A differential deficit in time- versus event-based prospective memory in Parkinson's disease

Naturalistic assessment of everyday multitasking in Parkinson's disease with and without mild cognitive impairment

Objective: Multitasking is an essential part of everyday functioning often not formally assessed by traditional neuropsychological tests. Although individuals with Parkinson's disease (PD) experience both motor and cognitive difficulties, previous research has demonstrated more pronounced functional difficulties with the presence of mild cognitive impairment (PD-MCI). The current study compared individuals with PD-MCI, PD with normal cognition (PD-NC), and healthy controls on a naturalistic task of multitasking, the Day Out Task (DOT). Method: Participants were 38 healthy older adults (HOA), 23 individuals with PD-NC, and 15 individuals with PD-MCI. Participants completed a battery of neuropsychological tasks and the DOT. Informants also completed a self-reported questionnaire of participants' everyday executive functioning. Results: Compared to PD-NC and HOA, participants with PD-MCI were less accurate and efficient and took longer to complete the DOT. After controlling for motor performance, only DOT accuracy remained worse, with poorer accuracy resulted from more subtasks being left incomplete or being completed inaccurately by the PD-MCI group. DOT sequencing was a significant predictor of informant reported everyday dysexecutive symptoms. Conclusions: The findings highlight that individuals with PD-MCI are likely to experience difficulties completing complex everyday tasks due to both motor and cognitive impairments. Clinicians may therefore recommend strategies to support efficiency and accuracy in complex tasks of everyday functioning in treatment considerations.

Inhibition mediates the relationship between age cohort and virtual reality-based prospective memory

INTRODUCTION

Prospective memory has received relatively little attention from a clinical perspective, yet it is an important part of daily functioning. Executive functions have been linked with prospective memory abilities, and age differences are found in both executive functions and prospective memory. The purpose of this study was to investigate whether age cohort differences in prospective memory abilities are mediated by executive functions, specifically inhibition.

METHOD

Participants (N = 108) consisted of young adults (n= 53) and older adults (n= 55) without any neurocognitive impairment. Participants completed a clinical interview and a battery of neuropsychological tests that included the Mini-Mental Status Exam-2 Standard Version (MMSE-2-SV), the Wisconsin Card Sorting Test-64 (WCST-64), the Delis-Kaplan Executive Functioning System Color-Word Interference Test (D-KEFS CWIT), and the Virtual Kitchen Protocol (VKP).

RESULTS

Young adults had higher prospective memory scores than older adults. Inhibition (i.e., D-KEFS CWIT) mediated the relationship between age cohort and prospective memory, while cognitive flexibility did not mediate the relationship.

CONCLUSIONS

Older adults may have diminished inhibition abilities that may negatively affect their ability to complete prospective memory tasks.

Poorer prospective memory performance is associated with reduced time monitoring among OEF/OIF/OND Veterans with a history of blast-related mild traumatic brain injury

Objective:Prospective memory (PM) or "remembering to remember" has been shown to be reduced in Veterans with histories of mild traumatic brain injury (mTBI), particularly on tasks with high strategic demands such as recalling time-based information in the absence of external cues. This study examined whether time monitoring during a PM task was reduced in Veterans with a history of mTBI and was associated with time-based PM performance. Method:Veterans with a history of mTBI (n = 49) and Veterans without a history of TBI (n = 16) completed the Memory for Intentions Screening Test (MIST) as a measure of PM during which their time monitoring (i.e. number of clock checks) was recorded. Results:Adjusting for age, education, depression, and PTSD symptoms, negative binomial regression revealed that the mTBI group checked the clock less frequently compared to the control group (Cohen's d = 0.84, p = 0.005). Within the mTBI group, less frequent time monitoring across the entire MIST task was associated with poorer time-based MIST performance (r_s = .57, p < 0.001), but not with event-based MIST (r_s = .04, p = 0.768). Conclusions:Veterans with a history of mTBI evidenced significantly reduced time monitoring during a PM task compared to Veterans without a history mTBI, which was associated with strategically-demanding PM. Current findings provide that mTBI-associated difficulties with strategic aspects of PM may be due to reduced time monitoring. Future studies are needed to determine if reduced time monitoring also contributes to mTBI-associated PM difficulties in the real-world (e.g. medication non-adherence).

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 memory in adults with down syndrome

Prospective memory (PM) refers to the ability to remember one's intentions (what I must do), at the appropriate time, in the future (when I must do it). The objective of this work is to study the performance of people with Down syndrome (DS) compared to two control groups, matched by mental age and chronological age. For this purpose, an adapted version of the virtual week, which is an ecological test to simulate the functioning of PM in everyday life, was used. The results suggest that people with DS have difficulties in PM that mainly concern the binding (association) between prospective (when to do) and retrospective (what to do) components. Moreover, people with DS perform better in PM when the task is repeated and time-based. These results are discussed in light of studies conducted with other populations.

Factor Structure of the Memory for Intentions Test (MIsT): A Conceptual Replication in Older Adults and People with HIV Disease

OBJECTIVE

The Memory for Intentions Test (MIsT) is a clinical measure of prospective memory that has strong evidence for convergent, discriminative, and ecological validity. This study uses a conceptual replication design to evaluate the latent structure of the MIsT in two parallel samples who commonly experience prospective memory deficits: older adults and people living with HIV disease.

PARTICIPANTS AND METHODS

Study participants included 303 people with HIV disease (ages 18-67) and 267 community-dwelling older adults (ages 50-91). Confirmatory factor analyses of the MIsT were conducted separately in each sample. We evaluated a one-factor model, as well as three two-factor models with the MIsT items loading onto each factor based on cue type, delay interval, or response modality.

RESULTS

The one-factor model provided the best (and most parsimonious) fit to the data in both study samples. All two-factor models also demonstrated good fit statistics, although correlations between the two factors in each model were high and none of the two-factor models provided a significantly better fit than the one-factor model.

CONCLUSIONS

Results of this conceptual replication study provide support for a robust factor structure of the MIsT across older adults and people with HIV disease. A total score for the MIsT provides the most parsimonious solution, although available evidence and theory also support the potential use of subscales (e.g., cue type). Future studies of the MIsT would be useful to determine its psychometrics in different clinical populations and across demographic factors (e.g., race/ethnicity).

The Chinese version of the Memory for Intentions Test (MIST): development and evaluation of its reliability and concurrent validity

This study aims to develop a simplified Chinese version of the "Memory for Intentions Test" (MIST), evaluate its reliability and concurrent validity, explore the inter-relationships among the MIST variables and the relationships between the MIST variables and socio-demographic factors.

