Exercise oximetry in patients with arterial claudication

We read with interest the paper of Kovacs et al. published in Atherosclerosis [1]. The authors used discontinuous transcutaneous oxygen pressure measurement (TcPO2) in patients with claudication and suggested that the performance of exercise-TcPO2 was lower than post-exercise toe pressure. One issue when using TcPO2 relates to the local heating of the skin that takes at least 15 min to attain stable values. Once stable values are reached, the simultaneous and continuous measurements of limb and chest TcPO2 before, during, and following exercise can accurately detect exercise-induced lower limb ischemia with calculation of the “DROP” (limb changes minus chest changes) and analysis of minimal-DROP [2,3], as well as exercise induced systemic hypoxemia by analysis of chest changes during exercise [4]

Apraxia and Alzheimer’s Disease: Review and Perspectives

Apraxia is one of the cognitive deficits that characterizes Alzheimer\u27s disease. Despite its prevalence and relevance to diagnosing Alzheimer\u27s disease, this topic has received little attention and is without comprehensive review. The review herein is aimed to fill this gap by first presenting an overview of the impairment caused in different clinical situations: pantomime of tool use, single tool use, real tool use, mechanical problem solving, function and manipulation knowledge tasks, and symbolic/meaningless gestures. On the basis of these results, we then propose alternative interpretations regarding the nature of the underlying mechanisms impaired by the disease. Also presented are principal methodological issues precluding firm conclusions from being drawn

Simultaneous dynamic electrical and structural measurements of functional materials

A new materials characterization system developed at the XMaS beamline, located at the European Synchrotron Radiation Facility in France, is presented. We show that this new capability allows to measure the atomic structural evolution (crystallography) of piezoelectric materials whilst simultaneously measuring the overall strain characteristics and electrical response to dynamically (ac) applied external stimuli

Mechanical problem-solving strategies in left-brain damaged patients and apraxia of tool use

Left brain damage (LBD) can impair the ability to use familiar tools (apraxia of tool use) as well as novel tools to solve mechanical problems. Thus far, the emphasis has been placed on quantitative analyses of patients’ performance. Nevertheless, the question still to be answered is, what are the strategies employed by those patients when confronted with tool use situations? To answer it, we asked 16 LBD patients and 43 healthy controls to solve mechanical problems by means of several potential tools. To specify the strategies, we recorded the time spent in performing four kinds of action (no manipulation, tool manipulation, box manipulation, and tool-box manipulation) as well as the number of relevant and irrelevant tools grasped. We compared LBD patients’ performance with that of controls who encountered difficulties with the task (controls−) or not (controls+). Our results indicated that LBD patients grasped a higher number of irrelevant tools than controls+ and controls−. Concerning time allocation, controls+ and controls− spent significantly more time in performing tool-box manipulation than LBD patients. These results are inconsistent with the possibility that LBD patients could engage in trial-and-error strategies and, rather, suggest that they tend to be perplexed. These findings seem to indicate that the inability to reason about the objects’ physical properties might prevent LBD patients from following any problem-solving strategy

A cognitive-based model of tool use in normal aging: Which components are at work?

While several cognitive domains have been widely investigated in the field of aging, the age-related effects on tool use are still an open issue and hardly any studies on tool use and aging is available. A significant body of literature has indicated that tool use skills might be supported by at least two different types of knowledge, namely, mechanical knowledge and semantic knowledge. However, neither the contribution of these kinds of knowledge to familiar tool use, nor the effects of aging on mechanical and semantic knowledge have been explored in normal aging. The aim of the present study was to fill this gap. To do so, 98 healthy elderly adults were presented with three tasks: a classical, familiar tool use task, a novel tool use task assessing mechanical knowledge, and a picture matching task assessing semantic knowledge. The results showed that aging has a negative impact on tool use tasks and on knowledge supporting tool use skills. We also found that aging did not impact mechanical and semantic knowledge in the same way, confirming the distinct nature of those forms of knowledge. Finally, our results stressed that mechanical and semantic knowledge are both involved in the ability to use familiar tools

Bostonia: The Boston University Alumni Magazine. Volume 10

Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs

Apraxie et maladie d’Alzheimer : revue et perspectives

Alzheimer’s disease is characterized by the progressive impairment of cognitive functions. Whereas the study of amnesia, aphasia, agnosia and dysexecutive impairments to a lesser extent has been well documented, apraxia has received little attention [1]. The aim of this review is to fill this gap by presenting an overview of the praxis impairment, which typically appears in the course of the disease. This review focuses on transitive gestures (i.e., tool use tasks) and intransitive gestures (i.e., symbolic and meaningless). On the basis of these results, we propose interpretations as to the nature of the underlying mechanisms impaired by the disease. Finally, we provide some answers to help clinicians to better understand and assess the apraxic disorders in Alzheimer’s disease

Stratégies d’évaluation des troubles d’utilisation d’objets

A substantial proportion of patients with brain damage and neurodegenerative diseases misuse common tools. However, this neuropsychological syndrome affecting everyday life is relatively unexplored in the field of experimental and clinical neuropsychology. Little is known about long-term evolution and specific evaluation and/or rehabilitation. This is partially due to the lack of an integrative theoretical framework taking into account all cognitive processes underlying gesture orientation, object selection, or action sequencing. Indeed, apraxia of tool use goes far beyond the traditional, obsolete distinction between ideational apraxia and ideomotor apraxia. This is a complex symptomatology requiring a conceptual and clinical differential analysis. After a brief overview of the theoretical principles underpinning our evaluation method, the purpose of this article is to describe the various types of tests that are required to exhaustively assess tool use disorders. We will then focus on tool use assessment: types of objects, basic knowledge related to them, presentation modalities, action planning. A case study is presented to illustrate how our analysis works

Bases neurocognitives de l’utilisation d’outils

L’utilisation d’outils est un trait définitoire de l’espèce humaine. En conséquence, la question des bases neurocognitives sous-tendant cette capacité devrait être au cœur des préoccupations des psychologues et des neuroscientifiques. Pourtant, depuis l’émergence de la psychologie scientifique à la fin du xxe siècle, cette question n’a reçu que peu d’intérêt. Une raison majeure à ce manque d’intérêt provient de la croyance que l’utilisation reposerait avant tout sur des connaissances sur la manipulation, comme si l’utilisation d’outils ne demandait pas de capacités intellectuelles ou de raisonnement, mais uniquement de savoir quel est le geste à réaliser avec un outil donné. Cette croyance a alimenté pendant plus d’un siècle, et alimente toujours, les principaux modèles des troubles d’utilisation d’outils dans le champ de la neuropsychologie. Cette mini-revue vise à présenter comment les avancées récentes en psychologie et en neurosciences cognitives ont contribué à réviser l’idée que la manipulation est centrale à l’utilisation d’outils, en proposant de nouveaux modèles théoriques basés sur l’hypothèse qu’utiliser un outil nécessite des capacités de raisonnement spécifique