The possibility of flexibly retrieving our memories using a first-person or a third-person perspective (1PP or 3PP) has been extensively investigated in episodic memory research. Here, we used a ...Virtual Reality-based paradigm to manipulate the visual perspective used during the encoding stage to investigate age-related differences in the formation of memories experienced from 1PP vs. 3PP. 32 young adults and 32 seniors participated in the study. Participants navigated through two virtual cities to encode complex real-life virtual events, from either a 1PP (as if from their egocentric viewpoint) or a 3PP, while actively controlling an avatar. While recognition accuracy was higher in young adults after encoding in 1PP compared to 3PP, there was no benefit in memory formation in 1PP for older adults. These findings are discussed in terms of both age-related changes in episodic memory functioning and self-referencing processes.
Abstract
Background
With population aging, a key question is whether new cohorts of older people are in better health than previous ones. This study aimed to compare the physical and cognitive ...performance of community-dwelling older adults assessed at similar age in 2005, 2010, and 2015.
Methods
This repeated cross-sectional analysis used data from the Lausanne cohort 65+, a three random sample population-based study. Performance of participants aged 66–71 years in 2005 (N = 1,309), 2010 (N = 1,253), and 2015 (N = 1,328) was compared using a battery of six physical and four cognitive tests. Analyses included tests for trend across samples and multivariable linear regression models.
Results
Adjusted performance in all four timed physical tests (gait speed, Timed Up-and-Go, five times chair stand, and Moberg Picking-Up) improved across samples from 2005 to 2015, by +12.7% (95% confidence interval {CI} +10.5%; +14.9%) to +20.4% (95% CI +17.7%; +23.0%) in females, and by +10.6% (95% CI +8.7%; +12.4%) to +16.7% (95% CI +13.4%; +20.0%) in males. In contrast, grip strength and balance did not improve across samples. Adjusted cognitive performance showed no change in the Trail Making Test, but worsened significantly across samples for the Mini-Mental State Examination, verbal fluency, and the clock drawing test in both females (−1.9% 95% CI −2.7%; −1.1% to −6.7% 95% CI −8.9%; −4.6%) and males (−2.5% 95% CI −3.4%; −1.6% to −8.0% 95% CI −11.1%; −4.9%).
Conclusions
Over the last decade, performance of adults aged 66–71 years improved significantly in timed physical tests but worsened in most cognitive measures among later-born samples.
Brain atrophy measured by magnetic resonance structural imaging has been proposed as a surrogate marker for the early diagnosis of Alzheimer's disease. Studies on large samples are still required to ...determine its practical interest at the individual level, especially with regards to the capacity of anatomical magnetic resonance imaging to disentangle the confounding role of the cognitive reserve in the early diagnosis of Alzheimer's disease. One hundred and thirty healthy controls, 122 subjects with mild cognitive impairment of the amnestic type and 130 Alzheimer's disease patients were included from the ADNI database and followed up for 24 months. After 24 months, 72 amnestic mild cognitive impairment had converted to Alzheimer's disease (referred to as progressive mild cognitive impairment, as opposed to stable mild cognitive impairment). For each subject, cortical thickness was measured on the baseline magnetic resonance imaging volume. The resulting cortical thickness map was parcellated into 22 regions and a normalized thickness index was computed using the subset of regions (right medial temporal, left lateral temporal, right posterior cingulate) that optimally distinguished stable mild cognitive impairment from progressive mild cognitive impairment. We tested the ability of baseline normalized thickness index to predict evolution from amnestic mild cognitive impairment to Alzheimer's disease and compared it to the predictive values of the main cognitive scores at baseline. In addition, we studied the relationship between the normalized thickness index, the education level and the timeline of conversion to Alzheimer's disease. Normalized thickness index at baseline differed significantly among all the four diagnosis groups (P < 0.001) and correctly distinguished Alzheimer's disease patients from healthy controls with an 85% cross-validated accuracy. Normalized thickness index also correctly predicted evolution to Alzheimer's disease for 76% of amnestic mild cognitive impairment subjects after cross-validation, thus showing an advantage over cognitive scores (range 63–72%). Moreover, progressive mild cognitive impairment subjects, who converted later than 1 year after baseline, showed a significantly higher education level than those who converted earlier than 1 year after baseline. Using a normalized thickness index-based criterion may help with early diagnosis of Alzheimer's disease at the individual level, especially for highly educated subjects, up to 24 months before clinical criteria for Alzheimer's disease diagnosis are met.
