Maria Isabel d’Ávila Freitas

Nutritional status of selenium in Alzheimer's disease patients

Studies have shown that various antioxidants are decreased in different age-related degenerative diseases and thus, oxidative stress would have a central role in the pathogenesis of many disorders that involve neuronal degeneration, including Alzheimers disease (AD). The present study aimed to assess the nutritional status of Se in AD patients and to compare with control subjects with normal cognitive function. The case-control study was carried out on a group of elderly with AD (n 28) and compared with a control group (n 29), both aged between 60 and 89 years. Se intake was evaluated by using a 3-d dietary food record. Se was evaluated in plasma, erythrocytes and nails by using the method of hydride generation atomic absorption spectroscopy. Deficient Se intake was largely observed in the AD group. AD patients showed significantly lower Se levels in plasma, erythrocytes and nails (32.59 microg/l, 43.74 microg/l and 0.302 microg/g) when compared with the control group (50.99 microg/l, 79.16 microg/l and 0.400 microg/g). The results allowed us to suggest that AD has an important relation with Se deficiency.

Glutathione Peroxidase 1 Pro198Leu Polymorphism in Brazilian Alzheimer's Disease Patients: Relations to the Enzyme Activity and to Selenium Status

Background/Aims: Oxidative stress plays a central role in Alzheimer’s disease (AD). Pro198Leu cytosolic glutathione peroxidase (GPx1) polymorphism seems to be associated with a lower activity of this enzyme, but there are no studies with AD patients. Thus, the aim was to determine the frequency of the GPx1 Pro198Leu polymorphism in AD patients and to verify its relation to glutathione peroxidase (GPx) activity and selenium (Se) status. Methods: The study was carried out in a group of AD elderly (n = 28) compared to a control group (n = 29). Blood Se concentrations were measured through hydride generation atomic absorption spectroscopy. GPx activity was determined using a commercial kit, and the polymorphism using amplified DNA sequencing. Results: The distribution of genotypes was not different between groups. The variant allele frequency was 0.179 (AD group) and 0.207 (control group). Although no differences regarding GPx activity were found between individuals with different genotypes, lower blood Se levels were found in Pro/Pro AD patients compared to Pro/Pro control subjects, which was not found in the Pro/Leu groups. Moreover, the association between the erythrocyte Se concentration and GPx activity was affected by the Pro198Leu genotype. Conclusions: Results indicate that this polymorphism had apparently affected Se status in AD patients and that more studies in this field are necessary.

The generation of visual inferences in normal elderly Influence of schooling and visual complexity

The generation of inferences makes the construction and comprehension of discourse easier, and integrates representations which add coherence to the arguments. Visuoperceptual and inferential deficits merge in the attempt to explain the difficulties that some individuals have in the comprehension of certain kinds of visual stimuli. Objectives a) To examine the performance of cognitively healthy elderly subjects in the execution of visual inferences using pictures of different levels of complexity; b) To compare the performance of subjects according to schooling level. Methods A total of 45 normal elderly aged from 61 to 82yrs (M=68; SD=0.57) were examined. The subjects were divided into three groups according to schooling level: Group 1 (1 to 4 years); Group 2 (5 to 8 years) and Group 3 (9 or more years). Each subject had to create a narrative based on four figures with controlled visual complexity. The narratives were transcribed, analysed and scored. Results For the essential inferences, the high educated group (3) had a better performance in both visually simple and complex conditions. On the visually complex figures, the medium educated group (2) was statistically equivalent to the high educated group for one figure and equivalent to the less educated group (1) for the other. There was no difference among the groups for the accessory propositions. Conclusions Visual complexity interferes with the subject’s ability to make inferences in low and medium educated individuals. High educated subjects maintain the same performance in making inferences, regardless of the visual complexity level.

Thalamic alexia with agraphia

Alexia with agraphia is defined as an acquired impairment affecting reading and writing ability. It can be associated with aphasia, but can also occur as an isolated entity. This impairment has classically been associated with a left angular gyrus lesion In the present study, we describe a case involving a patient who developed alexia with agraphia and other cognitive deficits after a thalamic hemorrhage. In addition, we discuss potential mechanisms of this cortical dysfunction syndrome caused by subcortical injury. We examined a patient who presented with alexia with agraphia and other cognitive deficits due to a hemorrhage in the left thalamus. Neuropsychological evaluation showed attention, executive function, arithmetic and memory impairments. In addition, language tests revealed severe alexia with agraphia in the absence of aphasia. Imaging studies disclosed an old thalamic hemorrhage involving the anterior, dorsomedial and pulvinar nuclei. Tractography revealed asymmetric thalamocortical radiations in the parietal region (left <right), and single photon emission computed tomography demonstrated hypoperfusion in the left thalamus that extended to the frontal and parietal cortices. Cortical cognitive deficits, including alexia with agraphia, may occur as the result of thalamic lesions. The probable mechanism is a diaschisis phenomenon involving thalamic tract disconnections.

Working memory Differences between young adults and the aged in listening tasks

Working memory is a system with a limited capacity which enables the temporary storage and manipulation of the information necessary for complex cognitive tasks. Numerous studies have suggested that performance in these tasks is related to age where older adults have a lesser performance than the young. Objective To analyze the processing functions of working memory in a listening task. Method 59 educated participants aged between 19 and 76 years having no memory complaints were divided into two groups (young and aged adults). The test administered was the adapted Listening Span, in which the subject listens to a sentence, judging whether it is true or false and, concomitantly, stores the last word of each sentence for later evocation. Results In the judgment task, performance of both groups approached to a similar average. Results of sentence recall demonstrated that with the increase in number of sentences at each level, performance of both groups declined. In the blocks of sentences 1 and 2 at level 1, all participants performed similarly. In the block of sentences 3, at level 1, there was a difference between the young and the aged. From this level onward (retention of 3 to 5 items), the aged and the young differed significantly. Conclusions An increase in the number of sentences diminished participants’ performance of temporary storage in the recall tasks, while not interfering in the processing of sentences during judgment. The difference between the young and the aged became more accentuated as item retention demands increased.

Evaluation of clinical comorbidities in cognitively impaired patients with depressive symptoms

In demented patients, depressive symptoms as well as cognition and clinical comorbidities can interact and induce a complex condition of severity and handicap. Objective The objective of this study was to evaluate the influence of depressive symptoms in cognitively impaired patients on associated clinical comorbidities in geriatric patients. Methods One-hundred-thirty-eight (138) patients were divided into two groups: the first contained cognitively impaired patients with depressive symptoms while the second comprised cognitively impaired patients without depressive symptoms. To quantify comorbidities, the Modified CIRS Scale was used. Results Out of the 138 patients, 52 were cognitively impaired with depressive symptoms and 86 were cognitively impaired without depressive symptoms, both having mean CDR of 1.74 (moderate dementia). The patients with depressive symptoms used more drugs (4.98 per patient vs. 3.45 per patient without depressive symptoms; p=0.001), presented more comorbidities (3.24 per patient vs. 2.46 per patient without depressive symptoms; p=0.009). However, these comorbidities were neither more severe nor more complex in the patients with depressive symptoms, with mean Comorbidity Severity Index of 1.45 in patients with and 1.37 in patients without depressive symptoms (p= 0.078) and mean Comorbidity Complexity Index of 2.41 in patients with depressive symptoms and 2.01 in those without depressive symptoms (p=0.103). Conclusion Cognitively impaired patients with depressive symptoms had a greater absolute number of comorbidities and took more drugs although these comorbid diseases were less severe and complex than in non-depressive cognitively impaired patients.