On the neuropsychology of metamemory: Contributions from the study of amnesia and dementia

Neural predictors of cognitive improvement by multi-strategic memory training based on metamemory in older adults with subjective memory complaints

Previous studies have indicated that memory training may help older people improve cognition. However, evidence regarding who will benefit from such memory trainings has not been fully discovered yet. Understanding the clinical and neural inter-individual differences for predicting cognitive improvement is important for maximizing the training efficacy of memory-training programs. The purpose of this study was to find the individual characteristics and brain morphological characteristics that predict cognitive improvement after a multi-strategic memory training based on metamemory concept. Among a total of 49 older adults, 39 participated in the memory-training program and 10 did not. All of them underwent brain MRIs at the entry of the training and received the neuropsychological tests twice, before and after the training. Stepwise regression analysis showed that lower years of education predicted cognitive improvement in the training group. In MRI, thinner cortices of precuneus, cuneus and posterior cingulate gyrus and higher white matter anisotropy of the splenium of corpus callosum predicted cognitive improvement in the training group. Old age, lower education level and individual differences in cortical thickness and white matter microstructure of the episodic memory network may predict outcomes following multi-strategic training.

Self-Awareness for Memory Impairment in Amnestic Mild Cognitive Impairment: A Longitudinal Study

AIM

To assess memory impairment insight as a predictor of dementia and Alzheimer's disease (AD) in amnestic mild cognitive impairment (MCI).

METHODS

To verify whether the awareness of memory impairment assessed by Geriatric Depression Scale (GDS) was associated with the risk of progression to dementia and AD in a cohort of MCI, we used a Cox regression model adjusted for age, sex, education, subtypes of amnestic MCI, Mini-Mental State Examination, Cumulative Illness Rating Scale severity index, and apolipoprotein E genotype.

RESULTS

During a follow-up of 27.7 (20.8) months, 205 (63.3%) of 324 patients with amnestic MCI progressed to dementia, including 141 to AD. No association was found in the unadjusted, partially adjusted (for sociodemographic variables), and fully adjusted multivariate Cox analysis between the awareness of memory impairment and the progression to dementia and AD.

DISCUSSION

Awareness or anosognosia of memory deficits, identified by GDS, is not useful to predict progression to dementia of patients with amnestic MCI.

Metacognition and Perspective-Taking in Alzheimer's Disease: A Mini-Review

Metacognition refers to the monitoring and regulation of cognitive processes and its impairment can lead to a lack of self-awareness of deficits, or anosognosia. In the context of different neurological and psychiatric disorders (e.g., traumatic brain injury, dementia, and schizophrenia), studies have shown that patients who present impairments in metacognitive abilities may be able to recognize such difficulties in others and in themselves when exposed to material in a third-person perspective. Considering that metacognitive impairments are an important characteristic of dementia, especially in Alzheimer's Disease (AD), studies of the relationship between metacognition and perspective-taking may be relevant to improve the quality of life of people with dementia. The current paper first briefly addresses the theme of metacognition and the impact of metacognitive deficits in people with AD. The focus then turns to the relationship between metacognition and perspective-taking in different neurological and psychiatric disorders, particularly AD. This relationship is also discussed based on theoretical models, particularly the Cognitive Awareness Model (CAM). Specifically, the CAM suggests the existence of distinct memory systems for self- and other-information, an idea which is supported by neuroimaging findings. We suggest that the Default Mode Network, as it has been shown to be implicated in self vs. other processing and is affected early in AD, could explain the impact of perspective-taking on awareness of deficits in AD. Finally, we present possible clinical implications of the relationship between metacognition and perspective-taking in AD. Indeed, we considered the possibility of improving patient's awareness through the use of a third-person perspective, which, consequently, may decrease the negative impacts of anosognosia in AD.

Awareness of deficits in Alzheimer's disease patients: analysis of performance prediction discrepancies

AIM

Unawareness has been operationalized in terms of a discrepancy between the patient's self-reports and three main categories of standards: judgment of a relative, clinical assessment, and objective test performance. The purpose of this study was to develop a new measure of deficit unawareness based on multidimensional, isomorphic, simple tasks and to examine the relationship between this measure and neuropsychological tests. METHODS : Analysis was conducted on cognitive performance prediction discrepancies in a sample of Alzheimer's disease (AD) patients and a matched comparison group.

RESULTS

Patients rated their cognitive functioning more highly than their performance, but their overall self-reports were lower than the overall self-reports of the comparison group. AD patients performed significantly lower than their predicted scores in all Dementia Rating Scale (DRS) domains, in contrast to comparison participants, who did not consistently perform significantly lower across domains. All unawareness scores were moderately inter-correlated, except for memory, and all unawareness scores with the exception of memory were correlated with overall neuropsychological functioning.

