The Associations of Objectively Measured Physical Activity and Sedentary Time with Cognitive Functions in School-Aged Children

Low levels of physical activity among children have raised concerns over the effects of a physically inactive lifestyle, not only on physical health but also on cognitive prerequisites of learning. This study examined how objectively measured and self-reported physical activity and sedentary behavior are associated with cognitive functions in school-aged children. The study population consisted of 224 children from five schools in the Jyväskylä school district in Finland (mean age 12.2 years; 56% girls), who participated in the study in the spring of 2011. Physical activity and sedentary time were measured objectively for seven consecutive days using the ActiGraph GT1M/GT3X accelerometer. Self-reported moderate to vigorous physical activity (MVPA) and screen time were evaluated with the questions used in the “WHO Health Behavior in School-aged Children” study. Cognitive functions including visual memory, executive functions and attention were evaluated with a computerized Cambridge Neuropsychological Test Automated Battery by using five different tests. Structural equation modeling was applied to examine how objectively measured and self-reported MVPA and sedentary behavior were associated with cognitive functions. High levels of objectively measured MVPA were associated with good performance in the reaction time test. High levels of objectively measured sedentary time were associated with good performance in the sustained attention test. Objectively measured MVPA and sedentary time were not associated with other measures of cognitive functions. High amount of self-reported computer/video game play was associated with weaker performance in working memory test, whereas high amount of computer use was associated with weaker performance in test measuring shifting and flexibility of attention. Self-reported physical activity and total screen time were not associated with any measures of cognitive functions. The results of the present study propose that physical activity may benefit attentional processes. However, excessive video game play and computer use may have unfavorable influence on cognitive functions.     

Energetic cost of learning and memory can cause cognitive impairment in honeybees

The energetic cost of cognitive functions can lead to either impairments in learning and memory, or to trade-offs with other functions, when the amount of available energy is limited. However, it has been suggested that, under such conditions, social groups such as honeybees might be able to ward off cognitive impairments in individual bees by adjusting resource allocation at the colony level. Using two complementary experiments, one that tests the effect of learning on subsequent energetic state and survival, and another that tests the effect of energetic state on learning and retention, we show that individual bees pay a significant energetic cost for learning and therefore suffer from significant cognitive deficits under energetic stress. We discuss the implications of such cognitive impairments for the recent observations of bees disappearing from their colonies as well as for social life in general.     

Rhodiola rosea in stress induced fatigue--a double blind cross-over study of a standardized extract SHR-5 with a repeated low-dose regimen on the mental performance of healthy physicians during night duty.

The aim of this study was to investigate the effect of repeated low-dose treatment with a standardized extract SHR/5 of rhizome Rhodiola rosea L, (RRE) on fatigue during night duty among a group of 56 young, healthy physicians. The effect was measured as total mental performance calculated as Fatigue Index. The tests chosen reflect an overall level of mental fatigue, involving complex perceptive and cognitive cerebral functions, such as associative thinking, short-term memory, calculation and ability of concentration, and speed of audio-visual perception. These parameters were tested before and after night duty during three periods of two weeks each: a) a test period of one RRE/placebo tablet daily, b) a washout period and c) a third period of one placebo/RRE tablet daily, in a double-blind cross-over trial. The perceptive and cognitive cerebral functions mentioned above were investigated using 5 different tests. A statistically significant improvement in these tests was observed in the treatment group (RRE) during the first two weeks period. No side-effects were reported for either treatment noted. These results suggest that RRE can reduce general fatigue under certain stressful conditions.     

