Henrique Cerqueira Guimarães

Neurobiology of apathy in Alzheimer's disease

Apathy is considered the most frequent neuropsychiatric disturbance in dementia and its outcome is generally deleterious. Apathy can be related to a dysfunction of the anatomical-system that supports the generation of voluntary actions, namely the prefrontal cortex and/or the prefrontal-subcortical circuits. In Alzheimers disease, pathological and neuroimaging data indicate that apathy is likely due to a dysfunction of the medial prefrontal cortex. Accordingly, in this review article, we propose a pathophysiological model to explain apathetic behavior in Alzheimers disease, combining data from neuroimaging, neuropathology and experimental research on the role of orbito-frontal cortex, anterior cingulate cortex, basal ganglia and dopamine in decision-making neurobiology.

The Pietà study: epidemiological investigation on successful brain aging in Caeté (MG), Brazil. Methods and baseline cohort characteristics

OBJECTIVES To present the methods and baseline characteristics of the Pietà study, a population-based survey investigating successful brain aging in the oldest-old. METHOD The study was conducted in Caeté (MG), Brazil. In 2007, 1,251 individuals aged 75+ years were living in the city and were invited to participate. Participants responded to a general health questionnaire and were submitted to clinical, neurological, cognitive, psychiatric and functional evaluations. A subgroup was submitted to neuropsychological testing, blood tests and magnetic resonance of the skull. Individuals were classified as having cognitive impairment-no dementia, dementia, parkinsonism, psychiatric disorders or successful brain aging. RESULTS We evaluated 639 individuals (51.1% of the target population; 64% women), aged 81.4±5.2 years and with 2.7±2.6 years of schooling. Almost 30% of the elderly were illiterates and 82.1% belonged to middle/middle-low socioeconomic levels. Almost 50% were widows, but only 14.3% were living alone. CONCLUSION The Pietà cohort is representative of the oldest-old Brazilian population. We believe the results of the study may contribute to increase our knowledge about healthy and pathological brain aging in the oldest-old.

Frontal assessment battery in a Brazilian sample of healthy controls: normative data

OBJECTIVE To show data on the performance of healthy subjects in the Frontal Assessment Battery (FAB), correlating with gender, age, education, and scores in the Mini-Mental State Examination (MMSE). METHODS Two hundred and seventy-five healthy individuals with mean age of 66.4 ± 10.6 years-old were evaluated. Mean total FAB scores were established according to the educational level. RESULTS Mean total FAB scores according to the educational level were 10.9 ± 2.3, for one to three years; 12.8 ± 2.7, for four to seven years; 13.8 ± 2.2, for eight to 11 years; and 15.3 ± 2.3, for 12 or more years. Total FAB scores correlated significantly with education (r=0.47; p<0.0001) and MMSE scores (r=0.39; p<0.0001). No correlation emerged between FAB scores, age, and gender. CONCLUSION In this group of healthy subjects, the Brazilian version of the FAB proved to be influenced by the education level, but not by age and gender.

Dementia caregiver burden in a Brazilian sample: Association to neuropsychiatric symptoms

Taking care of elderly demented individuals, especially when they present behavioral changes, can be very exhaustive for both family and caregivers. Generally, this leads to changes in the family lifestyle, and the caregiver must deal with a range of problems. Information on this topic in Latin America, including Brazil, remains scarce. Objective To investigate the relationship between the presence of neuropsychiatric symptoms and the level of caregiver burden in a group of Brazilian elderly with dementia. Methods The Brazilian versions of the Zarit Caregiver Burden Interview (ZBI) and of the Neuropsychiatric Inventory (NPI) were administered to a total of 83 family-caregivers of patients with dementia followed at a university-affiliated outpatient clinic. Pearson’s correlations were calculated to measure the level of association between the scores on both instruments. Results Among the caregivers, 83.1% were women, and had a mean age of 55.6±12.8 years. The ZBI scores ranged from 3 to 79 (mean=31.4). Patients’ NPI scores ranged from 0 to 102 (mean=26.9), consistent with a significant degree of behavioral manifestations in most patients. A significant positive correlation was found between ZBI and NPI scores (r=0.402; p=0.000). Conclusion The presence and severity of behavioral manifestations assessed by the NPI were associated with a high level of caregiver burden in this sample of Brazilian elderly with dementia.

