Abnormalities Of Visual Perception Research Articles

Analisis Kesulitan Belajar Matematika Materi Bangun Datar SDN Karang Tengah 7

This study aims to (1) reveal the types of difficulties experienced by fourth grade students at Karang Tengah 7 Public Elementary School, and (2) describe the mathematics learning difficulties experienced by fourth grade students at Karang Tengah 7 Elementary School. This study used an analytic descriptive method with a qualitative. The subjects in this study were students of class IV A at SD Negeri Karang Tengah 7. The subjects in this study were determined using purposive sampling. Data collection techniques used in this study were used by means of essay tests and interviews. The data analysis technique used in this study is data reduction, data presentation, and finally drawing conclusions. The results of the study (1) learning difficulties in mathematics experienced by fourth grade students at SD Negeri Karang Tengah 7, namely spatial relationship disorders, visual perception abnormalities, visual motor associations, difficulty using symbols, difficulties in language and reading, and (2) students who experience relationship disorders 12 students in the room, 14 students with visual perception abnormalities, 13 students with visual perception abnormalities, 8 students with difficulty understanding symbols, 2 students with language and reading difficulties.

Perceptual Functioning.

Perceptual disorders are not part of the diagnosis criteria for schizophrenia. Yet, a considerable amount of work has been conducted, especially on visual perception abnormalities, and there is little doubt that visual perception is altered in patients. There are several reasons why such perturbations are of interest in this pathology. They are observed during the prodromal phase of psychosis, they are related to the pathophysiology (clinical disorganization, disorders of the sense of self), and they are associated with neuronal connectivity disorders. Perturbations occur at different levels of processing and likely affect how patients interact and adapt to their surroundings. The literature has become very large, and here we try to summarize different models that have guided the exploration of perception in patients. We also illustrate several lines of research by showing how perception has been investigated and by discussing the interpretation of the results. In addition to discussing domains such as contrast sensitivity, masking, and visual grouping, we develop more recent fields like processing at the level of the retina, and the timing of perception.

Clinical Impact of Spontaneous Hyperactivity in Degenerating Retinas: Significance for Diagnosis, Symptoms, and Treatment.

Hereditary retinal degenerations result from varied pathophysiologic mechanisms, all ultimately characterized by photoreceptor dysfunction and death. Hence, much research on these diseases has concentrated on the outer retina. Over the past decade or so increasing attention has focused on concomitant changes in complex inner retinal neural circuits that process visual signals for transmission to the brain. One striking abnormality develops before the ultimately profound anatomic disruption of the inner retina. Highly elevated spontaneous activity was first demonstrated in central nervous system visual centers in vivo by Dräger and Hubel (1978), and subsequently has been confirmed in vitro, now in multiple animal models and by multiple investigators (see other contributions to this Research Topic). What evidence exists that this phenomenon occurs in human patients with retinal degeneration, and what is the ultimate effect of spontaneous hyperactivity in the output neurons, the retinal ganglion cells? Here I summarize abnormalities of visual perception among patients with retinal degeneration that may arise from hyperactivity. Next, I consider the disruption of neural encoding and anatomic connectivity that may result within the retina and in downstream visual centers of the brain. I then consider how specific characteristics of hyperactivity may distinguish various forms or stages of retinal degeneration, potentially helping in the near future to refine diagnosis and/or treatment choices for different patients. Finally, I review how consideration of these features may help optimize pharmacologic, gene, stem cell, prosthetic or other therapies to forestall visual loss or restore sight.

Integrated assessment of visual perception abnormalities in psychotic disorders and relationship with clinical characteristics.

The visual system is recognized as an important site of pathology and dysfunction in schizophrenia. In this study, we evaluated different visual perceptual functions in patients with psychotic disorders using a potentially clinically applicable task battery and assessed their relationship with symptom severity in patients, and with schizotypal features in healthy participants. Five different areas of visual functioning were evaluated in patients with schizophrenia and schizoaffective disorder (n = 28) and healthy control subjects (n = 31) using a battery that included visuospatial working memory (VSWM), velocity discrimination (VD), contour integration, visual context processing, and backward masking tasks. The patient group demonstrated significantly lower performance in VD, contour integration, and VSWM tasks. Performance did not differ between the two groups on the visual context processing task and did not differ across levels of interstimulus intervals in the backward masking task. Performances on VSWM, VD, and contour integration tasks were correlated with negative symptom severity but not with other symptom dimensions in the patient group. VSWM and VD performances were also correlated with negative sychizotypal features in healthy controls. Taken together, these results demonstrate significant abnormalities in multiple visual processing tasks in patients with psychotic disorders, adding to the literature implicating visual abnormalities in these conditions. Furthermore, our results show that visual processing impairments are associated with the negative symptom dimension in patients as well as healthy individuals.

