149 resultados para Perceptual confusion
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Historical references to the emergence of the current concept of ADHD typically cite descriptions from medical textbooks by Weikard (1775) and Crichton (An inquiry into the nature and origin of mental derangement: Comprehending a concise system of the physiology and pathology of the human mind and a history of the passion and their affects. Cardell Jr and Davies, Londres, 1798) on attention disorders, poems of Hoffman on hyperactive and impulsive behaviors (Der Struwwelpeter. Frankfurt am Main, Literarische Anstalt, 1843), as well as the work of Still (Lancet 1:1008-1012, 1077-1082, 1163-1168, 1902a, Lancet 159(4102):1008-1013, 1902b, Lancet 159(4103):1077-1082, 1902c, Lancet 159(4104):1163-1168, 1902d) on impulsive behaviors and defective moral regulation of behavior. The notion of "instability" developed by French physicians between 1887 and 1910 is rarely mentioned and often ignored. Writings from this period show that in France, the emergence of the concept of ADHD according to modern terminology comes from the notion of "mental instability" introduced in the 1890s under the leadership of Désiré-Magloire Bourneville at the Hospital Bicêtre in Paris, based on his observations of children and adolescents who had been labeled "abnormal" and placed in medical and educational institutions. In the early twentieth century, elaborating on the observations of Bourneville, Jean Phillipe and Georges Paul-Boncour showed the presence of a subgroup of "unstable" children who suffered from a disease entity in its own right within the population of "abnormal" schoolchildren (the terminology of the time). This new pathological entity included symptoms of hyperactivity, impulsivity and inattention, corresponding to today's classic triad of ADHD symptoms. While noting the lack of behavioral inhibition, clinical descriptions of Bourneville, Philip and Paul-Boncour also considered the notion of "moral disorder" which at that time played an important role in psychopathology. This resulted in some degree of confusion between impulsive symptoms and major behavioral disturbances often associated with ADHD.
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This study investigated the neural regions involved in blood pressure reactions to negative stimuli and their possible modulation by attention. Twenty-four healthy human subjects (11 females; age = 24.75 ± 2.49 years) participated in an affective perceptual load task that manipulated attention to negative/neutral distractor pictures. fMRI data were collected simultaneously with continuous recording of peripheral arterial blood pressure. A parametric modulation analysis examined the impact of attention and emotion on the relation between neural activation and blood pressure reactivity during the task. When attention was available for processing the distractor pictures, negative pictures resulted in behavioral interference, neural activation in brain regions previously related to emotion, a transient decrease of blood pressure, and a positive correlation between blood pressure response and activation in a network including prefrontal and parietal regions, the amygdala, caudate, and mid-brain. These effects were modulated by attention; behavioral and neural responses to highly negative distractor pictures (compared with neutral pictures) were smaller or diminished, as was the negative blood pressure response when the central task involved high perceptual load. Furthermore, comparing high and low load revealed enhanced activation in frontoparietal regions implicated in attention control. Our results fit theories emphasizing the role of attention in the control of behavioral and neural reactions to irrelevant emotional distracting information. Our findings furthermore extend the function of attention to the control of autonomous reactions associated with negative emotions by showing altered blood pressure reactions to emotional stimuli, the latter being of potential clinical relevance.
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Behavioral and brain responses to identical stimuli can vary with experimental and task parameters, including the context of stimulus presentation or attention. More surprisingly, computational models suggest that noise-related random fluctuations in brain responses to stimuli would alone be sufficient to engender perceptual differences between physically identical stimuli. In two experiments combining psychophysics and EEG in healthy humans, we investigated brain mechanisms whereby identical stimuli are (erroneously) perceived as different (higher vs lower in pitch or longer vs shorter in duration) in the absence of any change in the experimental context. Even though, as expected, participants' percepts to identical stimuli varied randomly, a classification algorithm based on a mixture of Gaussians model (GMM) showed that there was sufficient information in single-trial EEG to reliably predict participants' judgments of the stimulus dimension. By contrasting electrical neuroimaging analyses of auditory evoked potentials (AEPs) to the identical stimuli as a function of participants' percepts, we identified the precise timing and neural correlates (strength vs topographic modulations) as well as intracranial sources of these erroneous perceptions. In both experiments, AEP differences first occurred ∼100 ms after stimulus onset and were the result of topographic modulations following from changes in the configuration of active brain networks. Source estimations localized the origin of variations in perceived pitch of identical stimuli within right temporal and left frontal areas and of variations in perceived duration within right temporoparietal areas. We discuss our results in terms of providing neurophysiologic evidence for the contribution of random fluctuations in brain activity to conscious perception.