Altered expression of NCAM in hippocampus and cortex may underlie memory and learning deficits in rats with streptozotocin-induced diabetes mellitus

Neurological and structural changes are paralleled by cognitive deficits in diabetes mellitus. The present study was designed to evaluate the expression of neural cell adhesion molecules (NCAM) in the hippocampus, cortex and cerebellum and to examine cognitive functions in diabetic rats. Diabetes was induced in male albino rats via intraperitoneal streptozotocin injection. Learning and memory behaviors were investigated using a passive avoidance test and a spatial version of the Morris water maze test. NCAM expression was detected in the hippocampus, cortex and cerebellum by an immunoblotting method. The diabetic rats developed significant impairment in learning and memory behaviours as indicated by deficits in passive avoidance and water maze tests as compared to control rats. Expression of NCAM 180 and 120 kDa were found to be higher in hippocampus and cortex of diabetic rat brains compared to those of control, whereas expression of NCAM 140 kDa decreased in these brain regions. Our findings suggest that streptozotocin-induced diabetes impairs cognitive functions and causes an imbalance in expression of NCAM in those brain regions involved in learning and memory. Altered expression of NCAM in hippocampus may be an important cause of learning and memory deficits that occur in diabetes mellitus.     

Thyroid hormones and cognitive functioning in healthy, euthyroid women: a correlational study

Thyroid hormones (THs) play a critical role in differentiation, growth, and metabolism of animal and human organ systems, including the brain. Although associations between normal levels of THs and cognitive functions in healthy elderly individuals have been reported, the findings are inconsistent, possibly due to differences in study designs. Because thyroid disease occurs more frequently in women, the goal of the present study was to examine the relationship between levels of THs and performance on neuropsychological tests in 122 healthy, euthyroid women whose mean age was 51 years. Higher levels of free T3 were positively associated with longer completion times (slower performance) on Trail Making Test - Part A (p = 0.006) and Part B (p = 0.032) and on the Tower of London test (p = 0.002). Higher levels of thyroglobulin antibodies (TgAb) were positively correlated with more errors on the Trail Making Test Part B (p = 0.000), on the Word Fluency test (p = 0.023), and on the Design Fluency test (p = 0.045). No significant correlations between TH levels and scores on mood, verbal memory, or working memory measures were observed. The findings point to a possible link between THs and cognitive processes that are mediated primarily by frontal cortex, areas associated with executive function tasks, and suggest that elevations in levels of free T3 and TgAB within the normal range may negatively influence executive functions.     

Effects of a memory enhancing peptide on cognitive abilities of brain-lesioned mice: additivity with huperzine A and relative potency to tacrine.

Alzheimer's disease (AD) and related dementing disorders having cognitive manifestations represent an increasing threat to public health. In the present study, the effects of a memory enhancing NLPR tetra-peptide (MEP), huperzine A (Hup A), or a combination of the two on the cognitive abilities of brain-lesioned mice were evaluated and compared with tacrine in the passive avoidance and Y-water maze tests for the acquisition and retention aspects of cognitive functions. MEP at microg kg(-1) doses, and Hup A or tacrine at mg kg(-1) doses significantly reversed the cognition deficits induced by scopolamine. For acquisition ability, it was observed that mice administered with MEP (4.0 microg kg(-1)) spent less time escaping onto the platform in the water maze than those treated with tacrine (1.5 mg kg(-1)); whereas for memory retention, tacrine-administration resulted in a higher step-through latency in mice at the tested dose regime. In addition, co-administration of MEP (2.0 microg kg(-1)) and Hup A (0.1 mg kg(-1)) exhibited an additive effect resulting in considerable improvements in both acquisition and retention abilities of brain-lesioned mice. The results demonstrated that MEP was highly efficient in the rescue of cognitive abilities of brain-lesioned mice and in particular, the effective doses of MEP were about two orders of magnitude lower than that of tacrine, a therapeutic currently used in the treatment of AD. Moreover, MEP and Hup A were effective at reduced doses when the two were co-administered, providing a rationale for their combined usage in the treatment of cognitive deficits.     

