Memory, metamemory and their dissociation in temporal lobe epilepsy

The structure of metacognition in middle childhood: Evidence for a unitary metacognition-for-memory factor

It has been debated whether children's metacognitive monitoring and control processes rely on a general resource or whether metacognitive processes are task specific. Moreover, findings about the extent to which metacognitive processes are related to first-order task performance are mixed. The current study aimed to uncover the relationships among children's monitoring (discrimination between correct and incorrect responses), control (accurate withdrawal of wrong answers), and performance across three memory-based learning tasks: Kanji learning, text comprehension, and secret code learning. All tasks consisted of a study phase, a test phase, monitoring (confidence judgments), and control (maintaining/withdrawing responses). Participants were 325 children (151 second graders [Mage = 8.12 years] and 174 fourth graders [Mage = 10.20 years]). Confirmatory factor analyses showed that a model in which monitoring and control loaded on a joint factor and performance on a separate factor provided the best fit to the data. Fourth graders had better monitoring and control accuracy than second graders. However, the factor structure of metacognition was similar for both age groups, contradictory to the assumption that metacognition generalizes across tasks as children grow older. After accounting for task-specific processes, monitoring and control skills for language-based memory tasks appear to be generalizable in middle childhood. In sum, children's monitoring and control for three separate memory tasks appear to reflect a unitary metacognition-for-memory factor related to, but distinguishable from, performance.

Prospective Metamemory Monitoring of Episodic Visual Memory in Community-Dwelling Older Adults with Subjective Cognitive Decline and Mild Cognitive Impairment

OBJECTIVE

Metamemory tasks have been utilized to investigate anosognosia in older adults with dementia, though previous research has not systematically compared memory self-awareness in prodromal dementia groups. This represents an important oversight given that remedial and interventional efforts may be most beneficial before individuals' transition to clinical dementia. We examine differences in memory self-awareness and memory self-monitoring between cognitively healthy elderly controls and prodromal dementia groups.

METHODS

Participants with subjective cognitive decline despite intact objective neuropsychological functioning (SCD; n = 82), amnestic mild cognitive impairment (aMCI; n = 18), nonamnestic mild cognitive impairment (naMCI; n = 38), and normal cognitive functioning (HC; n = 120) were recruited from the Einstein Aging Study for a cross-sectional study. Participants completed an experimental visual memory-based global metamemory prediction task and subjective assessments of memory/cognition and self-awareness.

RESULTS

While, relative to HC, memory self-awareness and memory self-monitoring were preserved for delayed memory performance in SCD and aMCI, these processes were impaired in naMCI. Furthermore, results suggest that poor metamemory accuracy captured by our experimental task can be generalized to everyday memory problems.

CONCLUSIONS

Within the framework of the Cognitive Awareness Model, our findings provide preliminary evidence that poor memory self-awareness/self-monitoring in naMCI may reflect an executive or primary anosognosia, with implications for tailored rehabilitative interventions.

Accelerated forgetting in temporal lobe epilepsy: When does it occur?

OBJECTIVE

The main goal of the study was to analyse differences in the forgetting rates of Temporal Lobe Epilepsy (TLE) patients at different intervals (30 sec, 10 min, 1 day and 1 week) compared with those of healthy controls. A secondary aim of this research was to provide an assessment of the relationship between clinical epilepsy-related variables and forgetting rates in TLE patients.

METHOD

The sample was composed of 14 TLE patients and 14 healthy matched controls. All participants underwent a full standardised neuropsychological assessment including general intelligence, executive functioning, memory, language and other variables, such as depression, anxiety or everyday memory failures. Two specific memory tasks, consisting of cued recall of 4 short stories and 4 routes, were carried out at four different intervals.

RESULTS

There was a significant difference between groups at 10-min interval on the stories task, with the TLE group displaying greater forgetting than healthy controls. None of the other intervals on either task showed significant group differences. No differences were found when controlling for clinical epilepsy-related variables.

CONCLUSION

Forgetting of verbal information at 10 min was greater in patients with TLE compared with controls, but accelerated longer term forgetting was not found. This study suggests that a late consolidation process is not necessarily impaired in TLE patients.

