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

Executive control from healthy ageing to cognitive impairment: A systematic review of stroop and simon effects using psychophysiological and imaging techniques

BACKGROUND

The prevalence of cognitive impairment and dementia in the ageing population emphasises the need for strategies to mitigate cognitive decline. While research on Alzheimer's Disease (AD) has focused on early risk factors, less attention has been paid to protective factors such as cognitive reserve (CR) and cognitive control (CC).

METHODS

This review examines age-related changes in the prefrontal cortex (PFC) in healthy ageing and cognitive impairment. We analysed studies using Stroop and Simon tasks in conjunction with EEG, EEG/ERP, fNIRS and fMRI.

RESULTS

Of the 1411 articles reviewed, 49 studies met our criteria. The results suggest that the Stroop and Simon effects are essential for distinguishing between healthy ageing and cognitive impairment. Increased activity of the PFC supports task performance, especially in cognitive ageing. However, when compensatory mechanisms fail, deficits in Stroop and Simon effects may indicate cognitive impairment and reduced activation of the PFC.

CONCLUSION

This review emphasises the critical role of CR in attenuating age-related cognitive decline and highlights the importance of the PFC in maintaining CC.

Memory anosognosia in early Alzheimer's disease: A memory clinic study

BACKGROUND

Unawareness or anosognosia of memory impairment is a common phenomenon in patients with Alzheimer's disease (AD). Different findings have been reported regarding its presentation, assessment procedure, and cognitive correlates.

OBJECTIVE

To assess memory awareness of early AD patients predictively (before memory testing) and online (immediately after performing a memory test).

METHODS

All participants were outpatients of a memory clinic. AD patients were compared with participants having mild cognitive impairment (MCI) and a group with normal cognitive aging (NC). We used a performance-based assessment procedure to measure self-perceived memory abilities. An anosognosia ratio was calculated by matching self-estimates with objective memory scores derived from the Consortium to Establish a Registry for Alzheimer's disease Neuropsychological battery.

RESULTS

Memory anosognosia in terms of self-overestimation was found in almost half of the AD sample, only rarely in MCI, and was not present in NC. Most AD patients had both, a low prediction and also a deficient online accuracy of self-estimation. Memory overestimators were older, less educated, and had significantly poorer neuropsychological scores. A stepwise linear regression analysis showed that memory anosognosia was predicted by age, everyday functional abilities and neuropsychological variables, including executive and mnestic abilities.

CONCLUSIONS

Poor cognitive and memory functions combined with memory anosognosia are a hallmark of early AD. Further, mnemonic anosognosia as assessed by performance based measures separates AD patients already in the early disease stage from subjects with MCI or normal controls. Our findings highlight the importance of assessing memory self-appraisal in subjects attending a memory clinic, in addition to clinical and cognitive variables.

Subjective cognitive decline: Memory complaints, cognitive awareness, and metacognition

Cognitive complaints are common in elderly subjects and are a frequent reason for referral to memory clinics. If the complaints are not associated with objective cognitive impairment, the condition is labelled subjective cognitive decline (SCD). SCD is often considered as a stage antedating objective impairment, and an at-risk condition for subsequent dementia. Recent large-scale studies indicate that a significantly increased risk of clinical progression in subjects with SCD is associated with positivity for Alzheimer's disease (AD) biomarkers, a finding supporting the notion that SCD can be due to different mechanisms not associated with neurodegeneration, including functional cognitive disorders. In this paper we present a selective review of research on the relations among SCD, cognitive awareness, and metacognitive abilities. We propose that longitudinal studies of metacognitive efficiency in SCD may provide useful cues about the risk of progression to dementia and the possible presence of a functional cognitive disorder, with different implications for the management of this prevalent aging-related condition. HIGHLIGHTS: Subjective cognitive decline (SCD), a common cause of referral to memory clinics, can be due to multiple conditions. The predictive value of SCD for progression to Alzheimer's disease (AD) dementia is high in association with AD biomarker positivity. The awareness of cognitive decline is the mechanism responsible for the emergence of SCD and metacognition is the underlying neuropsychological function. The awareness of cognitive decline in clinical patients is usually assessed comparing an informant rating to the patient self-assessment, a method that can be affected by informant bias. While there is strong evidence that awareness starts to decline with the onset of objective cognitive impairment, progressively leading to the anosognosia of AD, the status of metacognitive efficiency in SCD needs to be further investigated. Quantitative, performance-based indexes of metacognitive efficiency may contribute both to the assessment of progression risk and to the management of subjects with functional cognitive disorders.

Resting-state networks and anosognosia in Alzheimer's disease

Background

Recent evidence suggests that anosognosia or unawareness of cognitive impairment in Alzheimer's Disease (AD) may be explained by a disconnection between brain regions involved in accessing and monitoring information regarding self and others. It has been demonstrated that AD patients with anosognosia have reduced connectivity within the default mode network (DMN) and that anosognosia in people with prodromal AD is positively associated with bilateral anterior cingulate cortex (ACC), suggesting a possible role of this region in mechanisms of awareness in the early phase of disease. We hypothesized that anosognosia in AD is associated with an imbalance between the activity of large-scale resting-state functional magnetic resonance imaging (fMRI) networks, in particular the DMN, the salience network (SN), and the frontoparietal network (FPN).

Methods

Sixty patients with MCI and AD dementia underwent fMRI and neuropsychological assessment including the Anosognosia Questionnaire Dementia (AQ-D), a measure of anosognosia based on a discrepancy score between patient's and carer's judgments. After having applied Independent Component Analysis (ICA) to resting fMRI data we performed: (i) correlations between the AQ-D score and functional connectivity in the DMN, SN, and FPN, and (ii) comparisons between aware and unaware patients of the DMN, SN, and FPN functional connectivity.

Results

We found that anosognosia was associated with (i) weak functional connectivity within the DMN, in posterior and middle cingulate cortex particularly, (ii) strong functional connectivity within the SN in ACC, and between the SN and basal ganglia, and (iii) a heterogenous effect concerning the functional connectivity of the FPN, with a weak connectivity between the FPN and PCC, and a strong connectivity between the FPN and ACC. The observed effects were controlled for differences in severity of cognitive impairment and age.

Conclusion

Anosognosia in the AD continuum is associated with a dysregulation of the functional connectivity of three large-scale networks, namely the DMN, SN, and FPN.