Role of Somatodendritic and Postsynaptic 5-HT1A Receptors on Learning and Memory Functions in Rats

Memory impairment is a major problem afflicting mankind. The association between memory functions and neurotransmitter functions is of great interest for understanding brain function. Serotonergic pathways play an important role in the modulation of memory functions but the importance of its receptor types and subtypes on memory functions is still unclear. Activation and blockade of various serotonin (5-HT) receptors has been reported to alter cognitive processes and 5-HT receptor antagonism could be beneficial in the treatment of cognitive diseases. The role of 5-HT on memory functions is complicated. Among the 5-HT receptors subtypes, 5-HT(1A) receptors are of special interest because these receptors are present in the brain areas involved in learning and memory functions such as hippocampus and cortex. The present study was therefore designed to investigate the effect of activation and blockade of somatodendritic and/or postsynaptic 5-HT(1A) receptor on learning and memory functions in rats using modified version of water maze. In this study, 8-OH-DPAT (8-hydroxy-2-(di-N-propylamino) tetralin) at 0.3?mg/kg significantly enhanced learning acquisition (LA), short-term memory (STM) and long term memory (LTM) of rats pre-injected with saline suggesting that the activation of pre-synaptic 5-HT(1A) receptors by its agonist enhanced the memory functions of rats. Conversely, rats injected with 8-OH-DPAT at 1.0?mg/kg exhibited impaired LA and STM and had no effect on LTM. It was also shown in this study that blockade of 5-HT(1A) receptors by spiperone enhanced LA, had no effect on STM but impaired the LTM, which showed that the blockade of 5-HT(1A) receptors by its antagonist exerts different effect on different types of memory. This study suggests that 5-HT(1A) receptor could be used as a significant pharmacological target for the treatment of CNS diseases. Unraveling the role of serotonin in cognition and memory disorders could provide better therapy and it may lead to new insights in our understandings of learning and memory.     

Neurodegenerative properties of chronic pain: cognitive decline in patients with chronic pancreatitis

Chronic pain has been associated with impaired cognitive function. We examined cognitive performance in patients with severe chronic pancreatitis pain. We explored the following factors for their contribution to observed cognitive deficits: pain duration, comorbidity (depression, sleep disturbance), use of opioids, and premorbid alcohol abuse. The cognitive profiles of 16 patients with severe pain due to chronic pancreatitis were determined using an extensive neuropsychological test battery. Data from three cognitive domains (psychomotor performance, memory, executive functions) were compared to data from healthy controls matched for age, gender and education. Multivariate multilevel analysis of the data showed decreased test scores in patients with chronic pancreatitis pain in different cognitive domains. Psychomotor performance and executive functions showed the most prominent decline. Interestingly, pain duration appeared to be the strongest predictor for observed cognitive decline. Depressive symptoms, sleep disturbance, opioid use and history of alcohol abuse provided additional explanations for the observed cognitive decline in some of the tests, but to a lesser extent than pain duration. The negative effect of pain duration on cognitive performance is compatible with the theory of neurodegenerative properties of chronic pain. Therefore, early and effective therapeutic interventions might reduce or prevent decline in cognitive performance, thereby improving outcomes and quality of life in these patients.     

Comparison of stool antigen immunoassay and serology for screening for Helicobacter pylori infection in intellectually disabled children

Diagnosis of active Helicobacter pylori infection in intellectually disabled (ID) children is problematic because they are unable to cooperate with performance of invasive tests. In this study, the non‐invasive methods of measuring serum IgG antibody concentrations and performing stool antigen tests were used to screen for H. pylori infection in ID children. Eighty‐seven children with intellectual disabilities were studied. The amount of serum IgG antibody against H. pylori was measured by the ELISA method. Stool samples were examined using an amplified IDEIA HpStAR kit. To assess categorical variables, X², Fisher's exact and Kappa tests were used. The stool antigen tests showed that 93.1% of the children had H. pylori antigen and the serology test that 85.1% of children were positive for H. pylori IgG antibodies. Agreement between results of H. pylori stool antigen (HpSA) testing and IgG antibody serology was 82.8%; however, according to the kappa measure of agreement this agreement is not statistically significant (value, 0.128; P = 0.19). Discordant results were observed for 15 children (17.2%): 11 (12.6%) who were positive on HpSA test but negative by serology and 4 (4.6%) who were IgG seropositive but had negative HpSA tests. This study showed a notably higher rate of H. pylori infection in ID children than has been reported by others for non‐ID children from the same geographical area. The HpSA test is a valid method for primary screening for H. pylori infection in ID children; it detects the specific antigens shed during active infections and has less cross‐reactivity than serological tests that detect antibodies. HpSA is a sensitive non‐invasive method for detecting infection in ID children and may serve as an accurate alternative to serology.     

