Irene León

Supervisory experience at work is linked to low rate of hippocampal atrophy in late life

Cultivation of an active cognitive lifestyle, including diverse and challenging educational, occupational and cognitively-loaded leisure activities may be protective against development of dementia but the mechanisms underlying this link are not clear. We used the Lifetime Experiences Questionnaire (LEQ) to assess the structural brain correlates of cognitive lifestyle in the Sydney Memory and Aging Study, a large population-based cohort of originally 1037 non-demented elderly aged over 70 years of age. After excluding those without structural Magnetic Resonance Image data or Mild Cognitive Impairment at their most recent assessment, 151 cognitively intact subjects were studied. Whole-brain voxel based morphometric analysis found that higher total Lifetime Experiences Questionnaire scores are linked with increased grey matter volume in the medial temporal lobe, especially in the hippocampus. Through a series of more specific analyses, we found that supervisory and managerial experience in midlife was the dominant contributor to this effect. Furthermore, in those with longitudinal neuroimaging data (N=91), we measured hippocampal structural changes over a 2-3 year period by gold-standard manual tracing. The rate of hippocampal atrophy in late-life in those with high level supervisory experience in midlife was five-times slower than those with no midlife supervisory experience (p<0.001). Individual differences in intracranial volume, age, gender, physical activity, depressive symptoms, or apolipoprotein ε4 genetic status could not explain these findings, nor could specific lifestyle patterns in late life. For the first time, we reveal that managerial and supervisory experience during our working life is connected to hippocampal integrity after retirement, some 20-30 years later. Our results stimulate several questions about the nature of work-related effects on longterm behaviour, structural neuroplasticity and neuroprotection, and may help explain differences in dementia-risk based on cognitive lifestyle.

Cognitive Reserve, Age, and Their Relation to Attentional and Executive Functions

The main objective of this research was to establish the relation between age, cognitive reserve (CR), and attentional and executive functions. One hundred and sixty healthy participants aged 20 to 65 years old completed a wide battery of frontal-lobe tasks using classical tests that assess planning and control of movement, problem solving, and inhibition of automatic response, visuomotor tracking, focused and sustained attention, shifting, spontaneity and reasoning. The total sum of the score in premorbid IQ (by means of the Weschsler Adult Intelligence Scale Vocabulary subtest), educational level, and type of profession was used as a proxy of CR. Subjects were divided into groups of low or high CR. Multiple linear and logistic analyses revealed that age is a predictor of the 20Q Test, Terman Merrils Picture task, Similarities, Digit Span (backward), Trail-Making Tests, Porteus Maze Trace, the “A” Letter Cancellation Test, and reciprocal inhibition. CR is a predictor of the Controlled Oral Word Association Test, Trail-Making Tests A and B, Digit Span (forward), and Similarities. In conclusion, a higher CR score is associated with better performance in almost all tests employed. But it has a significant contribution to performance on verbal fluency, behavioral spontaneity, reasoning, divided and complex attention, and working memory functions, which are mainly related to the dorsolateral prefrontal area.

Developmental gender differences in children in a virtual spatial memory task.

OBJECTIVE Behavioral achievements are the product of brain maturation. During postnatal development, the medial temporal lobe completes its maturation, and children acquire new memory abilities. In recent years, virtual reality-based tasks have been introduced in the neuropsychology field to assess different cognitive functions. In this work, desktop virtual reality tasks are combined with classic psychometric tests to assess spatial abilities in 4- to 10-year-old children. METHOD Fifty boys and 50 girls 4-10-years of age participated in this study. Spatial reference memory and spatial working memory were assessed using a desktop virtual reality-based task. Other classic psychometric tests were also included in this work (e.g., the Corsi Block Tapping Test, digit tests, 10/36 Spatial Recall Test). RESULTS In general terms, 4- and 5-year-old groups showed poorer performance than the older groups. However, 5-year-old children showed basic spatial navigation abilities with little difficulty. In addition, boys outperformed girls from the 6-8-year-old groups. Gender differences only emerged in the reference-memory version of the spatial task, whereas both sexes displayed similar performances in the working-memory version. CONCLUSION There was general improvement in the performance of different tasks in children older than 5 years. However, results also suggest that brain regions involved in allocentric memory are functional even at the age of 5. In addition, the brain structures underlying reference memory mature later in girls than those required for the working memory.

Virtual reality tasks disclose spatial memory alterations in fibromyalgia

OBJECTIVE The objective is to assess performance on virtual reality spatial memory tasks as well as classical neuropsychological tests in patients with fibromyalgia (FM). METHODS Fifteen FM patients and fifteen healthy age- and education-matched controls performed the virtual versions of the Morris water maze and the hole board (a virtual version called Boxes room). All participants also completed a comprehensive neuropsychological evaluation that included measures of general intelligence, attention/working memory and visuospatial memory. RESULTS Both virtual reality tasks were demonstrated to be sensitive to spatial memory alterations. FM patients performed significantly worse than controls in the spatial navigation tasks, showing significantly more errors than their matched controls, while no significant differences were found between patients and controls regarding standard neuropsychological testing. In addition, those FM patients with longer chronicity had lower auditory memory span, visuospatial memory and general intelligence within their group. CONCLUSION These results are the first to demonstrate that there is a spatial learning deficit in people with FM, which suggest that the hippocampal system can be disturbed in this syndrome.

