38 research outputs found
Vajdasági magyar nyelvhasználat egyetemisták körében
Jelen dolgozatomban Magyarországon, illetve Szerbiában tanuló vajdasági egyetemisták nyelvhasználatát hasonlítom össze. Arra a kérdésre szeretnék választ kapni, hogy a Szerbiában tanulóknak mennyire fontos az anyanyelvük, valamint hogy mennyi szerb eredetű, illetve „vajdasági” szót használnak, és mennyire vannak tisztában e szavak magyar megfelelőivel. A Magyarországon tanulóknál szintén arra voltam kíváncsi, mi a viszonyuk nyelvjárásukhoz, és hogy a magyar oktatás, a magyar környezet ellenére mennyire őrzik, használják az otthon használatos szerb vagy szerb eredetű szavakat
Vajdasági magyar nyelvhasználat egyetemisták körében
Jelen dolgozatomban Magyarországon, illetve Szerbiában tanuló vajdasági egyetemisták nyelvhasználatát hasonlítom össze. Arra a kérdésre szeretnék választ kapni, hogy a Szerbiában tanulóknak mennyire fontos az anyanyelvük, valamint hogy mennyi szerb eredetű, illetve „vajdasági” szót használnak, és mennyire vannak tisztában e szavak magyar megfelelőivel. A Magyarországon tanulóknál szintén arra voltam kíváncsi, mi a viszonyuk nyelvjárásukhoz, és hogy a magyar oktatás, a magyar környezet ellenére mennyire őrzik, használják az otthon használatos szerb vagy szerb eredetű szavakat
Retinal phenotyping of variants of Alzheimer's disease using ultra-widefield retinal images
Background: Posterior cortical atrophy (PCA) is the most common atypical variant of Alzheimer's disease (AD). Changes associated with PCA in the brain affect the visual cortex, but little is known about retinal changes in PCA. In this study, we explored retinal phenotypic variations in typical AD (tAD) and PCA. Methods: Retinal phenotyping was carried out on ultra-widefield (UWF) images of 69 control, 24 tAD, and 25 PCA participants. Results: Individuals with tAD (odds ratio [OR] = 2.76 [confidence interval (CI):1.24 to 6.10], P = .012) and PCA (OR = 3.40 [CI:1.25 to 9.22], P = .016) were more likely phenotyped as hard drusen. tAD (OR = 0.34 [CI:0.12 to 0.92], P = .035) were less likely to have soft drusen compared to control. Almost 3-fold increase in reticular pseudodrusen formation in tAD (OR = 2.93 [CI:1.10 to 7.76], P = .030) compared to control was estimated. Discussion: Studying the peripheral retina may contribute to a better understanding of differences in retinal phenotypes of different AD variants
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Increased choroidal thickness in adults with Down syndrome.
Introduction: People with Down syndrome (DS) are particularly susceptible to Alzheimer's disease (AD) due to the triplication of the amyloid precursor protein (APP) gene. In this cross-sectional study, we hypothesized that choroidal thinning reported in sporadic AD (sAD) is mirrored in adults with DS. Methods: The posterior pole of the eye for 24 adults with DS and 16 age-matched controls (Ctrl) were imaged with optical coherence tomography. Choroidal thickness (ChT) was measured and analyzed in relation to cognitive status and cerebral amyloid beta (Aβ) load. Results: ChT was increased in people with DS (pwDS) compared to Ctrl. This increase was associated with gender differences and positively correlated with cerebral Aβ load in a small subset. There was no significant correlation detected between ChT and age or cognitive status. Discussion: In contrast to sAD this study found a significantly thicker choroid in pwDS. Whether these changes are related to Aβ pathology in DS needs further investigation
Peripheral Retinal Imaging Biomarkers for Alzheimer’s Disease: A Pilot Study
Purpose: To examine whether ultra-widefield (UWF) retinal imaging can identify biomarkers for Alzheimer's disease (AD) and its progression. Methods: Images were taken using a UWF scanning laser ophthalmoscope (Optos P200C AF) to determine phenotypic variations in 59 patients with AD and 48 healthy controls at baseline (BL). All living participants were invited for a follow-up (FU) after 2 years and imaged again (if still able to participate). All participants had blood taken for genotyping at BL. Images were graded for the prevalence of age-related macular degeneration-like pathologies and retinal vascular parameters. Comparison between AD patients and controls was made using the Student t test and the χ2 test. Results: Analysis at BL revealed a significantly higher prevalence of a hard drusen phenotype in the periphery of AD patients (14/55; 25.4%) compared to controls (2/48; 4.2%) [χ2 = 9.9, df = 4, p = 0.04]. A markedly increased drusen number was observed at the 2-year FU in patients with AD compared to controls. There was a significant increase in venular width gradient at BL (zone C: 8.425 × 10-3 ± 2.865 × 10-3 vs. 6.375 × 10-3 ± 1.532 × 10-3, p = 0.008; entire image: 8.235 × 10-3 ± 2.839 × 10-3 vs. 6.050 × 10-3 ± 1.414 × 10-3, p = 0.004) and a significant decrease in arterial fractal dimension in AD at BL (entire image: 1.250 ± 0.086 vs. 1.304 ± 0.089, p = 0.049) with a trend for both at FU. Conclusions: UWF retinal imaging revealed a significant association between AD and peripheral hard drusen formation and changes to the vasculature beyond the posterior pole, at BL and after clinical progression over 2 years, suggesting that monitoring pathological changes in the peripheral retina might become a valuable tool in AD monitoring