7,8-dihydroxyflavone rescues spatial memory and synaptic plasticity in cognitively impaired aged rats

7,8-dihydroxyflavone (7,8-DHF) has recently been identified as a potential TrkB agonist that crosses the blood-brain barrier after i.p. administration. We previously demonstrated that 7,8-DHF in vitro rescues long-term synaptic plasticity in the hippocampus of aged rats. This study assessed the rescue effect of 7,8-DHF in vivo on aging-related cognitive impairment in rats, and further determined whether the effect of 7,8-DHF is age dependent. Aged rats at 22 and 30 months of age were pretested for spatial memory in Morris water maze. The aged-impaired rats were retested twice during 7,8-DHF or vehicle treatment, which started 3 weeks after the completion of the pretest. In the 22-month-old rats, daily i.p. administration of 7,8-DHF for 2 weeks improved spatial memory. The improvement in behavioral tests was associated with increases in synapse formation and facilitation of synaptic plasticity in the hippocampus, as well as the activation of several proteins crucial to synaptic plasticity and memory. A more extended treatment paradigm with 7,8-DHF was required to achieve a significant memory improvement in the severely impaired 30-month-old rats. Moreover, 7,8-DHF moderately facilitated the synaptic plasticity, modified the density but not number of spines in the hippocampus of the oldest rats. Taken together, our results suggest that 7,8-DHF can act in vivo to counteract aging-induced declines in spatial memory and synaptic plasticity and morphological changes of hippocampal neurons. The effect of 7,8-DHF is more pronounced in relatively younger impaired rats than in those of more advanced age. These findings demonstrate the reversal of age-dependent memory impairment by in vivo 7,8-DHF application and support the benefit of early treatment for cognitive aging.     

The impact of two education methods on knowledge of schistosomiasis transmission and prevention among schoolchildren in a rural community in northern Minas Gerais, Brazil

The objective of this study was to analyse the effect of using two health education approaches on knowledge of transmission and prevention of schistosomiasis of school children living in a rural endemic area in the state of Minas Gerais, Brazil. The 87 children participating in the study were divided into three groups based on gender, age and presence or absence of Schistosoma mansoni infection. In the first group the social representation model and illness experience was used. In the second group, we used the cognitive model based on the transmission of information. The third group, the control group, did not receive any information related to schistosomiasis. Ten meetings were held with all three groups that received a pre-test prior to the beginning of the educational intervention and a post-test after the completion of the program. The results showed that knowledge levels in Group 1 increased significantly during the program in regard to transmission (p = 0.038) and prevention (p = 0.001) of schistosomiasis. Groups 2 and 3 did not show significant increase in knowledge between the two tests. These results indicate that health education models need to consider social representation and illness experience besides scientific knowledge in order to increase knowledge of schistosomiasis transmission and prevention.     