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With an approach, based on chromosomal, biochemical and morphological analysis, we show that the animals wich are classically attributed to C. r. gueldenstaedti and/or to C. r. monacha belong in fact to the taxon C. suaveolens. The oriental forms, formely seen as C. russula, are of the same karyotype as C. suaveolens and are biochemically close to C. suaveolens in Central Europe. The origin of the taxonomical confusion might stem from the large morphological variation in and between populations of C. suaveolens in the Near East. Based on our results C. russula monacha Thomas, 1906 belongs to the polymorphic species C. suaveolens Pallas, 1811 and we propose to consider C. (russula) gueldenstaedti Pallas, 1881 as "incertae sedis".
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Although functional neuroimaging studies have supported the distinction between explicit and implicit forms of memory, few have matched explicit and implicit tests closely, and most of these tested perceptual rather than conceptual implicit memory. We compared event-related fMRI responses during an intentional test, in which a group of participants used a cue word to recall its associate from a prior study phase, with those in an incidental test, in which a different group of participants used the same cue to produce the first associate that came to mind. Both semantic relative to phonemic processing at study, and emotional relative to neutral word pairs, increased target completions in the intentional test, but not in the incidental test, suggesting that behavioral performance in the incidental test was not contaminated by voluntary explicit retrieval. We isolated the neural correlates of successful retrieval by contrasting fMRI responses to studied versus unstudied cues for which the equivalent "target" associate was produced. By comparing the difference in this repetition-related contrast across the intentional and incidental tests, we could identify the correlates of voluntary explicit retrieval. This contrast revealed increased bilateral hippocampal responses in the intentional test, but decreased hippocampal responses in the incidental test. A similar pattern in the bilateral amygdale was further modulated by the emotionality of the word pairs, although surprisingly only in the incidental test. Parietal regions, however, showed increased repetition-related responses in both tests. These results suggest that the neural correlates of successful voluntary explicit memory differ in directionality, even if not in location, from the neural correlates of successful involuntary implicit (or explicit) memory, even when the incidental test taps conceptual processes.
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Introduction: Schizophrenia is associated with multiple neuropsychological dysfunctions, such as disturbances of attention, memory, perceptual functioning, concept formation and executive processes. These cognitive functions are reported to depend on the integrity of the prefrontal and thalamo-prefrontal circuits. Multiple lines of evidence suggest that schizophrenia is related to abnormalities in neural circuitry and impaired structural connectivity. Here, we report a preliminary case-control study that showed a correlation between thalamo-frontal connections and several cognitive functions known to be impaired in schizophrenia. Materials and Methods: We investigated 9 schizophrenic patients (DSM IV criteria, Diagnostic Interview for Genetic Studies) and 9 age and sex matched control subjects. We obtained from each volunteer a DT-MRI dataset (3 T, _ _ 1,000 s/mm2), and a high resolution anatomic T1. The thalamo- frontal tracts are simulated with DTI tractography on these dataset, a method allowing inference of the main neural fiber tracks from Diffusion MRI data. In order to see an eventual correlation with the thalamo-frontal connections, every subject performs a battery of neuropsychological tests including computerized tests of attention (sustained attention, selective attention and reaction time), working memory tests (Plane test and the working memory sub-tests of the Wechsler Adult Intelligence Scale), a executive functioning task (Tower of Hanoï) and a test of visual binding abilities. Results: In a pilot case-control study (patients: n _ 9; controls: n _ 9), we showed that this methodology is appropriate and giving results in the excepted range. Considering the relation of the connectivity density and the neuropsychological data, a correlation between the number of thalamo- frontal fibers and the performance in the Tower of Hanoï was observed in the patients (Pearson correlation, r _ 0.76, p _ 0.05) but not in control subjects. In the most difficult item of the test, the least number of fibers corresponds to the worst performance of the test (fig. 2, number of supplementary movements of the elements necessary to realize the right configuration). It's interesting to note here that in an independent study, we showed that schizophrenia patients (n _ 32) perform in the most difficult item of the Tower of Hanoï (Mann-Whitney, p _ 0.005) significantly worse than control subjects (n _ 29). This has been observed in several others neuropsychological studies. Discussion: This pilot study of schizophrenia patients shows a correlation between the number of thalam-frontal fibers and the performance in the Tower of Hanoï, which is a planning and goal oriented actions task known to be associated with frontal dysfonction. This observation is consistent with the proposed impaired connectivity in schizophrenia. We aim to pursue the study with a larger sample in order to determine if other neuropsychological tests may be associated with the connectivity density.
