Clinical measures of prospective memory in amnestic mild cognitive impairment

Further clarification of cognitive processes of prospective memory in schizophrenia by comparing eye-tracking and ecologically-valid measurements

The aim of this study is to compare ecologically-valid measure (the Cambridge Prospective Memory Test, CAMPROMPT) and laboratory measure (eye-tracking paradigm) in assessing prospective memory (PM) in individuals with schizophrenia spectrum disorders (SSDs). In addition, eye-tracking indices are used to examine the relationship between PM and other cognitive domains in SSDs patients. Initially, the study sample was formed by 32 SSDs patients and 32 healthy control subjects (HCs) who were matched in sociodemographic profile and the performance on CAMPROMPT. An eye-tracking paradigm was employed to examine the differences in PM accuracy and key cognitive processes (e.g., cue monitoring) between the two groups. Additional 31 patients were then recruited to investigate the relationship between PM cue monitoring, other cognitive functions, and the severity of clinical symptoms within the SSDs group. The monitoring of PM cue was reflected in total fixation time and total fixation counts for distractor words. Cognitive functions were assessed using the Chinese version of the MATRICS Consensus Cognitive Battery (MCCB). The Positive and Negative Syndrome Scale (PANSS) was applied to assess psychopathology. SSDs patients exhibited fewer total fixation counts for distractor words and lower PM accuracy compared to HCs, even though they were priori matched on CAMPROMPT. Correlation analysis within the SSDs group (63 cases) indicated a negative correlation between PM accuracy and PANSS total score, and a positive correlation with working memory and attention/vigilance. Regression analysis within the SSDs group revealed that higher visual learning and lower PANSS total scores independently predicted more total fixation counts on distractor words. Impairment in cue monitoring is a critical factor in the PM deficits in SSDs. The eye-tracking laboratory paradigm has advantages over the ecologically-valid measurement in identifying the failure of cue detection, making it a more sensitive tool for PM deficits in patients with SSDs.

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.

Development of the Virtual Kitchen Protocol for Prospective Memory: a virtual reality-based measure of everyday prospective memory abilities

INTRODUCTION

Prospective memory is the ability to remember to accomplish a task at a specified point in the future. While this cognitive ability has a large impact on daily functioning, it is rarely assessed during neuropsychological evaluations. Furthermore, existing clinical prospective memory measures are few in number and have significant limitations, including applicability to everyday functioning and appropriate norming for older adulthood. There are also many gaps in the literature on prospective memory, such as how environmental factors affect performance across the lifespan.

METHOD

In the current study, we develop and establish a new virtual reality-based measure of prospective memory, the Virtual Kitchen Protocol for Prospective Memory. Young adults (ages 18-29; n = 56), healthy older adults (ages 60-90; n = 94), and clinical older adults (ages 62-90; n = 30) were compared on their performances on both the developed virtual reality prospective memory test and a parallel paper-and-pencil prospective memory test to investigate the impact of test environment across participant group.

RESULTS

The Virtual Kitchen Protocol for Prospective Memory was found to adequately differentiate between young adult, healthy older adult, and clinical older adult populations - suggesting baseline ability for prospective memory assessment in clinical settings with older adults and potential for future improvement of neuropsychological evaluations. Additionally, the developed virtual prospective memory task appeared to mimic environmental factors in everyday life but did not replicate the benefit previously measured in healthy older adults' prospective memory ability in naturalistic settings.

CONCLUSIONS

Overall, the current study built upon extant knowledge of prospective memory in both normal and abnormal aging, suggesting future directions in replicating familiar home environments. Findings provided additional evidence toward future validation of virtual reality assessment tools in clinical neuropsychological evaluations of cognitive abilities, such as prospective memory, with both healthy and clinical older adult populations.