Cognitive performances are selectively enhanced during chronic caloric restriction or resveratrol supplementation in a primate

Effects of an 18-month treatment with a moderate, chronic caloric restriction (CR) or an oral supplementation with resveratrol (RSV), a potential CR mimetic, on cognitive and motor performances were studied in non-human primates, grey mouse lemurs (Microcebus murinus).Thirty-three adult male mouse lemurs were assigned to three different groups: a control (CTL) group fed ad libitum, a CR group fed 70% of the CTL caloric intake, and an RSV group (RSV supplementation of 200 mg.kg(-1).day(-1)) fed ad libitum. Three different cognitive tests, two motor tests, one emotional test and an analysis of cortisol level were performed in each group.Compared to CTL animals, CR or RSV animals did not show any change in motor performances evaluated by rotarod and jump tests, but an increase in spontaneous locomotor activity was observed in both groups. Working memory was improved by both treatments in the spontaneous alternation task. Despite a trend for CR group, only RSV supplementation increased spatial memory performances in the circular platform task. Finally, none of these treatments induced additional stress to the animals as reflected by similar results in the open field test and cortisol analyses compared to CTL animals.The present data provided the earliest evidence for a beneficial effect of CR or RSV supplementation on specific cognitive functions in a primate. Taken together, these results suggest that RSV could be a good candidate to mimic long-term CR effects and support the growing evidences that nutritional interventions can have beneficial effects on brain functions even in adults.     

Sex steroid hormones and cognitive functioning in healthy, older men

The precise impact of age-related changes in hormone levels on cognition in men is still unclear due to differing study designs and contradictory findings. This study was undertaken to examine the relationship between endogenous sex hormone levels and cognitive functioning in healthy older men using a comprehensive battery of neuropsychological tests and measurement of serum sex hormone levels. Verbal learning and memory, visual-motor processing, spatial abilities, working memory and attention, and levels of testosterone and estradiol were evaluated in 54 healthy older men. Regression analyses revealed significant curvilinear associations between working memory function and both free and bioavailable testosterone levels, suggesting that an optimal hormone level may exist for maximal performance on tasks of executive/frontal lobe functioning. However, no other relationships were evident between either estradiol or testosterone levels and any of the other cognitive functions evaluated. Hormone assays performed at the end of the study revealed that a considerable portion of the healthy elderly men in our sample met criteria for hypogonadism and suggests that their low hormone levels may have mitigated against discovering other significant hormone-cognition relationships.     

Executive Functioning and Learning Skills of Adolescent Children Born at Fewer than 26 Weeks of Gestation

Aims

To assess the cognitive and behavioral aspects of executive functioning (EF) and learning skills in extremely preterm (EPT) children compared with term control children aged 10 to 15 years.

Methods

A total of 132 of 134 (98% of all eligible survivors) EPT children born at the 2 Swedish regional tertiary care centers from 1992 to 1998 (mean age = 12 years, mean birth weight = 718 g, and mean gestational age = 24.4 weeks) and 103 matched term controls were assessed. General intelligence was assessed using the Wechsler Intelligence Scale for Children (WISC-III-R), and cognitive aspects of EF were analyzed using EF-sensitive subscales of the WISC-III-R and Tower test of the Delis-Kaplan Executive Function Scale (D-KEFS). Behaviors related to EF and learning skills were assessed using the Five to Fifteen questionnaire, which is a validated parent and teacher instrument. Academic performance in school was assessed by teachers’ responses on Achenbach’s Teachers Report Form. Analyses performed included multivariate analyses of covariance (ANCOVA and MANCOVA) and logistic regression analyses.

Results

The EPT children displayed significant deficits in cognitive aspects of EF compared with the controls, exhibiting decreases on the order of 0.9 SD to 1.2 SD for tasks of verbal conceptual reasoning, verbal and non-verbal working memory, processing speed and planning ability (P <0.001 for all). After excluding the children with major neurosensory impairment (NSI) or a Full Scale intelligence quotient (FSIQ) of < 70, significant differences were observed on all tests. Compared with controls, parents and teachers of EPT children reported significantly more EF-related behavioral problems. MANCOVA of teacher-reported learning skills in children with FSIQ >70 and without major NSI revealed no interactions, but significant main effects were observed for the behavioral composite executive function score, group status (EPT vs control) and FSIQ, for which all effect sizes were medium to large. The corresponding findings of MANCOVA of the parent-reported learning skills were very similar. According to the teachers’ ratings, the EPT children were less well adjusted to the school environment.