Estimating Cognitive Reserve in Healthy Adults Using the Cognitive Reserve Scale

The concept of cognitive reserve emerged from observed disparities between brain pathology and clinical symptoms. It may explain better neuropsychological performance in healthy individuals. The objectives of this study were to measure reserve in healthy subjects using a new Cognitive Reserve Scale (CRS), analyze the internal consistency of the CRS, and analyze validity evidence. A total of 117 healthy individuals were divided into two groups: 87 adults (aged 18–64 years) and 30 elderly adults (≥65 years). All subjects completed the CRS and a comprehensive neuropsychological battery. The internal consistency of the scale was satisfactory (α = 0.77). No significant differences were observed between genders (t = 0.51, p = 0.611), and age was corrected by averaging the CRS score. The study of validity evidence showed that education affected the CRS (t = −2.98, p = 0.004, partial h2 = 0.07) and there was no significant relationship between the CRS and IQ (r = 0.09, p = 0.33). Occupational attainment and the CRS were not related (F2,116 = 0.11, p = 0.898). In line with previous studies on reserve, heterogeneity was observed in the analyses of relationships between the CRS and cognitive performance. There were significant relationships between CRS score and the Verbal Learning Spanish–Complutense Test last trial (r = 0.24, p = 0.009), sum (r = 0.32, p = 0.000), short-term (r = 0.29, p = 0.002) and long-term memory (r = 0.22, p = 0.018), Matrix Reasoning subtest (r = 0.20, p = 0.027) and Block Design subtest (r = 0.20, p = 0.029). No other neuropsychological variables correlated with the CRS (p>0.05). The CRS is a reliable instrument that reflects the frequency of participation in brain-stimulating activities across the lifetime. The associations between the CRS and education and neuropsychological performance support validity evidence.

Age and gender-related differences in a spatial memory task in humans

Cognitive skills decline with age. Our ability to keep oriented in our surrounding environment was demonstrated to be influenced by factors like age and gender. Introduction of virtual reality based tasks improved assessment of spatial memory in humans. In this study, spatial orientation was assessed in a virtual memory task in order to determine the effect of aging and gender on navigational skills. Subjects from 45 to 74 years of age were organized in three groups (45-54, 55-64, 65-74 years old). Two levels of difficulty were considered. Results showed that males outperformed females in 65-74 years-old group. In addition to this, females showed a more noticeable poor performance in spatial memory than males, since memory differences appeared between all age groups. On the other hand, 65-74 year-old males showed an impaired performance in comparison with 45-54 year-old group. These results support that spatial memory becomes less accurate as we age and gender is an important factor influencing spatial orientation skills.

Cognitive lifestyle in older persons: the population-based Sydney Memory and Ageing Study.

BACKGROUND Cognitive lifestyle may be an important modifiable risk factor for dementia but has not yet been comprehensively studied in healthy elderly. OBJECTIVE To examine gender- and lifespan-related differences in cognitive lifestyle in a population-based cohort. METHODS 872 individuals from the second wave of the Sydney Memory and Ageing Study (MAS) cohort were invited to complete the Lifetime of Experiences Questionnaire (LEQ), a validated measure of cognitive lifestyle. Of 555 questionnaires returned (64%), 253 were excluded due to prior diagnosis of mild cognitive impairment, leaving n = 302 cognitively-intact elders (mean age 80.1 years, ±SD 4.7, 40.1% men). RESULTS Total LEQ was significantly higher in men (97.9 ± 20.0) than women (90.0 ± 24.5), resulting mainly from midlife LEQ differences. Men were more likely to have worked in managerial or professional jobs (73.8% versus 39.5% women), and twice as likely to have supervised large groups of workers. In late life, women were significantly more likely to be living alone (68.1% versus 25.4% men), but otherwise significantly more engaged in specific cognitive activities, including reading novels (72.3% versus 52.0% men) and incorporating volunteer work (31.9% versus 19.7% men) and socializing (59.0% versus 37.0% men) into their typical day. Over the adult lifespan, it was more common for men and women to transition between LEQ tertiles than remain the same. CONCLUSIONS Cognitive lifestyle changes over the adult lifespan and exhibits a range of gender-based differences. While older women are more likely to be living alone they generally lead a more active current cognitive lifestyle.

