Linking the impact of aging on visual short-term memory capacity with changes in the structural connectivity of posterior thalamus to occipital cortices

Aging impacts both visual short-term memory (vSTM) capacity and thalamo-cortical connectivity. According to the Neural Theory of Visual Attention, vSTM depends on the structural connectivity between posterior thalamus and visual occipital cortices (PT-OC). We tested whether aging modifies the association between vSTM capacity and PT-OC structural connectivity. To do so, 66 individuals aged 20–77 years were assessed by diffusion-weighted imaging used for probabilistic tractography and performed a psychophysical whole-report task of briefly presented letter arrays, from which vSTM capacity estimates were derived. We found reduced vSTM capacity, and aberrant PT-OC connection probability in aging. Critically, age modified the relationship between vSTM capacity and PT-OC connection probability: in younger adults, vSTM capacity was negatively correlated with PT-OC connection probability while in older adults, this association was positive. Furthermore, age modified the microstructure of PT-OC tracts suggesting that the inversion of the association between PT-OC connection probability and vSTM capacity with aging might reflect age-related changes in white-matter properties. Accordingly, our results demonstrate that age-related differences in vSTM capacity links with the microstructure and connectivity of PT-OC tracts

Sex differences in presentation of atrial fibrillation : Findings from 30-day ambulatory monitoring in real-world practice

Background: Women are less likely to receive oral anticoagulation or ablation for treatment of atrial fibrillation (AF). Identification of sex differences in arrhythmia characteristics and symptoms may lead to a better understanding of potential reasons for these differences. Objectives: To determine sex differences in AF with respect to heart rate, duration, burden, and symptoms in patients undergoing mobile cardiac telemetry (MCT) monitoring. Methods: All patients who registered for ≤30-day MCT using PocketECG (MediLynx) in the USA in 2017 were included (n = 27,512, 58 % women). PocketECG records and transmits a three-lead ambulatory electrocardiogram (ECG) with real-time beat-to-beat analysis. Sex-related differences were analyzed with Chi2 and Spearmans rho. Results: Fewer women than men were diagnosed with AF lasting ≥30s (13.7 % versus [vs] 19.0 %, p < 0.001). AF burden was lower in women in all age groups <90 years (all p < 0.01). Women were older at the time of AF diagnosis (median 76 vs 73 years, p < 0.001), had faster heart rate during AF (mean: 104.7 ± 26.0 vs 96.7 ± 26.7 bpm, p < 0.001), and shorter AF duration (mean: 96.2 ± 176.0 vs 121.6 ± 189.9 min, p < 0.001). There was a non-significant trend toward more symptoms (such as dizziness, racing heart, fatigue, or palpitations) during AF in women compared to men (46.5 % vs 43.7 %, p = 0.062). Conclusions: AF was less prevalent and occurred at lower burdens in women than men in each age strata. Despite faster heart rates in AF in women, there were no significant sex differences in reported symptoms during AF. Sex differences in therapy cannot be explained by differences in symptoms or rates in AF. Condensed abstract: Real-world data on sex differences in AF using a 30-day MCT monitoring device remain scarce. We aim to determine the sex differences in AF with respect to prevalence, burden, heart rate, and symptom in patients undergoing ≤30-day MCT monitoring. Our data analysis suggests that fewer women than men had AF, women were older at diagnosis of AF, and women with AF had higher mean heart rate, shorter mean AF duration, and lower mean AF burden than men. Further studies are needed to examine reasons for sex differences, specifically in relation to AF therapy and its impact on clinical outcomes