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OBJECT: The aim of this study was to evaluate the long-term safety and efficacy of bilateral contemporaneous deep brain stimulation (DBS) in patients who have levodopa-responsive parkinsonism with untreatable motor fluctuations. Bilateral pallidotomy carries a high risk of corticobulbar and cognitive dysfunction. Deep brain stimulation offers new alternatives with major advantages such as reversibility of effects, minimal permanent lesions, and adaptability to individual needs, changes in medication, side effects, and evolution of the disease. METHODS: Patients in whom levodopa-responsive parkinsonism with untreatable severe motor fluctuations has been clinically diagnosed underwent bilateral pallidal magnetic resonance image-guided electrode implantation while receiving a local anesthetic. Pre- and postoperative evaluations at 3-month intervals included Unified Parkinson's Disease Rating Scale (UPDRS) scoring, Hoehn and Yahr staging, 24-hour self-assessments, and neuropsychological examinations. Six patients with a mean age of 55 years (mean 42-67 years), a mean duration of disease of 15.5 years (range 12-21 years), a mean "on/off' Hoehn and Yahr stage score of 3/4.2 (range 3-5), and a mean "off' time of 40% (range 20-50%) underwent bilateral contemporaneous pallidal DBS, with a minimum follow-up period lasting 24 months (range 24-30 months). The mean dose of levodopa in these patients could not be changed significantly after the procedure and pergolide was added after 12 months in five patients because of recurring fluctuations despite adjustments in stimulation parameters. All but two patients had no fluctuations until 9 months. Two of the patients reported barely perceptible fluctuations at 12 months and two at 15 months; however, two patients remain without fluctuations at 2 years. The mean improvements in the UPDRS motor score in the off time and the activities of daily living (ADL) score were more than 50%; the mean off time decreased from 40 to 10%, and the mean dyskinesia and complication of treatment scores were reduced to one-third until pergolide was introduced at 12 months. No significant improvement in "on" scores was observed. A slight worsening after 1 year was observed and three patients developed levodopa- and stimulation-resistant gait ignition failure and minimal fluctuations at 1 year. Side effects, which were controlled by modulation of stimulation, included dysarthria, dystonia, and confusion. CONCLUSIONS: Bilateral pallidal DBS is safe and efficient in patients who have levodopa-responsive parkinsonism with severe fluctuations. Major improvements in motor score, ADL score, and off time persisted beyond 2 years after the operation, but signs of decreased efficacy started to be seen after 12 months.