Identifying prospective memory deficits in multiple sclerosis: Preliminary evaluation of the criterion and ecological validity of a single item version of the memory for intentions test (MIST)

Objectives: Difficulties with prospective memory (PM) are not routinely assessed in persons with multiple sclerosis (MS) even though they can impact daily functioning. This study aimed to examine the preliminary criterion and ecological validity of a highly abbreviated Memory for Intentions Test (MIST) intended to serve as an initial screening of PM in persons with MS. Methods: Participants (n = 112) were classified as impaired if they performed 1.5 standard deviations below the normative mean on the MIST. Individual MIST trials with adequate difficulty and discriminability were examined using receiver operating characteristic analyses, with their classification accuracies, sensitivities, and specificities compared to each other. Regressions were run to evaluate their ecological validity, with appointment attendance and employment as the outcomes. Results: Two trials had a classification accuracy of ≥80%: Trial 3 (79% sensitivity, 84% specificity) and Trial 4 (57% sensitivity, 91% specificity). These two trials had comparable specificity (p=.127), with Trial 3 having slightly higher sensitivity (p=.083). Only Trial 4 was significantly associated with appointment attendance (b = 1.63, p=.047) and unemployment (aOR = 11.20, p=.027). Discussion:Trial 4 of the MIST, a verbal task with a time-based cue that requires participants to complete a pre-specified response after a 15-minute delay, has the potential to be a screener for PM.

Identifying Mild Cognitive Impairment by Using Human-Robot Interactions

BACKGROUND

Mild cognitive impairment (MCI), which is common in older adults, is a risk factor for dementia. Rapidly growing health care demand associated with global population aging has spurred the development of new digital tools for the assessment of cognitive performance in older adults.

OBJECTIVE

To overcome methodological drawbacks of previous studies (e.g., use of potentially imprecise screening tools that fail to include patients with MCI), this study investigated the feasibility of assessing multiple cognitive functions in older adults with and without MCI by using a social robot.

METHODS

This study included 33 older adults with or without MCI and 33 healthy young adults. We examined the utility of five robotic cognitive tests focused on language, episodic memory, prospective memory, and aspects of executive function to classify age-associated cognitive changes versus MCI. Standardized neuropsychological tests were collected to validate robotic test performance.

RESULTS

The assessment was well received by all participants. Robotic tests assessing delayed episodic memory, prospective memory, and aspects of executive function were optimal for differentiating between older adults with and without MCI, whereas the global cognitive test (i.e., Mini-Mental State Examination) failed to capture such subtle cognitive differences among older adults. Furthermore, robot-administered tests demonstrated sound ability to predict the results of standardized cognitive tests, even after adjustment for demographic variables and global cognitive status.

CONCLUSION

Overall, our results suggest the human-robot interaction approach is feasible for MCI identification. Incorporating additional cognitive test measures might improve the stability and reliability of such robot-assisted MCI diagnoses.

Cognitive performance in older adults at three months following mild traumatic brain injury

Introduction: In the context of limited research assessing outcomes following mild traumatic brain injury (mTBI) in older adults, this study evaluated cognitive outcomes through prospective memory, and expected that performance of an older mTBI group (≥65 years) would be lower compared to orthopedic and community controls. The study also explored whether cognitive resources (retrospective memory, executive function) moderated any association between presenting Glasgow Coma Scale (GCS) and prospective memory.Method: At three-months post-injury, a mTBI group (n = 39), an orthopedic control group (n = 63), and a community control group (n = 46) completed a neuropsychological assessment, including (i) prospective memory, using a standardized paper-and-pencil task (Cambridge Prospective Memory Test), an augmented reality task and a naturalistic task, and (ii) standardized measures of retrospective memory (Hopkins Verbal Learning Test) and executive function (Trail Making Test). Group performances were compared, and bootstrapped moderation analyses evaluated the role of cognitive resources in the relationship between GCS and prospective memory outcome.Results: The mTBI group, as compared to community controls, performed significantly lower on the augmented reality task (d = -0.64 to d = -0.79), and there was a small-moderate but non-significant effect (d = -0.45) on the naturalistic task. There were no differences between the mTBI group and orthopedic controls. Retrospective memory was a unique predictor of the augmented reality task (B = 1.83) and moderated the relationship between presenting GCS and the naturalistic task (B = -5.60). Executive function moderated the association between presenting GCS and augmented reality (B = -1.13) and naturalistic task (B = -1.57).Conclusions: At three-months post-mTBI, older adults are at risk of poor cognitive performance; and the relationship between GCS and prospective memory can be moderated by cognitive resources. Further follow-up is indicated to determine whether impairments resolve or persist over time.