Two hundred healthy, Chinese-speaking adults of the Han community participated in this study. Form A of the Chinese MIST and two prospective items of the Rivermead Behavioural Memory Test, Second Edition (RBMT-II, Chinese version) were administered to all participants to evaluate internal consistency, split-half reliability, and concurrent validity. Twenty of these participants were assessed twice on Form A with a two-week interval to examine test-retest reliability. They were also assessed on both Form A and Form B to examine alternate-form reliability.

The findings of the study indicated good internal consistency (Cronbach's α = .833) and excellent split-half reliability (r = .924-.930) among the six subscales of the Chinese MIST, although the internal consistency was low (Cronbach's α = .129) for individual PM trials. We also found adequate concurrent validity (ρ = .722, p< .001), test-retest reliability (ρ = .716, p < .001), and alternate-form reliability (ρ= .828, p < .001).

The Chinese MIST demonstrated suitable reliability and concurrent validity in the Chinese-speaking population. The present study provides a new standardized prospective memory test for the Chinese population, which would enhance future clinical research in this field on the Chinese mainland.

Recreational drug use and prospective memory

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 (< 7 days), 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.

Longitudinal declines in event-based, but not time-based, prospective memory among community-dwelling older adults

Age-related deficits in prospective memory (PM) are well established, but it is not known whether PM is stable over time among older adults. In this study, 271 community-dwelling older adults underwent abaseline neuropsychological evaluation and up to three follow-up visits, approximately 2.4 years apart. Mixed effects linear longitudinal models revealed small, but significant linear declines and between-subjects variability in event-based PM performance. There were no changes in performance on measures of time-based PM, retrospective memory, or executive functions. Changes in event-based PM were not associated with age, retrospective memory, executive functions, or everyday functioning. Among older adults, event-based PM appears to be more susceptible to linear declines than does time-based PM, which future research might examine with regard to the possible underlying cognitive mechanisms of cue encoding, monitoring, detection, and retrieval processes.

Branching Condition of the Color-Word Interference Test Enhances Prediction of Meta-Tasking in Community-Dwelling Older Adults

OBJECTIVES

Meta-tasking (MT) is an aspect of executive functioning (EF) that involves the ability to branch (i.e., to apply "if-then" rules) and to effectively interleave sub-goals of one task with sub-goals of another task. As such, MT is crucial for successful planning, coordination, and execution of multiple complex tasks in daily life. Traditional tests of EF fail to adequately measure MT. This study examined whether Condition 4 of the Color-Word Interference Test (CWIT-4; the inhibition/switching condition that requires branching) predicted MT beyond Condition 3 (CWIT-3; inhibition-only condition) and beyond other subtests from the Delis-Kaplan Executive Function System (D-KEFS) that have a switching condition.

METHOD

Ninety-eight non-Hispanic white community-dwelling older adults completed the first four subtests of the D-KEFS and an ecologically valid measure of MT.

RESULTS

Time to completion and total errors on CWIT-4 accounted for variance in MT above and beyond CWIT-3 and beyond the switching conditions of other D-KEFS subtests. Results remained virtually unchanged when controlling for demographics and general cognitive status.

CONCLUSIONS

Among older adults, CWIT-4 is more strongly associated with MT than other D-KFES tasks. Future research should examine whether CWIT-4 relates to lapses in instrumental activities of daily living among older adults above and beyond other EF tests.

Online pharmacy navigation skills are associated with prospective memory in HIV disease

OBJECTIVE

The increased use of online pharmacy services in the midst of the COVID-19 pandemic provides an important backdrop against which to examine the role of neurocognitive functions in health-related Internet navigation skills among persons with chronic medical conditions, such as HIV disease. Prospective memory (PM) is reliably impaired in HIV disease and is related to laboratory-based measures of medication management capacity in other populations. This study examined whether PM shows veridicality in relationship to online pharmacy navigation skills in persons with HIV disease.

METHOD

Participants included 98 persons with HIV disease age 50 and older who completed the Cambridge Prospective Memory Test (CAMPROMPT) and the Medication-Management Test-Revised (MMT-R) as part of a neuropsychological study. Participants also completed the Test of Online Pharmacy Skills (TOPS), which required them to navigate a simulated, experimenter-controlled online pharmacy to perform several naturalistic tasks (e.g., refill an existing prescription).

RESULTS

Lower PM had medium associations with poorer MMT-R and TOPS accuracy scores that were not better explained by other neurocognitive functions. The association between PM and TOPS accuracy was driven by errors of omission and did not vary meaningfully based on whether the intention was cued by time or an event.

CONCLUSIONS

These data suggest that PM cue detection processes show veridicality with online pharmacy navigation skills. Future studies might examine the benefits of PM-based strategies (e.g., salient prompts) in supporting online health navigation skills in populations that experience clinically impactful PM failures.

An exploration of prospective memory components and subtasks of the Memory for Intentions Test (MIST)

Introduction: Prospective Memory (PM), the ability to execute future intentions, decreases with age and memory-related disorders and may be an early predictor of dementia. The Memory for Intentions Test (MIST) allows the assessment of multiple aspects of PM using a range of subtasks. The current study evaluated and explored a Portuguese version of the MIST and its subtasks.Method: Forty-one patients with Mild Cognitive Impairment (MCI) and forty healthy participants performed the MIST, neuropsychological tests and questionnaires. Analyses were performed testing relationships between MCI and PM components of the MIST, and differences between subtasks of the test were explored.Results: Reliability of the PM component was acceptable within the patient group, but not within the control group. PM components were significantly lower in the MCI patients, but this effect was dependent on subtasks. Groups differed most strongly at shorter intervals. PM scores predicted MCI status. Correlations were found between PM components and cognitive functioning scales.Conclusions: The Portuguese version of the MIST seems suitable for use in clinical practice and research. MCI is differentially related to different PM components and subtasks of the MIST.

A meta-analytic review of prospection deficits in Parkinson's disease

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, and is associated with prominent motor deficits. However, neurocognitive impairment is also a common clinical feature that can contribute greatly to the overall disease burden. In the current study, a meta-analysis was conducted to gain a clearer understanding of how PD affects one of the most functionally important domains of cognition: prospection. The results indicate that, relative to controls, PD is associated with a large deficit in the capacity to engage in planning (g = -0.81, K = 25) and a moderate-sized deficit in prospective memory (g = -0.57, K = 16). Sub-analyses indicated that these deficits are evident for both time and event-based prospective memory, as well as for prospective memory tasks that have relatively limited ecological validity. Significant impairment was also evident for both medicated and non-medicated PD sub-groups, but for planning, these deficits were substantially greater in the unmedicated sub-group. The theoretical and practical implications of these findings are discussed.

