiment 1, but not in Experiment 2 which showed protective effects for specific, whole-word PM cues - emphasizing the role that deeper processing has on PM success. These studies highlight the ambiguity in the operational definition of focality and provide the groundwork for continued refinement of the definition.

Associations between intraindividual reaction time variability and prospective memory performance in patients with schizophrenia and healthy controls.

Introduction: Patients with schizophrenia exhibit prospective memory (PM) impairment. Intraindividual reaction time variability (IIRTV) is an index of attentional control that is required for PM. This study examined the differences in IIRTV between patients with schizophrenia and healthy controls and the relationship between IIRTV and PM performance.Method: Thirty-nine patients with schizophrenia and forty-two healthy controls were recruited to complete a PM task and the Sustained Attention to Response Task. IIRTV was calculated as the coefficient of variation (mean/SD) of reaction time over correctly responded trials in these tasks.Results: Patients with schizophrenia showed lower PM accuracy and increased IIRTV, while the associations between PM accuracy and IIRTV were significant in healthy controls but not in patients with schizophrenia.Conclusion: These findings suggest impaired PM and relationship between PM and attentional control in patients with schizophrenia.

Prospective Memory, Sustained Attention and Response Inhibition in Poly-Substance Users Stable on Methadone Maintenance Treatment.

Background: Prospective memory and response inhibition are interrelated constructs, though studied separately in the drug addiction literature. Also, although sustained attention underlies response inhibition, its role in the relation between these functions has been largely neglected. The limited research on the cognitive effects of methadone-maintenance treatment (MMT) further stresses the importance of investigating these effects. Objective: Therefore, the current study focused on possible effects of MMT combined with long-term drug abuse on all these functions. Thirty five long term opiate/poly-substance users in MMT and thirty four drug-free controls were screened for socioeconomic status, anxiety, depression and general, non-verbal intelligence and then tested on a self-report measure of prospective memory and on the Go/No-Go task. Results: Compared to controls, the MMT group scored worse in all functions assessed. Prospective memory scores were also negatively related to Go/NoGo accuracy scores. Conclusion: As predicted, (a) the MMT participants show impairments in prospective memory, sustained attention and response inhibition and (b) prospective memory, response inhibition and sustained attention are related constructs. The results of this study could inform current rehabilitation and relapse prevention cognitive training practices.