Amplitude of low-frequency fluctuation of resting-state fMRI in primary nocturnal enuresis and attention deficit hyperactivity disorder

Children with attention deficit hyperactivity disorder (ADHD) and nocturnal enuresis (NE) have similar symptoms, for example, inattention and dysfunction of working memory. We investigate disorder-specific abnormal activity by using the simple resting-state functional magnetic resonance imaging (RS-fMRI) metric amplitude of low-frequency fluctuation (ALFF). About 18 ADHD, NE, and typically developing children were examined by RS-fMRI and the child behavior checklist (CBCL) test. One-way ANOVA were used to compare the ALFF values of the three groups and post hoc was done. We conducted Pearson correlation analysis on the results of the three groups' scales with ALFF values at the discrepant brain areas after then. Significant group effect was found in the bilateral medial prefrontal cortex (MPFC), left inferior temporal gyrus (ITG), left middle temporal gyrus (MTG), cerebellum anterior lobe (CAL), and left inferior parietal lobule (IPL). There was no shared abnormal region for ADHD and NE. Specially, ADHD showed increased ALFF in the bilateral MPFC, left ITG, and CAL and showed decreased ALFF in the left MTG. The children with NE showed increased ALFF in the left IPL. This study reveals the brain mechanism of cognitive changes on ADHD and NE, which provides neuroimaging basis for behavioral differences among different diseases.

Memory monitoring and memory control in chronic stroke patients Dissociated processes

Memory problems are common in stroke patients, although little is known about how accurately chronic stroke patients can monitor and control memory processes.

Objective

The performance of memory and metamemory in stroke patients and healthy controls were investigated, as well as dissociation between performances.

Methods

10 adults with right hemisphere lesion (mean [M] age=53.2 [SD=9.7]), 10 with left hemisphere lesion (M age=60.4 [SD=6.6]) and 20 healthy participants (M age=56.5 [SD=9.3] with no neurological disease, matched for sex, age and years of education participated in a multiple-case design study. Participants completed a metamemory experimental paradigm, as well as immediate and delayed word recall and recognition tasks.

Results

Data indicated that 10 out of the 20 patients presented significantly lower scores compared to controls, two of which had global deficits (functional association). Functional dissociations between memory monitoring (judgments of learning, JOL), control (allocation of study time) and capacity (cued-recall task) among patients were found for eight cases, suggesting these processes are independent.

Conclusion

These findings reveal stroke patients may have specific metamemory impairment and can contribute to the understanding of cognitive models of metamemory processing.

Effects of HD-tDCS on memory and metamemory for general knowledge questions that vary by difficulty

BACKGROUND

The ability to monitor one's own memory is an important feature of normal memory and is an aspect of 'metamemory'. Lesion studies have shown dissociations between memory and metamemory, but only single dissociations have been shown using transcranial direct current stimulation (tDCS). One potential reason that only single dissociations have been shown is that tDCS effects may be moderated by task difficulty.

OBJECTIVE/HYPOTHESIS

We used high definition (HD) tDCS to test for dissociable roles of the dorsolateral prefrontal cortex (DLPFC) and anterior temporal lobe (ATL) in semantic long-term memory and metamemory tasks. We also tested whether general knowledge question difficulty moderated the effects of HD-tDCS.

METHODS

Across 3 sessions, participants received active HD-tDCS over the left DLPFC or left ATL, or sham HD-tDCS during general knowledge recall and recognition tests, and a 'feeling-of-knowing' metamemory task. General knowledge questions were blocked by difficulty. Repeated measures ANOVAs were used to examine the effects of HD-tDCS on memory and metamemory tasks by memory question difficulty.

RESULTS

HD-tDCS over the ATL led to improved recall compared to DLPFC and sham HD-tDCS, and this occurred only for medium difficulty questions. In contrast, for non-recalled questions, HD-tDCS over the DLPFC led to improved recognition accuracy and improved feeling-of-knowing accuracy compared to ATL and sham HD-tDCS, and this was not moderated by memory question difficulty.

CONCLUSION (S)

HD-tDCS can be used to dissociate the roles of the ATL and DLPFC in different memory and 'metamemory' tasks. The effects of HD-tDCS on task may be moderated by task difficulty, depending on the nature of the task and site of stimulation.

