Cognitive anosognosia and behavioral changes in probable Alzheimer's disease patients

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.

Effectiveness of sorting tests for detecting cognitive decline in older adults with dementia and other common neurodegenerative disorders: A meta-analysis

The demand for simple, accurate and time-efficient screens to detect cognitive decline at point-of-care is increasing. Sorting tests are often used to detect the 'executive' deficits that are commonly associated with behavioural-variant frontotemporal dementia (bvFTD), but their potential for use as a cognitive screen with older adults is unclear. A comprehensive search of four databases identified 142 studies that compared the sorting test performance (e.g. WCST, DKEFS-ST) of adults with a common neurodegenerative disorder (e.g. Alzheimer's disease, vascular dementia, bvFTD, Parkinson's disease) and cognitively-healthy controls. Hedges' g effect sizes were used to compare the groups on five common test scores (Category, Total, Perseveration, Error, Description). The neurodegenerative disorders (combined) showed large deficits on all scores (g -1.0 to -1.3), with dementia (combined subtypes) performing more poorly (g -1.2 to -2.1), although bvFTD was not disproportionately worse than the other dementias. Overall, sorting tests detected the cognitive impairments caused by common neurodegenerative disorders, especially dementia, highlighting their potential suitability as a cognitive screen for older adults.

Subjective memory complaint as a useful tool for the early detection of Alzheimer's disease

PURPOSE

Despite their high prevalence in Alzheimer's disease (AD), and the increasing level of concern they have generated, subjective memory complaints (SMCs) are poorly understood. This study investigated the accuracy with which SMC can separate mild cognitive impairment (MCI) and early AD from cognitive normal (CN), and explored whether the discrimination ability is similar to or better than that of the Mini-Mental State Exam (MMSE).

PATIENTS AND METHODS

This study recruited 175 CN subjects, 52 with MCI, and 66 with probable AD aged 60 years or older. To test the independent contributions of SMC and MMSE scores to the classification of cognitive status (CN vs MCI or early AD), logistic regression analyses were performed, adjusting for the following potential confounding variables: age, gender, Frontal Assessment Battery score, modified Hachinski Ischemic Scale score, and apolipoprotein E ε4 status. Receiver operating characteristic (ROC) curve analyses were used to determine the discrimination accuracy of SMC and MMSE scores, and area under the ROC curve (AUROC) was also calculated.

RESULTS

In the highly educated (≥7 years), nondepressed (Geriatric Depression Scale ≤15) subgroup, SMC showed good accuracy in discriminating cognitively impaired subjects from CN after adjusting for potential confounding variables (the AUROC of the adjusted SMC was 0.841 for MCI discrimination, and it was 0.858 for MCI plus early AD discrimination). Both SMC and MMSE scores significantly contributed to differentiating between CN and MCI (OR=2.372, 95% CI=1.086-5.177; OR=0.730, 95% CI=0.566-0.941, respectively) after adjusting for the same covariates. However, in the highly educated and nondepressed subgroups, SMC showed significant predictive power for MCI from CN (OR=3.119, 95% CI=1.190-8.176; OR=3.328, 95% CI=1.320-8.396, respectively), whereas MMSE scores did not.

CONCLUSION

Our findings support the usefulness of SMC, which was comparable or even superior to MMSE scores, for detecting MCI or early AD.

Heterogeneity of Cognitive Anosognosia and its Variation with the Severity of Dementia in Patients with Alzheimer's Disease

Currently, the lack of awareness of deficits, i.e., anosognosia, is a major obstacle in the healthcare circuit that delays the diagnosis of Alzheimer's disease (AD). However, a clear framework is lacking in the literature related to this phenomenon in terms of its definition, mechanisms, and objects. The aim of this study is to assess the different levels of cognitive anosognosia using a prediction-performance procedure and to identify the potential correlates of these levels. A sample of patients with probable AD was divided into three groups according to the severity of dementia (mild (MiD), moderate (MoD), and moderately severe (MSD) dementia), ranked according to the results of the Mini-Mental State Examination. We observed the following three scores: the real score, the prediction score, and the anosognosia score. These scores were calculated based on the prediction-performance task MISAwareness from the Dementia Rating Scale for cognitive processes (i.e., Attention, Initiation, Conceptualization, Construction, and Memory). We obtained a strong plateau effect between the MiD and MoD groups for anosognosia scores for actual performance or prediction for both the level of overall functioning and for specific processes. The sole exception was the result for memory processes. Moreover, the profiles of the patients' responses on the Memory subscale were substantially different and, indeed, opposite from those for the other processes. The main results confirm the multidimensionality of anosognosia and its variability with the stage of dementia and specifically implicate memory processes that indicate a cleavage between memory and other cognitive functions.