Differences in virtual and physical head orientation predict sickness during active head-mounted display-based virtual reality.

During head-mounted display (HMD)-based virtual reality (VR), head movements and motion-to-photon-based display lag generate differences in our virtual and physical head pose (referred to as DVP). We propose that large-amplitude, time-varying patterns of DVP serve as the primary trigger for cybersickness under such conditions. We test this hypothesis by measuring the sickness and estimating the DVP experienced under different levels of experimentally imposed display lag (ranging from 0 to 222 ms on top of the VR system's ~ 4 ms baseline lag). On each trial, seated participants made continuous, oscillatory head rotations in yaw, pitch or roll while viewing a large virtual room with an Oculus Rift CV1 HMD (head movements were timed to a computer-generated metronome set at either 1.0 or 0.5 Hz). After the experiment, their head-tracking data were used to objectively estimate the DVP during each trial. The mean, peak, and standard deviation of these DVP data were then compared to the participant's cybersickness ratings for that trial. Irrespective of the axis, or the speed, of the participant's head movements, the severity of their cybersickness was found to increase with each of these three DVP summary measures. In line with our DVP hypothesis, cybersickness consistently increased with the amplitude and the variability of our participants' DVP. DVP similarly predicted their conscious experiences during HMD VR-such as the strength of their feelings of spatial presence and their perception of the virtual scene's stability.

Retroauricular pain caused by Eagle syndrome: A rare presentation due to compression by styloid process elongation.

Eagle syndrome is a rare condition presenting with retroauricular pain (usually as main symptom) associated with dysphagia, headache, neck pain on rotation and, much rarelier, stroke. This occurs due to styloid process elongation. Sometimes, there is also styloid ligament calcification, which can cause compression of nerves and arteries and the symptoms above. Treatment can be conservative with pain modulators (e.g. pregabalin) or infiltrations (steroids or anesthetics drugs). In refractory cases, surgical approach aiming to reduce the size of the styloid process can be performed. We present a rare case of Eagle syndrome (documented by computed tomography) with good response to clinical treatment.

Retroauricular pain caused by Eagle syndrome: A rare presentation due to compression by styloid process elongation / Dor retroauricular causada pela síndrome de Eagle: uma apresentação rara por compressão pelo alongamento do processo estiloide

Summary Eagle syndrome is a rare condition presenting with retroauricular pain (usually as main symptom) associated with dysphagia, headache, neck pain on rotation and, much rarelier, stroke. This occurs due to styloid process elongation. Sometimes, there is also styloid ligament calcification, which can cause compression of nerves and arteries and the symptoms above. Treatment can be conservative with pain modulators (e.g. pregabalin) or infiltrations (steroids or anesthetics drugs). In refractory cases, surgical approach aiming to reduce the size of the styloid process can be performed. We present a rare case of Eagle syndrome (documented by computed tomography) with good response to clinical treatment.

Resumo A síndrome de Eagle é uma condição rara na qual ocorre dor retroauricular (usualmente é o principal sintoma) associada a disfagia, cefaleia, cervicalgia durante a rotação da cabeça e, mais raramente, a AVC. Isso ocorre por conta do alongamento do processo estiloide e, às vezes, há também calcificação do ligamento estiloide. Essas estruturas podem comprimir nervos e artérias causando os sintomas citados. O tratamento pode ser conservador com moduladores da dor, como pregabalina, ou com infiltrações (corticoides ou drogas anestésicas). Em casos refratários, cirurgia para reduzir o tamanho do processo estiloide pode ser realizada. É apresentado um caso raro de síndrome de Eagle (documentado com tomografia computadorizada) com boa resposta ao tratamento clínico.

Prevalence and Determinants of Bullying Among Health Care Workers in Portugal.

Bullying is defined as systematic exposure to humiliation as well as hostile and violent behaviors against one or more individuals. These behaviors are a serious, growing problem, which affects a significant proportion of health care professionals. To support the hospital's risk management policy, a cross-sectional study was undertaken to determine the prevalence of bullying in this institution and identify the determinants of bullying. Bullying was measured using the Negative Acts Questionnaire-Revised, Portuguese version (NAQ-R), a self-administered tool. The questionnaire was made available in digital format on the hospital's internal network (Intranet) and in hard copy; questionnaires were returned via nonidentified internal mail addressed to the occupational health unit or deposited in suggestion boxes located throughout the hospital. Multiple questionnaire delivery methods guaranteed data anonymity and confidentiality. The prevalence of bullying in this hospital was 8% (95% confidence interval [CI] = [6.2, 10.2]). Reported bullying was predominantly vertical and more frequently occurring among nurses, clerical staff, and health care assistants (12.5%, 7.6%, 6.4%, respectively; p = .005). After adjusting for gender, age, occupation, type of contract, and work schedule, only type of contract was significantly associated with bullying in the workplace; the risk of bullying was twice as high among government employees compared to workers with indefinite duration employment contracts ( p = .038). This study identified a high prevalence of bullying among health professionals; hence a program to prevent and control this phenomenon was implemented in this institution.