CONCLUSION

A methodological and conceptual difficulty has been identified, and this raises the issue of the generalizability of studies with a focus on memory unawareness. The method proposed seems a good tool to assess the relationships between unawareness and several different aspects of cognitive functioning, in particular executive functioning.

Impaired awareness of deficits in Alzheimer's disease: the role of everyday executive dysfunction

The present study analyzed the awareness of deficits in 117 mild Alzheimer's disease participants. Since few studies have examined the cognitive and behavioral domains of reduced awareness in detail, we performed a domain-specific assessment using the Awareness of deficit Questionnaire - Dementia scale with the novel aim of describing the relationship with everyday executive dysfunction. Through the use of the subtests of the Behavioral Assessment of the Dysexecutive Syndrome, we hypothesized that executive cognitive functions may play an important role in the reduced awareness of deficits. We also considered other variables of interest to provide a novel comprehensive explanation of this phenomenon. Our first approach to the study was a factor analysis considering the role of these variables in the awareness of deficits; subsequently, regression analysis models were used to define which variables were associated with a reduction of awareness in cognitive and behavioral domains. In particular, the factors retained from the factor analysis, in terms of inhibition, self-monitoring, set-shifting, and mood orientation changes, appear to be important skills for awareness of instrumental activities of daily living (R(2) = .32). We also found hypo manic mood orientation and a tendency through apathy to be prominent indications of reduced behavioral awareness (R(2) = .13).

[Awareness of memory deficit in patients with amnesia]

This study investigated the impaired self-awareness (ISA) of memory deficit in 63 brain injury patients with amnesia. The purpose of this study was (a) to elucidate the relation between degree of ISA and memory deficit measured by several neuropsychological memory tests, (b) to examine the relation between degree of ISA and the post-injury duration, and (c) to investigate the influence of ISA on independent behaviors and occupational outcomes. We measured ISA by using discrepancy methods, which is the difference of the evaluated frequency of the patient's memory problems in daily living as judged by the patients themselves and by their family caregivers. The results showed that the patients underestimated their memory problems more than their caregivers did. Regarding the relationship of ISA and neuropsychological memory tests, performance involving orientation, delayed recall of a story, and abstract figures (Rey Complex Figure Test) were related. Moreover, the degree of ISA influenced independent behavior and occupational outcomes. However, the duration from post-injury did not influence the degree of ISA. These results indicate that not only an approach to enhance neuropsychological memory functions but also an approach to develop an appropriate self-awareness of memory deficit is important for independent living and social reintegration.

Medial prefrontal functional connectivity--relation to memory self-appraisal accuracy in older adults with and without memory disorders

It is tentatively estimated that 25% of people with early Alzheimer's disease (AD) show impaired awareness of disease-related changes in their own cognition. Research examining both normative self-awareness and altered awareness resulting from brain disease or injury points to the central role of the medial prefrontal cortex (MPFC) in generating accurate self-appraisals. The current project builds on this work - examining changes in MPFC functional connectivity that correspond to impaired self-appraisal accuracy early in the AD time course. Our behavioral focus was self-appraisal accuracy for everyday memory function, and this was measured using the Memory Function Scale of the Memory Awareness Rating Scale - an instrument psychometrically validated for this purpose. Using regression analysis of data from people with healthy memory (n=12) and people with impaired memory due to amnestic mild cognitive impairment or early AD (n=12), we tested the hypothesis that altered MPFC functional connectivity - particularly with other cortical midline structures and dorsolateral prefrontal cortex - explains variation in memory self-appraisal accuracy. We spatially constrained (i.e., explicitly masked) our regression analyses to those regions that work in conjunction with the MPFC to evoke self-appraisals in a normative group. This empirically derived explicit mask was generated from the result of a psychophysiological interaction analysis of fMRI self-appraisal task data in a separate, large group of cognitively healthy individuals. Results of our primary analysis (i.e., the regression of memory self-appraisal accuracy on MPFC functional connectivity) were generally consistent with our hypothesis: people who were less accurate in making memory self-appraisals showed attenuated functional connectivity between the MPFC seed region and proximal areas within the MPFC (including subgenual anterior cingulate cortex), bilateral dorsolateral prefrontal cortex, bilateral caudate, and left posterior hippocampus. Contrary to our expectations, MPFC functional connectivity with the posterior cingulate was not significantly related to accuracy of memory self-appraisals. Results reported here corroborate findings of variable memory self-appraisal accuracy during the earliest emergence of AD symptoms and reveal alterations in MPFC functional connectivity that correspond to impaired memory self-appraisal.