Altération de la perception visuelle élémentaire en psychiatrie

Objectives Abnormalities in visual perception are not at the foreground of schizophrenia symptomatology [1] , [2] , [3] . They are nonetheless often found in the patients’ complaints during prodromal phases, and have been described as one of the best predictor of schizophrenia conversion. What is the link between perceptual disorders and clinical symptoms in schizophrenia ? After a short discussion of different perceptual abnormalities, we will focus on the time structure of perception, that illustrates possible links between low-level perception disorders, predictive coding and the sense of minimal self (the self that helps to feel as being present here and now). Methods We tested the link between the sense of self and time disorders in 28 stabilized patients with schizophrenia and 24 matched controls. We evaluated time expectation, as indexed by the ability to benefit from the passage of time to react to a visual target : expectation increases with time, leading to shorter reaction times. We additionally check to which amount this phenomena is modulated when the targets are missing in some trials, and can be compensated for by attention cues. In parallel, minimal self-disorders were evaluated with the EASE (phenomenological scale). Results Patients can expect sensory signals and react to unusual events like missing targets as well as controls. However, the patients who display disorders of the minimal self (EASE) do not benefit from the passage of time, and all patients display disrupted time expectation when the occurrence of events is uncertain. Conclusion The results suggest a link between timing and minimal self disorders. Time expectation helps to link events with one another and to transform a chain of discontinuous events in a continuous flow. Conversely, fragile time expectations may lead to a sense of discontinuity, which could disrupt the flow of sensory signals, thus contributing to minimal self-disorders.

Life threatening pericardial and neurologic presentations in systemic lupus erythematosus

Background: Posterior reversible encephalopathy syndrome (PRES) is characterized by altered mental status, visual perception abnormalities and seizures. Systemic lupus erythematosus (SLE) is a rare etiology of PRES and affects less than 1% of SLE patients. We present a unique case of a new-onset SLE patient presenting with borderline cardiac tamponade requiring emergent pericardiocentesis and hospital course complicated by intractable seizures found to have PRES on imaging.Case presentation: A 21-year-old female underwent outpatient evaluation for new-onset SLE presenting to the emergency room with dyspnea. She was found to have a large circumferential pericardial effusion with borderline tamponade features requiring emergent pericardiocentesis. On her fifth hospital day, she developed generalized motor seizure (tonic-clonic) with magnetic resonance imaging (MRI) revealing bilateral parieto-occipital edema consistent with a radiographic diagnosis of PRES. Induction therapy with mycophenolate was started and follow-up studies showed improvement in the cortical and subcortical regions on MRI with no evidence of recurrent pericardial effusion.Conclusions: PRES is a rare complication of lupus and has been infrequently described in literature. It is thought that the association is secondary to the effect of SLE on endothelial dysfunction and the effect of cytotoxic medication on the loss of autoregulation of systemic hypertension. It is important to recognize this condition and its significant associations as early detection and intervention often lead to favorable outcomes. To our knowledge, this is the first case report of SLE with associations of both PRES and circumferential pericardial effusion with tamponade physiology, both of which are rare in the SLE patient population.

Electrophysiological Responses to Emotional Facial Expressions in Individuals with Autism Spectrum Disorder: a Systematic Review

Studies on processing of emotional faces in individuals with autism spectrum disorder (ASD) have shown mixed findings. The goal of this systematic review was to investigate brain electrical responses to emotional facial expressions in individuals with ASD. We conducted a literature search of nine databases and grey literature sources up to Jan 2017, resulting in 943 studies. Eleven studies met inclusion criteria, with quality assessments varying from three to six out of 10. This systematic review demonstrates that individuals with ASD show a lack of sensitivity to different emotional expressions, especially fear, compared to their peers. Atypical brain responses in processing emotional faces may reflect the abnormalities in visual perception and information processing that are present early in life.

Cortical Thickness of Functionally Defined Visual Areas in Schizophrenia and Bipolar Disorder.