When stroke survivors' self-ratings are inconsistent with the ratings of others: a cohort study examining biopsychosocial factors associated with impaired self-awareness of functional abilities

Background Stroke survivors' self-ratings of functional abilities are often inconsistent with ratings assigned by others (e.g. clinicians), a phenomenon referred to as 'impaired self-awareness' (ISA). There is limited knowledge of the biopsychosocial contributors and consequences of post-stroke ISA measured across the rehabilitation journey. This multi-site cohort study explored biopsychosocial correlates of ISA during subacute rehabilitation (inpatient) and at 4 months post-discharge (community-dwelling). Methods Forty-five subacute stroke survivors participated (Age M (s.d.) =  71.5 (15.6), 56% female), and 38 were successfully followed-up. Self-assessments were compared to those of an independent rater (occupational therapist, close other) to calculate ISA at both time points. Survivors and raters completed additional cognitive, psychological and functional measures. Results Multivariate regression (multiple outcomes) identified associations between ISA during inpatient admission and poorer outcomes at follow-up, including poorer functional cognition, participation restriction, caregiver burden, and close other depression and anxiety. Regression models applied cross-sectionally, including one intended for correlated predictors, indicated associations between ISA during inpatient admission and younger age, male sex, poorer functional cognition, poorer rehabilitation engagement and less frequent use of non-productive coping (adjusted R 2  = 0.60). ISA at community follow-up was associated with poorer functional cognition and close other anxiety (adjusted R 2  = 0.66). Conclusions Associations between ISA and poorer outcomes across the rehabilitation journey highlight the clinical importance of ISA and the value of assessment and management approaches that consider the potential influence of numerous biological and psychosocial factors on ISA. Future studies should use larger sample sizes to confirm these results and determine the causal mechanisms of these relationships.

The dual-path hypothesis for the emergence of anosognosia in Alzheimer's disease

Although neurocognitive models have been proposed to explain anosognosia in Alzheimer's disease (AD), the neural cascade responsible for its origin in the human brain remains unknown. Here, we build on a mechanistic dual-path hypothesis that brings error-monitoring and emotional processing systems as key elements for self-awareness, with distinct impacts on the emergence of anosognosia in AD. Proceeding from the notion of anosognosia as a dimensional syndrome, varying between a lack of concern about one's own deficits (i.e., anosodiaphoria) and a complete lack of awareness of deficits, our hypothesis states that (i) unawareness of deficits would result from primary damage to the error-monitoring system, whereas (ii) anosodiaphoria would more likely result from an imbalance between emotional processing and error-monitoring. In the first case, a synaptic failure in the error-monitoring system, in which the anterior and posterior cingulate cortices play a major role, would have a negative impact on error (or deficits) awareness, preventing patients from becoming aware of their condition. In the second case, an impairment in the emotional processing system, in which the amygdala and the orbitofrontal cortex play a major role, would prevent patients from monitoring the internal milieu for relevant errors (or deficits) and assigning appropriate value to them, thus biasing their impact on the error-monitoring system. Our hypothesis stems on two scientific premises. One comes from preliminary results in AD patients showing a synaptic failure in the error-monitoring system along with a decline of awareness for cognitive difficulties at the time of diagnosis. Another comes from the somatic marker hypothesis, which proposes that emotional signals are critical to adaptive behavior. Further exploration of these premises will be of great interest to illuminate the foundations of self-awareness and improve our knowledge of the underlying paths of anosognosia in AD and other brain disorders.

Translation, reliability and validity of Persian version of Adolescent/Adult Sensory Profile in dementia

Our study aimed at the reliability and validity of the Persian version of the Adolescent/Adult Sensory Profile (AASP). This study was conducted on 130 people with dementia as well as 77 healthy elderlies. After translating the AASP into Persian, its content validity was determined based on 9 experts working in the same field. Cronbach's alpha and the Intraclass correlation coefficient (ICC) were calculated to assess the internal consistency and test-retest reliability of the Persian version of AASP. The two groups of people with dementia and healthy elderlies were compared in terms of scores in the four quadrants by performing an Independent t-test. All items in the Content Validity Ratio (CVR) and Content Validity Index (CVI) received an acceptable score. The Cronbach's alpha score for different parts of AASP was also calculated (α between 0.894 and 0.916; p < 0.001). The test-retest reliability of sub-tests of AASP was excellent (ICC between 0.885 and 0.948; p < 0.001). There was a statistically significant difference between the healthy Elderlies and dementia persons for low registration, sensory avoiding quadrants (p < 0.05). The Persian version of the AASP questionnaire is a reliable and valid questionnaire for people with dementia in Iran.

Associations between Cortical Thickness and Metamemory in Alzheimer's Disease

Metacognitive deficits affect Alzheimer's disease (AD) patient safety and increase caregiver burden. The brain areas that support metacognition are not well understood. 112 participants from the Imaging and Genetic Biomarkers for AD (ImaGene) study underwent comprehensive cognitive testing and brain magnetic resonance imaging. A performance-prediction paradigm was used to evaluate metacognitive abilities for California Verbal Learning Test-II learning (CVLT-II 1-5) and delayed recall (CVLT-II DR); Visual Reproduction-I immediate recall (VR-I Copy) and Visual Reproduction-II delayed recall (VR-II DR); Rey-Osterrieth Complex Figure Copy (Rey-O Copy) and delayed recall (Rey-O DR). Vertex-wise multivariable regression of cortical thickness was performed using metacognitive scores as predictors while controlling for age, sex, education, and intracranial volume. Subjects who overestimated CVLT-II DR in prediction showed cortical atrophy, most pronounced in the bilateral temporal and left greater than right (L > R) frontal cortices. Overestimation of CVLT-II 1-5 prediction and DR performance in postdiction showed L > R associations with medial, inferior and lateral temporal and left posterior cingulate cortical atrophy. Overconfident prediction of VR-I Copy performance was associated with right greater than left medial, inferior and lateral temporal, lateral parietal, anterior and posterior cingulate and lateral frontal cortical atrophy. Underestimation of Rey-O Copy performance in prediction was associated with atrophy localizing to the temporal and cingulate areas, and in postdiction, with diffuse cortical atrophy. Impaired metacognition was associated to cortical atrophy. Our results indicate that poor insight into one's cognitive abilities is a pervasive neurodegenerative feature associated with AD across the cognitive spectrum.

