Functional Outcomes at 90 Days in Octogenarians Undergoing Thrombectomy for Acute Ischemic Stroke: A Prospective Cohort Study and Meta-Analysis

Background: Elderly patients account for 30% of acute ischemic stroke (AIS) but are under-represented in randomized controlled trials of endovascular thrombectomy (EVT). Meta-analysis of “real world” studies evaluating 90-day outcomes in elderly patients ≥80 years have been limited to small numbers undergoing EVT with older generation devices.Methods: A retrospective analysis of 181 prospectively collected patients who received EVT for anterior circulation AIS at an Australian center over 2.5-years. The study aims to determine (i) 90-day functional outcomes (modified Rankin Scale mRS 0–2) in patients ≥80 vs. <80 years, (ii) the interaction of prognostic factors and age and (iii) compare our data to those previously reported using a meta-analysis of outcomes in observational studies using second generation thrombectomy devices.Results: We analyzed 2,387 patients (≥80 years, n = 649; <80 years, n = 1,738) from 14 studies including our study (≥80 years, n = 71; <80 years, n = 110). Twenty-eight percent of our and 30% of the meta-analysis elderly cohort achieved good 90-day mRS compared to 55 and 52%, respectively of younger patients (p < 0.001). Twenty-seven percent of our and 26% of the meta-analysis elderly cohort died compared to 16% (p = 0.07) and 15% (p < 0.0001), respectively of younger patients. Baseline NIHSS≥16 correlated with poor prognosis in elderly (OR 16.4; 95% CI 4.49–59.91, p < 0.001) and younger (OR 8.73;95% CI 3.35–22.80, p < 0.001) patients. Prior rt-PA was associated with favorable outcome in younger (OR 2.90; 95%CI 1.29–6.52, p = 0.01) patients only.Conclusion: EVT has less favorable outcomes in elderly patients. However, results are better than outcomes in historical controls not treated with thrombectomy providing further support for EVT in the elderly

Line orientation adaptation: local or global?

Prolonged exposure to an oriented line shifts the perceived orientation of a subsequently observed line in the opposite direction, a phenomenon known as the tilt aftereffect (TAE). Here we consider whether the TAE for line stimuli is mediated by a mechanism that integrates the local parts of the line into a single global entity prior to the site of adaptation, or the result of the sum of local TAEs acting separately on the parts of the line. To test between these two alternatives we used the fact the TAE transfers almost completely across luminance contrast polarity [1]. We measured the TAE using adaptor and test lines that (1) either alternated in luminance polarity or were of a single polarity, and (2) either alternated in local orientation or were of a single orientation. We reasoned that if the TAE was agnostic to luminance polarity and was parts-based, we should obtain large TAEs using alternating-polarity adaptors with single-polarity tests. However we found that (i) TAEs using one-alternating-polarity adaptors with all-white tests were relatively small, increased slightly for two-alternating-polarity adaptors, and were largest with all-white or all-black adaptors. (ii) however TAEs were relatively large when the test was one-alternating polarity, irrespective of the adaptor type. (iii) The results with orientation closely mirrored those obtained with polarity with the difference that the TAE transfer across orthogonal orientations was weak. Taken together, our results demonstrate that the TAE for lines is mediated by a global shape mechanism that integrates the parts of lines into whole prior to the site of orientation adaptation. The asymmetry in the magnitude of TAE depending on whether the alternating-polarity lines was the adaptor or test can be explained by an imbalance in the population of neurons sensitive to 1st-and 2nd-order lines, with the 2nd-order lines being encoded by a subset of the mechanisms sensitive to 1st-order lines

Altering brain dynamics with transcranial random noise stimulation

Random noise can enhance the detectability of weak signals in nonlinear systems, a phenomenon known as stochastic resonance (SR). This concept is not only applicable to single threshold systems but can also be applied to dynamical systems with multiple attractor states, such as observed during the phenomenon of binocular rivalry. Binocular rivalry can be characterized by marginally stable attractor states between which the brain switches in a spontaneous, stochastic manner. Here we used a computational model to predict the effect of noise on perceptual dominance durations. Subsequently we compared the model prediction to a series of experiments where we measured binocular rivalry dynamics when noise (zero-mean Gaussian random noise) was added either to the visual stimulus (Exp. 1) or directly to the visual cortex (Exp. 2) by applying transcranial Random Noise Stimulation (tRNS 1 mA, 100–640 Hz zero -mean Gaussian random noise). We found that adding noise significantly reduced the mixed percept duration (Exp. 1 and Exp. 2). Our results are the first to demonstrate that both central and peripheral noise can influence state-switching dynamics of binocular rivalry under specific conditions (e.g. low visual contrast stimuli), in line with a SR-mechanism

Safety and Feasibility of Transradial Access for Neurointervention Procedures in Patients With Radial Artery Occlusion