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.

Effects of Mental Imagery on Prospective Memory: A Process Analysis in Individuals with Amnestic Mild Cognitive Impairment

INTRODUCTION

Prospective memory (PM) is a multiphasic cognitive function important for autonomy and functional independence but is easily disrupted by pathological aging processes. Through cognitive simulation of perceptual experiences, mental imagery could be an effective compensatory strategy to enhance PM performance. Nevertheless, relevant research in individuals with amnestic mild cognitive impairment (MCI) has been limited, and the underlying mechanism of the therapeutic effect has not been sufficiently elucidated. The present study aimed to examine complex PM performances and the effect of mental imagery on each phase in older adults with MCI and to investigate the underlying cognitive mechanism from a process perspective.

METHODS

Twenty-eight MCI and 32 normal aging controls completed a seminaturalistic PM task, in addition to a series of neuropsychological tests. Participants from each group were randomly assigned to a mental imagery condition or a standard repeated encoding condition before performing the PM task. Four indices were used to measure performance in the intention formation, intention retention, intention initiation, and intention execution phases of PM. Performances in each phase was compared between the 2 diagnostic groups and the 2 instruction conditions.

RESULTS

The MCI group performed worse than the normal aging group in the intention formation and intention retention phases. The participants in the mental imagery condition performed significantly better than those in the standard condition during the intention formation, intention retention, and intention execution phases, regardless of the diagnostic group. Moreover, there was a significant interaction between the group and condition during intention retention, showing that people with MCI benefited even more from mental imagery than normal aging in this phase. Performance in the intention retention phase predicted performance in the intention initiation and intention execution phases.

DISCUSSION

PM deficits in MCI mainly manifest during planning and retaining intentions. Mental imagery was able to promote performance in all but the initiation phase, although a trend for improvement was observed in this phase. The effects of mental imagery may be exerted in the intention retention phase by strengthening the PM cue-action bond, thereby facilitating the probability of intention initiation and bolstering fidelity to the original plan during intention execution.

Prospective memory and spontaneous compensatory mnemonic strategy use in the laboratory and daily life in HIV-associated neurocognitive disorders

INTRODUCTION

Older adults with HIV-associated neurocognitive disorders (HAND) are at high risk for deficits in the resource-demanding, strategic aspects of prospective memory (PM) that can adversely affect health outcomes. This study examined the frequency and correlates of spontaneous compensatory strategy use during a laboratory-based PM task and its associations with the use of mnemonic strategies in daily life.

METHOD

Participants included 53 older adults with HAND, 89 older persons with HIV without HAND, and 62 seronegatives who completed the Cambridge Prospective Memory Test (CAMPROMPT), on which the type, frequency, and quality of their compensatory strategy use was quantified. Participants also completed self-report measures of PM symptoms and the frequency of mnemonic compensatory strategy use in daily life.

RESULT

There were no significant group-level effects on strategy use during the CAMPROMPT. Persons with HAND had moderately lower time-, but not event-based PM scores. Higher compensatory strategy use was strongly associated with better PM, particularly for time-based cues. Moreover, higher compensatory strategy use on the CAMPROMPT was associated with more frequent general mnemonic strategy use in daily life, and specifically with more frequent use of internal PM strategies (e.g., visualization) for medication adherence.

CONCLUSION

Spontaneous compensatory mnemonic strategy use can support PM performance among older adults with HAND in the laboratory. Strategy use in the laboratory may be a marker for the extent to which older adults with HAND use other compensatory strategies to support memory in their daily life. Future studies may examine whether compensatory mnemonic strategies can be taught and used to support PM in the daily lives of older persons with HIV disease.