Apathy Is the Best Dimension to Consider for Awareness Assessment in Alzheimer’s Disease

Previous studies have reported the major role of apathy in awareness assessment among Alzheimer’s patients using the patient-caregiver discrepancy method, whatever the awareness dimension assessed. Using the Apathy Evaluation Scales among other awareness scales, we report that apathy is the sole awareness dimension distinguishing healthy controls (25), mild (57) and moderate-to-moderately-severe (11) Alzheimer’s patients. A linear regression showed that the Mini-Mental State Examination score used as a risk factor for non-awareness was the only factor associated with awareness of apathy and was the best predictor. This suggests that apathy is the most discriminant dimension for awareness assessment in Alzheimer’s disease.

OUP accepted manuscript

Lack of awareness of cognitive impairment (i.e. anosognosia) could be a key factor for distinguishing between neuropsychological post-COVID-19 condition phenotypes. In this context, the 2-fold aim of the present study was to (i) establish the prevalence of anosognosia for memory impairment, according to the severity of the infection in the acute phase and (ii) determine whether anosognosic patients with post-COVID syndrome have a different cognitive and psychiatric profile from nosognosic patients, with associated differences in brain functional connectivity. A battery of neuropsychological, psychiatric, olfactory, dyspnoea, fatigue and quality-of-life tests was administered 227.07 ± 42.69 days post-SARS-CoV-2 infection to 102 patients (mean age: 56.35 years, 65 men, no history of neurological, psychiatric, neuro-oncological or neurodevelopmental disorder prior to infection) who had experienced either a mild (not hospitalized; n = 45), moderate (conventional hospitalization; n = 34) or severe (hospitalization with intensive care unit stay and mechanical ventilation; n = 23) presentation in the acute phase. Patients were first divided into two groups according to the presence or absence of anosognosia for memory deficits (26 anosognosic patients and 76 nosognosic patients). Of these, 49 patients underwent an MRI. Structural images were visually analysed, and statistical intergroup analyses were then performed on behavioural and functional connectivity measures. Only 15.6% of patients who presented mild disease displayed anosognosia for memory dysfunction, compared with 32.4% of patients with moderate presentation and 34.8% of patients with severe disease. Compared with nosognosic patients, those with anosognosia for memory dysfunction performed significantly more poorly on objective cognitive and olfactory measures. By contrast, they gave significantly more positive subjective assessments of their quality of life, psychiatric status and fatigue. Interestingly, the proportion of patients exhibiting a lack of consciousness of olfactory deficits was significantly higher in the anosognosic group. Functional connectivity analyses revealed a significant decrease in connectivity, in the anosognosic group as compared with the nosognosic group, within and between the following networks: the left default mode, the bilateral somatosensory motor, the right executive control, the right salient ventral attention and the bilateral dorsal attention networks, as well as the right Lobules IV and V of the cerebellum. Lack of awareness of cognitive disorders and, to a broader extent, impairment of the self-monitoring brain system, may be a key factor for distinguishing between the clinical phenotypes of post-COVID syndrome with neuropsychological deficits.

Awareness of Cognitive Decline in Patients With Alzheimer's Disease: A Systematic Review and Meta-Analysis

Background: Identifying a poor degree of awareness of cognitive decline (ACD) could represent an early indicator of Alzheimer's disease (AD). Objectives: (1) to understand whether there is evidence of poor ACD in the pre-dementia stages of AD; (2) to summarize the main findings obtained investigating ACD in AD; (3) to propose a conceptual framework. Data Sources: We searched Scopus, Pubmed, and the reference lists for studies published up to August 2020. Original research articles must report a measure of ACD and included individuals with AD dementia, or prodromal AD (or MCI), or being at risk for AD. Data Synthesis: All studies covering preclinical, prodromal, and AD dementia were systematically reviewed. We intended to perform a meta-analysis of empirical studies on preclinical AD or prodromal AD (or MCI), to compare ACD between clinical groups. Due to the paucity of literature on preclinical AD, meta-analysis was only possible for prodromal AD (or MCI) studies. Results: We systematically reviewed 283 articles, and conducted a meta-analysis of 18 articles on prodromal AD (or MCI), showing that ACD was not significantly different between patients with amnestic and non-amnestic MCI (SMD = 0.09, p = 0.574); ACD was significantly poorer in amnestic MCI (SMD = -0.56, p = 0.001) and mild AD (SMD = -1.39, p < 0.001) than in controls; ACD was also significantly poorer in mild AD than in amnestic MCI (SMD = -0.75, p < 0.001), as well as poorer than in non-amnestic MCI (SMD = -1.00, p < 0.001). We also discuss key findings on ACD in AD, such as its neural and cognitive correlates. Conclusions and Implications: We propose that patients may be complaining of their initial subtle cognitive changes, but ACD would soon start to decrease. The individual would show mild anosognosia in the MCI stage, and severe anosognosia in dementia. The evaluation of ACD (comparing self-report to cognitive scores or to informant-report) could be useful to guide the clinician toward a timely diagnosis, and in trials targeting early-stage AD.

Domains of awareness in Alzheimer's disease: The influence of executive function

OBJECTIVE

Awareness is a developing area in dementia research and the evaluation of its domains has been increasingly included as part of care for people with Alzheimer's disease (PwAD). Our aim is to examine whether executive dysfunction is associated with awareness domains.

METHODS

A consecutive series of 75 people with mild-to-moderate Alzheimer's disease completed assessments about global cognitive function, executive functioning, and their awareness of disease. Their primary caregivers' dyad provided information about demographics, awareness of disease, dementia severity, neuropsychiatric symptoms, and functional status.

RESULTS

Different types of executive dysfunction were presented as a predictor for awareness of disease (cognitive flexibility, inhibitory control, and working memory), of emotional state (short-term memory and attention) and of social functioning and relationships (visuospatial organization, integrative functions, and abstract thinking). Awareness of cognitive functioning and health condition and of functional activity impairments exhibit only global cognitive function as a predictor.

CONCLUSIONS

Findings confirm some degree of independence between awareness domains. The importance of identifying differences in domains of awareness relies in the understanding of awareness as a clinical phenomenon in order to guide the management and support of PwAD and their caregivers.