Prospective memory impairment in patients with white matter lesions

OBJECTIVE

A vast majority of the episodic memory literature in white matter lesions (WML) had focused on "retrospective memory (RM)", little was known about prospective memory (PM) in WML patients. The aim of our study was to investigate the effect of WML patients on event-based prospective memory (EBPM) and time-based prospective memory (TBPM). In addition, our study attempted to understand the possible mechanisms of PM damage in WML patients.

METHODS

A total of 42 WML patients and 40 age and education level matched healthy controls were included. EBPM (an action whenever particular words were presented) and TBPM (an action at certain times) were performed to test the involvement of PM in WML. The extent of WML within cholinergic pathways were assessed using the cholinergic pathways hyperintensities scale (CHIPS).

RESULTS

A significant difference was found in the performance of Montreal Cognitive Assessment (MOCA) (21.8 ± 3.9 vs. 26.6 ± 1.7, p < 0.05) and TBPM (2.88 ± 1.21 vs. 4.27 ± 0.78, p < 0.05), but not Mini-Mental State Examination (MMSE) (26.9 ± 2.8 vs. 27.3 ± 1.2, p > 0.05) and EBPM (3.62 ± 1.25 vs.4.47 ± 1.11, p > 0.05) in WML patients compared with the healthy controls. Moreover, TBPM and MOCA scores were negatively correlated with CHIPS scores.

CONCLUSIONS

WML patients were impaired in TBPM but not in EBPM, supporting that EBPM and TBPM have different neural mechanisms. Our results demonstrated that WML are involved in the TBPM probably by affecting the central cholinergic pathway.

Development and reliability of the Prospective Memory Assessment for Children & Youth (PROMACY): A preliminary study in a nonclinical sample

Prospective memory (PM), "remembering to remember," has been linked to important functional outcomes in adults. Studies of PM in children and adolescents would benefit from the development and validation of developmentally appropriate clinical measures with known psychometric properties. The Prospective Memory Assessment for Children & Youth (PROMACY), a performance-based measure of PM, was developed for the Pediatric HIV/AIDS Cohort Study Adolescent Master Protocol, Memory and Executive Functioning Substudy, and includes Summary, Time-, and Event-based scores derived from eight trials with an ongoing word search task. Fifty-four healthy perinatally HIV-exposed, uninfected children and youth, mean age 13 years, 54% female, 76% Black/non-Hispanic, and 61% impoverished were included in this psychometric analysis. PROMACY Summary Scores demonstrated low, but broadly acceptable internal consistency as measured by Cronbach's alpha and Spearman-Brown. Better PROMACY performance was associated with older age, but no other demographic factors. Generally medium-sized correlations were observed between the PROMACY Summary Score and standard clinical measures of retrospective memory, working memory, executive functions, and IQ. Findings from this preliminary psychometric study of nonclinical children and youth provide cautious support for the internal consistency and construct validity of PROMACY's Summary Score that awaits replication and extension in larger samples of healthy children, youth and clinical populations.

Intraindividual variability in neurocognitive performance is associated with time-based prospective memory in older adults

INTRODUCTION

Older adults demonstrate poorer prospective memory (PM) performance than younger adults, particularly for time-based cues and other strategically demanding PM tasks. Intraindividual variability (IIV) in neurocognitive test performance is an index of cognitive control that may be related to the execution of strategically demanding PM tasks.

METHOD

Participants included 194 older Australian adults (age 50 to 88 years) who completed the Memory for Intentions Screening Test (MIST), the Prospective and Retrospective Memory Questionnaire (PRMQ), and clinical measures of executive functions. A measure of naturalistic time-based PM was also administered, in which participants were asked to call the examiner 24 hours after their appointment to report how many hours they slept. IIV was calculated as the mean-adjusted coefficient of variation (CoV) across subtests of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

RESULTS

IIV was significantly associated with time-based PM in the laboratory, independent of demographics. Additionally, IIV significantly predicted performance on a naturalistic time-based PM trial, independent of demographics and chronic medical conditions. IIV was not related to event-based laboratory PM or self-reported PM symptoms in daily life. Clinical measures of executive functions were similarly associated with time-based PM and the naturalistic PM task, but not with event-based PM or subjective PM symptoms.

CONCLUSIONS

These results indicate that cognitive control, as indexed by IIV in neurocognitive performance, may play a role in naturalistic PM, as well as in highly strategic, but not automatic, laboratory-based PM among older adults.

Impairment in the Intention Formation and Execution Phases of Prospective Memory in Parkinson's Disease

Objective: Patients with Parkinson's disease have prospective memory impairments. However, little is known about distinct phases of prospective memory in these patients. This study was designed to elucidate the specific phase(s) of prospective memory that are impaired in patients with Parkinson's disease. Methods: The study included 31 Parkinson's disease patients and 27 healthy controls. The four phases of prospective memory (intention formation, retention, initiation, and execution) were examined in a complex prospective memory task. In this task, the participants were asked to form a sophisticated plan for performing six subtasks to obtain the highest score, and then execute the plan following a cue embedded in a questionnaire. Global cognitive function and relevant cognitive abilities, including attention, short-term memory, working memory, and inhibition, were also evaluated during the retention phase of the prospective memory task. Results: Intention formation was impaired in Parkinson's disease patients (p < 0.001 vs. healthy controls). This impairment could not be attributed to deficits in other cognitive functions. The score of intention execution was also lower in Parkinson's disease patients (p = 0.004 vs. healthy controls). Such a difference was related to working memory deficits in Parkinson's disease. The intention retention and initiation were intact in Parkinson's disease patients. The score of intention execution correlated negatively with disease severity and disease duration. Conclusions: Prospective memory in Parkinson's disease patients is impaired at the phase of intention formation. The worsening performance of intention execution in Parkinson's disease may be related to working memory deficits. In addition, prospective memory impairment might progress with increasing disease duration and severity.