Retinal Imaging in Alzheimer’s Disease
Identifying biomarkers of Alzheimer's disease (AD) will accelerate the understanding of its pathophysiology, facilitate screening and risk stratification, and aid in developing new therapies. Developments in non-invasive retinal imaging technologies, including optical coherence tomography (OCT), OCT angiography and digital retinal photography, have provided a means to study neuronal and vascular structures in the retina in people with AD. Both qualitative and quantitative measurements from these retinal imaging technologies (eg, thinning of peripapillary retinal nerve fibre layer, inner retinal layer, and choroidal layer, reduced capillary density, abnormal vasodilatory response) have been shown to be associated with cognitive function impairment and risk of AD. The development of computer algorithms for respective retinal imaging methods has further enhanced the potential of retinal imaging as a viable tool for rapid, early detection and screening of AD. In this review, we present an update of current retinal imaging techniques and their potential applications in AD research. We also discuss the newer retinal imaging techniques and future directions in this expanding field
Optic nerve thinning and neurosensory retinal degeneration in the rTg4510 mouse model of frontotemporal dementia
Visual impairments, such as difficulties in reading and finding objects, perceiving depth and structure from motion,
and impaired stereopsis, have been reported in tauopathy disorders, such as frontotemporal dementia (FTD). These
impairments however have been previously attributed to cortical pathologies rather than changes in the neurosensory
retina or the optic nerve. Here, we examined tau pathology in the neurosensory retina of the rTg(tauP301L)4510
mouse model of FTD. Optic nerve pathology in mice was also assessed using MRI, and corresponding measurements
taken in a cohort of five FTD sufferers and five healthy controls. rTg(tauP301L)4510 mice were imaged (T2-weighted
MRI) prior to being terminally anesthetized and eyes and brains removed for immunohistochemical and histological
analysis. Central and peripheral retinal labelling of tau and phosphorylated tau (pTau) was quantified and retinal layer
thicknesses and cell numbers assessed. MR volumetric changes of specific brain regions and the optic nerve were
compared to tau accumulation and cell loss in the visual pathway. In addition, the optic nerves of a cohort of healthy
controls and behavioural variant FTD patients, were segmented from T1- and T2-weighted images for volumetric study.
Accumulation of tau and pTau were observed in both the central and peripheral retinal ganglion cell (RGC), inner
plexiform and inner nuclear layers of the neurosensory retina of rTg(tauP301L)4510 mice. This pathology was
associated with reduced nuclear density (− 24.9 ± 3.4%) of the central RGC layer, and a reduced volume (− 19.3 ± 4.6%)
and elevated T2 signal (+ 27.1 ± 1.8%) in the optic nerve of the transgenic mice. Significant atrophy of the cortex
(containing the visual cortex) was observed but not in other area associated with visual processing, e.g. the lateral
geniculate nucleus or superior colliculus. Atrophic changes in optic nerve volume were similarly observed in FTD
patients (− 36.6 ± 2.6%). The association between tau-induced changes in the neurosensory retina and reduced optic
nerve volume in mice, combined with the observation of optic nerve atrophy in clinical FTD suggests that ophthalmic
tau pathology may also exist in the eyes of FTD patients. If tau pathology and neurodegeneration in the retina were to
reflect the degree of cortical tau burden, then cost-effective and non-invasive imaging of the neurosensory retina
could provide valuable biomarkers in tauopathy. Further work should aim to validate whether these observations are
fully translatable to a clinical scenario, which would recommend follow-up retinal and optic nerve examination in FT