Patients with schizophrenia show specific abnormalities in visual perception, and patients with bipolar disorder may have related perceptual deficits. During tasks that highlight perceptual dysfunction, patients with schizophrenia show abnormal activity in visual brain areas, including the lateral occipital complex (LOC) and early retinotopic cortex. It is unclear whether the anatomical structure of those visual areas is atypical in schizophrenia and bipolar disorder. In members of those two patient groups and healthy controls, we localized LOC and early retinotopic cortex individually for each participant using functional magnetic resonance imaging (MRI), then measured the thickness of those regions of interest using structural MRI scans. In both regions, patients with schizophrenia had the thinnest cortex, controls had the thickest cortex, and bipolar patients had intermediate cortical thickness. A control region, motor cortex, did not show this pattern of group differences. The thickness of each visual region of interest was significantly correlated with performance on a visual object masking task, but only in schizophrenia patients. These findings suggest an anatomical substrate for visual processing abnormalities that have been found with both neural and behavioral measures in schizophrenia and other severe mental illnesses.

MP34-10 DOES 3D TECHNOLOGY AFFECT VISUAL SYSTEM ?

You have accessJournal of UrologySurgical Technology & Simulation: Instrumentation & Technology III1 Apr 2016MP34-10 DOES 3D TECHNOLOGY AFFECT VISUAL SYSTEM ? ANDREA TASCA, GIUSEPPE BENEDETTO, FILIPPO NIGRO, LUIGI BARTOLOMEI, NADIA MINICUCCI, and SABINO PISANI ANDREA TASCAANDREA TASCA More articles by this author , GIUSEPPE BENEDETTOGIUSEPPE BENEDETTO More articles by this author , FILIPPO NIGROFILIPPO NIGRO More articles by this author , LUIGI BARTOLOMEILUIGI BARTOLOMEI More articles by this author , NADIA MINICUCCINADIA MINICUCCI More articles by this author , and SABINO PISANISABINO PISANI More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.02.1568AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES 3 D technology has been extensively used in the last years during laparoscopic and robotic surgery. The polarized lenses required to obtain adequate images during the procedures can induce visual fatigue and headache. These phenomena anecdotally reported by surgeons have not been adequately investigated until now and pertinent bibliographic reports are poor. The aim of our study was to document and characterize possible abnormalities in visual perception after 3 D compared to 2 D laparoscopy. METHODS The members of three different surgical teams, each including two surgeons and one scrub nurse, were individually studied in the last six months. Each team member has been tested before and after 2 D and 3 D laparoscopic procedures (3+3, respectively for each team) lasting from about 150 to 240 min. The employed techniques (radical and partial nephrectomy, radical prostatectomy, dismembered pyeloplasty and living donor nephrectomy) were homogeneously distributed among the 2 groups. Before and after every surgery, the components underwent a standard optical test including visual field evaluation, visual evoked potentials and optometric tests. The last included Gabor, Random Dot, stereo circles, fixation disparity, optotype stereo and phoria-T. The results obtained for each component were recorded for the 2 visual systems and statistically analyzed using Wicoxon signed rank and Mc Nemar tests as appropriate. RESULTS No differences between pre and post standard visual tests were evident for any of the surgical teams’ components referred to both 2 D and 3 D systems. The same results were obtained for the neuro-sensitive tests. At the optometric evaluation a significant alteration of pre vs post random dot test was found only in the contest of 3 D procedures (32.5+/- 4.6 vs 45.0+/-7.5; p<0.05). After qualitative analysis a significant alteration was documented after 3D vs 2 D procedures for fixation disparity (75% vs 37.5%; p<0.05) and phoria-T test (37,5% vs 12.5%; p<0.05). CONCLUSIONS Our results indicate that 3 D system induces an overall damage of visual function evident at the optometric evaluation. This damage does not involve ocular function or optical nerve but rather the stream nerve fibres that travel from the occipital cortex to the posterior parietal area (magno system) and to temporal lobe (parvo system). These fibers are responsible of stereoptic function which represents the cognitive elaboration of visual signal by brain cortex. © 2016FiguresReferencesRelatedDetails Volume 195Issue 4SApril 2016Page: e474-e475 Advertisement Copyright & Permissions© 2016MetricsAuthor Information ANDREA TASCA More articles by this author GIUSEPPE BENEDETTO More articles by this author FILIPPO NIGRO More articles by this author LUIGI BARTOLOMEI More articles by this author NADIA MINICUCCI More articles by this author SABINO PISANI More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Altering Visual Perception Abnormalities: A Marker for Body Image Concern.