Prospective memory is dysfunctional in migraine without aura

Introduction Prospective memory is the ability to carry out a delayed intended action, so to maintain and retrieve future plans, goals and activities. Deficits of prospective memory negatively impact on patients and caregivers' everyday living and determine poor adherence to treatment. Since frontal regions are involved in both event- and time-based prospective memory tasks and are impaired in migraine without aura, defects of prospective memory might occur in migraine without aura patients; until now this issue has not been investigated. The aim of the current study was to explore time- versus event-based prospective memory in migraine without aura. Patients and methods Ninty-one consecutive migraine without aura patients and 84 healthy subjects were enrolled in the study. They underwent a standardized measure of prospective memory evaluating both time-based and event-based prospective memory, and the Montreal Cognitive Assessment assessing global cognitive status. Moreover, all participants completed the Beck Depression Inventory-II and a self-administered version of the Apathy Evaluation Scale, to assess severity of depressive symptoms and apathy, respectively. Results Migraine without aura and healthy subjects did not differ on demographic aspects (i.e. age, education and gender). However, individuals with migraine without aura demonstrated impaired prospective memory performance compared to healthy subjects, with a greater impairment demonstrated for the time-based tasks. Within the migraine without aura group, no significant association was found between prospective memory performance and clinical scores, apathy, and depression. Conclusions Individuals with migraine without aura experience particular difficulty executing a future intention; therefore, migraine without aura is associated with dysfunction of prospective memory.

Encoding strategy training and self-reported everyday prospective memory in people with Parkinson disease: a randomized-controlled trial

Objective To compare the effects of laboratory-based training in implementation intentions (II; experimental strategy) and verbal rehearsal (VR; control strategy) on self-reported everyday prospective memory among people with Parkinson disease (PD) and to investigate potential correlates of change in self-reported everyday prospective memory in response to this training. Method This was a randomized-controlled trial. Participants with mild to moderate PD without dementia underwent one session of training in either II (n = 25) or VR (n = 27). Then they were instructed to use their strategy as much as possible in their everyday lives to help them remember to do things. The Prospective and Retrospective Memory Questionnaire Prospective Scale (PRMQ-Pro) administered at baseline and one month after training assessed training-related change in self-reported everyday prospective memory. Baseline depressive symptoms, perceptions of the strategy (credibility, expectancy), prospective memory-related awareness, global cognition, and disease severity were correlated to PRMQ-Pro Change scores (post minus pre) to determine their association with response to training. Results The VR group's PRMQ-Pro scores declined from pre to post training, while the II group's remained stable (p = .03). This effect was driven by change in self-cued everyday prospective memory tasks. Higher baseline depressive symptoms, treatment expectancy, and global cognition related to better response to training in the II group (rs ≤ -.40, ps ≤ .05). Conclusions II training may prevent everyday prospective memory decline among people with PD. In addition, people with higher depression, stronger expectations of improvement from strategy training, or better global cognition may benefit the most from II training.

A systematic review of prospective memory in HIV disease: from the laboratory to daily life

OBJECTIVE

Prospective memory (PM) is described as the capacity to form and maintain an intention that is executed in response to a specific cue. Neural injury and associated neurocognitive disorders are common among persons living with HIV disease, who might therefore be susceptible to impairment in PM.

METHOD

This literature review utilized a structured qualitative approach to summarize and evaluate our current understanding of PM functioning in people living with HIV disease. 33 studies of PM in HIV+ persons met criteria for inclusion.

RESULTS

Findings showed that HIV is associated with moderate deficits in PM, which appear to be largely independent of commonly observed comorbid factors. The pattern of PM deficits reveals dysregulation of strategic processes that is consistent with the frontal systems pathology and associated executive dysfunction that characterizes HIV-associated neural injury. The literature also suggests that HIV-associated PM deficits present a strong risk of concurrent problems in a wide range of health behaviors (e.g. medication non-adherence) and activities of daily living (e.g. employment). Early attempts to improve PM in HIV disease have revealed that supporting strategic processes might be effective for some individuals.

CONCLUSIONS

HIV-associated PM deficits are common and exert a significant adverse effect on the daily lives and health of infected persons. Much work remains to be done to understand the cognitive architecture of HIV-associated PM deficits and the most efficient means to enhance PM functioning and improve health outcomes in persons living with HIV.

A comparison of laboratory, clinical, and self-report measures of prospective memory in healthy adults and individuals with brain injury

Individuals with traumatic brain injury (TBI) have demonstrated deficits in prospective memory (PM) functioning when compared to healthy adults. These deficits have been measured using laboratory measures, clinical measures, and self-report questionnaires. However, PM has been shown to involve multiple cognitive processes and have a variety of stages. Thus, it is not known whether these measures all assess the same aspects of PM. Thus, this study was designed to measure the convergent validity of the three types of PM measures in both healthy adults and individuals with TBI. We aimed to investigate the convergent validity of the three types of tasks in two ways. First, we sought to investigate whether the PM deficits experienced by people with TBI are consistent across tasks. Second, we sought to examine the relationship between the three types of tasks. Results demonstrated that while all three types of measures were sensitive to PM deficits in TBI, there were differences in the aspects/processes of PM being measured. Data from the laboratory measure suggested a specific difficulty with detecting the correct cue. Data from the clinical measure suggested that TBI has a greater effect on time-based cues than event-based cues and that the primary deficit is a prospective intention retrieval deficit rather than the retrospective memory component. In addition, those with TBI did not differ from healthy adults when the time delay was short enough, suggesting that PM is not universally impaired. Data from the self-report questionnaire suggested that those with TBI are more sensitive to difficulties with basic activities of daily living rather than instrumental activities on daily living. These results are discussed in terms of rehabilitation techniques that could focus first on cue detection and use basic activities of daily living as outcome measures.

Improving Prospective Memory in Persons With Parkinson Disease: A Randomized Controlled Trial

BACKGROUND

Prospective memory (PM) is essential for productive and independent living and necessary for compliance with prescribed health behaviors. Parkinson disease (PD) can cause PM deficits that are associated with activity limitations and reduced quality of life. Forming implementation intentions (IIs) is an encoding strategy that may improve PM in this population.

OBJECTIVE

To determine the effect of IIs on PM performance in PD.

METHODS

This was a laboratory-based randomized controlled trial. Participants with mild to moderate PD without dementia (n = 62) performed a computerized PM test (Virtual Week) under standard instructions. One week later they were randomly allocated to perform it again while using either IIs or a rehearsal (RR) encoding strategy.

RESULTS

PM performance was better with the use of both strategies relative to standard instructions. This effect was larger for tasks with event-based compared with time-based cues. In addition, IIs resulted in a larger effect than RR for the nonrepeated tasks.

CONCLUSIONS

Strategies that support full encoding of PM cues and actions can improve PM performance among people with PD, particularly for tasks with cues that are readily available in the environment. IIs may be more effective than RR for nonrepeated tasks, but this finding warrants verification. Future work should address transfer of strategy use from the laboratory to everyday life. Targeted strategies to manage PM impairment could improve function and quality of life and significantly affect clinical care for people with PD.