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.

Early detection of cognitive disturbances in mild cognitive impairment: a systematic review of observational studies

Mild cognitive impairment (MCI) is an intermediate state between normal cognition and early dementia and is not considered as a typical outcome of brain aging. It has been estimated that 10% to 20% of individuals above 65 years of age will be diagnosed as having MCI. The increased rate of dementia and the importance of early detection of its forerunners have encouraged researchers to focus on detecting MCI and modifiable risk factors with the hope of developing better ways of managing dementia and its consequences. The main aim of this study was to systematically review the related literature concerning the cognitive changes in the spectrum of cognitive aging to cognitive impairment. Articles included in this review were identified through searching the databases of PubMed, Psych Info, Embase, ProQuest, and Scopus. Many domains like verbal memory, language, executive function, visual memory, attentional skills, and working memory showed acceptable predictive power. Testing subdomains such as executive function, speed of processing, working memory and semantic language are critical and others may indicate some suggestions for further clinical deteriorations in normal individuals. Although various cognitive instruments have been used for evaluation of impaired cognitive domains, it remains challenging to select the most appropriate ones having high-level accuracy and their related cognitive subdomains. It also revealed that none of the identified cognitive domains solely fulfilled the criteria for MCI screening; in clinical settings, multiple neuropsychological batteries may be used for one single cognitive domain, while longitudinal studies prefer the use of at least two cognitive measures for each domain to improve accuracy and research settings might focus on only a single neuropsychological test. However, along with episodic memory, testing for amnestic MCI, executive function could increase the chance of early detection of MCI. Executive control has been found to deteriorate the earliest in MCI patients.

Prospective memory in schizophrenia: A meta-analysis of comparative studies

BACKGROUND

Impairment of prospective memory (PM) in schizophrenia has gained increasing attention. This meta-analysis systematically examined PM impairment in schizophrenia.

METHODS

Both English (PubMed, PsycINFO, EMBASE, and Cochrane Library) and Chinese (WanFang, Chinese Biomedical and China Journal Net databases) databases were systematically searched from their inception until August 14, 2017. Case-control studies of PM in schizophrenia were included. Standardized mean differences (SMDs) and their 95% confidence interval (CI) were calculated using the random-effects model.

RESULTS

Twenty-nine case-control studies (n = 2492) were included in the analyses. The overall and three subtypes of PM were compared between patients with schizophrenia (n = 1284) and healthy controls (n = 1208). Compared to healthy controls, patients performed significantly poorer in overall (SMD = -1.125), time-based (SMD = -1.155), event-based (SMD = -1.068), and activity-based PM (SMD = -0.563). Subgroup analyses revealed significant differences between older and younger patients (SMD = -1.398 vs. -0.763), higher male predominance and no sex predominance (SMD = -1.679 vs. -0.800), lower and higher education level (SMD = -1.373 vs.-0.637), chronic and first-episode patients (SMD = -1.237 vs. -0.641) and between eco-valid and dual-task laboratory measurements (SMD = -1.542 vs. -0.725) regarding overall PM. Meta-regression analysis showed that higher negative symptom score was significantly associated with more severe overall PM impairment in patients (P = 0.022).

CONCLUSIONS

In this meta-analysis the overall PM and all its subtypes, particularly the time-based PM, were significantly impaired in schizophrenia.

Memory complaints in amnestic Mild Cognitive Impairment: More prospective or retrospective?

OBJECTIVE

Patients with amnestic Mild Cognitive Impairment (aMCI), usually considered an early stage of Alzheimer's disease, have deficits not only in retrospective memory (RM), that is, recalling of past events, words or people, but also on prospective memory (PM), the cognitive ability of remembering to execute delayed intentions in the future. This study investigated whether patients with aMCI refer more PM complaints as compared with RM complaints, and whether this might depend upon short-term vs long-term items or time-based vs event-based tasks.