Frontal lobe neurology and the creative mind

Concepts from cognitive neuroscience strongly suggest that the prefrontal cortex (PFC) plays a crucial role in the cognitive functions necessary for creative thinking. Functional imaging studies have repeatedly demonstrated the involvement of PFC in creativity tasks. Patient studies have demonstrated that frontal damage due to focal lesions or neurodegenerative diseases are associated with impairments in various creativity tasks. However, against all odds, a series of clinical observations has reported the facilitation of artistic production in patients with neurodegenerative diseases affecting PFC, such as frontotemporal dementia (FTD). An exacerbation of creativity in frontal diseases would challenge neuroimaging findings in controls and patients, as well as the theoretical role of prefrontal functions in creativity processes. To explore this paradox, we reported the history of a FTD patient who exhibited the emergence of visual artistic productions during the course of the disease. The patient produced a large amount of drawings, which have been evaluated by a group of professional artists who were blind to the diagnosis. We also reviewed the published clinical cases reporting a change in the artistic abilities in patients with neurological diseases. We attempted to reconcile these clinical observations to previous experimental findings by addressing several questions raised by our review. For instance, to what extent can the cognitive, conative, and affective changes following frontal damage explain changes in artistic abilities? Does artistic exacerbation truly reflect increased creative capacities? These considerations could help to clarify the place of creativity—as it has been defined and explored by cognitive neuroscience—in artistic creation and may provide leads for future lesion studies.

Direct and Indirect Assessments of Activities of Daily Living in Behavioral Variant Frontotemporal Dementia and Alzheimer Disease

Background: There is limited information about the functional profile of behavioral variant frontotemporal dementia (bvFTD). Objective: To compare direct and indirect assessments of activities of daily living (ADLs) in bvFTD and Alzheimer disease (AD) and their relationship with cognitive performance. Methods: In all, 20 patients with bvFTD, 30 patients with AD, and 34 normal controls (NCs), matched for age, education, and severity of dementia, completed the Direct Assessment of Functional Performance (DAFS-BR) and usual cognitive measures. The Disability Assessment for Dementia (DAD) was completed by caregivers. Results: In DAFS-BR, patients with bvFTD and AD had similar performance but lower than NCs. In DAD, there were no significant differences for effective performance, but patients with bvFTD had lower scores for initiation and planning/organization. Patients with bvFTD were less impaired than AD in cognition. Conclusion: Functional changes in bvFTD seem to be better documented by indirect measures.

Determinants of Theory of Mind performance in Alzheimer’s disease: A data-mining study

Whether theory of mind (ToM) is preserved in Alzheimers disease (AD) remains a controversial subject. Recent studies have showed that performance on some ToM tests might be altered in AD, though to a lesser extent than in behavioural-variant Frontotemporal Dementia (bvFTD). It is however, unclear if this reflects a genuine impairment of ToM or a deficit secondary to the general cognitive decline observed in AD. Aiming to investigate the cognitive determinants of ToM performance in AD, a data-mining study was conducted in 29 AD patients then replicated in an independent age-matched group of 19 AD patients to perform an independent replication of the results. 44 bvFTD patients were included as a comparison group. All patients had an extensive neuropsychological examination. Hierarchical clustering analyses showed that ToM performance clustered with measures of executive functioning (EF) in AD. ToM performance was also specifically correlated with the executive component extracted from a principal component analysis. In a final step, automated linear modelling conducted to determine the predictors of ToM performance showed that 48.8% of ToM performance was significantly predicted by executive measures. Similar findings across analyses were observed in the independent group of AD patients, thereby replicating our results. Conversely, ToM impairments in bvFTD appeared independent of other cognitive impairments. These results suggest that difficulties of AD patients on ToM tests do not reflect a genuine ToM deficit, rather mediated by general (and particularly executive) cognitive decline. They also suggest that EF has a key role in mental state attribution, which support interacting models of ToM functioning. Finally, our study highlights the relevancy of data-mining statistical approaches in clinical and cognitive neurosciences.