Background Transradial access (TRA) has proven advantages in interventional cardiology and neurointervention. There is limited literature detailing radial artery occlusion (RAO) recanalization, and generally, RAO necessitates alternate access. The purpose of this study was to evaluate the safety and feasibility of TRA in patients with RAO, allowing successful completion of the intended neurointervention procedure. Methods and Results Prospectively maintained databases at 2 Australian high‐volume neurointervention centers between January 2019 and February 2022 were reviewed. All consecutive patients with RAO who underwent attempted TRA for diagnostic neuroangiography or neurointervention procedures were included. Sixty‐one attempts at TRA through RAO for neurointervention procedures were performed in 42 patients. The mean age was 54.9 years, and 65.6% were women. Fifty‐three cases (86%) successfully completed the intended neurointervention procedure following RAO recanalization: 33 cases of diagnostic cerebral angiography, 9 cases of cerebral vasospasms, 6 cases of aneurysm repairs, 3 cases of endovascular thrombectomies, 1 case of carotid artery stenting/angioplasty, and 1 case of intracranial dural arteriovenous fistula embolization. Six cases (9.8%) required conversion to alternate access to complete the procedure because of failed TRA or anatomical challenges to select the target vessel. Two cases (3.2%) experienced transient minor radial artery extravasation without clinical sequelae. No major complications were encountered. Conclusions TRA in patients with RAO for neurointervention procedures is both safe and feasible, with no significant additional equipment or cost. RAO is not a contraindication to radial artery access in neurointervention

Successful endovascular and surgical treatment of spinal extradural metameric arteriovenous malformation : case report

A report of successful combined endovascular and surgical management of an unusual case of metameric (juvenile) spinal arteriovenous malformation (AVM) is presented. The malformation had extradural and paraspinal components, but no intradural elements. It had caused rapid neurological deterioration to near-complete paraplegia prior to treatment (American Spinal Injury Association [ASIA] Grade C). A combination of endovascular occlusion of major feeding vessels and excision of the malformation resulted in a complete neurological recovery (ASIA Grade E). The authors conclude that selected metameric AVMs can be successfully treated with multimodal therapy. This case further illustrates the fact that not all spinal vascular malformations are easily categorized.5 page(s

Using noise for the better: The effects of transcranial random noise stimulation on the brain and behavior

Van der Groen, O., Potok, W., Wenderoth, N., Edwards, G., Mattingley, J.B. and Edwards, D. Using noise for the better: The effects of transcranial random noise stimulation on the brain and behavior. NEUROSCI BIOBEHAV REV X (X) XXX-XXX 2021.- Transcranial random noise stimulation (tRNS) is a non-invasive electrical brain stimulation method that is increasingly employed in studies of human brain function and behavior, in health and disease. tRNS is effective in modulating perception acutely and can improve learning. By contrast, its effectiveness for modulating higher cognitive processes is variable. Prolonged stimulation with tRNS, either as one longer application, or multiple shorter applications, may engage plasticity mechanisms that can result in long-term benefits. Here we provide an overview of the current understanding of the effects of tRNS on the brain and behavior and provide some specific recommendations for future research.ISSN:0149-7634ISSN:1873-752

Using noise for the better: The effects of transcranial random noise stimulation on the brain and behavior

NEUROSCI BIOBEHAV REV X (X) XXX-XXX 2021.- Transcranial random noise stimulation (tRNS) is a non-invasive electrical brain stimulation method that is increasingly employed in studies of human brain function and behavior, in health and disease. tRNS is effective in modulating perception acutely and can improve learning. By contrast, its effectiveness for modulating higher cognitive processes is variable. Prolonged stimulation with tRNS, either as one longer application, or multiple shorter applications, may engage plasticity mechanisms that can result in long-term benefits. Here we provide an overview of the current understanding of the effects of tRNS on the brain and behavior and provide some specific recommendations for future research

Stochastic resonance enhances the rate of evidence accumulation during combined brain stimulation and perceptual decision-making

<div><p>Perceptual decision-making relies on the gradual accumulation of noisy sensory evidence. It is often assumed that such decisions are degraded by adding noise to a stimulus, or to the neural systems involved in the decision making process itself. But it has been suggested that adding an optimal amount of noise can, under appropriate conditions, enhance the quality of subthreshold signals in nonlinear systems, a phenomenon known as <i>stochastic resonance</i>. Here we asked whether perceptual decisions made by human observers obey these stochastic resonance principles, by adding noise directly to the visual cortex using transcranial random noise stimulation (tRNS) while participants judged the direction of coherent motion in random-dot kinematograms presented at the fovea. We found that adding tRNS bilaterally to visual cortex enhanced decision-making when stimuli were just below perceptual threshold, but not when they were well below or above threshold. We modelled the data under a drift diffusion framework, and showed that bilateral tRNS selectively increased the drift rate parameter, which indexes the rate of evidence accumulation. Our study is the first to provide causal evidence that perceptual decision-making is susceptible to a stochastic resonance effect induced by tRNS, and to show that this effect arises from selective enhancement of the rate of evidence accumulation for sub-threshold sensory events.</p></div

Book 1.indb

Abstract Introduction: Clinical use of the Amplatzer vascular plug in the cardiopulmonary and peripheral vasculatures has been described extensively in the literature. We present our initial experience in adapting this device for therapeutic sacrifi ce of major craniocerebral arteries