Examining the relationships between bilingualism and cognitive abilities in older adults: a pilot study

Ένας από τους παράγοντες που θεωρούνται ευεργετικοί για το γνωστικό απόθεμα των ηλικιωμένων στην υπάρχουσα βιβλιογραφία είναι η διγλωσσία. Ειδικότερα, η διγλωσσία, κατά τη γήρανση, έχει συσχετιστεί με καλά διατηρημένες εκτελεστικές λειτουργίες, αλλά με επιδόσεις λεκτικής επεξεργασίας χαμηλότερου επιπέδου, σε σύγκριση με τη μονογλωσσία. Η πρώτη υπόθεση της παρούσας μελέτης ήταν ότι οι δίγλωσσοι ηλικιωμένοι θα εμφανίζουν υψηλότερη βαθμολογία σε έργο μέτρησης γνωστικών ικανοτήτων ανώτερης τάξης. Υπήρχε η υπόθεση, αντιθέτως, ότι οι μονόγλωσσοι ηλικιωμένοι θα υπερτερούσαν των δίγλωσσων σε δοκιμασία που μετρά τη γενική γνωστική ικανότητα, τουλάχιστον όσον αφορά σε υποσυνθήκες της δοκιμασίας που απαιτούν λεκτική επεξεργασία. Οι συμμετέχοντες χωρίστηκαν σε μια ομάδα με 10 δίγλωσσους ηλικιωμένους, ομιλούντες την ελληνική γλώσσα και μια άλλη γλώσσα, και σε μια δεύτερη ομάδα με 10 μονόγλωσσους ηλικιωμένους, ομιλούντες την ελληνική γλώσσα. Οι ομάδες ήταν εξισωμένες ως προς την ηλικία, το εκπαιδευτικό επίπεδο και το φύλο. Η εκτελεστική λειτουργία εξετάστηκε μέσω ενός  οπτικοχωρικού έργου που μετρά το μακροπρόθεσμο σχεδιασμό. Χορηγήθηκε, επίσης, σύντομη δοκιμασία που μετρά τη γενική γνωστική ικανότητα σε ηλικιωμένους. Τα αποτελέσματα έδειξαν ότι οι δίγλωσσοι έχουν την τάση να εμφανίζουν υψηλότερη επίδοση ως προς τις εκτελεστικές λειτουργίες. Ωστόσο, σε σχέση με τη γενική γνωστική ικανότητα, οι μονόγλωσσοι ηλικιωμένοι έχουν σημαντικά υψηλότερη επίδοση. Ως εκ τούτου, το πλεονέκτημα των δίγλωσσων όσον αφορά τη διατήρηση εκτελεστικών λειτουργιών στη γήρανση δεν υποστηρίχθηκε σαφώς. Από την άλλη πλευρά, αναδύθηκε και συζητήθηκε ένα μειονέκτημα της γενικής γνωστικής τους ικανότητας, σε σύγκριση με τους μονόγλωσσους, που εν μέρει οφείλεται σε ελλείμματα στις λεκτικές διεργασίες.One of the factors that are considered beneficial for the cognitive reserve of older adults in the current literature is bilingualism. Specifically, bilingualism has been associated with well-preserved executive functions in aging but a lower-level lexical processing performance, as compared to monolingualism. The first hypothesis of the present study was that bilingual older adults would display higher score in a task measuring higher-order cognitive abilities. On the other hand, it was assumed that monolingual older adults would outperform bilinguals in a test measuring general cognitive ability at least as regards subtests that require lexical processing. The participants were divided into an older adult group of 10 bilingual speakers of Greek language and of another language, and a second older adult group of 10 monolingual speakers of Greek language, matched in age, educational level and gender. Executive functioning was examined via a task measuring long-term spatial planning. A short test of general cognitive ability was also administered. The results showed that bilinguals tended to display higher performance as regards executive functioning. However, in relation to general cognitive ability, monolingual older adults had significantly higher performance. Hence, the bilinguals’ advantage as regards the maintenance of executive functions in aging was not clearly supported. On the other hand, a disadvantage in general cognitive ability probably due to deficits in lexical processing, as compared to monolinguals emerged and was further discussed

Quantitative magnetization transfer imaging as a biomarker for effects of systemic inflammation on the brain

