Mild cognitive impairment and prospective memory: translating the evidence into neuropsychological practice

Meta-prospective memory accuracy in older adults with and without suspected Mild Cognitive Impairment (sMCI)

This study examined if the relationship between generalized and task-specific appraisals of prospective memory (PM) and actual PM performance (i.e., meta-PM accuracy) differed between healthy and suspected Mild Cognitive Impairment (sMCI) older adults. Older adults recruited included 50 healthy and 31 sMCI participants from the community and an outpatient neuropsychology clinic. Data collected consisted of self-reported appraisals and task-specific predictions/postdictions of PM performance, objective PM performance, and executive functioning (EF). The sMCI group had significantly lower scores on objective PM and EF measures related to simple and complex task-switching. Moreover, sMCI participants displayed lower task-specific meta-PM accuracy in the direction of overconfidence, but they displayed relatively equivalent generalized meta-PM accuracy when compared to the healthy group. Notably, the sMCI group's task-specific inaccuracies became non-significant in relation to the healthy group on the final long-term PM tasks after exposure to metacognitive reflection on the first two PM tasks. Despite lower scores on EF measures, EF performance did not explain task-specific meta-PM differences between groups beyond neurocognitive status. Based on these data, sMCI patients may be better assisted by metacognitive calibration strategies, EF protocols, and the implementation of general compensatory memory strategies as targets for early intervention and prevention of neurocognitive decline.

Effectiveness of a Visual Imagery Training Program to Improve Prospective Memory in Older Adults with and without Mild Cognitive Impairment: A Randomized Controlled Study

Prospective memory (PM) problems in aging and, to a greater extent, in mild cognitive impairment (MCI), compromise functional independence. This study examined the effectiveness of a cognitive training program based on visual imagery to improve PM among older adults with and without MCI. Participants were older adults, 24 with MCI and 24 cognitively healthy (HOA). Half of them (12 MCI and 12 HOA) were randomly assigned to the PM training program, the other half to the no-training control group. All participants also completed a pre- and post-test evaluation, including neuropsychological tests, questionnaires, and the Ecological Test of Prospective Memory (TEMP). There was no significant effect of the intervention on the TEMP total, event-based or time-based scores for either the MCI or HOA groups. However, the trained MCI group committed fewer false alarms (i.e., more efficient identification of prospective cues) in the event-based condition of the TEMP at post-test. On the other hand, all trained participants performed better than control participants on retrospective memory tests, which suggests that visual imagery-based training is more effective to improve retrospective memory than PM. Possible explanations for these results are explored.

Prospective memory impairment in neurological disorders: implications and management

Prospective memory is a core neurocognitive ability that refers to memory for future intentions, such as remembering to take medications and to switch off appliances. Any breakdown in prospective memory, therefore, has serious implications for the ability to function independently in everyday life. In many neurological disorders, including Parkinson disease and dementia, prospective memory deficits are common even in the earliest stages and typically become more severe with disease progression. Consequently, clinical assessment of prospective memory is of critical importance. This article provides an overview of the various manifestations and neural bases of prospective memory deficits. To facilitate clinical decision-making, validated measures of this construct are identified and their suitability for clinical practice is discussed, focusing in particular on clinical sensitivity and psychometric properties. The article concludes by reviewing the approaches that can be used to rehabilitate different types of prospective memory impairment, and algorithms to guide the evaluation and treatment of these impairments are provided.

From retrospective to prospective memory research: a framework for investigating the deactivation of intentions

The definition of episodic memory has evolved into a multifaceted concept that gathered great attention in several research areas in psychology and neuroscience. Prospective memory (PM), or the ability to remember to perform delayed intentions at a later moment in the future, represents one side of this capacity for which that has been a growing interest. In this review, we examined a counterintuitive finding: PM intentions may persist and affect our behaviour despite successful goal attainment and task completion, which in daily life may be as serious as taking medication twice. This review aims to elucidate the existing knowledge and identify some unresolved questions concerning this specific memory failure. Therefore, this review provides an overview of the uprising research dedicated to both PM omission and commission errors, including an analysis of its definitions, of the current theoretical approaches of PM retrieval, and the main procedures used in this field to offer an integrative perspective on this topic. Finally, the last section is devoted to discussing future directions to test the predictions of our suggested theoretical explanations for PM deactivation. This might be an avenue for research that is likely to extend our understanding of episodic memory's usefulness in everyday life.