Investigating Neuroimaging Correlates of Early Frailty in Patients With Behavioral Variant Frontotemporal Dementia: A MRI and FDG-PET Study

Frailty is a dynamic clinical condition characterized by the reduction of interconnections among different psychobiological domains, which leads to a homeostatic vulnerability. The association between physical frailty and cognitive dysfunctions is a possible predictor of poor prognosis in patients with neurodegenerative disorders. However, this construct has not been fully analyzed by a multidimensional neuropsychogeriatric assessment matched with multimodal neuroimaging methods in patients with behavioral variant frontotemporal dementia (bvFTD). We have investigated cognitive dysfunctions and frailty status, assessed by both a neuropsychological evaluation and the Multidimensional Prognostic Index (MPI), in a sample of 18 bvFTD patients and compared to matched healthy controls. Gray matter (GM) volume (as assessed by voxel-based morphometry) and metabolism (on 18fluorodeoxyglucose positron emission tomography) were first separately compared between groups, then voxelwise compared and correlated to each other within patients. Linear regression of the MPI was performed on those voxels presenting a significant correlation between altered GM volume and metabolism. The neuropsychological assessment reflected the diagnoses and the functional-anatomical alterations documented by neuroimaging analyses. In particular, the majority of patients presented significant executive dysfunction and mood changes in terms of apathy, depression, and anxiety. In the overall MPI score, the patients fell in the lower range (indicating an early frailty status). On imaging, they exhibited a bilateral decrease of GM density and hypometabolism involving the frontal pole, the anterior opercular region, and the anterior cingulate cortex. Greater atrophy than hypometabolism was observed in the bilateral orbitofrontal cortex, the triangular part of the inferior frontal gyrus, and the ventral striatum, whereas the contrary was detected in the bilateral dorsal anterior cingulate cortex and pre-supplementary motor area. MPI scores significantly correlated only with the co-occurrence of a decrease of GM density and hypometabolism in the right anterior insular cortex, but not with the separate pathological phenomena. Our results show a correlation between a specific pattern of co-occurring GM atrophy and hypometabolism with early frailty in bvFTD patients. These aspects, combined with executive dysfunction and mood changes, may lead to an increased risk of poor prognosis, highlighting a potentially critical and precocious role of the insula in the pathogenesis of frailty.

Domains of Awareness in Young and Late Onset Dementia

BACKGROUND

There is a lack of research investigating whether there are differences in the domains of awareness according to the age at onset of dementia.

OBJECTIVE

This study is designed to investigate differences in awareness of cognitive functioning and health condition, functional activity impairments, emotional state, and social functioning and relationships among people with young onset (YOD) and late onset dementia (LOD); and examine associations between awareness and its domains with cognition, functionality, neuropsychiatric symptoms, social and emotional functioning, and quality of life (QoL) in both groups.

METHODS

A group of 136 people with dementia and their respective caregivers (YOD = 50 and LOD = 86) were consecutively selected. We assessed awareness of disease, dementia severity, cognition, functionality, neuropsychiatric symptoms, social and emotional functioning, and QoL.

RESULTS

People with YOD had more neuropsychiatric symptoms than people with LOD. People with YOD were more aware of disease (total score), of their cognitive functioning and health condition and of their functional activity impairments, even if this group was more severely cognitive impaired and had a worse level of functionality than LOD group. Multivariate linear regressions showed that functionality has a wide relationship to awareness for people with YOD. While neuropsychiatric symptoms and QoL has a greater relation to awareness for people with LOD.

CONCLUSION

Different clinical variables are associated to different domains in YOD and LOD groups, reinforcing the heterogeneity of awareness in dementia.

The Association Between Impaired Awareness and Depression, Anxiety, and Apathy in Mild to Moderate Alzheimer's Disease: A Systematic Review

Objectives: Impaired awareness of cognitive and functional deficits is a common feature of Alzheimer's disease (AD). Although a lack of awareness has been suggested to be a protective factor against experiencing affective symptoms, such as depression, anxiety, and apathy which are common in AD, there is conflicting evidence about the links between them. This systematic review examines the evidence for an association between impaired awareness and depressive, anxiety, and apathy symptoms in mild to moderate AD. Method: We searched four databases (OvidMedline, Embase, PsycInfo, and PsycArticles) using terms encompassing awareness, apathy, depression, anxiety, and mild-moderate AD. We included studies that assessed the relationship between awareness and depressive symptoms, anxiety symptoms, or apathy. We assessed included papers for quality and report results using a narrative approach, prioritizing high quality studies. Results: We identified 1,544 articles, and twenty-seven studies fulfilled inclusion criteria (high-quality = 15; moderate-quality = 12). Most high-quality studies reported that impaired awareness in early-stage AD is cross-sectionally linked with fewer depressive symptoms and anxiety symptoms (correlation ranged from -0.3 to -0.7), but with more apathy. Conclusions: High-quality studies suggested that in people with early AD, impaired awareness is related to fewer depressive and anxiety symptoms and to more apathy. Future research should focus on elucidating causality among impaired awareness and these symptoms in AD.

Neuropsychological Correlates of Anosognosia for Objective Functional Difficulties in Older Adults on the Mild Cognitive Impairment Spectrum

OBJECTIVE

To examine the neuropsychological correlates of anosognosia for instrumental activities of daily living (IADLs) in older adults with mild cognitive impairment (MCI) and mild dementia.

METHOD

Participants (n = 103; age range = 54-88, 52% female) with MCI and mild dementia were recruited from neurology and geriatrics clinics for cross-sectional analysis. They completed neuropsychological tests along with subjective and performance-based assessments of six IADLs: financial management, driving, grocery shopping, nutrition evaluation, telephone use, and medication management. For each IADL, participants were classified as having anosognosia when there was objective difficulty but no subjective complaints.

RESULTS

Depending on functional domain, 13-39% of the sample had objective IADL difficulty, and of those, 65-93% lacked insight into these deficits. Binomial logistic regression models controlling for demographic variables revealed that measures of global cognition, executive function, visual attention, and verbal memory predicted classification of anosognosia, and these relationships varied across IADLs. In contrast, basic auditory attention, working memory, depressive symptoms, nor cognitive reserve were significantly related to anosognosia for any IADL.

CONCLUSION

Results support the Conscious Awareness Model, which theorizes that accurate metacognitive output is reliant on attentional, memory, and executive functioning systems. Findings from this study suggest that anosognosia for different IADLs may arise from breakdowns at varying points in this model, explaining both inter- and intra-patient variability in self-awareness of functional deficits.

Awareness of cognitive decline trajectories in asymptomatic individuals at risk for AD

Background

Lack of awareness of cognitive decline (ACD) is common in late-stage Alzheimer’s disease (AD). Recent studies showed that ACD can also be reduced in the early stages.

Methods

We described different trends of evolution of ACD over 3 years in a cohort of memory-complainers and their association to amyloid burden and brain metabolism. We studied the impact of ACD at baseline on cognitive scores’ evolution and the association between longitudinal changes in ACD and in cognitive score.