Conclusion

EPT children born in the 1990s who received active perinatal care are at an increased risk of executive dysfunction, even after excluding children with significant neurodevelopmental disabilities. Even mild to moderate executive dysfunctions has a significant impact on learning skills. These findings suggest the need for timely interventions that address specific cognitive vulnerabilities and executive dysfunctions.     

Lycopene attenuates diabetes-associated cognitive decline in rats

Diabetes-induced learning and memory impairment, characterized by impaired cognitive functions and neurochemical and structural abnormalities, involve direct neuronal damage caused by intracellular glucose. The present study was designed to investigate the effect of lycopene, a potent anti-oxidant and anti-inflammatory molecule, on cognitive functions, oxidative stress and inflammation in streptozotocin (STZ)-induced diabetic rats. Cognitive functions were investigated using a spatial version of the Morris water maze test. Acetylcholinesterase activity, a marker of cholinergic dysfunction, was increased by 1.8 fold in the cerebral cortex of diabetic rats. There was about 2 fold and 2.2 fold rise in thiobarbituric acid-reactive substance levels in cerebral cortex and hippocampus of diabetic rats, respectively. Non-protein thiol levels and enzymatic activities of superoxide dismutase and catalase were decreased in both cerebral cortex and hippocampal regions of diabetic rat brain. Total nitric oxide levels in cerebral cortex and hippocampus was increased by 2.4 fold and 2 fold respectively. Serum tumor necrosis factor-alpha, an inflammatory marker, was found to increase by 8 fold in diabetic rats. Chronic treatment with lycopene (1, 2 and 4 mg/kg; p.o.) significantly and dose dependently attenuated cognitive deficit, increased acetylcholinesterase activity, oxidative-nitrosative stress and inflammation in diabetic rats. The results emphasize the involvement of oxidative-nitrosative stress and peripheral inflammation in the development of cognitive impairment in diabetic animals and point towards the therapeutic potential of lycopene in diabetes-induced learning and memory impairment.     

The influence of low-frequency left prefrontal repetitive transcranial magnetic stimulation on memory for words but not for faces

Brain imaging studies suggest localization of verbal working memory in the left dorsolateral prefrontal cortex (DLPFC) while face processing and memory is localized in the inferior temporal cortex and other brain areas. The goal of this study was to assess the effect of left DLPFC low-frequency repetitive transcranial magnetic stimulation (rTMS) on verbal recall and face recognition. The study revealed a significant decrease of free recall in word encoding under rTMS (110% of motor threshold, 0.9 Hz) in comparison with sham stimulation (p=0.03), while no significant difference was found with facial memory tests. Our findings support the essential role of the left DLPFC in word but not facial memory and confirm the content specific arrangement of cortical areas involved in semantic memory. As a non-invasive tool, rTMS is useful for cognitive brain mapping and the functional localization of the category specific memory system.     

Characterization of mice lacking the gene for cholecystokinin

CCK acts peripherally as a satiating peptide released during meals in response to lipid feeding and centrally functions in the modulation of feeding, exploratory, and memory activities. The present study determined metabolic parameters, food intake, anxiety-like behaviors, and cognitive function in mice lacking the CCK gene. We studied intestinal fat absorption, body composition, and food intake of CCK knockout (CCK-KO) mice by using the noninvasive measurement of intestinal fat absorption along with quantitative magnetic resonance (QMR) imaging and the DietMax system, respectively. Additionally, exploratory and memory capacities were assessed by monitoring running wheel activity and conducting elevated plus-maze and Morris water-maze tests with these mice. Compared with wild-type (WT) littermate controls, CCK-KO mice had normal food intake, fat absorption, body weight, and body mass. CCK-KO mice ate more food than control animals during the light period and less food during the dark period. Energy expenditure was unchanged between the genotypes; however, CCK-KO mice displayed greater fatty acid oxidation. CCK-KO mice were as active as WT animals in the running wheel test. CCK-KO mice spent more time in the closed arms of an elevated plus-maze, indicative of increased anxiety. Additionally, CCK-KO mice exhibited attenuated performance in a passive avoidance task and impaired spatial memory in the Morris water maze test. We conclude that CCK is involved in metabolic rate and is important for memory and exploration. CCK is intimately involved in multiple processes related to cognitive function and food intake regulation.     

