Syncope

Syncope is defined as an acute, brief and transient loss of consciousness and postural tone with spontaneous and complete recovery. Neurovascular ultrasound has contributed to elucidate the underlying mechanism of different types of syncope. In routine diagnostic work-up of patients with syncope, however, neurovascular ultrasound is not among the first line tools. In particular, an ultrasound search for occlusive cerebro-vascular disease is of limited value because cerebral artery obstruction is a very rare and questionable cause of syncope. Transcranial Doppler sonography monitoring of the cerebral arteries is useful in the diagnostic work-up of patients with suspicion of postural related, cerebrovascular, cough and psychogenic syncope, and in some cases for differentiating focal epileptic seizures from transient ischemic attacks and migraine with aura.

Unexplained syncope--is screening for carotid sinus hypersensitivity indicated in all patients aged >40 years?

OBJECTIVE: To determine the frequency, age distribution and clinical presentation of carotid sinus hypersensitivity (CSH) among 373 patients (age range 15-92 years) referred to two autonomic referral centres during a 10-year period. METHODS: Carotid sinus massage (CSM) was performed both supine and during 60 degree head-up tilt. Beat-to-beat blood pressure, heart rate and a three-lead electrocardiography were recorded continuously. CSH was classified as cardioinhibitory (asystole > or = 3 s), vasodepressor (systolic blood pressure fall > or = 50 mm Hg) or mixed. All patients additionally underwent autonomic screening tests for orthostatic hypotension and autonomic failure. RESULTS: CSH was observed in 13.7% of all patients. The diagnostic yield of CSM was nil in patients aged < 50 years (n = 65), 2.4% in those aged 50-59 years (n = 82), 9.1% in those aged 60-69 years (n = 77), 20.7% in those aged 70-79 years (n = 92) and reached 40.4% in those > 80 years (n = 57). Syncope was the leading clinical symptom in 62.8%. In 27.4% of patients falls without definite loss of consciousness was the main clinical symptom. Mild and mainly systolic orthostatic hypotension was recorded in 17.6%; evidence of sympathetic or parasympathetic dysfunction was found in none. CONCLUSIONS: CSH was confirmed in patients > 50 years, the incidence steeply increasing with age. The current European Society of Cardiology guidelines that recommend testing for CSH in all patients > 40 years with syncope of unknown aetiology may need reconsideration. Orthostatic hypotension was noted in some patients with CSH, but evidence of sympathetic or parasympathetic failure was not found in any of them.

[The hospitalized patient with fever and mental status changes]

The case is discussed of a 74-year-old patient hospitalised with acute colitis, who newly developed headache, fever, and mental status changes on the 14th day after admission. The course of the disease was characterised by rapid progression with loss of consciousness and the development of extensive brain oedema, despite broad-spectrum antibiotic therapy. The patient died on the 17th of hospitalisation.

NIHSS score and arteriographic findings in acute ischemic stroke

BACKGROUND AND PURPOSE: To test the hypothesis that the National Institutes of Health Stroke Scale (NIHSS) score is associated with the findings of arteriography performed within the first hours after ischemic stroke. METHODS: We analyzed NIHSS scores on hospital admission and clinical and arteriographic findings of 226 consecutive patients (94 women, 132 men; mean age 62+/-12 years) who underwent arteriography within 6 hours of symptom onset in carotid stroke and within 12 hours in vertebrobasilar stroke. RESULTS: From stroke onset to hospital admission, 155+/-97 minutes elapsed, and from stroke onset to arteriography 245+/-100 minutes elapsed. Median NIHSS was 14 (range 3 to 38), and scores differed depending on the arteriographic findings (P<0.001). NIHSS scores in basilar, internal carotid, and middle cerebral artery M1 and M2 segment occlusions (central occlusions) were higher than in more peripherally located, nonvisible, or absent occlusions. Patients with NIHSS scores > or =10 had positive predictive values (PPVs) to show arterial occlusions in 97% of carotid and 96% of vertebrobasilar strokes. With an NIHSS score of > or =12, PPV to find a central occlusion was 91%. In a multivariate analysis, NIHSS subitems such as "level of consciousness questions," "gaze," "motor leg," and "neglect" were predictors of central occlusions. CONCLUSIONS: There is a significant association of NIHSS scores and the presence and location of a vessel occlusion. With an NIHSS score > or =10, a vessel occlusion will likely be seen on arteriography, and with a score > or =12, its location will probably be central.