Results

76.8% of subjects constantly had an accurate ACD (reference class). 18.95% showed a steadily heightened ACD and were comparable to those with accurate ACD in terms of demographic characteristics and AD biomarkers. 4.25% constantly showed low ACD, had significantly higher amyloid burden than the reference class, and were mostly men. We found no overall effect of baseline ACD on cognitive scores’ evolution and no association between longitudinal changes in ACD and in cognitive scores.

Conclusions

ACD begins to decrease during the preclinical phase in a group of individuals, who are of great interest and need to be further characterized.

Trial registration

The present study was conducted as part of the INSIGHT-PreAD study. The identification number of INSIGHT-PreAD study (ID-RCB) is 2012-A01731-42.

Reduced Self-Awareness Following a Combined Polar and Paramedian Bilateral Thalamic Infarction. A Possible Relationship With SARS-CoV-2 Risk of Contagion?

Reduced self-awareness is a well-known phenomenon investigated in patients with vascular disease; however, its impact on neuropsychological functions remains to be clarified. Importantly, selective vascular lesions provide an opportunity to investigate the key neuropsychological features of reduced self-awareness in neurocognitive disorders. Because of its rarity, we present an unusual case of a woman affected by a combined polar and paramedian bilateral thalamic infarction. The patient underwent an extensive neuropsychological evaluation to assess cognitive, behavioral, and functional domains, with a focus on executive functions. She was assessed clinically in the acute phase and after 6 months from the stroke, both clinically and by magnetic resonance imaging. The patient developed a cognitive impairment, characterised by prevalent executive dysfunction associated with reduced self-awareness and mood changes, in terms of apathy and depression. Such condition persisted after 6 months. In May 2020, the patient underwent the serology test in chemiluminescence to detect IgG antibodies against SARS-CoV-2. The result of the quantitative test highlighted a high probability of previous contact with the virus. We suggest that reduced self-awareness related to executive dysfunction and behavioral changes may be due to combined polar and paramedian bilateral thalamic lesion. Metacognitive–executive dysfunction affecting the instrumental abilities of everyday life might make people less able to take appropriate precautions, facilitating the risk of SARS-CoV-2 contagion.

Executive Dysfunction and Reduced Self-Awareness in Patients With Neurological Disorders. A Mini-Review

Awareness of deficits in patients with neurological disorders may be described as a theoretical unitary phenomenon, which has been analysed reaching interesting results in the last decades. Awareness of deficits manifests itself in a continuum ranging from full awareness to total absence. In line with a neurocognitive approach, a reduction in self-awareness could be explained considering executive dysfunction associated with prefrontal cortex anatomo-functional changes. Our mini-review will focus on reduced self-awareness in neurological disorders, such as Alzheimer’s disease, behavioural Frontotemporal Dementia and Acquired Brain Injuries. Results achieved thanks to an explanatory investigative approach combined with a theoretical reference model will be presented. Data suggest the key role of executive functions in supporting adequate self-awareness towards patients’ cognitive-behavioural profile and instrumental activity autonomy. The Cognitive Awareness Model seems to be one of the best theoretical model to better approach this phenomenon.

Awareness of Psychiatric Symptoms in a Mixed Clinical Sample of Older Adults

OBJECTIVE

This study examined the neuropsychological correlates and impact on caregiver distress of reduced awareness of mood symptoms in patients with suspected neurodegenerative disease.

METHOD

Records from a clinical sample of older adults were examined (N = 940).

RESULTS

More than one-third of patient and caregiver ratings of mood symptoms did not agree (comparing patient and caregiver self-report measures); 27.9% of patients were unaware of depression (UoD) and 16.6% of patients were unaware of anxiety (UoA). The UoD group exhibited poorer verbal memory and executive abilities and the UoA group exhibited poorer verbal memory than those with preserved awareness. Unawareness was not associated with caregiver distress.

CONCLUSIONS

These findings highlight the importance of capturing informant report in clinical practice with older adults suspected of cognitive impairment. Unawareness of mood symptoms was related to memory dysfunction and-to a lesser extent-to executive abilities and may have implications for addressing patient and caregiver needs for disorders affecting these cognitive systems.

Clinical and Cognitive Correlates of Insight in Bipolar Disorder

Insight is greatly impaired in Bipolar Disorder (BD), especially during mania. Cognitive impairment is also present in BD. Despite that, few studies have investigated a possible association between these two aspects. The main goal of the current study is to compare BD affective states regarding performance in cognitive testing and investigate clinical and cognitive predictors for insight loss in BD. The study investigated a sample of 65 patients who were evaluated in one of the BD phases (mania, euthymia or depression). All the subjects underwent neuropsychological evaluation and completed the Insight Scale for Affective Disorders (ISAD). The relationship between level of insight and clinical/cognitive variables was analyzed through multiple regression models. No significant differences were found among BD phases regarding performance on cognitive testing. Insight was more impaired in mania then in depression or euthymia. Predictors for loss of insight were: severity of manic symptoms and impairments in selective attention (Symbol search test), divided attention (Trail making test) and inhibition (Stroop test). The sample size is a potential limitation of the current study. Nevertheless, the results suggest this had limited impact, with group differences being detected for a number of variables. The results found have important clinical importance, suggesting, for example, that rehabilitation of specific cognitive skills may improve insight in BD.

Poor awareness of IADL deficits is associated with reduced regional brain volume in older adults with cognitive impairment

Performance of instrumental activities of daily living (IADLs) can become compromised in older adults with mild cognitive impairment (MCI). Patients' level of insight into their everyday functioning varies both amongst individuals and across domains assessed, with some individuals exhibiting complete unawareness of deficits. The current cross-sectional study examined the neuroanatomical substrates of self-awareness in order to help explain the variability in this phenomenon in older adults across a continuum of cognitive impairment. Eighty-five participants (ages 54-88, mean age = 73 years, 57% female, 89% Caucasian) diagnosed with MCI or mild probable dementia underwent structural magnetic resonance imaging. Level of self-awareness was assessed by calculating the discrepancy between objective and subjective performance across six IADLs (Financial Management, Driving, Grocery Shopping, Nutrition Evaluation, Medication Management, and Telephone Use). Over-estimation of current abilities occurred in 13-31% of the sample depending on which IADL was evaluated. Poor awareness was significantly related to reduced volume in the bilateral medial prefrontal cortex, middle and posterior cingulate cortex, right insular cortex, and cerebellum. No associations were found with total white matter lesion load. These findings were broadly consistent across all functional domains assessed, supporting the theory that cortical midline and cerebellar structures are involved in self-referential processing across a variety of different cognitive and behavioral skills. Longitudinal studies are needed to confirm this association.