Fostering Self-Management of Everyday Memory in Older Adults: A New Intervention Approach

Traditional memory strategy training interventions improve older adults' performance on tests of episodic memory, but have limited transfer to episodic memory tasks, let alone to everyday memory. We argue that an alternative approach is needed to assist older adults to compensate for age-related cognitive declines and to maintain functional capacity in their own natural ecologies. We outline a set of principles regarding how interventions can successfully train older adults to increase successful goal pursuit to reduce risks of everyday memory failures. We argue that training individuals to use metacognitive self-regulatory strategies to proactively manage formulation and pursuit of daily goals can compensate for age-related cognitive changes and increase the likelihood of goal attainment. We then describe an intervention approach that instantiates these principles in a multi-modal intervention that is unique in its three-phase approach: (1) individualized assessment of an individual's current approaches to self-regulation; (2) training memory strategies, self-management skills, and new habits of mind in a group training context; and (3) a behavioral shaping period in which individuals receive coaching and feedback on their efforts to use trained procedures to improve everyday cognition. A recently completed study conducted an initial test of the intervention, with highly encouraging results. We advocate further efforts to replicate, extend, and fine-tune this type of intervention. The ultimate goal is to be able to deliver the intervention in a way that increases its potential reach, including to subpopulations of older adults at risk for everyday cognitive impairments.

The role of anterior prefrontal cortex in prospective memory: an exploratory FDG-PET study in early Alzheimer's disease

From previous studies in healthy volunteers the prefrontal regions are deeply involved in prospective memory (PM), although little is known about the functional neural basis of PM in prodromal Alzheimer's disease (AD). To this end, we retrospectively recruited 18 patients with mild cognitive impairment caused by AD and 23 matched healthy control subjects who had undergone ¹⁸F-fluorodeoxyglucose positron emission tomography and the PM-specific paradigm test. Brain metabolism was correlated with the PM score in the 2 groups separately to find those brain areas correlated with PM performance, which were then used as a hub for an inter-regional metabolic connectivity analyses (inter-regional correlation analysis). Of note, in mild cognitive impairment caused by AD, but not in healthy control subjects, PM score positively correlated with metabolic levels in the right anterior prefrontal cortex (middle and inferior frontal gyri), which disclosed a loss of interhemispheric connectivity in the inter-regional correlation analysis. According to our findings, the functioning of the right anterior prefrontal cortex and its interhemispheric metabolic connectivity is crucial in early AD to sustain PM performance, which deteriorates along with progressive metabolic failure of the interconnected areas.

Instruments Measuring Prospective Memory: A Systematic and Meta-Analytic Review

OBJECTIVE

To identify the available measures to assess prospective memory (PM) abilities, to describe their content, and to quantitatively summarize the effects of various diseases on PM depending on the type of assessment.

METHOD

Three databases (PsycInfo, PsycArticles and PubMed) were searched up to June 2019 to identify the existing PM measures. The identified PM measures were classified according to the type of assessment: test batteries, single-trial procedures, questionnaires, and experimental procedures. The characteristics and psychometric properties were presented. PM performances were compared between patients with various diseases and controls depending on the type of assessment.

RESULTS

Most of the 16 measures identified evaluated both event- and time-based tasks, were linked to functional outcomes, showed empirical evidences regarding validity and reliability, and provided parallel versions. To a slightly lesser extent, few measures provided normative data, translations/adaptation into another language, cutoff scores for diagnostic purposes, qualitative scoring, parallel version, and external aids during the test. Compared to healthy controls, patients had significantly poorer performances when PM was assessed with experimental procedures. Heterogeneous data precluded the interpretation of a summary effect for test batteries, single-trial procedures, and questionnaires. Planned subgroup analyses indicated consistent PM impairment for patients compared to controls for three test batteries. However, PM complaints did not differ between patients and controls.

CONCLUSIONS

These results suggest that the use of PM test batteries and experimental procedures are relevant for detecting performance variations in diverse clinical populations. Clinical implications and directions for future research are discussed.