Metacognitive monitoring in moderate and severe traumatic brain injury

The ability to engage in self-reflective processes is a capacity that may be disrupted after neurological compromise; research to date has demonstrated that patients with traumatic brain injury (TBI) show reduced awareness of their deficits and functional ability compared to caretaker or clinician reports. Assessment of awareness of deficit, however, has been limited by the use of subjective measures (without comparison to actual performance) that are susceptible to report bias. This study used concurrent measurements from cognitive testing and confidence judgments about performance to investigate in-the-moment metacognitive experiences after moderate and severe traumatic brain injury. Deficits in metacognitive accuracy were found in adults with TBI for some but not all indices, suggesting that metacognition may not be a unitary construct. Findings also revealed that not all indices of executive functioning reliably predict metacognitive ability.

Anosognosia for memory impairment in Alzheimer's disease

Stewart G, McGeown WJ, Shanks MF, Venneri A. Anosognosia for memory impairment in Alzheimer's disease. Objective To investigate whether patients with Alzheimer's disease (AD) were able to alter their awareness of memory deficits after exposure to a memory task.

METHODS

Thirty normal older adults and 23 mild AD patients participated in the study. Anosognosia was assessed using discrepancies between self- and informant-evaluations of cognitive and functional performance. Participants estimated their performance on the Verbal Paired Associates task at different points in time (before, immediately after the task and after a 1-h delay).

RESULTS

AD patients were generally less able to judge their memory abilities than healthy older adults, and tended to overestimate their task performance beforehand. Their prediction accuracy increased immediately after the task, but after a 1-h delay, they again misjudged their abilities at pretesting accuracy levels. Self-carer discrepancy scores of awareness of deficits in memory and other areas correlated significantly with memory tests but not with other neuropsychological tasks in the assessment, and larger discrepancy scores were associated with poorer performance.

CONCLUSION

AD patients can monitor their task performance online, but are unable to maintain awareness of their deficits over time. Loss of awareness of memory deficits (or of any other deficits) in early stage AD may indicate damage to a system which updates a personal knowledge base with recent information. Failure to retain this information impedes abstraction from episodic to semantic memory.

Primary and secondary anosognosia for memory impairment in patients with Alzheimer's disease

The neuropsychology of anosognosia for memory impairment in Alzheimer's disease (AD) was examined in 92 AD patients and 92 case matched individuals for comparison, using three quantitative methods of assessment: Experimenter Rating Scale (ERS), Objective Judgement Discrepancy (OJD) and Subjective-Rating Discrepancy (SRD). The OJD showed significant domain specific correlations with memory functioning as well as a significant correlation with susceptibility to intrusional errors. Memory or executive dysfunction may affect the immediate ability to judge cognitive performance in a domain specific manner (secondary anosognosia). Longer-term awareness of cognitive deficit appears less influenced by impaired basic cognitive functions, than by the decline of metacognitive function (primary anosognosia).

Objective metamemory testing captures awareness of deficit in Alzheimer's disease

For reasons that remain unknown, there is marked inter-person variability in awareness of episodic memory loss in patients with Alzheimer's disease (AD). Existing research designs, primarily subjective in nature, have been at a relative disadvantage for evaluating disordered metamemory and its relation to the clinical and neuropathological heterogeneity of AD, as well as its prognosis for various disease outcomes. The current study sought to establish an objective means of evaluating metamemory in AD by modifying traditional metacognitive paradigms in which participants are asked to make predictions regarding their own memory performance. Variables derived from this measure were analyzed in relation to clinically rated awareness for memory loss. As predicted, a range of awareness levels existed across patients with mild to moderate AD (n=24) and clinical ratings of awareness (CRA) were significantly associated with verbal episodic memory monitoring (r = .46, p = .03). Further, patients who were rated as aware of their memory loss remained well calibrated over the course of the task whereas those rated as relatively unaware grew over-confident in their predictions [F (1, 33) = 4.19, p = .02]. Findings suggest that over-confidence may be related to impaired online error recognition and compromised use of metamemory strategies such as the Memory for Past Test (MPT) heuristic. Importantly, clinically rated awareness did not vary as a function of demographic variables, global cognition, or verbal memory. However, participants characterized as relatively unaware were impaired on a nonverbal memory task as compared to aware participants [F (1, 20) = 6.98, p = .02]. The current study provides preliminary support for the use of a recognition-based verbal episodic memory monitoring task as a quantitative measure of awareness for memory loss in AD, and offers insight into the manner in which metamemory breaks down. Discrepancies in nonverbal memory across the two awareness groups provide preliminary support for the idea that metamemory variability in AD may be related to the neuroanatomic presentation of the disease, with disordered awareness potentially reflective of a critical level of right hemisphere involvement.