METHODS

Patients with aMCI (n = 178) and healthy controls (n = 160) underwent the Prospective and Retrospective Memory Questionnaire (PRMQ), a 16-item instrument to appraise differences between PM and RM complaints, as well as a general mental state examination, a subjective memory complaints questionnaire, objective memory tests, and assessment of depressive symptoms and activities of daily living.

RESULTS

Patients with aMCI reported more memory complaints evaluated with the PRMQ (total score = 44.3 ± 10.8) as compared with controls (36.7 ± 9.8, P < 0.001). Using a mixed effect repeated-measures analysis of covariance (ANCOVA) showed that participants generally referred more retrospective than prospective memory complaints. Patients with aMCI had significantly more complaints on short-term memory as compared with long-term memory, and more complaints in time-based (auto-initiated) as compared with event-based tasks, than healthy controls.

CONCLUSION

Patients with aMCI reported significantly more difficulties on short-term memory, presumably reflecting internal temporal lobe pathology typical of Alzheimer's disease, and more complaints on time-based tasks, which are cognitively very demanding, but did not seem particularly troubled regarding prospective memory.

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

OBJECTIVE

There has been a recent rapid development of research characterizing prospective memory performance in mild cognitive impairment (MCI) in older age. However, this body of literature remains largely separated from routine clinical practice in neuropsychology. Furthermore, there is emerging evidence of effective interventions to improve prospective memory performance. Therefore, our objective in this article was to offer a clinical neuropsychological perspective on the existing research in order to facilitate the translation of the evidence-base into clinical practice.

METHOD

By conducting a critical review of the existing research related to prospective memory and MCI, we highlight how this data can be introduced into clinical practice, either within diagnostic assessment or clinical management.

CONCLUSIONS

Prospective memory is impaired in older adults with MCI, with a pattern of performance that helps with differential diagnosis from healthy aging. Clinical neuropsychologists are encouraged to add prospective memory assessment to their toolbox for diagnostic evaluation of clients with MCI. Preliminary findings of prospective memory interventions in MCI are promising, but more work is required to determine how different approaches translate to increasing independence in everyday life.

A review of prospective memory in individuals with acquired brain injury

OBJECTIVE

Prospective memory (PM) deficits have emerged as an important predictor of difficulty in daily life for individuals with acquired brain injury (BI). This review examines the variables that have been found to influence PM performance in this population. In addition, current methods of assessment are reviewed with a focus on clinical measures. Finally, cognitive rehabilitation therapies are reviewed, including compensatory, restorative and metacognitive approaches.

METHOD

Preferred reporting items for systematic reviews and meta-analyses guidelines were used to identify studies. Studies were added that were identified from the reference lists of these.

RESULTS

Research has begun to elucidate the contributing variables to PM deficits after BI, such as attention, executive function and retrospective memory components. Imaging studies have identified prefrontal deficits, especially in the region of BA10 as contributing to these deficits. There are now several clinical measures available with good psychometric properties. Rehabilitation techniques have mostly focused on compensatory strategies, but, in addition, some restorative and metacognitive approaches have shown preliminary promise.

CONCLUSIONS

PM deficits are a common and important deficit after BI. Clinical evaluation is recommended and further understanding of rehabilitation techniques is needed.

Diagnostic Accuracy of Memory Measures in Alzheimer's Dementia and Mild Cognitive Impairment: a Systematic Review and Meta-Analysis

With an increasing focus on biomarkers in dementia research, illustrating the role of neuropsychological assessment in detecting mild cognitive impairment (MCI) and Alzheimer's dementia (AD) is important. This systematic review and meta-analysis, conducted in accordance with PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) standards, summarizes the sensitivity and specificity of memory measures in individuals with MCI and AD. Both meta-analytic and qualitative examination of AD versus healthy control (HC) studies (n = 47) revealed generally high sensitivity and specificity (≥ 80% for AD comparisons) for measures of immediate (sensitivity = 87%, specificity = 88%) and delayed memory (sensitivity = 89%, specificity = 89%), especially those involving word-list recall. Examination of MCI versus HC studies (n = 38) revealed generally lower diagnostic accuracy for both immediate (sensitivity = 72%, specificity = 81%) and delayed memory (sensitivity = 75%, specificity = 81%). Measures that differentiated AD from other conditions (n = 10 studies) yielded mixed results, with generally high sensitivity in the context of low or variable specificity. Results confirm that memory measures have high diagnostic accuracy for identification of AD, are promising but require further refinement for identification of MCI, and provide support for ongoing investigation of neuropsychological assessment as a cognitive biomarker of preclinical AD. Emphasizing diagnostic test accuracy statistics over null hypothesis testing in future studies will promote the ongoing use of neuropsychological tests as Alzheimer's disease research and clinical criteria increasingly rely upon cerebrospinal fluid (CSF) and neuroimaging biomarkers.