Comparing different tests to detect early manifestation of prospective memory decline in aging

Objective: Prospective memory (PM) is the ability to remember to perform future intentions. Previous studies have demonstrated that, compared to a younger cohort, healthy older adults have impairments in PM. Considering the importance of early detection of age-related PM decline, the present study aims to compare the performance of healthy older adults using three well-known PM tests commonly used in clinical settings.Method: In the present study, we tested 70 older adults (65-95 years old) using the Cambridge Prospective Memory Test (CAMPROMPT), the Memory for Intentions Screening Test (MIST) and the Royal Prince Alfred Prospective Memory Test (RPA-ProMem). In order to compare performance across tests and the interaction between age and cues, we performed a linear mixed model with random intercept and random slopes. Moreover, additional mixed models with random intercept were run for analyzing the additional information provided by MIST and RPA-ProMem regarding delay responses, response modality effects and type of errors committed.Results: Our data showed a drop in PM performance as age increased detected by all three tests. Furthermore, CAMPROMPT was the most sensitive test to identify differences in PM for event-and time-based cues, at least for participants with 65-77 years old. When data were analyzed in term of delay responses, participants were more accurate for 2 min delay (MIST) and 30 in delay (RPA-ProMem). Participants were less accurate when response modality was "verbal" compared to "action" (MIST) and made more PM errors as age increased.Conclusions: Overall, the study provides important information regarding age-related PM decline and can help researchers as well as clinicians in deciding the preferred test to evaluate PM performance.

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.

Prospective memory in clinical populations

OBJECTIVE

Prospective memory (PM) has emerged as a form of episodic memory that is frequently impaired in a variety of clinical populations. Neuropsychologists who routinely evaluate these populations are often unaware of the possibility of PM deficits or the impact these deficits may have on everyday functioning. The objective of this special issue is to provide an overview of the nature of prospective deficits in a range of clinical populations, to discuss neuropsychological assessment techniques, and to critically evaluate management strategies.

METHOD

We solicited papers from established researchers and issued a general call for papers for the special issue on PM in clinical populations.

RESULTS

We received submissions from the nine authors that we solicited. These submissions range from developmental disorders, including autism, attention deficit hyperactivity disorder, and dyslexia; to disorders of adulthood, such as schizophrenia, HIV, brain injury, and multiple sclerosis; and finally disorders that tend to occur at older ages, such as Parkinson's disease and mild cognitive impairment. In addition, we have included four original research articles that provide novel data on other populations. These are children and adolescents with 22q11.2 deletion syndrome, first-degree relatives of people with schizophrenia, individuals with mild brain injury, and individuals with idiopathic REM sleep behavioral disorder.

CONCLUSIONS

The issue highlights the need for clinical neuropsychologists to be aware of the possible existence of deficits in PM in a variety of clinical populations and the importance of both assessment and management strategies to reduce the impact on daily life.

Do importance instructions improve time-based prospective remembering in autism spectrum conditions?

This study explored the impact of motivation on the memory for delayed intentions (so-called, prospective memory, PM) in autistic individuals. Specifically, we were interested in the effects of personal (i.e., receiving a reward) as compared to social motivation (i.e., performing a favour for someone). Given the well-established theory of mind deficits in autism, we expected autistic individuals to benefit more strongly from personal than social importance manipulations, whereas the opposite pattern was predicted for controls. Sixty-one adolescents with autism and 61 typically developing adolescents participated, with each group distributed equally to one of the three motivation conditions of standard, social and personal reward. Participants worked on a 2-back picture-based ongoing task in which a time-based PM task was embedded. A mixed 2 (Group) x 3 (Motivation condition) analysis of covariance with age, verbal and non-verbal abilities as covariates and correct PM responses as dependent variable indicated solely a main effect of group, with controls outperforming the autism group. In contrast to our expectations, there was no main effect of condition, no significant interaction, and none of the covariates had any significant impact. However, further planned analyses revealed that controls only outperformed autistic individuals in the personal reward condition. Controls performed significantly best when a personal reward was promised, whereas there were no significant differences between the motivation conditions for autistic individuals. Findings are discussed in terms of underlying processes.