Assessing a Metacognitive Account of Associative Memory Impairments in Temporal Lobe Epilepsy

Previous research has pointed to a deficit in associative recognition in temporal lobe epilepsy (TLE). Associative recognition tasks require discrimination between various combinations of words which have and have not been seen previously (such as old-old or old-new pairs). People with TLE tend to respond to rearranged old-old pairs as if they are “intact” old-old pairs, which has been interpreted as a failure to use a recollection strategy to overcome the familiarity of two recombined words into a new pairing. We examined this specific deficit in the context of metacognition, using postdecision confidence judgements at test. We expected that TLE patients would show inappropriate levels of confidence for associative recognition. Although TLE patients reported lower confidence levels in their responses overall, they were sensitive to the difficulty of varying pair types in their judgements and gave significantly higher confidence ratings for their correct answers. We conclude that a strategic deficit is not at play in the associative recognition of people with TLE, insofar as they are able to monitor the status of their memory system. This adds to a growing body of research suggesting that recollection is impaired in TLE, but not metacognition.

Metacognitive knowledge and experience in recently diagnosed patients with bipolar disorder

INTRODUCTION

Metacognition, which refers to an individual's ability to assess their own cognitive ability or performance, is poorly understood in bipolar disorder. This study was conducted to evaluate two aspects of metacognitive ability in recently diagnosed patients with bipolar disorder: (a) metacognitive knowledge, pertaining to awareness of one's own general cognitive functioning; and (b) metacognitive experience, referring to awareness of one's cognitive performance on a specific, online cognitive task.

METHOD

Participants consisted of 50 clinically euthymic patients recently diagnosed with Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (DSM-IV) bipolar I disorder who were within three months of resolution of their first manic episode, and a comparison group of 38 demographically similar healthy volunteers. To assess metacognitive knowledge, participants provided a general rating of their estimated cognitive ability prior to completing a neuropsychological battery, and self-ratings were compared to actual ability based on a composite score of overall cognitive functioning. To assess metacognitive experience, subjects provided a postdiction rating of their perceived memory performance after completing a list learning verbal memory test, and self-ratings were compared to actual memory performance. Measures of both relative and absolute accuracy of ratings were obtained.

RESULTS

Results indicated that patients showed diminished accuracy in rating their general cognitive ability, implying deficits in metacognitive knowledge. In contrast, patients were accurate in rating their online memory performance, suggesting intact metacognitive experience.

CONCLUSIONS

Findings suggest that in patients with bipolar disorder, intact task-specific cognitive self-appraisals may fail to generalize to or to modify inaccurate global cognitive self-appraisals. Further research using more comprehensive metacognitive tasks is warranted in bipolar disorder.

Differential Neural Correlates Underlie Judgment of Learning and Subsequent Memory Performance

Judgment of learning (JOL) plays a pivotal role in self-regulated learning. Although the JOLs are in general accurate, important deviations from memory performance are often reported, especially when the JOLs are made immediately after learning. Nevertheless, existing studies have not clearly dissociated the neural processes underlying subjective JOL and objective memory. In the present study, participants were asked to study a list of words that would be tested 1 day later. Immediately after learning an item, participants predicted how likely they would remember that item. Critically, the JOL was performed on only half of the studied items to avoid its contamination on subsequent memory. We found that during encoding, compared to items later judged as "will be forgotten," those judged as "will be remembered" showed stronger activities in the default-mode network, including the ventromedial prefrontal cortex (PFC) and posterior cingulate cortex, as well as weaker functional connectivity between the left dorsolateral PFC and the visual cortex. The exact opposite pattern was found when comparing items that were actually remembered with those that were later forgotten. These important neural dissociations between JOL and memory performance shed light on the neural mechanisms of human metamemory bias.

Neuropsychological deficits in temporal lobe epilepsy: A comprehensive review

Temporal lobe epilepsy (TLE) is the most prevalent form of complex partial seizures with temporal lobe origin of electrical abnormality. Studies have shown that recurrent seizures affect all aspects of cognitive functioning, including memory, language, praxis, executive functions, and social judgment, among several others. In this article, we will review these cognitive impairments along with their neuropathological correlates in a comprehensive manner. We will see that neuropsychological deficits are prevalent in TLE. Much of the effort has been laid on memory due to the notion that temporal lobe brain structures involved in TLE play a central role in consolidating information into memory. It seems that damage to the mesial structure of the temporal lobe, particularly the amygdale and hippocampus, has the main role in these memory difficulties and the neurobiological plausibility of the role of the temporal lobe in different aspects of memory. Here, we will cover the sub-domains of working memory and episodic memory deficits. This is we will further proceed to evaluate the evidences of executive function deficits in TLE and will see that set-shifting among other EFs is specifically affected in TLE as is social cognition. Finally, critical components of language related deficits are also found in the form of word-finding difficulties. To conclude, TLE affects several of cognitive function domains, but the etiopathogenesis of all these dysfunctions remain elusive. Further well-designed studies are needed for a better understanding of these disorders.