Dementia with lewy bodies--diagnosis and treatment

Dementia with Lewy bodies (DLB) accounts for 15-20% of all autopsy confirmed dementias in old age. Characteristic histopathological changes are intracellular Lewy bodies and Lewy neurites, with abundant senile plaques but sparse neurofibrillary tangles. Core clinical features are fluctuating cognitive impairment, persistent visual hallucinations and extrapyramidal motor symptoms (parkinsonism). One of these core features has to be present for a diagnosis of possible DLB, and two for probable DLB. Supportive features are repeated falls, syncope, transient loss of consciousness, neuroleptic sensitivity, delusions and hallucinations in other modalities. DLB is clinically under-diagnosed and frequently misclassified as systemic delirium or dementia due to Alzheimer's disease or cerebrovascular disease. Therapeutic approaches to DLB can pose difficult dilemmas in pharmacological management. Neuroleptic medication is relatively contraindicated because some patients show severe neuroleptic sensitivity, which is associated with increased morbidity and mortality. Antiparkinsonian medication has the potential to exacerbate psychotic symptoms and may be relatively ineffective at relieving extrapyramidal motor symptoms. Recently there is converging evidence that treatment with cholinesterase inhibitors can offer a safe alternative for the symptomatic treatment of cognitive and neuropsychiatric features in DLB. This review will focus on the clinical characteristics of DLB, its differential diagnosis and on possible management strategies.

Atypical visual processing in posttraumatic stress disorder

BACKGROUND: Many patients with Posttraumatic Stress Disorder (PTSD) feel overwhelmed in situations with high levels of sensory input, as in crowded situations with complex sensory characteristics. These difficulties might be related to subtle sensory processing deficits similar to those that have been found for sounds in electrophysiological studies. METHOD: Visual processing was investigated with functional magnetic resonance imaging in trauma-exposed participants with (N = 18) and without PTSD (N = 21) employing a picture-viewing task. RESULTS: Activity observed in response to visual scenes was lower in PTSD participants 1) in the ventral stream of the visual system, including striate and extrastriate, inferior temporal, and entorhinal cortices, and 2) in dorsal and ventral attention systems (P < 0.05, FWE-corrected). These effects could not be explained by the emotional salience of the pictures. CONCLUSIONS: Visual processing was substantially altered in PTSD in the ventral visual stream, a component of the visual system thought to be responsible for object property processing. Together with previous reports of subtle auditory deficits in PTSD, these findings provide strong support for potentially important sensory processing deficits, whose origins may be related to dysfunctional attention processes.

Hypernatremia in critically ill patients

Hypernatremia is common in intensive care units. It has detrimental effects on various physiologic functions and was shown to be an independent risk factor for increased mortality in critically ill patients. Mechanisms of hypernatremia include sodium gain and/or loss of free water and can be discriminated by clinical assessment and urine electrolyte analysis. Because many critically ill patients have impaired levels of consciousness, their water balance can no longer be regulated by thirst and water uptake but is managed by the physician. Therefore, the intensivists should be very careful to provide the adequate sodium and water balance for them. Hypernatremia is treated by the administration of free water and/or diuretics, which promote renal excretion of sodium. The rate of correction is critical and must be adjusted to the rapidity of the development of hypernatremia.