Effects of drinking patterns on prospective memory performance in college students

OBJECTIVE

Traditional college students are at a critical juncture in the development of prospective memory (PM). Their brains are vulnerable to the effects of alcohol.

METHOD

There were 123 third and fourth year college students, 19-23 years old, who completed the Self-Rating Effects of Alcohol (SREA), Modified Timeline Follow-back (TFLB), Brief Young Adult Alcohol Consequences Scale (BYAACS), and Alcohol Effects Questionnaire (AEQ) once per month on a secure online database, as reported elsewhere (Dager et al., 2013). Data from the 6 months immediately before memory testing were averaged. In a single testing session participants were administered the Mini International Neuropsychiatric Interview-Diagnostic and Statistical Manual for Mental Disorders-Fourth Edition-Text Revision (MINI-DSM-IV-TR), measures of PM (event-based and time-based), and retrospective memory (RM). Based on the average score of six consecutive monthly responses to the SREA, TLFB, and AEQ, students were classified as nondrinkers, light drinkers, or heavy drinkers (as defined previously; Dager et al., 2013). Alcohol-induced amnesia (blackout) was measured with the BYAACS.

RESULTS

We found a relationship between these alcohol use classifications and time-based PM, such that participants who were classified as heavier drinkers were more likely to forget to perform the time-based PM task. We also found that self-reported alcohol-induced amnesia (blackouts) during the month immediately preceding memory testing was associated with lower performance on the event-based PM task. Participants' ability to recall the RM tasks suggested the PM items were successfully encoded even when they were not carried out, and we observed no relationship between alcohol use and RM performance.

CONCLUSION

Heavy alcohol use in college students may be related to impairments in PM. (PsycINFO Database Record

The effects of HIV disease and older age on laboratory-based, naturalistic, and self-perceived symptoms of prospective memory: does retrieval cue type and delay interval matter?

There is a rising prevalence of older HIV+ adults who are at risk of deficits in higher order neurocognitive functions and associated problems in everyday functioning. The current study applied multiprocess theory to examine the effects of HIV and aging on measures of laboratory-based, naturalistic, and self-perceived symptoms of prospective memory (PM). Participants included 125 Younger (48 with HIV, age = 32 ± 4.6 years) and 189 Older (112 with HIV, age = 56 ± 4.9 years) adults. Controlling for global neurocognitive functioning, mood, and other demographics, older age and HIV had independent effects on long-delay time-based PM in the laboratory, whereas on a naturalistic PM task older HIV- adults performed better than older HIV+ adults and younger persons. In line with the naturalistic findings, older age, but not HIV, was associated with a relative sparing of self-perceived PM failures in daily life across longer delay self-cued intervals. Findings suggest that, even in relatively younger aging cohorts, the effects of HIV and older age on PM can vary across PM delay intervals by the strategic demands of the retrieval cue type, are expressed differently in the laboratory and in daily life, and are independent of other higher order neurocognitive functions (e.g., retrospective memory).

Retrieval cue and delay interval influence the relationship between prospective memory and activities of daily living in older adults

OBJECTIVE

Older adults commonly experience mild declines in everyday functioning and the strategic aspects of prospective memory (PM). This study used multiprocess theory to examine whether the strategic demands of retrieval cue type (event vs. time based) and delay interval length (2 vs. 15 min) influence the relationship between PM and activities of daily living (ADLs) in older adults.

METHOD

Participants included 97 community-dwelling older adults recruited from the Western Australia Participant Pool. Participants were administered the Memory for Intentions Screening Test (MIST) and Prospective and Retrospective Memory Questionnaire (PRMQ) as part of a larger neurocognitive assessment. A knowledgeable informant completed the Activities of Daily Living Questionnaire (ADLQ), from which a cutpoint of ≥ 1 was used to classify participants into "ADL normal" (n = 37) or "mild ADL problems" (n = 60) groups. Repeated measures multivariate analysis of variance (MANOVA) controlling for age was conducted with ADL group as the between-subjects factor and either MIST or PRMQ cue and delay scores as the within-subjects factors.

RESULTS

We observed a significant ADL group by PM interaction on the MIST, with pair-wise analyses showing that the mild ADL problems group performed worse than ADL normal participants on the 15-min time-based scale (p < .001, Cohen's d = 0.71). No other MIST or PRMQ cue-delay variable differed between the two ADL groups (ps > .10).

CONCLUSION

Findings indicate that decrements in strategically demanding cue monitoring and detection over longer PM delays may partly explain older adults' mild problems in everyday functioning. Findings may inform neuropsychological interventions aimed at maintaining ADL independence and enhancing quality of life in older adults.

Event-based prospective memory in patients with Parkinson's disease: the effect of emotional valence

The present study investigated the effect of Parkinson’s disease (PD) on prospective memory (PM) tasks by varying the emotional content of the PM actions. Twenty-one older adults with PD and 25 healthy older adults took part in the present study. Participants performed three virtual days in the Virtual Week task. On each virtual day, participants performed actions with positive, negative or neutral content. Immediately following each virtual day, participants completed a recognition task to assess their retrospective memory for the various PM tasks. PD patients were less accurate than the control group at both PM accuracy and recognition task accuracy. The effect of emotional valence was also evident, indicating that all participants were more accurate on positive PM tasks than both negative and neutral. This study confirmed PM impairment in PD patients and extended previous research showing how positive emotional stimuli can influence PM performance.

Self-predictions of prospective memory in HIV-associated neurocognitive disorders: evidence of a metamemory deficit

HIV-associated neurocognitive disorders (HAND) are associated with deficits in prospective memory (PM; "remembering to remember"), conferring risk of daily functioning declines. However, self-perceptions of PM functioning are not reliably associated with PM performance in HIV, suggesting a possible deficit in awareness of PM abilities (meta-PM). Our study examined meta-PM in HAND and its correlates using self-predictions of laboratory-based PM performance. Performance-based PM abilities, self-reported prediction of PM performance, and PM complaints in everyday life were assessed in 49 individuals with HAND, 93 HIV+ without HAND (HIV+ noHAND), and 121 seronegative adults (HIV-). After controlling for group-level differences, HAND was associated with a greater number of PM symptoms in everyday life and worse PM performance when compared with both HIV+ noHAND and HIV- samples. Although HAND individuals reported somewhat lower predictions regarding their laboratory PM performance relative to the other study groups, they nevertheless exhibited significantly greater inaccurate overconfidence in time-based PM abilities. Within the HAND group, overconfidence in time-based meta-PM was associated with executive dysfunction and antiretroviral (ARV) nonadherence. HAND individuals evidenced a moderate deficit in awareness of PM functioning characterized by overconfidence in time-based PM abilities. Overconfidence in PM may result in absence of compensatory strategy use, and lead to increased errors in daily functioning (e.g., ARV nonadherence).