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Postoperative delirium after cardiac surgery is associated with increased morbidity and mortality as well as prolonged stay in both the intensive care unit and the hospital. The authors sought to identify modifiable risk factors associated with the development of postoperative delirium in elderly patients after elective cardiac surgery in order to be able to design follow-up studies aimed at the prevention of delirium by optimizing perioperative management. A post hoc analysis of data from patients enrolled in a randomized controlled trial was performed. A single university hospital. One hundred thirteen patients aged 65 or older undergoing elective cardiac surgery with cardiopulmonary bypass. None. MEASUREMENTS AND MAINS RESULTS: Screening for delirium was performed using the Confusion Assessment Method (CAM) on the first 6 postoperative days. A multivariable logistic regression model was developed to identify significant risk factors and to control for confounders. Delirium developed in 35 of 113 patients (30%). The multivariable model showed the maximum value of C-reactive protein measured postoperatively, the dose of fentanyl per kilogram of body weight administered intraoperatively, and the duration of mechanical ventilation to be independently associated with delirium. In this post hoc analysis, larger doses of fentanyl administered intraoperatively and longer duration of mechanical ventilation were associated with postoperative delirium in the elderly after cardiac surgery. Prospective randomized trials should be performed to test the hypotheses that a reduced dose of fentanyl administered intraoperatively, the use of a different opioid, or weaning protocols aimed at early extubation prevent delirium in these patients.
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Introduction : L'équipe mobile de soins palliatifs intra hospitalière (EMSP) du Centre Hospitalier Universitaire Vaudois (CHUV) a été mise en place en 1996. Il s'agit d'une des premières équipes interdisciplinaire de consultants mise à disposition d'un hôpital tertiaire. Le CHUV est l'hôpital de proximité de la ville de Lausanne (850 lits) mais aussi un hôpital de référence pour le reste du canton. En 2007, il y a eu 38'359 patients hospitalisés au CHUV. Les facteurs d'évaluation du taux d'utilisation d'une équipe mobile de soins palliatifs consultantes sont variés et complexes. Plusieurs méthodes sont décrites dans la littérature pour tenter de répondre à cette problématique. Avant de pouvoir évaluer l'utilisation de notre équipe mobile consultante de soins palliatifs intra hospitalière, il nous est apparu nécessaire de mieux décrire et définir la population qui meurt dans notre institution. McNamara et collègues ont proposé des critères qui classifient une population palliative comme « minimale », « intermédiaire » ou « maximale ». L'objectif de cette étude est de déterminer le taux de patients décédés au CHUV sur une période de 4 mois (Γ1 février au 31 mai 2007) suivie par notre EMSP en utilisant la méthode de classification «minimal » et « maximal ». Méthode : les archives médicales du CHUV ont été analysées pour chaque patient adulte décédé pendant la période sélectionnée. Les populations « maximal » et « minimal » de ces patients ont été ensuite déterminées selon des critères basés sur les codes diagnostiques figurants sur les certificats de décès. De ces deux populations, nous avons identifié à partir de notre base de données, les patients qui ont été suivie par notre EMSP. Le CHUV utilise les mêmes codes diagnostiques (International Classification of Disease, ICD) que ceux utilisés dans la classification de McNamara. Une recherche pilote effectuée dans les archives médicales du CHUV manuellement en analysant en profondeur l'ensemble du dossier médical a révélé que la classification de la population « minimal » pouvait être biaisée notamment en raison d'une confusion entre la cause directe du décès (complication d'une maladie) et la maladie de base. Nous avons estimé le pourcentage d'erreur de codification en analysé un échantillon randomisé de patients qui remplissait les critères « minimal ». Résultats : sur un total de 294 décès, 263 (89%) remplissaient initialement les critères « maximal » et 83 (28%) les critères «minimal», l'analyse de l'échantillon randomisé de 56 dossiers de patients sur les 180 qui ne remplissaient pas les critères « minimal » ont révélé que 21 (38%) auraient dus être inclus dans la population « minimal ». L'EMSP a vu 67/263 (25.5%) de la population palliative « maximal » et 56/151 (37.1%) de la population palliative « minimal ». Conclusion : cette étude souligne l'utilité de la méthode proposée par McNamara pour déterminer la population de patients palliatifs. Cependant, notre travail illustre aussi une limite importante de l'estimation de la population « minima » en lien avec l'imprécision des causes de décès figurant sur les certificats de décès de notre institution. Nos résultats mettent aussi en lumière que l'EMSP de notre institution est clairement sous- utilisée. Nous prévoyons une étude prospective de plus large envergure utilisant la même méthodologie afin d'approfondir les résultats de cette étude pilote.