The body image concern (BIC) continuum ranges from a healthy and positive body image, to clinical diagnoses of abnormal body image, like body dysmorphic disorder (BDD). BDD and non-clinical, yet high-BIC participants have demonstrated a local visual processing bias, characterised by reduced inversion effects. To examine whether this bias is a potential marker of BDD, the visual processing of individuals across the entire BIC continuum was examined. Dysmorphic Concern Questionnaire (DCQ; quantified BIC) scores were expected to correlate with higher discrimination accuracy and faster reaction times of inverted stimuli, indicating reduced inversion effects (occurring due to increased local visual processing). Additionally, an induced global or local processing bias via Navon stimulus presentation was expected to alter these associations. Seventy-four participants completed the DCQ and upright-inverted face and body stimulus discrimination task. Moderate positive associations were revealed between DCQ scores and accuracy rates for inverted face and body stimuli, indicating a graded local bias accompanying increases in BIC. This relationship supports a local processing bias as a marker for BDD, which has significant assessment implications. Furthermore, a moderate negative relationship was found between DCQ score and inverted face accuracy after inducing global processing, indicating the processing bias can temporarily be reversed in high BIC individuals. Navon stimuli were successfully able to alter the visual processing of individuals across the BIC continuum, which has important implications for treating BDD.

The role of eye movement driven attention in functional strabismic amblyopia.

Strabismic amblyopia “blunt vision” is a developmental anomaly that affects binocular vision and results in lowered visual acuity. Strabismus is a term for a misalignment of the visual axes and is usually characterized by impaired ability of the strabismic eye to take up fixation. Such impaired fixation is usually a function of the temporally and spatially impaired binocular eye movements that normally underlie binocular shifts in visual attention. In this review, we discuss how abnormal eye movement function in children with misaligned eyes influences the development of normal binocular visual attention and results in deficits in visual function such as depth perception. We also discuss how eye movement function deficits in adult amblyopia patients can also lead to other abnormalities in visual perception. Finally, we examine how the nonamblyopic eye of an amblyope is also affected in strabismic amblyopia.

Use of a polysulfone hemodialysis membrane may prevent recurrent posterior reversible encephalopathy syndrome in a patient undergoing hemodialysis

A 71-year-old woman underwent hemodialysis (HD) treatment for chronic kidney disease. During HD, she developed headache, abnormalities in visual perception, and generalized convulsion. Brain magnetic resonance imaging (MRI) showed T2-hyperintensity lesions in the posterior lobe, and an electroencephalogram showed slow waves in all areas. Twenty days later, the T2-hyperintensity lesions had vanished. Furthermore, perfusion computed tomography (CT) and single-photon emission CT with N-isopropyl[(123)I]-p-iodoamphetamine (IMP-SPECT) showed no significant abnormalities. The patient was diagnosed with posterior reversible encephalopathy syndrome (PRES) because she displayed typical clinical symptoms and MRI findings. Although several antihypertensive and antiseizure medications were administered, the patient experienced recurrent PRES. Therefore, we used a polysulfone dialyzer to reduce the oxidative stress and inflammation while preserving vascular endothelial function. After use of a polysulfone dialyzer membrane, the patient had no PRES episodes during the clinical course. This is the first study to demonstrate that use of a polysulfone dialyzer membrane instead of a cellulose membrane may prevent recurrent PRES.

Irreversible Hemorrhagic Complication of Recurrent Posterior Reversible Encephalopathy Syndrome in a Patient with Systemic Lupus Erythematosus

A diagnosis of posterior reversible encephalopathy syndrome (PRES) is based on a combination of clinical symptoms including headache, altered alertness, abnormalities of visual perception, and seizure, and characteristic neuroimaging findings of transient white matter edema, mostly in the posterior parietal-temporaloccipital regions of the brain (1, 2). Conditions commonly associated with PRES include severe hypertension, eclampsia/ preeclampsia, immunosuppressive medications including cyclosporine and taclorimus, antineoplastic agents, and various cause of renal failure (3, 4). PRES as a complication of systemic lupus erythematosus (PRES-SLE) is not uncommon and neurologic or psychiatric abnormalities occur in up to two-thirds of patients with SLE (4). Usually PRES is reversible vasogenic edema in the posterior circuation territories, although atypical findings such as conversion to irreversible cytotoxic edema, hemorrhage, and enhancement have been described (3). And cytotoxic edema surrounded by extensive vasogenic edema resulted in poor outcome. We report a case of PRESSLE showing irreversible hemorrhagic transformation as a complication of recurrent PRES.