A novel neurocognitive approach for placebo analgesia in neurocognitive disorders

Neural correlates of placebo analgesia (PA) in patients with neurocognitive disorders have not yet been elucidated. The present study aimed to evaluate how and to what extent executive (dys)functions of the medial prefrontal cortex (MPFC) may be related to PA. To this end, twenty-three subjects complaining of different cognitive deficits (from mild cognitive impairment likely due to Alzheimer's disease to mild AD) were recruited. PA was investigated by a well-known experimental venipuncture pain paradigm (open versus hidden [O-H] application of lidocaine). Patients also underwent a comprehensive neuropsychological evaluation and a functional magnetic resonance imaging (fMRI) GO/No-GO task for eliciting selective activation of the MPFC. Selected neuropsychological variables were correlated to the OH-PA paradigm. The association between the fMRI response on the "No-GO" versus "GO" contrast and PA was investigated over the whole-brain by regression analysis. We showed the existence of a relationship between a lower PA and MPFC dysfunctions through the neuropsychological and fMRI assessment. A separate voxel-based morphometry (VBM) analysis controlled for possible influence of grey matter (GM) volume reduction on both fMRI results and PA. fMRI results were not directly affected by, and therefore independent of, disease-specific GM atrophy, which was indeed located more anteriorly within the rostral anterior cingulate and inversely correlated with PA. Our findings shed new light on the underestimated contribution of executive (dys)functions mediated by the MPFC (response-inhibition, self-monitoring and set-shifting abilities) in PA pathogenesis, with a special purely (i.e. independently from brain structural alterations) functional role played by the MCC. Results are discussed in terms of possible clinical relevance in the management of patients with neurocognitive disorders.

Neuropsychological correlates of instrumental activities of daily living in neurocognitive disorders: a possible role for executive dysfunction and mood changes

ABSTRACTSince baseline executive dysfunction predicts worsening Instrumental Activities of Daily Living (i-ADL) over time and progression to Alzheimer's Disease (AD), we aimed to analyze the role of neuropsychological variables to outline which factors can contribute to functional impairment. Specific attention to executive functions (EFs) has been given.A total of 144 subjects complaining of different cognitive deficits - ranging from "MCI likely due to AD" to "mild AD patients" - underwent an overall neuropsychological assessment. The Behavioral Assessment of the Dysexecutive Syndrome was used to analyze EFs. We conducted multiple linear regression analyses to study whether the level of independent living skills - assessed with the Lawton-scale - could be associated with cognitive and behavioral measurements.We found a significant association between i-ADL and specific EFs measured by Rule Shift Cards (p = 0.04) and Modified Six Elements (p = 0.02). Moreover, considering i-ADL scores, we observed an involvement of mood changes and a reduced awareness of deficits in terms of Hamilton Depression Rating Scale (p = 0.02) and Awareness of Deficit Questionnaire - Dementia scale (p < 0.0001), respectively.Our results suggest the importance of considering the association between a reduction in i-ADL and executive dysfunction in patients who have AD etiopathology, for which the ability to inhibit a response, self-monitoring, set-shifting and mood deflection play a key role. Besides, no straightforward associations between i-ADL scores and global cognition, memory, language comprehension, attention, and perspective taking abilities were found.

Repressive Coping Does Not Contribute to Anosognosia in First-Diagnosis Patients With Alzheimer Disease

Anosognosia is common in patients with Alzheimer disease (AD) even in early stages. Although neural correlates and the impact of cognitive dysfunctions have been described, possible psychodynamic processes such as a repressive coping style as described in other illnesses, have not been examined. Our study aimed to examine possible psychological influence factors on illness perception embracing a repressive coping style and cognitive functions in AD patients in the diagnostic process. Fifty-four subjects with mild AD diagnosed in our memory clinic were enrolled. Anosognosia was evaluated using a patient-caregiver discrepancy rating. All patients underwent comprehensive neuropsychological testing. In addition, characteristics of a repressive coping style were assessed. In total, 79.6% of our patients showed a lack of awareness at least to some degree. 33.3% of the patients were classified as repressors. Repressors and nonrepressors did not differ in cognition, or the unawareness score. Multivariate regression analysis showed that repressive coping style did not significantly contribute to anosognosia, but that verbal memory and naming ability had a strong influence. Although our data indicate that a high proportion of patients with mild AD show characteristics of repressive coping, this possible defense mechanism had no influence on the awareness of illness-related deficits measured by caregiver patient discrepancy.

Neuropsychological Correlates of Pre-Frailty in Neurocognitive Disorders: A Possible Role for Metacognitive Dysfunction and Mood Changes

Background

Recent studies have suggested that cognitive functions in patients with neurocognitive disorders have a significant role in the pathogenic mechanisms of frailty. Although pre-frailty is considered an intermediate, preclinical state, epidemiological research has begun to dislodge cognition and frailty into their specific subcomponents to understand the relationship among them. We aim to analyse the possible association between pre-frailty and neuropsychological variables to outline which factors can contribute to minor and major neurocognitive disorders.

Methods

60 subjects complaining of different cognitive deficits underwent a deep-in-wide frailty and neuropsychological assessment. We conducted three multiple linear regression analyses adjusted for a combination of demographic measures and involving several neuropsychological–behavioural parameters selected by the literature on physical frailty.

Results

We found a significant association between frailty—as measured by the multidimensional prognostic index (MPI)—and action monitoring and monetary gain (cognitive domain), depression and disinhibition (behavioural domain). Moreover, an association between MPI and impaired awareness for instrumental activities disabilities exists.

Conclusion

We propose a novel framework for understanding frailty associated with metacognitive–executive dysfunction.

Anosognosia and Its Relation to Psychiatric Symptoms in Early-Onset Alzheimer Disease

BACKGROUND

We investigated differences in the prevalence of anosognosia and neuropsychiatric symptoms (NPSs) characteristics according to disease severity in patients with early-onset Alzheimer disease (EOAD).

METHODS

We recruited 616 patients with EOAD. We subdivided participants into 2 groups based on the presence or absence of anosognosia and then again by Clinical Dementia Rating (CDR) scale. We compared the differences in the Neuropsychiatric Inventory (NPI) scores according to anosognosia and disease severity.