Domain-specific impairment in metacognitive accuracy following anterior prefrontal lesions

Convergent evidence supports a role for anterior prefrontal cortex (PFC) in metacognition—the capacity to evaluate cognitive processes—but whether metacognition relies on global or domain-specific substrates is unknown. Fleming et al. report that patients with anterior PFC lesions show impaired perceptual metacognition despite intact memory metacognition, supporting a domain-specific account.

Humans have the capacity to evaluate the success of cognitive processes, known as metacognition. Convergent evidence supports a role for anterior prefrontal cortex in metacognitive judgements of perceptual processes. However, it is unknown whether metacognition is a global phenomenon, with anterior prefrontal cortex supporting metacognition across domains, or whether it relies on domain-specific neural substrates. To address this question, we measured metacognitive accuracy in patients with lesions to anterior prefrontal cortex (n = 7) in two distinct domains, perception and memory, by assessing the correspondence between objective performance and subjective ratings of performance. Despite performing equivalently to a comparison group with temporal lobe lesions (n = 11) and healthy controls (n = 19), patients with lesions to the anterior prefrontal cortex showed a selective deficit in perceptual metacognitive accuracy (meta-d’/d’, 95% confidence interval 0.28–0.64). Crucially, however, the anterior prefrontal cortex lesion group’s metacognitive accuracy on an equivalent memory task remained unimpaired (meta-d’/d’, 95% confidence interval 0.78–1.29). Metacognitive accuracy in the temporal lobe group was intact in both domains. Our results support a causal role for anterior prefrontal cortex in perceptual metacognition, and indicate that the neural architecture of metacognition, while often considered global and domain-general, comprises domain-specific components that may be differentially affected by neurological insult.

Metamemory in temporal lobe epilepsy: a study of sensitivity to repetition at encoding

The purpose of the current study was to determine whether the level of metacognitive sensitivity previously observed in global Judgments-of-Learning (JOLs) in temporal lobe epilepsy (TLE) patients could also be established when making item-by-item JOLs. Fourteen TLE patients and 14 control participants were compared on a memory task where 39 semantically unrelated word pairs were presented at three different levels of repetition. Thirteen word pairs were assigned to each level. A combined JOL and Feeling-of-Knowing (FOK) task was used to examine metamemory monitoring and control processes. The results showed that control participants outperformed TLE patients on recall and recognition. However, both groups were sensitive to repetition of the word pairs throughout the list, revealing intact online monitoring and control processes at encoding. These results are consistent with the findings of Howard et al. (2010) of intact metamemory in TLE patients and extend the findings of Andrés et al. (2010) of metamemory sensitivity from the global level to the item-by-item level. Finally, the current findings provide additional evidence of a dissociation between memory and metamemory in TLE patients.

Fluoxetine restores spatial learning but not accelerated forgetting in mesial temporal lobe epilepsy

Learning and memory dysfunction is the most common neuropsychological effect of mesial temporal lobe epilepsy, and because the underlying neurobiology is poorly understood, there are no pharmacological strategies to help restore memory function in these patients. We have demonstrated impairments in the acquisition of an allocentric spatial task, in patients with unilateral hippocampal sclerosis. We also show that patients have accelerated forgetting of the learned spatial task and that this is associated with damage to the non-dominant hippocampal formation. We go on to show a very similar pattern of chronic allocentric learning and accelerated forgetting in a status epilepticus model of mesial temporal lobe epilepsy in rats, which is associated with reduced and abnormal hippocampal neurogenesis. Finally, we show that reversal of the neurogenic deficit using fluoxetine is associated with reversal of the learning deficit but not the accelerated forgetting, pointing to a possible dissociation in the underlying mechanisms, as well as a potential therapeutic strategy for improving hippocampal-dependent learning in patients with mesial temporal lobe epilepsy.