BACKGROUND Systemic inflammation impairs brain function and is increasingly implicated in the etiology of common mental illnesses, particularly depression and Alzheimer's disease. Immunotherapies selectively targeting proinflammatory cytokines demonstrate efficacy in a subset of patients with depression. However, efforts to identify patients most vulnerable to the central effects of inflammation are hindered by insensitivity of conventional structural magnetic resonance imaging. METHODS We used quantitative magnetization transfer (qMT) imaging, a magnetic resonance imaging technique that enables quantification of changes in brain macromolecular density, together with experimentally induced inflammation to investigate effects of systemic inflammatory challenge on human brain microstructure. Imaging with qMT was performed in 20 healthy participants after typhoid vaccination and saline control injection. An additional 20 participants underwent fluorodeoxyglucose positron emission tomography following the same inflammatory challenge. RESULTS The qMT data demonstrated that inflammation induced a rapid change in brain microstructure, reflected in increased magnetization exchange from free (water) to macromolecular-bound protons, within a discrete region of insular cortex implicated in representing internal physiologic states including inflammation. The functional significance of this change in insular microstructure was demonstrated by correlation with inflammation-induced fatigue and fluorodeoxyglucose positron emission tomography imaging, which revealed increased resting glucose metabolism within this region following the same inflammatory challenge. CONCLUSIONS Together these observations highlight a novel structural biomarker of the central physiologic and behavioral effects of mild systemic inflammation. The widespread clinical availability of magnetic resonance imaging supports the viability of qMT imaging as a clinical biomarker in trials of immunotherapeutics, both to identify patients vulnerable to the effects of systemic inflammation and to monitor neurobiological responses

Effect of blood glucose level on standardized uptake value (SUV) in F-18- FDG PET-scan : a systematic review and meta-analysis of 20,807 individual SUV measurements

Objectives To evaluate the effect of pre-scan blood glucose levels (BGL) on standardized uptake value (SUV) in F-18-FDG-PET scan. Methods A literature review was performed in the MEDLINE, Embase, and Cochrane library databases. Multivariate regression analysis was performed on individual datum to investigate the correlation of BGL with SUVmax and SUVmean adjusting for sex, age, body mass index (BMI), diabetes mellitus diagnosis, F-18-FDG injected dose, and time interval. The ANOVA test was done to evaluate differences in SUVmax or SUVmean among five different BGL groups (200 mg/dl). Results Individual data for a total of 20,807 SUVmax and SUVmean measurements from 29 studies with 8380 patients was included in the analysis. Increased BGL is significantly correlated with decreased SUVmax and SUVmean in brain (p <0.001, p <0.001,) and muscle (p <0.001, p <0.001) and increased SUVmax and SUVmean in liver (p = 0.001, p = 0004) and blood pool (p=0.008, p200 mg/dl had significantly lower SUVmax. Conclusion If BGL is lower than 200mg/dl no interventions are needed for lowering BGL, unless the liver is the organ of interest. Future studies are needed to evaluate sensitivity and specificity of FDG-PET scan in diagnosis of malignant lesions in hyperglycemia.Peer reviewe

99mTc-MAG3 Diuretic Renography: Intra- and Inter-Observer Repeatability in the Assessment of Renal Function.

The aim of the present study is to evaluate the intra- and inter-observer agreement in assessing the renal function by means of 99mTc-MAG3 diuretic renography. One hundred and twenty adults were enrolled in the study. One experienced and one junior radiographer processed the renograms twice by assigning manual and semi-automated regions of interest. The differential renal function (DRF, %), time to maximum counts for the right and left kidney (TmaxR-TmaxL, min) and time to half-peak counts (T1/2, min) were calculated. The Bland-Altman analysis (bias±95% limits of agreement), Lin's concordance correlation coefficient and weighted Fleiss' kappa coefficient were used to assess agreement. Based on the Bland-Altman analysis, the intra-observer repeatability results for the experienced radiographer using the manual and the semi-automated techniques were 0.2 ± 2.6% and 0.3 ± 6.4% (DRF), respectively, -0.01 ± 0.24 and 0.00 ± 0.34 (TmaxR), respectively, and 0.00 ± 0.26 and 0.00 ± 0.33 (TmaxL), respectively. For the junior radiographer, the respective results were 0.5 ± 5.0% and 0.8 ± 9.4% (DRF), 0.00 ± 0.44 and 0.01 ± 0.28 (TmaxR), and 0.01 ± 0.28 and -0.02 ± 0.44 (TmaxL). The inter-observer repeatability for the manual method was 0.6 ± 5.0% (DRF), -0.10 ± 0.42 (TmaxR) and -0.05 ± 0.38 (TmaxL), and for the semi-automated method -0.2 ± 9.1% (DRF), 0.00 ± 0.31 (TmaxR) and -0.05 ± 0.40 (TmaxL). The weighted Fleiss' kappa coefficient for the T1/2 assessments ranged between 0.85-0.97 for both intra- and inter-observer repeatability with both methods. These findings suggest a very good repeatability in DRF assessment with the manual method-especially for the experienced observer-but a less good repeatability with the semi-automated approach. The calculation of Tmax was also operator-dependent. We conclude that reader experience is important in the calculation of renal parameters. We therefore encourage reader training in renal scintigraphy. Moreover, the manual tool seems to perform better than the semi-automated tool. Thus, we encourage cautious use of automated tools and adjunct validation by manual methods where possible