RESULTS

The percentage of patients with anosognosia in each CDR group steadily increased as the CDR rating increased (CDR 0.5 8.6% vs CDR 1 13.6% vs CDR 2 26.2%). The NPI total score was significantly higher in patients with anosognosia in the CDR 0.5 and 1 groups; by contrast, it had no association in the CDR 2 group. Frontal lobe functions were associated with anosognosia only in the CDR 0.5 and 1 groups. After stratification by CDR, in the CDR 0.5 group, the prevalence of agitation ( P = .040) and appetite ( P = .013) was significantly higher in patients with anosognosia. In the CDR 1 group, patients with anosognosia had a significantly higher prevalence of delusions ( P = .032), hallucinations ( P = .048), and sleep disturbances ( P = .047). In the CDR 2 group, we found no statistical difference in the frequency of symptoms between patients with and without anosognosia.

CONCLUSION

These results confirm that the prevalence of anosognosia as well as the individual NPS and cognitive functions associated with it differ according to EOAD severity.

Neural correlates of reduced awareness in instrumental activities of daily living in frontotemporal dementia

A decline in instrumental activities of daily living has been described as the earliest functional deficit in patients with neurodegenerative disease. It embraces specific competencies such as: "recalling the date and telephone calls, orienting to new places, remembering the location of objects at home, understanding conversation and the plot of a movie, keeping belongings in order, doing mental calculations and handling money, remembering appointments and shopping lists and performing clerical work". Since changes in instrumental daily living activities are one of the descriptors of behavioural-variant frontotemporal dementia, we decided to investigate the neural correlates of a reduced awareness in this specific domain in twenty-three consecutive behavioural-variant frontotemporal dementia patients. Gray matter volume changes associated with a reduced awareness for the instrumental domain, assessed using a validated caregiver-patient discrepancy questionnaire, were examined. Interestingly, we found disabilities in instrumental daily living activities and a reduced awareness of these to be related to medial prefrontal cortex atrophy, where the mid-cingulate cortices, dorsal anterior insula and cuneous play an important role. Importantly, if the executive system does not function correctly, the comparator mechanism of action self-monitoring does not detect mismatches between the current and previous performance states stored in the personal database, and produces a reduced awareness for the instrumental domain.

Self-awareness of cognitive efficiency: Differences between healthy elderly and patients with mild cognitive impairment (MCI)

INTRODUCTION

Self-estimation of performance implies the ability to understand one's own performance with relatively objective terms. Up to date, few studies have addressed this topic in mild cognitive impairment (MCI) patients. The aim of the present study was to compare objective measures of performance with subjective perception of specific performance on cognitive tests and investigate differences in assessment between MCI patients and healthy elderly.

METHOD

Thirty-five participants diagnosed with MCI (women = 16, men = 19, mean age = 65.09 years ±SD = 7.81, mean education = 12.83 years ±SD = 4.32) and 35 control subjects similar in terms of age and education (women = 20, men = 15, mean age = 62.46 years ± SD = 9.35, mean education = 14.26 ± SD = 2.84) were examined with an extended battery of neuropsychological tests. After every test they were asked to self-evaluate their performance by comparing it to what they considered as average for people of their age and educational level. This self-evaluation was reported on a scale ranging from -100 to +100.

RESULTS

Significant differences were found in the self-assessment patterns of the two groups in memory measures of verbal and visual delayed recall, visuospatial perception, and tests of attention. MCI patients overestimated their performance on every cognitive domain while control participants underestimated their performance on measures of verbal memory.

CONCLUSIONS

The present results indicate that accuracy of self-report is not uniform across groups and functional areas. The discrepancies in the MCI patients indicate unawareness of their memory deficits, which is contradictory to subjective memory complaints as being an important component for clinical diagnosis.

Concepts and objects of awareness in Alzheimer’s disease: an updated systematic review

ABSTRACT Objectives To compare and discuss the objects of awareness in Alzheimer’s disease (AD): awareness of cognitive deficits, of functional activities, of social-emotional functioning and behavioral impairment. Methods A search in the PsycINFo, Pilots, PubMed/Medline and ISI electronic databases according to Prisma methodology was performed. We included studies about awareness in people with AD published between 2010 and 2015, with the combination of keywords: “Alzheimer AND awareness of deficits”, “Alzheimer AND anosognosia”, “Alzheimer AND insight”, “dementia AND awareness of deficits”, “dementia AND anosognosia”, “dementia AND insight”. The articles were categorized according to the specific object of awareness. Results Seven hundred and ten records were identified and, after application of the exclusion criteria, 191 studies were retrieved for potential use. After excluding the duplicates, 46 studies were included. Most studies assessed the cognitive domain of awareness, followed by the functional, social-emotional, and behavioral impairment domains. Memory deficits were not sufficient to explain impaired awareness in AD. Longitudinal studies did not find discrepancies between patients and caregivers’ reports, indicating that awareness is not related to cognition. Conflicting findings were observed, including the relation between awareness, mood, severity of disease, and personal characteristics. Conclusions The studies show lack of conceptual consensus and significant methodological differences. The inclusion of samples without differentiation of dementia etiology is associated to symptomatic differences, which affect awareness domains. Awareness in AD is a complex and multidimensional construct. Different objects elicit different levels of awareness.

Clinical associations of anosognosia in mild cognitive impairment and Alzheimer's disease

AIMS AND OBJECTIVE

While loss of insight of cognitive deficits is a common phenomenon in patients with Alzheimer's disease (AD), there is a lack of consensus regarding the presence of impaired insight among patients with mild cognitive impairment (MCI). We aim to investigate the clinical, cognitive, and behavioral associations of anosognosia in AD and MCI subjects.

METHODS

A consecutive series of 87 subjects (30 healthy older patients, 21 MCI, and 36 AD) each accompanied by a caregiver, underwent clinical assessment including the evaluation of insight using the Anosognosia Questionnaire for Dementia (AQD). We also separately assessed Intellectual Function (AQD-IF) and Behavior domains of the AQD scale. Regression models were subsequently used to investigate associations of AQD scores with cognitive and other neuropsychiatric symptoms, including depression and apathy.

RESULTS

Both AD and MCI groups demonstrated significant anosognosia compared with the healthy control group. In the AD group, 55.6% had "Mild Anosognosia," and 27.8% had "Severe Anosognosia." In the MCI group, 42.9% showed "Mild Anosognosia," and 9.5% had "Severe Anosognosia." Greater levels of AQD-Total and AQD-IF were associated with lower Mini-mental state examination and higher apathy scores in the AD group. In the MCI group, caregiver burden was significantly associated with AQD-Total (p = 0.016) and AQD-IF (p = 0.039).