Time-based prospective memory functioning in mild cognitive impairment associated with Parkinson's disease: relationship with autonomous management of daily living commitments

OBJECTIVE

Prospective memory (PM), that is, the ability to keep in memory and carry out intentions in the future, is reported to be impaired in individuals with Parkinson's disease (PD). PM failure may be also associated with reduced daily living functioning in these patients. Little is known, however, about the relationship between mild cognitive impairment (MCI) and time-based PM functioning in PD patients and the possible impact of PM deficits on patients' autonomy in daily living. Here we aimed to investigate whether MCI associated with PD affects time-based PM. We also wished to determine whether PM impairment accounts for reduced autonomous management of medication in these patients.

METHOD

The study included 48 PD patients with MCI, 33 PD patients without cognitive disorders (PDN) and 20 healthy controls. The time-based PM procedure required that subjects perform an action after a fixed time. The PM procedure was incorporated in the standard neuropsychological assessment. One score was computed for the ability to retrieve the intention (prospective component) and one for remembering the action to be executed (retrospective component). The Pill Questionnaire was administered to assess the ability to manage medication.

RESULTS

PD patients with MCI performed less accurately in the PM procedure than HC and tended to perform poorer than PDN. Moreover, in PD patients with MCI, accuracy on the prospective component of the PM task and performance on the Modified Card Sorting Test significantly predicted the ability to manage medication.

CONCLUSIONS

RESULTS document that reduced efficiency of time-based PM processes in PD is specifically related to the presence of MCI. The same data indicate that PM weakness may be associated with impaired daily living functioning and decreased autonomy.

Dopamine D1 and D5 receptors modulate spike timing-dependent plasticity at medial perforant path to dentate granule cell synapses

Although evidence suggests that DA modulates hippocampal function, the mechanisms underlying that dopaminergic modulation are largely unknown. Using perforated-patch electrophysiological techniques to maintain the intracellular milieu, we investigated how the activation of D1-type DA receptors regulates spike timing-dependent plasticity (STDP) of the medial perforant path (mPP) synapse onto dentate granule cells. When D1-type receptors were inhibited, a relatively mild STDP protocol induced LTP only within a very narrow timing window between presynaptic stimulation and postsynaptic response. The stimulus protocol produced timing-dependent LTP (tLTP) only when the presynaptic stimulation was followed 30 ms later by depolarization-induced postsynaptic action potentials. That is, the time between presynaptic stimulation and postsynaptic response was 30 ms (Δt = +30 ms). When D1-type receptors were activated, however, the same mild STDP protocol induced tLTP over a much broader timing window: tLTP was induced when -30 ms ≤ Δt ≤ +30 ms. The result indicated that D1-type receptor activation enabled synaptic potentiation even when postsynaptic activity preceded presynaptic stimulation within this Δt range. Results with null mice lacking the Kv4.2 potassium channel and with the potassium channel inhibitor, 4-aminopyridine, suggested that D1-type receptors enhanced tLTP induction by suppressing the transient IA-type K(+) current. Results obtained with antagonists and DA receptor knock-out mice indicated that endogenous activity of both D1 and D5 receptors modulated plasticity in the mPP. The DA D5 receptors appeared particularly important in regulating plasticity of the mPP onto the dentate granule cells.

Prospective memory in adults with high-functioning autism spectrum disorders: exploring effects of implementation intentions and retrospective memory load

This study examined, for the first time, the impact of implementation intentions on prospective memory (PM) performance in adults with autism spectrum disorders (ASD) and further explored the role of retrospective memory for PM in ASD. PM was assessed with Virtual Week, a computerized game simulating upcoming everyday-life tasks. Twenty-seven adults with ASD and 27 age- and ability-matched controls were included. Half of the participants were instructed to form implementation intentions (i.e., encoding PM tasks in form of if-then statements), while the rest received simple PM instructions. Results provide first tentative evidence for beneficial effects of implementation intentions and PM tasks with low demands on retrospective memory for adults with ASD's PM. Overall, results point to the importance of planning and retrospective memory for successful prospective remembering in ASD.

Prospective memory performance of patients with Parkinson's disease depends on shifting aptitude: evidence from cognitive rehabilitation

This study investigated the effect of cognitive training aimed at improving shifting ability on Parkinson's disease (PD) patients' performance of prospective memory (PM) tasks. Using a double-blind protocol, 17 PD patients were randomly assigned to two experimental arms. In the first arm (n=9) shifting training was administered, and in the second (placebo) arm (n=8), language and respiratory exercises. Both treatments consisted of 12 sessions executed over 4 weeks. PM and shifting measures (i.e., Trail Making Test and Alternate Fluency Test) were administered at T0 (before treatment) and T1 (immediately after treatment). A mixed analysis of variance was applied to the data. To evaluate the effects of treatment, the key effect was the interaction between Group (experimental vs. placebo) and Time of Assessment (T0 vs. T1). This interaction was significant for the accuracy indices of the PM procedure (p<.05) and for the performance parameters of the shifting tasks (p ≤.05). Tukey's HSD tests showed that in all cases passing from T0 to T1 performance significantly improved in the experimental group (in all cases p ≤.02) but remained unchanged in the placebo group (all p consistently>.10). The performance change passing from T0 to T1 on the Alternate Fluency test and the PM procedure was significantly correlated (p<.05). Results show that the cognitive training significantly improved PD patients' event-based PM performance and suggest that their poor PM functioning might be related to reduced shifting abilities.

Construct validity of the Memory for Intentions Screening Test (MIST) in healthy older adults

The Memory for Intentions Screening Test (MIST) is a clinical measure of prospective memory. There is emerging support for the sensitivity and ecological relevance of the MIST in clinical populations. In the present study, the construct validity of the MIST was evaluated in 40 younger (18-30 years), 24 young-old (60-69 years), and 37 old-old (70+ years) healthy adults. Consistent with expectations derived from the prospective memory and aging literature, older adults demonstrated lower scores on the MIST's primary scale scores (particularly on the time-based scale), but slightly better performance on the seminaturalistic 24-hour trial. Among the healthy older adults, the MIST showed evidence of both convergent (e.g., verbal fluency) and divergent (e.g., visuoperception) correlations with standard clinical tests, although the magnitude of those correlations were comparable across the time- and event-based scales. Together, these results support the discriminant and convergent validity of the MIST as a measure of prospective memory in healthy older adults.