Awareness of deficit in multiple sclerosis

The present study examined awareness of deficits among individuals with multiple sclerosis (MS). A total of 74 pairs of persons with MS and their significant others participated. Awareness of cognitive deficit was measured by discrepancy scores between patient reports of their cognitive abilities and objective test results. Awareness of functional deficit was measured by the discrepancy between the patient and significant other reports of the functional abilities of the patient. Results suggest that about one third of MS patients have diminished awareness of their cognitive and/or functional deficits. Unawareness of deficit was more common among patients with secondary-progressive MS than among those with relapse-remitting MS. Executive dysfunction was strongly associated with unawareness of cognitive deficits but not unawareness of functional deficits. Unawareness of cognitive deficits and unawareness of functional deficits appear to be tapping different aspects of unawareness of deficit.

Preserved metamemorial ability in patients with mild Alzheimer's disease: shifting response bias

Patients with mild Alzheimer's disease (AD) display a greater tendency to endorse unstudied items as "old" on memory tests than healthy older adults. This liberal response bias may result in mistaken beliefs about the completion of common tasks. This research attempted to determine whether it was possible to shift the response bias of mild AD patients to be more conservative on a recognition memory test through behavioral intervention. Patients with mild AD and matched controls were evaluated with two almost identical paradigms, separated by about one week. For each session, 30 words were studied and 60 words (half studied, half novel) were shown at test. During one session participants were told that 30% of words were old, and at the other session that 70% were old. We found that both groups were able to shift their response bias between the two conditions. That patients with mild AD were able to successfully shift their response bias demonstrates that--despite their overall liberal response bias and poor memory relative to controls--one component of metamemorial ability is preserved in patients with mild AD.

Metamemory experiments in neurological populations: a review

Metamemory refers to knowledge about one's memory capabilities and strategies that can aid memory, as well as the processes involved in memory self-monitoring. Although metamemory has been studied in cognitive psychology for several decades, there have been fewer studies investigating the neuropsychology of metamemory. In recent years, a growing number of studies of neurological patient groups have been conducted in order to investigate the neural correlates of metamemory. In this review, we examine the neuropsychological evidence that the frontal lobes are critically involved in monitoring and control processes, which are the central components of metamemory. The following conclusions are drawn from this literature: (1) There is a strong correlation between indices of frontal lobe function or structural integrity and metamemory accuracy (2) The combination of frontal lobe dysfunction and poor memory severely impairs metamemorial processes (3) Metamemory tasks vary in subject performance levels, and quite likely, in the underlying processes these different tasks measure, and (4) Metamemory, as measured by experimental tasks, may dissociate from basic memory retrieval processes and from global judgments of memory.

Memory Impairment and Awareness of Memory Deficits inEarly-Stage Alzheimer's Disease

Recognition memory of auditory verbal learning tests and awareness of memory deficits were examined in 24 individuals with early-stage Alzheimer's disease (AD) using a performance prediction-postdiction paradigm. Individuals with AD displayed impaired recognition memory, and recognition performance correlated positively with regional cerebral blood flow at rest in bilateral prefrontal areas and the left medial temporal area. In addition, underawareness of memory deficits was also marked even at this early stage. Individuals with AD retrospectively overestimated memory performance after actual performance, but appeared to benefit from feedback, and displayed intact online awareness of memory dysfunction, leading to normal prediction of the second session. However, individuals with AD failed to retrospectively incorporate incidents of memory failure into generalized self-belief systems. Brain/ behavior correlational analyses suggest that the prefrontal cortex and posterior dorsomedial regions including the precuneus may be involved in self-awareness.

Metacognitive theory and assessment in dementia: do we recognize our areas of weakness?

