Efficacy of Mechanical Thrombectomy Using Stent Retriever and Balloon-Guiding Catheter.

PURPOSE: Intra-arterial therapy of acute ischemic stroke has developed rapidly in recent years. Due to proven efficacy in randomized trials, stent retrievers were replacing first-generation thrombectomy devices and have been defined as method of choice. However, aspiration catheters or a combination of several techniques have shown promising rates of successful recanalizations. To create a basis for comparison of the new approaches according to real-world data, we determined the first pass recanalization rate of an evidence-based standard technique with the use of a stent retriever in combination with a balloon-guiding catheter. The assessment was based on the number of required passages and reperfusion rate, but not on clinical results. METHODS: Patients from our institution with anterior circulation occlusions and mechanical thrombectomy by using stent retrievers in combination with balloon-guiding catheters were analyzed retrospectively. Reperfusion was graded with the "thrombolysis in cerebral infarction" (TICI) classification on post-interventional angiograms. Additionally, the number of passes and the duration of the recanalization procedure were recorded. RESULTS: Between 2014 and July 2017, 201 patients met the inclusion criteria. Successful recanalization, defined as a TICI scale 2b/3, was 91% (TICI 2b was achieved in 44% and TICI 3 in 47%) after the procedure. After the first passage, successful recanalization was achieved in 65% of the patients. Mean number of passes was 1.4 (1-5 passes) for all patients. Median duration of the procedure was 49 min (0:11-2:35 h). CONCLUSIONS: Even a standard thrombectomy technique with the use of a stent retriever together with a balloon-guiding catheter provides reasonable recanalization rates with only one passage. The results can be taken as benchmark for alternative and more complex techniques.

Do houseflies think? Patterns of induction and biological beliefs in development.

A current debate within the cognitive development literature addresses how best to characterize conceptual change. Within one proposal, development primarily consists of a series of radical conceptual shifts or restructurings in which the most current understanding is inexplicable within (incommensurate with) prior conceptual structure. Alternatively, development is discussed as more gradual enrichment of multiple existing early explanatory systems, allowing for commensurability over time and change. This paper examines the literature in this debate with specific focus on naive biological understanding, and discusses a series of studies on preschoolers' inductive inferences across biological and non-biological kinds. Children were taught a series of biological properties for a human being (e.g. eating, sleeping etc.), and asked to generalize these properties to both biological (e.g. dogs, worms) and non-biological kinds (e.g. clouds, tables). The results of these studies support the gradual-enrichment proposal. Specifically, 4-year-olds seem to possess limited, but coherent and independent biological theory which may form the basis of mature understanding of biological kinds. These results are discussed in terms of multiple explanatory systems which both preschoolers and adults can employ across development to effectively guide their decisions within a given domain.

Two dogmas of conceptual empiricism: implications for hybrid models of the structure of knowledge.

Concepts seem to consist of both an associative component based on tabulations of feature typicality and similarity judgments and an explanatory component based on rules and causal principles. However, there is much controversy about how each component functions in concept acquisition and use. Here we consider two assumptions, or dogmas, that embody this controversy and underlie much of the current cognitive science research on concepts. Dogma 1: Novel information is first processed via similarity judgments and only later is influenced by explanatory components. Dogma 2: Children initially have only a similarity-based component for learning concepts; the explanatory component develops on the foundation of this earlier component. We present both empirical and theoretical arguments that these dogmas are unfounded, particularly with respect to real world concepts; we contend that the dogmas arise from a particular species of empiricism that inhibits progress in the study of conceptual structure; and finally, we advocate the retention of a hybrid model of the structure of knowledge despite our rejection of these dogmas.

Conceptualizing a nonnatural entity: anthropomorphism in God concepts.

We investigate the problem of how nonnatural entities are represented by examining university students' concepts of God, both professed theological beliefs and concepts used in comprehension of narratives. In three story processing tasks, subjects often used an anthropomorphic God concept that is inconsistent with stated theological beliefs; and drastically distorted the narratives without any awareness of doing so. By heightening subjects' awareness of their theological beliefs, we were able to manipulate the degree of anthropomorphization. This tendency to anthropomorphize may be generalizable to other agents. God (and possibly other agents) is unintentionally anthropomorphized in some contexts, perhaps as a means of representing poorly understood nonnatural entities.