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.

Face-name memory training in subjective memory decline: how does office-based training translate to everyday situations?

This study aimed to examine whether people with subjective memory decline (SMD) benefit from face-name memory training (single session) as much as older adult controls in an office-based setting. Approximately 2 months later, groups were reassessed for translation to a naturalistic setting. In the office setting, there was a significant interaction between stimulus type (cued name; uncued name) and training condition (spaced retrieval, semantic association, no training), but no group differences nor interactions. Semantic association was only beneficial for cued names, whereas spaced retrieval was beneficial in cued and uncued conditions. In the naturalistic setting, however, there were no training effects. Naturalistic performance was predicted by demographics, cognition, and motivation. All groups reported improved memory control beliefs and contentment. Our study demonstrates the benefit of simple memory strategies for older adults, including those with SMD, in office-based settings. Translation to everyday settings is complex and may require prior intervention to increase motivation.

Clinical Utility of the Envelope Task in Mild Cognitive Impairment and Dementia

Objective: Prospective memory (PM) is a cognitive function defined as the ability to perform an intention at an appropriate moment in the future. In the aging population, PM is essential for maintaining independent daily living. Introduced as a simple and quick way to assess PM in clinical settings, the envelope task has to date received very limited empirical and practical interest. Methods: The present study investigated the task’s clinical utility in detecting PM impairment in a sample composed of 49 healthy older adults (OA), 41 patients with Alzheimer’s disease, and 64 individuals with amnestic and nonamnestic mild cognitive impairment (MCI) of heterogeneous etiology: 17 of idiopathic nature, 20 presenting an idiopathic rapid-eye movement sleep behaviour disorder, and 27 patients diagnosed with idiopathic Parkinson’s disease. Results: The envelope task was highly sensitive and specific in discriminating Alzheimer’s disease patients from OA. Although it was specific in distinguishing MCI individuals from OA, its sensitivity was modest, especially in patients presenting a nonamnestic MCI subtype. Conclusions: Given its high specificity and simple low-cost administration procedure, the envelope task is a promising instrument for clinicians who seek to rapidly assess PM impairment in their daily practice.

Prospective memory in subjective cognitive decline: a preliminary study on the role of early cognitive marker in dementia

Accumulating evidence shows that subjective cognitive decline (SCD) without impairment on conventional neuropsychological tests may indicate increased risk for Alzheimer disease. Previous studies of mild cognitive impairment have demonstrated the potential role of prospective memory (PM) in the early detection of cognitive decline. We thus aimed to investigate the performance of people with SCD on PM tasks relative to their healthy controls (HCs). Forty-one participants with SCD and demographically matched HCs received regular cognitive testing as well as 2 single-trial naturalistic time-based and event-based PM tasks. Statistical analyses showed that the individuals with SCD performed worse on the time-based PM task, especially on the prospective component, when compared with their HCs. Our findings suggest that PM, especially the time-based one on the prospective component, may be an early cognitive marker of dementia. This implies an underlying difficulty among subjects with SCD in self-initiation that exacerbates their memory difficulties. Further investigation on a large scale is needed.