Anosognosia, disordered awareness of cognitive and behavioral deficits, is a striking and common symptom of Alzheimer's disease (AD), yet its etiology, clinical correlates, and prognostic value are unclear. Historically, disordered awareness has been a conceptually challenging phenomenon, evidenced by the numerous and diverse theories that aim to explain the manner in which this syndrome arises. We review many of these theories, focusing on the neuroanatomic substrates of awareness, and highlighting the potential roles of critical regions such as the right prefrontal and parietal cortices in enabling self-awareness. We then address methodological limitations such as use of subjective measurement tools that likely contribute to the conceptual ambiguity surrounding anosognosia. We argue that metacognitive techniques used in healthy adults, such as the Feeling of Knowing task, offer models for dissecting awareness into clear and identifiable cognitive components in patients with AD. We critique several studies that have pioneered such tasks in AD, and offer guidelines for future implementation of such methods. A final goal of this review is to advocate for a multidimensional approach to studying metacognitive skills that will facilitate the objective investigation of deficit awareness as it relates to a variety of disease variables such as prognosis, neuropsychological profile, neuropathological distribution, psychiatric symptoms, and clinical course.

Development and validation of the Subjective Awareness of Neuropsychological Deficits Questionnaire for Children (SAND-C)

Although lowered awareness of abilities has been associated with poorer outcome in adults with neurological compromise, a dearth of research exists examining whether lowered awareness exists in younger populations. Using findings from recent literature and expert opinion, a 47-item Subjective Awareness of Neuropsychological Deficits Questionnaire for Children (SAND-C) was created to assess awareness of cognitive functioning in 6 domains (attention, psychomotor, visual-spatial, language, memory, and executive functioning). Confirmatory factor analysis (CFA) of the SAND-C was conducted on a sample consisting of 365 healthy children and 48 children with epilepsy. The SAND-C was found to have strong reliability. Factor analysis confirmed the a priori 6 factor model, but the 6-factor model was only marginally better than a more parsimonious 1-factor solution. Post-hoc exploratory factor analyses indicate that the SAND-C may measure more constructs for adolescents than for younger children. The difference between younger and older children may reflect developmental changes in metacognitive awareness and abstraction about their own abilities.

Awareness of financial skills in dementia

The present study examined the relations among levels of cognitive functioning, executive dysfunction, and awareness of financial management capabilities among a sample of 42 community-dwelling persons with dementia. Financial tasks on the Measure of Awareness of Financial Skills (MAFS) were dichotomized as simple or complex based on Piaget's operational levels of childhood cognitive development. Severity of global cognitive impairment and executive dysfunction were significantly related to awareness of financial abilities as measured by informant-participant discrepancy scores on the MAFS. For persons with mild and moderate/severe dementia, and persons with and without executive dysfunction, proportions of awareness within simple and complex financial task categories were tabulated. Significantly less awareness of financial abilities occurred on complex compared with simple tasks. Individuals with mild dementia were significantly less aware of abilities on complex items, whereas persons with moderate/severe dementia were less aware of abilities, regardless of task complexity. Similar patterns of awareness were observed for individuals with and without executive dysfunction. These findings support literature suggesting that deficits associated with dementia first occur for complex cognitive tasks involving inductive reasoning or decision-making in novel situations, and identify where loss of function in the financial domain may first be expected.

Self-Awareness of Deficits in Parkinson Disease

Anosognosia is an unawareness or denial of deficits. While it has mainly been associated with damage to cortical brain regions, anosognosia has also been reported in patients with subcortical brain disease. The present study investigated whether anosognosia is a feature of Parkinson disease. Forty-eight Parkinson disease patients with predominantly left- (N = 16) or right-sided (N = 32) motor symptoms who eventually underwent right or left pallidotomies, and 48 individuals identified as caregivers completed questionnaires rating severity of PD. There was no discrepancy in report between patients and caregivers as a function of pallidotomy side. However, as a group, patients rated themselves as significantly less impaired on 2 measures of activities of daily living, indicating that basal ganglia dysfunction may alter insight into severity of illness. Patients and caregivers in the left-symptom PD group differed significantly on selected measures of functional independence. This suggests the potential interaction of laterality and handedness. The importance of future investigations in PD patients with more severe cognitive impairment is stressed.

Cognitive components of deficit awareness in Alzheimer's disease

Awareness of deficit was examined in 24 patients with Alzheimer's disease (AD) and their spouses (for a total of 48 participants) using performance prediction-postdiction and questionnaire discrepancy (QD) paradigms. Participants estimated their own memory performances as well the performances of spouses and of a fictional, memory-disordered patient observed on videotape. Patients overpredicted self-performances, but the extent of overestimation decreased for postdictions. Patients and caregivers accurately estimated caregiver performances but overestimated performances of the fictional patient. QD data revealed that patients underestimated their difficulties performing daily functioning tasks as compared with caregiver reports. Awareness of deficit is a complex ability, involving dissociable cognitive processes. AD patients may display intact immediate awareness of memory dysfunction but fail to incorporate incidents of memory failure into generalized self-belief systems.