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INTRODUCTION: For decades, clinicians dealing with immunocompromised and critically ill patients have perceived a link between Candida colonization and subsequent infection. However, the pathophysiological progression from colonization to infection was clearly established only through the formal description of the colonization index (CI) in critically ill patients. Unfortunately, the literature reflects intense confusion about the pathophysiology of invasive candidiasis and specific associated risk factors. METHODS: We review the contribution of the CI in the field of Candida infection and its development in the 20 years following its original description in 1994. The development of the CI enabled an improved understanding of the pathogenesis of invasive candidiasis and the use of targeted empirical antifungal therapy in subgroups of patients at increased risk for infection. RESULTS: The recognition of specific characteristics among underlying conditions, such as neutropenia, solid organ transplantation, and surgical and nonsurgical critical illness, has enabled the description of distinct epidemiological patterns in the development of invasive candidiasis. CONCLUSIONS: Despite its limited bedside practicality and before confirmation of potentially more accurate predictors, such as specific biomarkers, the CI remains an important way to characterize the dynamics of colonization, which increases early in patients who develop invasive candidiasis.
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This study investigated the spatial, spectral, temporal and functional proprieties of functional brain connections involved in the concurrent execution of unrelated visual perception and working memory tasks. Electroencephalography data was analysed using a novel data-driven approach assessing source coherence at the whole-brain level. Three connections in the beta-band (18-24 Hz) and one in the gamma-band (30-40 Hz) were modulated by dual-task performance. Beta-coherence increased within two dorsofrontal-occipital connections in dual-task conditions compared to the single-task condition, with the highest coherence seen during low working memory load trials. In contrast, beta-coherence in a prefrontal-occipital functional connection and gamma-coherence in an inferior frontal-occipitoparietal connection was not affected by the addition of the second task and only showed elevated coherence under high working memory load. Analysis of coherence as a function of time suggested that the dorsofrontal-occipital beta-connections were relevant to working memory maintenance, while the prefrontal-occipital beta-connection and the inferior frontal-occipitoparietal gamma-connection were involved in top-down control of concurrent visual processing. The fact that increased coherence in the gamma-connection, from low to high working memory load, was negatively correlated with faster reaction time on the perception task supports this interpretation. Together, these results demonstrate that dual-task demands trigger non-linear changes in functional interactions between frontal-executive and occipitoparietal-perceptual cortices.
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The concept of autism is reviewed in its historical evolution. It is suggested that the Bleulerian insistence on the withdrawal component in autism contributed to the decline of its use in adult psychiatry. Phenomenology offers another approach to grasping the nature of autism as a relational (subject-outer world) phenomenon. European phenomenological psychiatry in the field of schizophrenia is introduced and its attempts to reveal the essence of autism are presented. Autism is here considered as a "loss of vital contact with reality" (Minkowski), "inconsistency of natural experience" (Binswanger), or "the global crisis of common sense" (Blankenburg). It is proposed that autism represents dysfunctional perceptual/expressive attunement to the outer world. The usefulness of this concept is briefly examined in relation to the diagnosis and etiopathogenesis of schizophrenia.
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Schizotypy refers to a set of personality traits thought to reflect the subclinical expression of the signs and symptoms of schizophrenia. Here, we review the cognitive and brain functional profile associated with high questionnaire scores in schizotypy. We discuss empirical evidence from the domains of perception, attention, memory, imagery and representation, language, and motor control. Perceptual deficits occur early and across various modalities. Whilst the neural mechanisms underlying visual impairments may be linked to magnocellular dysfunction, further effects may be seen downstream in higher cognitive functions. Cognitive deficits are observed in inhibitory control, selective and sustained attention, incidental learning and memory. In concordance with the cognitive nature of many of the aberrations of schizotypy, higher levels of schizotypy are associated with enhanced vividness and better performance on tasks of mental rotation. Language deficits seem most pronounced in higher-level processes. Finally, higher levels of schizotypy are associated with reduced performance on oculomotor tasks, resembling the impairments seen in schizophrenia. Some of these deficits are accompanied by reduced brain activation, akin to the pattern of hypoactivations in schizophrenia spectrum individuals. We conclude that schizotypy is a construct with apparent phenomenological overlap with schizophrenia and stable inter-individual differences that covary with performance on a wide range of perceptual, cognitive and motor tasks known to be impaired in schizophrenia. The importance of these findings lies not only in providing a fine-grained neurocognitive characterisation of a personality constellation known to be associated with real-life impairments, but also in generating hypotheses concerning the aetiology of schizophrenia.