Anti-aliasing Wiener filtering for wave-front reconstruction in the spatial-frequency domain for high-order astronomical adaptive-optics systems.

Computationally efficient wave-front reconstruction techniques for astronomical adaptive-optics (AO) systems have seen great development in the past decade. Algorithms developed in the spatial-frequency (Fourier) domain have gathered much attention, especially for high-contrast imaging systems. In this paper we present the Wiener filter (resulting in the maximization of the Strehl ratio) and further develop formulae for the anti-aliasing (AA) Wiener filter that optimally takes into account high-order wave-front terms folded in-band during the sensing (i.e., discrete sampling) process. We employ a continuous spatial-frequency representation for the forward measurement operators and derive the Wiener filter when aliasing is explicitly taken into account. We further investigate and compare to classical estimates using least-squares filters the reconstructed wave-front, measurement noise, and aliasing propagation coefficients as a function of the system order. Regarding high-contrast systems, we provide achievable performance results as a function of an ensemble of forward models for the Shack-Hartmann wave-front sensor (using sparse and nonsparse representations) and compute point-spread-function raw intensities. We find that for a 32×32 single-conjugated AOs system the aliasing propagation coefficient is roughly 60% of the least-squares filters, whereas the noise propagation is around 80%. Contrast improvements of factors of up to 2 are achievable across the field in the H band. For current and next-generation high-contrast imagers, despite better aliasing mitigation, AA Wiener filtering cannot be used as a standalone method and must therefore be used in combination with optical spatial filters deployed before image formation actually takes place.

Middle cerebral artery aneurysms: challenges for microsurgical approach

The authors present their series about middle cerebral artery (MCA) aneurysms. They discuss anatomical aspects as well as the results and complications of surgical treatment. Besides, they defend the idea that for having good results, it is necessary an extent Sylvian´s cistern dissection, permitting an adequate exposure of the aneurysms and their relationships not only with the MCA but with its branches, emphasizing too the not usefulness of temporary clipping in the approach of this pathology.

Clinical presentation, treatment and outcome of patients with cerebral metastases: the University of São Paulo series.

INTRODUCTION: Secondary neoplasias are the most common tumors affecting the central nervous system and several clinical aspects of this disease are still controversial. METHOD: Forty-seven consecutive patients with the diagnosis of cerebral metastases (CM) were retrospectively studied at the Clinical Hospital of Sao Paulo University Medical School. Mean age was 53.9 years and 25 patients were female. RESULTS: The most frequent primary sites were breast, lung and skin. Symptoms were related to increased intracranial pressure (ICP) in 48.9%, focal neurological events in 27.7% and both in 17.0%. Single brain metastases were found in 57.4% of those cases, the frontal lobe being most frequently affected. Surgical treatment was performed in 68.1%, radiotherapy in 40.4% and chemotherapy in 17.0%. CONCLUSION: After statistical analysis, there was a trend towards prolonged survival of female patients, patients with ICP symptoms and the surgical group. Data from different centers are essential to establish the best management of CM.

Clinical presentation, treatment and outcome of patients with cerebral metastases: the University of São Paulo series

INTRODUÇÃO: As neoplasias secundárias são o principal grupo de tumores que afetam o sistema nervoso central. Diversos aspectos da evolução e tratamento desta doença são controversos. MÉTODO: Quarenta e sete pacientes com metástase cerebral foram estudados retrospectivamente no Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo. A idade média foi 53,9 anos e 25 pacientes eram do sexo feminino. RESULTADOS: Os sítios primários mais freqüentes foram mama, pulmão e pele. Os sintomas apresentados foram relacionados à hipertensão intracraniana (HIC) em 48,9%, sintomas focais em 27,7% e ambos em 17,0%. Metástases únicas foram encontradas em 57,8% dos casos. O tratamento foi cirurgia em 68,1% dos casos, radioterapia em 40,4% e quimioterapia em 17,0%. CONCLUSÃO: Após análise estatística, foram encontradas tendências a maior sobrevida nos pacientes do sexo feminino, no grupo de pacientes que apresentava sintomas de HIC e no grupo cirúrgico. Dados de diferentes centros são essenciais para o estabelecer a melhor forma de tratamento para as mestástases cerebrais.