Open lung approach versus standard protective strategies : Effects on driving pressure and ventilatory efficiency during anesthesia - A pilot, randomized controlled trial

Background Low tidal volume (VT) during anesthesia minimizes lung injury but may be associated to a decrease in functional lung volume impairing lung mechanics and efficiency. Lung recruitment (RM) can restore lung volume but this may critically depend on the post-RM selected PEEP. This study was a randomized, two parallel arm, open study whose primary outcome was to compare the effects on driving pressure of adding a RM to low-VT ventilation, with or without an individualized post-RM PEEP in patients without known previous lung disease during anesthesia. Methods Consecutive patients scheduled for major abdominal surgery were submitted to low-VT ventilation (6 ml·kg-1) and standard PEEP of 5 cmH2O (pre-RM, n = 36). After 30 min estabilization all patients received a RM and were randomly allocated to either continue with the same PEEP (RM-5 group, n = 18) or to an individualized open-lung PEEP (OL-PEEP) (Open Lung Approach, OLA group, n = 18) defined as the level resulting in maximal Cdyn during a decremental PEEP trial. We compared the effects on driving pressure and lung efficiency measured by volumetric capnography. Results OL-PEEP was found at 8±2 cmH2O. 36 patients were included in the final analysis. When compared with pre-RM, OLA resulted in a 22% increase in compliance and a 28% decrease in driving pressure when compared to pre-RM. These parameters did not improve in the RM-5. The trend of the DP was significantly different between the OLA and RM-5 groups (p = 0.002). VDalv/VTalv was significantly lower in the OLA group after the RM (p = 0.035). Conclusions Lung recruitment applied during low-VT ventilation improves driving pressure and lung efficiency only when applied as an open-lung strategy with an individualized PEEP in patients without lung diseases undergoing major abdominal surgery. Trial registration ClinicalTrials.gov NCT02798133

Cognitive Vulnerability in Aging May Be Modulated by Education and Reserve in Healthy People

Aging is related to a deterioration of cognitive performance and to multiple alterations in the brain. Even before the beginning of a noticeable cognitive decline, the framework which holds cognitive function experiences these alterations. From a system-vulnerability point of view of cognition, the deterioration associated with age would be the collection of repercussions during a life. Brain function and structure are modified in a multidimensional way, which could concern different aspects like structural integrity, functional activity, connectivity, or glucose metabolism. From this point of view, the effects of aging could affect the most brain systems and their functional activity. In this study, we analyze the functional development of three cognitive domains in relation to aging, educational level, and cognitive reserve (CR). A total of 172 healthy subjects were divided into two age groups (young and old), and completed a battery of classic neuropsychological tests. The tests were organized and analyzed according to three cognitive domains: working memory and flexibility, visuoconstructive functions, and declarative memory. Subjects also completed a questionnaire on CR. Results showed that the performance in all cognitive domains decreased with age. In particular, tests related to working memory, flexibility, and visuoconstructive abilities were influenced by age. Nevertheless, this effect was attenuated by effects of education, mainly in visuoconstructive domain. Surprisingly, visual as well as verbal memory tests were not affected either by aging, education, or CR. Brain plasticity plays a prominent role in the aging process, but, as other studies have shown, the plasticity mechanism is quite different in healthy vs. pathological brains. Moreover, this plasticity brain mechanism could be modulated by education and CR. Specially, cognitive domains as working memory, some executive functions and the visuoconstructive abilities seem to be modulated by education. Therefore, it seems to be crucial, to propose mechanisms of maintenance of a healthy and enriched brain, since it promotes auto-regulatory mechanisms of well-aging.

Virtual reality assessment of walking and non-walking space in men and women with virtual reality-based tasks

Far space and near space refer to different spatial features in which we unfold our behaviour. On the one hand, classical visuospatial neuropsychological tests assess spatial abilities in the near space; on the other, far space typically involves new spatial memory tasks in which participants display their behaviour in an environment, either interacting with objects or searching for targets. The Boxes Room Task is a virtual test that assesses spatial memory in the far space. Based upon this task, a new test was developed in which participants could not move about within the context, but they could actually perceive it from a specific viewpoint. In this work, both versions of the task were compared with one another. Furthermore, they were also compared with the results of 10/36 spatial recall test, a task assessing spatial memory in the near space. Two conditions were applied in all tasks, both in stable and rotated contexts. Our study included one hundred and twenty healthy young participants who were divided into two groups. The first group performed the Walking Space Boxes Room Task. A second group performed the Non-Walking Space Boxes Room Task as well as another traditional neuropsychological test for near space assessment, the 10/36 spatial recall test. Results proved that orientation in the non-walking space was more difficult than in the walking space. Additionally, our test also showed that men outperformed women in both virtual reality-based tasks, although they did not do it in the traditional 10/36 spatial recall test. In short, this work exposes that virtual-reality technologies provide tools to assess spatial memory, being more sensitive than traditional tests in the detection of small performance changes.