"Forgetting to remember" in Huntington's disease: a study of laboratory, semi-naturalistic, and self-perceptions of prospective memory

Prospective memory (PM) is dependent on executive processes known to be impaired in Huntington's disease (HD); however, no study to the authors' knowledge has investigated PM in this group. We examined performance-based, semi-naturalistic, and self-reported PM in 20 individuals diagnosed with mild-moderate HD and 20 demographically similar controls. Relative to controls, HD participants demonstrated significantly lower scores in time-based PM, event-based PM (at a trend level), and the semi-naturalistic PM trial, all of which were marked by omission errors. HD participants demonstrated comparable recognition memory for the PM intentions relative to controls. HD and control participants also showed comparable scores in self-reported PM complaints. The results suggest that HD is associated with deficits in the strategic aspects of PM. HD-associated PM deficits also are evident in real-world situations, which may relate to an apparent meta-memory deficit for PM functioning as indicated by HD participants' overestimation of their PM performance on self-report.

Retrospective and Prospective Views on the Role of the Hippocampus in Interval Timing and Memory for Elapsed Time

The overlap of neural circuits involved in episodic memory, relational learning, trace conditioning, and interval timing suggests the importance of hippocampal-dependent processes. Identifying the functional and neural mechanisms whereby the hippocampus plays a role in timing and decision-making, however, has been elusive. In this article we describe recent neurobiological findings, including the discovery of hippocampal ‘time cells’, dependency of duration discriminations in the minutes range on hippocampal function, and the correlation of hippocampal theta rhythm with specific features of temporal processing. These results provide novel insights into the ways in which the hippocampus might interact with the striatum in order to support both retrospective and prospective timing. Suggestions are also provided for future research on the role of the hippocampus in memory for elapsed time.

Prospective memory in Parkinson's disease: a meta-analysis

Prospective memory (PM) refers to the ability to remember to carry out an intended action in the future and it is pervasive in our daily living. A failure to execute an intended action (e.g., take medication) at the appropriate juncture in future (e.g., after dinner) can negatively affect our daily functioning and at times, may have devastating effects (e.g., forgetting to turn off the gas stove before leaving the house). Patients with Parkinson's disease (PD) exhibit widespread cognitive deficits including deficits in PM. The present study provides a meta-analytic review of PM in PD. Results across nine studies indicated time and event-based PM to be similarly impaired in PD, with time-based PM compromised to a slightly larger extent (Hedges' g = -0.71) as compared to event-based PM (Hedges' g = -0.55). The impairment in PM is more likely due to failure in self-initiated retrieval of intention to be executed, rather than forgetting the content of the intention itself. Furthermore, factors such as intervening task complexity and the mediating role of other executive functions have also been proposed to be responsible for impaired PM in PD.

Prospective memory in Parkinson disease during a virtual week: effects of both prospective and retrospective demands

OBJECTIVE

This study investigated the effect of Parkinson's disease (PD) on event-based prospective memory tasks with varying demand on (1) the amount of strategic attentional monitoring required for intention retrieval (prospective component), and (2) the retrospective memory processes required to remember the contents of the intention or the entire constellation of prospective memory tasks.

METHOD

Twenty-four older adults with PD and 28 healthy older adults performed the computerized Virtual Week task, a multi-intention prospective memory paradigm that simulates everyday prospective memory tasks. The Virtual Week included regular (low retrospective memory demand) and irregular (high retrospective memory demand) prospective memory tasks with cues that were focal (low strategic monitoring demand) or less focal (high strategic monitoring demand) to the ongoing activity.

RESULTS

For the regular prospective memory tasks, PD participants were impaired when the prospective memory cues were less focal. For the irregular prospective memory tasks, PD participants were impaired regardless of prospective memory cue type. PD participants also had impaired retrospective memory for irregular tasks, which was associated with worse prospective memory for these tasks during the Virtual Week.

CONCLUSIONS

When retrospective memory demands are minimized, prospective memory in PD can be supported by cues that reduce the executive control demands of intention retrieval. However, PD-related deficits in self-initiated encoding or planning processes have strong negative effects on the performance of prospective memory tasks, with increased retrospective memory demand.

Patterns of prospective memory impairment among individuals with depression: the influence of cue type and delay interval

The present study investigated the impact of cue type and delay interval on prospective memory performance in depressed, compared to non-depressed, individuals using a clinically relevant measure, the Memory for Intentions Screening Test. The depressed group demonstrated impaired performance on time-based, but not event-based, prospective memory tasks relative to the nondepressed group. The depressed group also demonstrated impaired prospective memory on tasks with longer delay intervals (15 min), but not on tasks with shorter delay intervals (2 min). These data support theoretical frameworks that posit that depression is associated with deficits in cognitive initiative (i.e., reduced ability to voluntarily direct attention to relevant tasks) and thus that depressed individuals are susceptible to poor performance on strategically demanding tasks. The results also raise multiple avenues for developing interventions (e.g., implementation intentions) to improve prospective memory performance among individuals with depression, with potential implications for medication and other treatment adherence.

Revisiting the age-prospective memory-paradox: the role of planning and task experience

The present study aimed at investigating age-related differences in prospective memory performance using a paradigm with high ecological validity and experimental control. Thirty old and 30 young adults completed the Dresden Breakfast task; a meal preparation task in the lab that comprises several subtasks including event- and time-based prospective memory tasks. Participants were required to plan how to perform the task. Results showed that young adults outperformed old adults: they completed more subtasks, showed better event- and time-based prospective memory performance and planning quality. In contrast, old adults adhered to their plans more closely than young adults. Further exploratory gender-specific analyses indicated that old women did not differ from young men in time-based prospective memory performance, general task performance and time monitoring in contrast to old men. Possibly, differences in experience in breakfast preparation might account for these differential findings.

Event-based prospective memory in the rat

People plan to act in the future when an appropriate event occurs, a capacity known as event-based prospective memory. Prospective memory involves forming a representation of a planned future action, subsequently inactivating the representation, and ultimately reactivating it at an appropriate point in the future. Recent studies suggest that monkeys, chimpanzees, and rats display elements of prospective memory, but it is uncertain if the full sequence (activation-inactivation-reactivation) that occurs in humans also occurs in nonhumans. Here, we asked if rats exhibit event-based prospective memory. Rats completed an ongoing temporal-discrimination task while waiting for a large meal. To promote the use of event-based prospective memory, we created an event (tone pulses) that provided information that the meal could be obtained soon. Event-based prospective memory was suggested by the dramatic decline in ongoing-task performance after the event, with excellent performance at other times. To document that the event initiated memory activation, we arranged for the event to occur at novel times. Finally, multiple, repeated presentations of the event on the same day demonstrate that rats inactivate and reactivate the memory representation in an on-demand, event-based fashion. Development of an animal model of prospective memory may be valuable to probe the biological underpinnings of memory disorders.