Categorical effects in the perception of faces.

These studies suggest categorical perception effects may be much more general than has commonly been believed and can occur in apparently similar ways at dramatically different levels of processing. To test the nature of individual face representations, a linear continuum of "morphed" faces was generated between individual exemplars of familiar faces. In separate categorization, discrimination and "better-likeness" tasks, subjects viewed pairs of faces from these continua. Subjects discriminate most accurately when face-pairs straddle apparent category boundaries; thus individual faces are perceived categorically. A high correlation is found between the familiarity of a face-pair and the magnitude of the categorization effect. Categorical perception therefore is not limited to low-level perceptual continua, but can occur at higher levels and may be acquired through experience as well.

An abstract to concrete shift in the development of biological thought: the insides story.

For more than a century, theorists of cognitive development have embraced some form of the thesis that cognitive development proceeds from concrete to abstract knowledge. In contrast to this view, we suggest an abstract to concrete shift in the development of biological thought. In five studies we examine children's expectations for what could be inside animals and machines and we find that children of all ages respond systematically, revealing abstract expectations for how the insides of animals and machines should differ. By 8 years, children seem to have more concrete expectations for the nature of insides, and are substantially more accurate than preschoolers. More broadly, we suspect that an abstract to concrete progression may capture important features of how knowledge develops in the realm of biological thought and in many other areas of understanding as well.

Early differentiation of causal mechanisms appropriate to biological and nonbiological kinds.

Although Piaget characterized young children as precausal until about 7-8 years of age, recent work indicates that preschoolers do honor fundamental principles of causality. This literature has mainly focused on general principles invoked in reasoning about mechanical events. By contrast, the present study examined whether children differentiate between the causal mechanisms appropriate for different conceptual domains. The results of 3 preliminary investigations and 1 main experiment suggested that preschoolers prefer natural mechanisms for color inheritance in biological kinds, particularly when causal substrates resemble their consequences. By contrast, the same children recognized the importance of human intentions in producing the color of an artifact, and also judged that mechanical mechanisms serve to mediate between intentions and outcomes. The results are relevant to recent studies on the development of biological thought, and overall suggest that early causal reasoning reflects both domain-specific and domain-general principles.

The relation between syllable number and visual complexity in the acquisition of word meanings.

Four experiments were conducted to explore the correlation between syllable number and visual complexity in the acquisition of novel words. In the first experiment, adult English speakers invented nonsense words as names for random polygons differing in visual complexity. Visually simple polygons received names containing fewer syllables than visually complex polygons did. In addition, analyses of English word-object pairings indicated that a significant correlation between syllable number and visual complexity exists in the English lexicon. In Experiments 2 and 3, adult English speakers matched monosyllabic novel words more often than trisyllabic novel words with visually simple objects, whereas trisyllabic matches were more common for visually complex objects. Experiment 4 replicated these findings with children, indicating that the assumption of a correlation between word and visual complexity exists during the period of intense vocabulary growth. Although the actual correlation between syllable number and visual complexity is small, other posited constraints on word meaning are also limited in strength. However, an increasing number of small, language-specific word-meaning correlations are being uncovered. Given the documented ability of speakers to detect and use these subtle correlations, we argue that a more fruitful approach to word-meaning acquisition would forgo the search for a few broad, powerful word-meaning constraints, and we attempt to uncover individually weak, but perhaps jointly powerful word-meaning correspondences.

On the development of biologically specific beliefs: the case of inheritance.

5 experiments investigated children's intuitions about genetic transmission of features. After parent animals possessing an abnormal feature were described, children were asked whether their baby would be born with that feature in abnormal or normal form. Features were either internal or external, inborn or acquired after birth, and had functional or nonfunctional consequences for the parents. Among preschoolers, features with functional consequences were considered inherited much more frequently than any other type, but only when the functional consequences were biological rather than social or psychological. Older children demonstrated more awareness of the inheritance of inborn traits. Overall, the results suggest young children have principled, specifically biological notions of inheritance.