Swallowing Activity Assessed by Ambulatory Impedance-pH Monitoring Predicts Awake and Asleep Periods at Night

INTRODUCTION: Voluntary muscle activity, including swallowing, decreases during the night. The association between nocturnal awakenings and swallowing activity is under-researched with limited information on the frequency of swallows during awake and asleep periods. AIM: The aim of this study was to assess nocturnal swallowing activity and identify a cut-off predicting awake and asleep periods. METHODS: Patients undergoing impedance-pH monitoring as part of GERD work-up were asked to wear a wrist activity detecting device (Actigraph(®)) at night. Swallowing activity was quantified by analysing impedance changes in the proximal esophagus. Awake and asleep periods were determined using a validated scoring system (Sadeh algorithm). Receiver operating characteristics (ROC) analyses were performed to determine sensitivity, specificity and accuracy of swallowing frequency to identify awake and asleep periods. RESULTS: Data from 76 patients (28 male, 48 female; mean age 56 ± 15 years) were included in the analysis. The ROC analysis found that 0.33 sw/min (i.e. one swallow every 3 min) had the optimal sensitivity (78 %) and specificity (76 %) to differentiate awake from asleep periods. A swallowing frequency of 0.25 sw/min (i.e. one swallow every 4 min) was 93 % sensitive and 57 % specific to identify awake periods. A swallowing frequency of 1 sw/min was 20 % sensitive but 96 % specific in identifying awake periods. Impedance-pH monitoring detects differences in swallowing activity during awake and asleep periods. Swallowing frequency noticed during ambulatory impedance-pH monitoring can predict the state of consciousness during nocturnal periods

The dementia cognitive fluctuation scale, a new psychometric test for clinicians to identify cognitive fluctuations in people with dementia.

OBJECTIVES Cognitive fluctuation (CF) is a common feature of dementia and a core diagnostic symptom for dementia with Lewy bodies (DLB). CF remains difficult to accurately and reliably detect clinically. This study aimed to develop a psychometric test that could be used by clinicians to facilitate the identification of CF and improve the recognition and diagnosis of DLB and Parkinson disease, and to improve differential diagnosis of other dementias. METHODS We compiled a 17-item psychometric test for identifying CF and applied this measure in a cross-sectional design. Participants were recruited from the North East of England, and assessments were made in individuals' homes. We recruited people with four subtypes of dementia and a healthy comparison group, and all subjects were administered this pilot scale together with other standard ratings. The psychometric properties of the scale were examined with exploratory factor analysis. We also examined the ability of individual items to identify CF to discriminate between dementia subtypes. The sensitivity and specificity of discriminating items were explored along with validity and reliability analyses. RESULTS Participants comprised 32 comparison subjects, 30 people with Alzheimer disease, 30 with vascular dementia, 29 with DLB, and 32 with dementia associated with Parkinson disease. Four items significantly discriminated between dementia groups and showed good levels of sensitivity (range: 78.6%-80.3%) and specificity (range: 73.9%-79.3%). The scale had very good levels of test-retest (Cronbach's alpha: 0.82) and interrater (0.81) reliabilities. The four items loaded onto three different factors. These items were: 1) marked differences in functioning during the daytime; 2) daytime somnolence; 3) daytime drowsiness; and 4) altered levels of consciousness during the day. CONCLUSIONS We identified four items that provide valid, sensitive, and specific questions for reliably identifying CF and distinguishing the Lewy body dementias from other major causes of dementia (Alzheimer disease and vascular dementia).

Zazen meditation and no-task resting EEG compared with LORETA intracortical source localization

Meditation is a self-induced and willfully initiated practice that alters the state of consciousness. The meditation practice of Zazen, like many other meditation practices, aims at disregarding intrusive thoughts while controlling body posture. It is an open monitoring meditation characterized by detached moment-to-moment awareness and reduced conceptual thinking and self-reference. Which brain areas differ in electric activity during Zazen compared to task-free resting? Since scalp electroencephalography (EEG) waveforms are reference-dependent, conclusions about the localization of active brain areas are ambiguous. Computing intracerebral source models from the scalp EEG data solves this problem. In the present study, we applied source modeling using low resolution brain electromagnetic tomography (LORETA) to 58-channel scalp EEG data recorded from 15 experienced Zen meditators during Zazen and no-task resting. Zazen compared to no-task resting showed increased alpha-1 and alpha-2 frequency activity in an exclusively right-lateralized cluster extending from prefrontal areas including the insula to parts of the somatosensory and motor cortices and temporal areas. Zazen also showed decreased alpha and beta-2 activity in the left angular gyrus and decreased beta-1 and beta-2 activity in a large bilateral posterior cluster comprising the visual cortex, the posterior cingulate cortex and the parietal cortex. The results include parts of the default mode network and suggest enhanced automatic memory and emotion processing, reduced conceptual thinking and self-reference on a less judgmental, i.e., more detached moment-to-moment basis during Zazen compared to no-task resting.