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La littérature scientifique confirme que les soignants ont besoin de soutien. Par-delà la surchage clinique et administrative, le stress lié à la signifiance des facteurs contextuels est une source de détresse importante. La reconnaissance et la gestion de ce stress peuvent soutenir le clinicien de manière durable. L'article discute les éléments clés de ces stresseurs, notamment le rôle des émotions du soignant, la reconnaissance des limites, la confusion concernant l'empathie, l'influence du développement et de la trajectoire de vie sur l'identité professionnelle ainsi que le conflit que représente le fait d'être un soignant qui a besoin d'aide. A growing body of evidence indicates that health care professionals are in need of support. Beside heavy clinical patient volume or administrative duties, stress related to the significance of contextual factors is an important source of clinician's distress. Identification of and working through such stress can be a durable source of support. This article discusses key elements of these stressors, namely, the role of emotions of the clinician, awareness of limits, confusion about empathy, the influence of development and life trajectory on professional identity and the conflicting roles of the health care provider being in need of support http://titan.medhyg.ch/mh/formation/article.php3?sid=32934
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Introduction: Delirium is frequent in hospitalized older people, with incidence rate up to 40% in acute care. Delirium is associated with several adverse consequences, including increased mortality and institutionalization. This study aims to investigate the prevalence, incidence, and consequences of delirium in patients hospitalized in an acute care unit for elderly (ACE unit). Methods: Over a 3 months period, every patient (N = 93, mean age 84.1 ± 7.8 years, 66/93(71%) women) admitted to a 28-bed ACE unit were systematically assessed for delirium. Trained nurses used the Confusion Assessment Method (CAM) instrument to determine the presence of delirium at admission and on each subsequent day over patients' stay. Delirium prevalence rate was defined as the proportion of patients with a positive CAM within 24 hours of admission to the ACE unit. Delirium incidence rate was defined as the proportion of patients with a negative CAM at admission whose CAM became positive at least once during their stay. This evaluation was part of a functional assessment, including Basic Activities of Daily Life (Katz BADL, from 0 to 6, higher score indicating better function). Delirium prevention interventions and specific treatment was provided if needed. Results: Overall,25/93(27%)patients had delirium during their stay. Prevalence of delirium at admission was 10/93 (11%), with an incidence of 15/83(18%). Compared with non-delirious patients, those with delirium were more frequently men (10/25(40%) vs 17/68(25%), p <.001) and had reduced functional status at admission(BADL 2.0 ± 1.9 vs 3.6 ± 2.1, p = .004). They tended to be older (86.0 ± 6.7 vs 83.3 ± 8.1 years, p = .110). At discharge, delirium was associated with reduced functional status (BADL 2.0 ± 2.1 vs 4.3 ± 1.9, p <.001), lower rate of home discharge (6/20(30%) vs 28/65 (43%), p = .009) and increased mortality (5/25 (20%) vs 3/68 (5%), p <.001). On average, patients with delirium stayed 5.7 days longer (17.0 ± 9.8 vs 11.31 ± 6.3, p = .011). Conclusion: Delirium occurred in almost a third of these older patients, even though its incidence was relatively low in this frail population. Despite specific management, delirium remained associated with higher risk for adverse outcomes at discharge. These results suggest that early preventive interventions, implemented as soon as possible after hospital admission, might be needed in similar population to achieve better outcomes. Effectiveness of such interventions will be evaluated in future studies.