Traditionally, the ventral occipito-temporal (vOT) area, but not the superior parietal lobules (SPLs), is thought as belonging to the neural system of visual word recognition. However, some dyslexic ...children who exhibit a visual attention span disorder – i.e. poor multi-element parallel processing – further show reduced SPLs activation when engaged in visual multi-element categorization tasks. We investigated whether these parietal regions further contribute to letter-identity processing within strings. Adult skilled readers and dyslexic participants with a visual attention span disorder were administered a letter-string comparison task under fMRI. Dyslexic adults were less accurate than skilled readers to detect letter identity substitutions within strings. In skilled readers, letter identity differs related to enhanced activation of the left vOT. However, specific neural responses were further found in the superior and inferior parietal regions, including the SPLs bilaterally. Two brain regions that are specifically related to substituted letter detection, the left SPL and the left vOT, were less activated in dyslexic participants. These findings suggest that the left SPL, like the left vOT, may contribute to letter string processing.
► Detection of substituted letters within strings is impaired in dyslexic adults. ► This impairment relates to underactivation of the left superior parietal lobule. ► The left ventral occipito-temporal area also is less activated. ► These two brain regions may belong to the same neural network. ► The left superior parietal lobule contributes to visual word recognition.
Several brain imaging studies identified brain regions that are consistently involved in writing tasks; the left premotor and superior parietal cortices have been associated with the peripheral ...components of writing performance as opposed to other regions that support the central, orthographic components. Based on a meta-analysis by Planton, Jucla, Roux, and Demonet (2013), we focused on five such writing areas and questioned the task-specificity and hemispheric lateralization profile of the brain response in an functional magnetic resonance imaging (fMRI) experiment where 16 right-handed participants wrote down, spelled out orally object names, and drew shapes from object pictures. All writing-related areas were activated by drawing, and some of them by oral spelling, thus questioning their specialization for written production. The graphemic/motor frontal area (GMFA), a subpart of the superior premotor cortex close to Exner's area (Roux et al., 2009), was the only area with a writing-specific lateralization profile, that is, clear left lateralization during handwriting, and bilateral activity during drawing. Furthermore, the relative lateralization and levels of activation in the superior parietal cortex, ventral premotor cortex, ventral occipitotemporal cortex and right cerebellum across the three tasks brought out new evidence regarding their respective contributions to the writing processes.
Handwriting is a modality of language production whose cerebral substrates remain poorly known although the existence of specific regions is postulated. The description of brain damaged patients with ...agraphia and, more recently, several neuroimaging studies suggest the involvement of different brain regions. However, results vary with the methodological choices made and may not always discriminate between “writing-specific” and motor or linguistic processes shared with other abilities.
We used the “Activation Likelihood Estimate” (ALE) meta-analytical method to identify the cerebral network of areas commonly activated during handwriting in 18 neuroimaging studies published in the literature. Included contrasts were also classified according to the control tasks used, whether non-specific motor/output-control or linguistic/input-control. These data were included in two secondary meta-analyses in order to reveal the functional role of the different areas of this network.
An extensive, mainly left-hemisphere network of 12 cortical and sub-cortical areas was obtained; three of which were considered as primarily writing-specific (left superior frontal sulcus/middle frontal gyrus area, left intraparietal sulcus/superior parietal area, right cerebellum) while others related rather to non-specific motor (primary motor and sensorimotor cortex, supplementary motor area, thalamus and putamen) or linguistic processes (ventral premotor cortex, posterior/inferior temporal cortex).
This meta-analysis provides a description of the cerebral network of handwriting as revealed by various types of neuroimaging experiments and confirms the crucial involvement of the left frontal and superior parietal regions. These findings provide new insights into cognitive processes involved in handwriting and their cerebral substrates.
Baby-boomers might be more health-conscious than earlier birth cohorts, but limited evidence has been produced so far. To investigate such changes, this study compared health-related behaviors at age ...65 to 70 among three successive five-year birth cohorts (pre-war: born 1934-1938; war: born 1939-1943 and baby-boom: born 1944-1948) representative of the community-dwelling population. Information about alcohol use, smoking, physical activity, and nutrition was compared across the three cohorts (
= 4,270 participants) using Chi-squared test. Alcohol and the mean nutritional intake score did not vary across cohorts, whereas the consumption of nonalcoholic drinks increased significantly from pre-war to war and to baby-boom cohort (p<.001). Other differences across cohorts were observed only in women: the proportion of women who never or rarely engaged in sports decreased from 52.9% in the pre-war cohort to around 43% in subsequent cohorts (p<.001), while the proportion of women who had never smoked was higher in the pre-war cohort (56.1%) than in the war and the baby-boom cohorts (49.8% and 46.8%, respectively, p<.001). Overall, these results show some positive changes in older persons' health behaviors over time. Nevertheless, considerable room remains for improving lifestyles through public health interventions.
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