Lateral impact in closed head injury: A substantially increased risk for diffuse axonal injury—A preliminary study

OBJECTIVE: Assessment, whether location of impact causing different facial fracture patterns was associated with diffuse axonal injury in patients with severe closed head injury. METHODS: Retrospectively all patients referred to the Trauma Unit of the University Hospital of Zurich, Switzerland between 1996 and 2002 presenting with severe closed head injuries (Abbreviated Injury Scale (AIS) (face) of 2-4 and an AIS (head and neck) of 3-5) were assessed according to the Glasgow Coma Scale (GCS) and the Injury Severity Score (ISS). Facial fracture patterns were classified as resulting from frontal, oblique or lateral impact. All patients had undergone computed tomography. The association between impact location and diffuse axonal injury when correcting for the level of consciousness (using the Glasgow scale) and severity of injury (using the ISS) was calculated with a multivariate regression analysis. RESULTS: Of 200 screened patients, 61 fulfilled the inclusion criteria for severe closed head injury. The medians (interquartile ranges 25;75) for GCS, AIS(face) AIS(head and neck) and ISS were 3 (3;13), 2 (2;4), 4 (4;5) and 30 (24;41), respectively. A total of 51% patients had frontal, 26% had an oblique and 23% had lateral trauma. A total of 21% patients developed diffuse axonal injury (DAI) when compared with frontal impact, the likelihood of diffuse axonal injury increased 11.0 fold (1.7-73.0) in patients with a lateral impact. CONCLUSIONS: Clinicians should be aware of the substantial increase of diffuse axonal injury related to lateral impact in patients with severe closed head injuries.

Physical oceanography and current velocity during Nathaniel B. Palmer cruise NBP97-05

An extensive set of conductivity-temperature-depth (CTD)/lowered acoustic Doppler current profiler (LADCP) data obtained within the northwestern Weddell Sea in August 1997 characterizes the dense water outflow from the Weddell Sea and overflow into the Scotia Sea. Along the outer rim of the Weddell Gyre, there is a stream of relatively low salinity, high oxygen Weddell Sea Deep Water (defined as water between 0° and ?0.7°C), constituting a more ventilated form of this water mass than that found farther within the gyre. Its enhanced ventilation is due to injection of relatively low salinity shelf water found near the northern extreme of Antarctic Peninsula's Weddell Sea shelf, shelf water too buoyant to descend to the deep-sea floor. The more ventilated form of Weddell Sea Deep Water flows northward along the eastern side of the South Orkney Plateau, passing into the Scotia Sea rather than continuing along an eastward path in the northern Weddell Sea. Weddell Sea Bottom Water also exhibits two forms: a low-salinity, better oxygenated component confined to the outer rim of the Weddell Gyre, and a more saline, less oxygenated component observed farther into the gyre. The more saline Weddell Sea Bottom Water is derived from the southwestern Weddell Sea, where high-salinity shelf water is abundant. The less saline Weddell Sea Bottom Water, like the more ventilated Weddell Sea Deep Water, is derived from lower-salinity shelf water at a point farther north along the Antarctic Peninsula. Transports of Weddell Sea Deep and Bottom Water masses crossing 44°W estimated from one LADCP survey are 25 ? 10**6 and 5 ? 10**6 m**3/s, respectively. The low-salinity, better ventilated forms of Weddell Sea Deep and Bottom Water flowing along the outer rim of the Weddell Gyre have the position and depth range that would lead to overflow of the topographic confines of the Weddell Basin, whereas the more saline forms may be forced to recirculate within the Weddell Gyre.