Influence of the compensation of the geomagnetic field on human cognitive processes

The influence of the compensation of the geomagnetic field to a level less than 0.4 microT on human cognitive processes has been studied. Forty persons took part in the study; they were divided by sex and age into four groups. The cognitive abilities of the persons were tested. Each person took part in two experiments: in control conditions and under the exposure to zero magnetic field. A 45-min exposure to zero magnetic field caused statistically significant changes in five of eight parameters of the cognitive tests. The magnitude of the effects varied between 1.3 and 6.2%, with an average value for all tests being 2.1% (p < 0.002, MANOVA). Exposure to zero magnetic field led predominantly to an increase in the number of errors and the time the task was performed as compared with the controls. Men passed the tests in zero magnetic field better than women, and young people did it better than aged persons. Groups of persons were distinguished that responded differently to zero magnetic field, the differences being not related to the age or gender.     

Effects of the pharmacologic manipulation of testosterone on cognitive functioning in women with polycystic ovary syndrome: a randomized, placebo-controlled treatment study

In a previous study, we found that women with polycystic ovary syndrome (PCOS), an endocrine disorder characterized by chronic hyperandrogenism, performed more poorly than healthy, matched controls on a number of neuropsychological tests, in particular tests of verbal fluency, verbal memory, manual dexterity, and visuospatial working memory. This randomized, placebo-controlled trial was undertaken to investigate whether pharmacologic manipulation of free testosterone (free T) levels in women with PCOS might affect their performance on cognitive tests. Nineteen women with PCOS completed a battery of neuropsychological tests before and after 3 months of treatment with either an anti-androgen (cyproterone acetate) plus estrogen or with a placebo. Hormone treatment of women with PCOS caused a significant reduction in their free T levels but did not affect performance on tests visuospatial ability, verbal memory, manual dexterity, or perceptual speed. Women treated with hormone therapy did, however, demonstrate an improvement in their performance on a test of verbal fluency compared to their pre-treatment scores. These findings suggest that changes in free T levels do not have a significant impact on cognitive performance in women with PCOS, although reductions in free T may be beneficial for verbal fluency.     

Epidemiological aspects of toxoplasmosis in schoolchildren residing in localities with urban or rural characteristics within the city of Rio de Janeiro, Brazil

Immunofluorescence tests (IF) for toxoplasmosis were performed on a total of 608 schoolchildren in elementary and junior high grades. 166 being in the Bonsucesso district (an urban region of Rio de Janeiro) and 442 children from locations within the lowlands of Jacarepaguá (with rural characteristics). All the IF-IgM were nonreactive, whilst 416 schoolchildren (68.4%) were IF-IgG serum-reactive (greater than or equal to 1:16). The percentages of serum-reactives in Jacarepaguá were significantly higher than in Bonsucesso, both as regards the total number of schoolchildren (p less than 0.001), as also when subdivided according to the age-grades from six to eight years (p less than 0.001) or from twelve to fourteen (p less than 0.05). Both in Jacarepaguá and in Bonsucesso, the prevalence of reactions in the 12 to 14 year age-grade was significantly greater than in the 6 to 8 year age-grade (p less than 0.001 in both cases). Expressively larger prevalences of serum reactions were found in Jacarepaguá among schoolchildren who preferred eating raw or undercooked meat, as well as among those having cats as pets; this occurred equally in the 6 to 8 year and in the 12 to 14 year age-grades. In Bonsucesso, the only significant difference was in the 6 to 8 year age-grades that had cats as pets. Thus, it has been verified that the risk of infection is greater and more precocious in localities with rural characteristics than in urban regions.