CONCLUSION

The results indicated that anosognosia is common in both AD and MCI patients and associated with cognitive dysfunction and apathy in AD. The findings of this study warrant further research to delineate the mechanisms of anosognosia as it poses a challenge to treatment outcomes.

The Italian validation of the Anosognosia Questionnaire for Dementia in Alzheimer's disease

Although the Anosognosia Questionnaire-Dementia (AQ-D) is one of the main instruments for assessing awareness in Alzheimer's disease (AD), the normative data were until now limited to people from Argentina and Japan. This study aims to validate this instrument in an European context, in particular in an Italian sample. In a multicenter project (Verona, Padova, and Trapani), 130 patients with AD and their caregivers participated in the study. Psychometric characteristics of AQ-D are confirmed indicating that the scale permits the early identification of anosognosia and the correct care management of patients. Indeed, anosognosia results to be present also in patients with very mild AD (moderate: 44.44%; mild: 47.17%; and very mild: 23.73%). Moreover, the results indicate that deficits in awareness may vary in severity and that different types of anosognosia may be identified.

Unawareness of bipolar disorder: the role of the cingulate cortex

Reduced awareness of illness is a well-known phenomenon that has been understudied in remitted patients with bipolar disorder. In particular, the relationship between reduced awareness and executive dysfunction is an intriguing question that has yet to be resolved. The aim of the current study is to analyze the link between reduced awareness, brain dysfunction, and concomitant cognitive-behavioral disturbances from a neurocognitive perspective. In previous studies, we demonstrated the role of the anterior cingulate cortex (ACC) in the unawareness of distinct pathologies that exhibit overlapping symptoms in the context of overlapping circuit-specific dysfunction. Given the clinical importance of the results obtained, the present study considers six aware and four unaware remitted bipolar disorder patients. Cingulate functionality was assessed with functional magnetic resonance imaging while patients performed a go/no-go task. Patients were also studied on an overall cognitive task battery and with behavioral assessment of mood changes in terms of apathy and disinhibited behavior. Unaware patients showed frontoparietal hypo-perfusion, with a significant reduction of task-sensitive activity in the bilateral superior and middle frontal gyrus, putamen, insular, and ACCs.

O insight no transtorno bipolar: uma revisão sistemática

Objetivos Realizar uma revisão sistemática para compreender que fatores estão relacionados a uma maior ou menor consciência de morbidade no transtorno bipolar (TB), como o insight varia em função do estado afetivo e estabelecer uma comparação com outros transtornos mentais. Métodos Realizou-se uma revisão sistemática da literatura científica sobre o insight em pacientes com TB. Foram buscados estudos clínicos originais sobre o tema nas bases de dados Medline, ISI e SciELO. Os termos de busca empregados foram: “insight” OR “awareness” AND “bipolar” OR “mania” OR “manic”. Resultados Foram selecionados 55 artigos. O insight no TB parece ser mais prejudicado do que na depressão unipolar, porém menos do que na esquizofrenia. Com relação ao TB, um menor nível de insight está relacionado à presença de sintomas psicóticos e de alterações cognitivas. Além disso, um comprometimento do insight está associado a uma menor adesão ao tratamento. Por outro lado, uma maior preservação do insight pode estar associada a maior ideação suicida. Finalmente, a fase maníaca cursa com um nível inferior de insight quando comparada à fase depressiva ou de eutimia. Conclusão No TB, o insight está significativamente prejudicado, especialmente na mania. Diversos fatores clínicos parecem influenciar o nível de insight.

Self-unawareness of levodopa induced dyskinesias in patients with Parkinson's disease

The study analyzes the presence of dyskinesias-reduced-self-awareness in forty-eight patients suffering from Parkinson's disease (PD). As the association with executive dysfunction is a matter of debate and we hypothesize it plays an important role in dyskinesias self-unawareness, we analyzed the role of dopaminergic treatment on the medial-prefrontal-ventral-striatal circuitry using a neurocognitive approach. Special attention was given to metacognitive abilities related to action-monitoring that represent a novel explanation of the phenomenon. PD patients were assessed using different rating scales that we devised to measure movement awareness disorders. In order to ascertain whether each variable measured at a cognitive-clinical level contributes to predicting the scores of the movement-disorder-awareness-scales, we conducted multiple logistic regression models using the latter as binary dependent variables. We used the Wisconsin Card Sorting Test-metacognitive-version to assess the executive functions of the prefrontal-ventral-striatal circuitry. Data showed that a reduction of self-awareness using the Dyskinesia rating scale was associated with global monitoring (p=.04), monitoring resolution (p=.04) and control sensitivity (p=.04). Patients failed to perceive their performance, distinguish between correct and incorrect sorts, be confident in their choice and consequently decide to gamble during the task. We did not find any association with executive functions using the hypo-bradykinesia rating scale. Our findings indicate that when the comparator mechanism for monitoring attentive performance is compromised at a prefrontal striatal level, patients lose the ability to recognize their motor disturbances that do not achieve conscious awareness.

Consciência do déficit na doença de Alzheimer: diferenças entre os domínios cognitivo e funcional

OBJETIVOS: Revisar sistematicamente desenhos de estudo, instrumentos de avaliação e fatores relacionados ao comprometimento dos domínios cognitivo e funcional da consciência do déficit em pessoas com doença de Alzheimer (DA). MÉTODO: Pesquisa nas bases de dados PubMed e ISI de estudos sobre consciência do déficit na DA publicados entre 2008 e 2013. As palavras-chave utilizadas foram: "dementia", "Alzheimer", "awareness", "awareness of memory" e "awareness of functioning", "deficits", "cognition". RESULTADOS: Os 10 artigos selecionados utilizaram os conceitos "falta de consciência do déficit", "anosognosia", "insight", "falta de consciência das dificuldades cognitivas" e "consciência limitada das deficiências". A etiologia do comprometimento da consciência do déficit foi relacionada a fatores biológicos como gravidade clínica da doença, associações neuroanatômicas, alterações neuropsiquiátricas e fatores psicológicos e sociais. O desenho de estudo mais utilizado foi o corte transversal. No domínio cognitivo, a memória e as funções executivas foram as duas principais funções investigadas. No domínio funcional, foram encontradas associações com a disfunção executiva, declínio da interação social, depressão e a influência do desempenho ocupacional. CONCLUSÕES: As distintas hipóteses etiológicas, a operacionalização variável do conceito e a falta de instrumentos de avaliação padronizados impossibilitam a obtenção de resultados homogêneos. Essas dificuldades comprometem a compreensão e a investigação dos domínios cognitivo e funcional.