La crítica al sujeto en la filosofía de Theodor W. Adorno

El propósito de la presente tesis es realizar una lectura de la crítica al concepto de subjetividad en la filosofía de Theodor W. Adorno. Los objetivos de tal lectura son fundamentalmente dos: por un lado, particularizar la crítica adorniana en el marco de otras críticas al concepto de subjetividad que marcaron el campo de la filosofía contemporánea y, al mismo tiempo, establecer un diálogo con las lecturas que de la filosofía adorniana hicieron algunos miembros más jóvenes de la denominada Escuela de Frankfurt: Jürgen Habermas, Albrecht Wellmer -críticas al compromiso con una filosofía de la conciencia- así como Axel Honneth -crítica al modelo funcionalista de análisis de lo social-. Para esto se pondrá de relieve la centralidad del materialismo adorniano en el que el concepto de naturaleza cumple un rol central, así como el carácter crítico-normativo que de este materialismo se podría plantear. Con esto se hará posible tanto diferenciar la crítica adorniana como defenderla según la confianza de que con ella se puede hacer pensable un concepto de subjetividad no represivo capaz de desarticular la rigidez del modelo moderno de identidad personal

Conflictos obreros en Mendoza (1969-1974) : cambios en las formas de organización y de lucha producto del Mendozazo : Un análisis del 'borramiento' del conflicto como política de la memoria de la historiografía regional

El trabajo estudia los procesos de toma de conciencia que tuvieron lugar en la provincia de Mendoza a principios de los años '70. Momento en que distintas fracciones de la clase obrera construyeron alternativas políticas que buscaban la superación del sistema social vigente, nos abocamos a conocer los alineamientos político-sociales que asumieron los trabajadores alejados de los grandes centros industriales. Analizamos también el desarrollo de los conflictos intragremiales, los que en gran medida dejan entrever procesos de construcción de autonomía. Optamos por abordar el estudio de los conflictos obreros a nivel provincial a través de una medición cuantitativa de sus luchas, metodología que entendemos nos permite objetivar los procesos de lucha de clases en que se encontraba el conjunto de la sociedad argentina. En esta línea, el Mendozazo [abril de 1972] aparece como un hito central a dilucidar, entendiéndolo como un salto en cantidad y en calidad respecto de los procesos de toma de conciencia. Éste expresa un proceso de ruptura, que en su búsqueda por lograr ya sea la democratización o la superación de la forma en que se encuentra organizada la sociedad, entronca con las luchas nacionales del período. Nos interrogamos acerca su génesis y desarrollo, y por los cambios ocurridos en las formas de organización y de lucha de los trabajadores a nivel provincial como producto de este hecho social de masas. Para ello elaboramos un mapa de los conflictos obreros entre los años 1969 y 1974, que nos permite registrar la intensidad de los conflictos, el lugar de su ocurrencia, los sectores más movilizados y los objetivos de su acción. Asimismo, da cuenta de la dinámica de la conflictividad de carácter inter e intragremial, política y teórica; disputas que no estuvieron escindidas del posicionamiento que las distintas fracciones obreras asumieron respecto de las fuerzas sociales que por entonces disputaban el poder en la Argentina. Estos datos cuanti-cualitativos son luego puestos en diálogo con un estudio en profundidad, que analiza la experiencia del SOEP, sindicato de obreros y empleados públicos surgido al calor del Mendozazo. El mismo nos sirve para pensar cómo el proceso de avance de las fracciones más retardatarias de la sociedad logró cooptar a ciertos sectores que habían iniciado un proceso de autonomía e indisciplinamiento social; puesto que tanto de los resultados que arroja el mapeo como del proceso que muestra el estudio de caso seleccionado, se desprende que al menos hasta el momento que comprende este trabajo, el disciplinamiento gremial no fue un proceso que necesitó de grandes niveles de violencia material, sino que expresa un momento de construcción de hegemonía por parte de los sectores del denominado sindicalismo ortodoxo