A pilot study of prospective memory functioning in early breast cancer survivors

AIMS

To evaluate prospective memory (PM) functioning in early breast cancer (BC) survivors and its association with fatigue and depression.

METHODS

The Memory for Intention Screening Test, the Center for Epidemiologic Studies Depression Scale and the Functional Assessment of Cancer Therapy-Fatigue subscale were administered to 80 patients and 80 aged-matched healthy controls.

RESULTS

Patients performed more poorly than controls on the memory test (p < 0.001) and had a higher rate of impairment (odds ratio = 5.5, p < 0.01). Fatigue mediated the relationship between Group membership and PM performance.

CONCLUSIONS

BC survivors exhibited a clear pattern of PM deficit and fatigue was a major contributor to this deficit. This suggests that a common mechanism may be involved in fatigue symptoms and memory disturbances experienced by patients. Further research is needed to evaluate the role of adjuvant therapy in PM deficits and to explore whether interventions targeted at improving fatigue may also improve memory functioning in BC survivors.

Event-based prospective memory and everyday forgetting in healthy older adults and individuals with mild cognitive impairment

An event-based nonfocal task was used to evaluate prospective memory (PM) and the relationship between PM, neuropsychological testing data, and everyday forgetting. Twenty-four participants with mild cognitive impairment (MCI) and 24 age- and education-matched cognitively healthy adults responded to a nonfocal PM cue, while completing an ongoing working memory task. Neuropsychological testing data and self- and informant-report of frequency of forgetting were also gathered. Compared to healthy adults, the MCI participants exhibited significantly poorer prospective remembering and ongoing task performance, despite similar self-reported effort directed to the PM task. Both self- and informant-report indicated that the MCI group was experiencing a higher frequency of everyday forgetting than the healthy adult group. Self-report of everyday forgetting was correlated with PM task performance for the healthy adults, but not for the MCI participants. For the healthy adults, correlational analyses also showed significant relationships between PM accuracy and tests of memory and executive functioning, suggesting that both spontaneous retrieval processes and effortful, strategic monitoring may be important in supporting prospective remembering for this nonfocal PM task. The stronger relationships between PM accuracy and memory and language tests for the MCI group suggest that their poorer event-based prospective remembering might be linked to impaired spontaneous retrieval processes, which are thought to be supported by medial temporal structures.

Prospective memory and antiretroviral medication non-adherence in HIV: an analysis of ongoing task delay length using the memory for intentions screening test

Using multi-process framework by McDaniel and Einstein (2000), the current study examined whether the length of prospective memory (PM) delay intervals as measured by the 2- and 15-min subscales of the Memory for Intentions Screening Test (MIST) have differential predictive value for antiretroviral (ARV) adherence. Participants included 74 HIV-infected individuals whose ARV adherence was tracked with an electronic monitoring system. Participants were classified as "adherent" (n = 49) or "non-adherent" (n = 25) based on recorded pill bottle openings of ≥90% of prescribed doses over 30 days. An adherence group by MIST delay interval interaction was observed, such that non-adherent participants had worse performance on the 15-min, but not 2-min delay PM MIST subscales. The observed MIST 15-min delay effects were significantly more pronounced on time- versus event-cued PM trials. Long-delay time-based PM was predictive of non-adherence independent of demographics, mood state, self-reported adherence, and general cognitive functioning. Findings from this clinical study indicate that ARV non-adherence may be particularly associated with deficits in strategic cue monitoring over longer PM delays, which may inform interventions to improve adherence among persons living with HIV infection.

Remembering the past and planning for the future in rats

A growing body of research suggests that rats represent and remember specific earlier events from the past. An important criterion for validating a rodent model of episodic memory is to establish that the content of the representation is about a specific event in the past rather than vague information about remoteness. Recent evidence suggests that rats may also represent events that are anticipated to occur in the future. An important capacity afforded by a representation of the future is the ability to plan for the occurrence of a future event. However, relatively little is known about the content of represented future events and the cognitive mechanisms that may support planning. This article reviews evidence that rats remember specific earlier events from the past, represent events that are anticipated to occur in the future, and develops criteria for validating a rodent model of future planning. These criteria include representing a specific time in the future, the ability to temporarily disengage from a plan and reactivate the plan at an appropriate time in the future, and flexibility to deploy a plan in novel conditions.

The epidemiology and clinical manifestations of dysexecutive syndrome in Parkinson's disease

This mini-review summarizes the evidence of the cognitive and behavioral features of dysexecutive syndrome in Parkinson’s disease (PD). Deficits in response inhibition, set-shifting, mental flexibility, and strategy have been frequently described from the earliest stages of PD, although there are inconsistencies in study findings due to the complexity of the executive function (EF) construct and methodological limitations. Behavioral disorders of PD, e.g., apathy, distractibility, perseverative behavior, and impulse-control disorders, may be viewed as the other side of dysexecutive syndrome. Despite the interrelationship between the cognitive and behavioral domains, some reports reveal that the two syndromes may be dissociated, suggesting that both aspects must be clinically assessed. EFs are widely associated with the prefrontal areas, although dysexecutive syndrome may be observed in patients with damage to other brain regions. EFs drive numerous abilities essential to daily life, such as prospective remembering and language comprehension, which may be impaired in PD subjects. Considering the impact of dysexecutive syndrome on independence and quality of life, early detection of executive impairment is crucial in the management of PD.

Prospective memory deficits are associated with poorer everyday functioning in Parkinson's disease

Although individuals with Parkinson's disease (PD) evidence moderate deficits in prospective memory (PM), it is not known whether PM deficits confer an increased risk of poorer everyday functioning. In the current study, 33 individuals with PD and 26 demographically similar normal controls (NC) were administered performance-based and self-report measures of PM and everyday functioning, including medication and financial management. As compared to NC, PD participants demonstrated significantly lower scores on performance-based measures of PM and financial capacity, worse performance at a trend level on performance-based medication management and endorsed significantly greater self-reported declines in PM and instrumental activities of daily living (iADLs). In the PD sample, the laboratory measure of PM significantly correlated with performance-based measures of financial capacity and medication management and a self-report measure of medication management. Self-reported PM failures significantly correlated with perceived declines in iADLs, worse medication management, and poorer health-related quality of life. Although future studies are needed to examine the incremental ecological validity of PM in PD, findings from this study extend prior research by providing preliminary evidence that PM impairment may play a significant role in a range of critical everyday functions in PD.