The clinical utility of informants' appraisals on prospective and retrospective memory in patients with early Alzheimer's disease

Increasing studies suggest the importance of including prospective memory measures in clinical evaluation of dementia due to its sensitivity and functional relevance. The Prospective and Retrospective Memory Questionnaire (PRQM) is originally a self-rated memory inventory that offers a direct comparison between prospective and episodic memory. However, the informant's report has been recognized as a more valid source of cognitive complaints. We thus aimed to examine the validity of the informant-rated form of the PRMQ in assessing memory function of the patients and in detecting individuals with early dementia. The informants of 140 neurological outpatients with memory complaints completed the Taiwan version of the PRMQ. Tests of prospective memory, short-term memory, and general cognitive ability were also administered to non-demented participants and patients with early stages of Alzheimer's disease (AD). Results showed significant relationships between the PRMQ ratings and objective cognitive measures, and showed that higher ratings on the PRMQ were associated with increasing odds of greater dementia severity. Receiver operative characteristic (ROC) curves showed an adequate ability of the PRMQ to identify patients with dementia (93% sensitivity and 84% specificity). Hierarchical regression revealed that the PRMQ has additional explanatory power for dementia status after controlling for age, education and objective memory test results, and that the prospective memory subscale owns predictive value for dementia beyond the retrospective memory subscale. The present study demonstrated the external validity and diagnostic value of informants' evaluation of their respective patients' prospective and retrospective memory functioning, and highlighted the important role of prospective memory in early dementia detection. The proxy-version of the PRMQ is a useful tool that captures prospective and episodic memory problems in patients with early AD, in combination with standardized cognitive testing.

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

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

Prospective memory on a novel clinical task in older adults with mild cognitive impairment and subjective cognitive decline

Despite the relevance of prospective memory to everyday functioning and the ability to live independently, prospective memory tasks are rarely incorporated into clinical evaluations of older adults. We investigated the validity and clinical utility of a recently developed measure, the Royal Prince Alfred Prospective Memory Test (RPA-ProMem), in a demographically diverse, non-demented, community-dwelling sample of 257 older adults (mean age = 80.78 years, 67.7% female) with amnestic mild cognitive impairment (aMCI, n = 18), nonamestic mild cognitive impairment (naMCI, n = 38), subjective cognitive decline (SCD, n = 83) despite intact performance on traditional episodic memory tests, and healthy controls (HC, n = 118). Those with aMCI and naMCI performed significantly worse than controls on the RPA-ProMem and its subtasks (time-based, event-based, short-term, long-term). Also, those with SCD scored significantly lower than controls on long-term, more naturalistic subtasks. Additional results supported the validity and inter-rater reliability of the RPA-ProMem and demonstrated a relation between test scores and informant reports of real-world functioning. The RPA-ProMem may help detect subtle cognitive changes manifested by individuals in the earliest stages of dementia, which may be difficult to capture with traditional episodic memory tests. Also, assessment of prospective memory can help guide the development of cognitive interventions for older adults at risk for dementia.

Deficits in retrospective and prospective components underlying prospective memory tasks in amnestic mild cognitive impairment

OBJECTIVES

By use of purer indices of PM and RM components than previous studies and adoption of three PM task types, the present study aimed to investigate the deficits of these two components underlying global impairment at a PM task in individuals with amnestic mild cognitive impairment (aMCI).

METHODS

Nineteen aMCI patients and 22 normal controls were examined on event-, time- and activity-based PM tasks. Separate scores were obtained for initiation of intentions (i.e. PM component) and for the content of the intentions (i.e. RM component).

RESULTS

Individuals with aMCI achieved lower PM component (but not RM component) scores than NCs across all three PM tasks. Furthermore, there was a trend for greater impairment on activity-based than time-based and event-based PM tasks, but which did not reach significance. In addition, a significant association between PM component and an executive function test was observed in aMCI group. PM task performance, especially activity-based PM task performance and PM component performance, successfully discriminated between aMCI and NC and was able to do so above and beyond the executive function tests.

CONCLUSIONS

Our finding suggested that the deficits in PM component, related to a disrupted executive control processes, were responsible for the impaired ability of individuals with aMCI to realize delayed intentions.