Cortisol, HDL-c, VLDL-c, and APOE Polymorphisms as Laboratorial Parameters Associated to Cognitive Impairment No Dementia (CIND) and Dementia

Population aging is a global phenomenon whose main consequence is the increase of chronic degenerative diseases, including dementia. The aim of this case–control study was to evaluate the laboratorial parameters lipid profile, cortisol, and apolipoprotein E (APOE) gene genotype, comparing cognitively healthy controls and subjects with cognitive impairment no dementia (CIND) and dementia in a group of elderly people.

Genetic predisposition to higher production of interleukin-6 through -174 G > C polymorphism predicts global cognitive decline in oldest-old with cognitive impairment no dementia.

Interleukin 6 (IL-6) is a pro-inflammatory cytokine upregulated in neurodegenerative contexts. The polymorphism IL-6 -174 G > C influences release levels of this cytokine. We aimed to evaluate the influence of IL-6 -174 G > C on global cognitive score of a group with cognitive impairment no dementia in one year of follow-up.Methods The subjects were categorized in two groups: short-term decline in global cognitive score and those with short-term stability or improvement. IL-6 174 G > C information were compared among these groups.Results We observed that individuals with cognitive impairment no dementia with GGlowergenotype were more frequent among global cognitive score non-decliners while carriers of at least one Chigherallele were more frequent in the group with global cognitive score decliners (p = 0.012; RR = 3.095 IC95%= 1.087-8.812).Conclusion These results suggest that the higher expression of IL-6 gene may be an independent risk factor for cognitive decline among individuals with cognitive impairment no dementia.

Cognitive performance of community-dwelling oldest-old individuals with major depression: the Pietà study

BACKGROUND Individuals with late-life depression (LLD) may present cognitive symptoms. We sought to determine whether a brief cognitive battery (BCB) could identify cognitive and functional deficits in oldest-old individuals with LLD and a low level of education. METHODS We evaluated 639 community-dwelling individuals aged 75+ years in Caeté (MG), Brazil. We used the MINI and GDS-15 to diagnose major depression and evaluate its severity, respectively. The cognitive evaluation comprised the Mini-Mental State Examination (MMSE), BCB, clock-drawing test, category fluency test (animals) and Pfeffers Functional Activities Questionnaire (FAQ). RESULTS Fifty-four (11.6%) of the included individuals were diagnosed with LLD; on average, these participants were aged 81.0 ± 4.8 years and had 3.9 ± 3.4 years of schooling, and 77.8% of the subjects with LLD were female. Depressed individuals scored lower than subjects without dementia/depression on the MMSE overall (p < 0.001) and on several of the MMSE subscales, namely, time (p < 0.001) and spatial orientation (p = 0.021), attention/calculation (p = 0.019), and language (p = 0.004). Individuals with LLD performed worse on the incidental and (p = 0.011) immediate memory (p = 0.046) and learning tasks (p = 0.039) of the BCB. Individuals with LLD also performed worse on the category fluency test (p = 0.006), clock-drawing test (p = 0.011) and FAQ (p < 0.001). Depression severity was negatively correlated with incidental memory (ρ = -0.412; p = 0.003) and positively correlated with FAQ score (ρ = 0.308; p = 0.035). In the multiple regression analysis, only temporal orientation and FAQ score remained independently associated with LLD. CONCLUSION Individuals with depression and a low level of education presented several cognitive and functional deficits. Depression severity was negatively correlated with incidental memory and functionality. Our findings serve as a description of the presence of cognitive dysfunction in individuals with LLD and suggest that these deficits may be identified based on the results of a BCB.