Fragile Early Visual Percepts Mark Genetic Liability Specific to Schizophrenia

Disruption of visual percepts by a subsequent stimulus (ie, backward masking) has been consistently noted in schizophrenia, with some evidence that this fragility in early perception is present in people with genetic liability for the disorder. Given the potential of backward masking paradigms to mark neural processes that confer risk for schizophrenia, it is important to test the diagnostic specificity of abnormalities in visual perception. To more fully assess whether masking visual stimuli reveals a marker of genetic liability (ie, endophenotype) specific to schizophrenia, we tested 44 people with the disorder, 29 people with bipolar disorder, 56 first-degree biological relatives of people with schizophrenia, 26 first-degree biological relatives of people with bipolar disorder, and 43 nonpsychiatric control participants using a magnocellular-biased visual backward masking procedure that included target-to-mask onset asynchronies ranging from 0 to 80 ms. Relatives of people with schizophrenia who were without schizophrenia spectrum disorders exhibited impaired performance compared with nonpsychiatric control participants and relatives of people with bipolar disorder when a visual mask interrupted early perception (eg, 27 ms). A similar vulnerability of early processes was noted in people with schizophrenia, yet they also had impaired performance when masks occurred at later time points (ie, 80 ms). Performance deficits were not attributable to intellectual function, measures of attention and memory, symptomatology, or medication dosage. Bipolar patients and their relatives failed to exhibit deficits on the backward masking task. Fragility of early visual percepts appears to mark genetic liability specific to schizophrenia and may serve as an endophenotype for the disorder.

Posterior Reversible Encephalopathy Syndrome Mimicking a Left Middle Cerebral Artery Stroke

Certain Acute Clinical presentations are highly suggestive of stroke caused by specific mechanisms. One example of this would be the sudden onset of aphasia without hemiparesis often reflecting cerebral embolism, frequently from a cardiac source. Posterior reversible encephalopathy syndrome (PRES) describes a usually reversible neurologic syndrome with a variety of presenting symptoms from headache, altered mental status, seizures, vomiting, diminished spontaneity and speech, abnormalities of visual perception and visual loss. We report a patient presenting with elevated blood pressure, CT characteristics of PRES but a highly circumscribed neurologic syndrome (Wernicke's Aphasia without hemiparesis) suggestive of a cardioembolic stroke affecting the left MCA territory. That is, PRES mimicked a focal stroke syndrome. The importance of recognizing this possibility is that his deficits resolved with blood pressure control, while other treatments, such as intensifying his anticoagulation would have been inappropriate. In addition, allowing his blood pressure to remain elevated as is often done in the setting of an acute stroke might have perpetuated the underlying pathophysiology of PRES leading to a worse clinical outcome. For this reason PRES needs to be recognized quickly and treated appropriately.

Altered dynamic coupling of lateral occipital complex during visual perception in schizophrenia

IntroductionThere is mounting evidence that visual perception abnormalities in schizophrenia are partly explained by a dysfunction of the lateral occipital complex (LO). We previously demonstrated that schizophrenia patients had broader topography and reduced magnitude of activity of LO. However, the functional connectivity of LO with other brain regions during visual perception has not been directly investigated in schizophrenia. Materials and methodsEighteen patients with schizophrenia and eighteen matched controls performed a backward masking task during functional magnetic resonance imaging (fMRI). Stimulus onset asynchronies were manipulated to change the level of target visibility. To examine connectivity with LO function we conducted psychophysiological interactions (PPI) analyses using: 1) a region of interest (ROI) approach and 2) a whole brain analysis. ROIs were defined based on a contrast of trials on which a target was presented versus null trials in which no stimuli were presented. ResultsEleven ROIs were identified. Both groups showed similar strength of coupling between LO and the 11 ROIs when visibility was not taken into account. Healthy controls showed clear changes in coupling between LO and prefrontal and parietal regions as a function of target visibility (higher coupling with more visible targets). In comparison, patients showed reduced dynamic coupling with LO in the right superior frontal gyrus (significant after correcting for multiple comparisons) and a trend for reduced coupling in the left precuneus and left inferior frontal regions. Whole brain analysis identified additional regions that showed dynamic coupling with LO in healthy controls, but not in patients. DiscussionThe increased coupling between LO and higher-level parietal and prefrontal regions during visual awareness in healthy controls likely reflects visual reentrant processing. The lack of modulation of coupling between LO and key prefrontal and parietal regions found in schizophrenia may partly reflect abnormalities in LO tuning. The altered LO coupling may contribute to visual perception abnormalities in schizophrenia.

Top-down and bottom-up visual information processing of non-social stimuli in high-functioning autism spectrum disorder

Individuals with high-functioning autism spectrum disorder (HF-ASD) often show superior performance in simple visual tasks, despite difficulties in the perception of socially important information such as facial expression. The neural basis of visual perception abnormalities associated with HF-ASD is currently unclear. We sought to elucidate the functioning of bottom-up and top-down visual information processing in HF-ASD using event-related potentials (ERPs). Eleven adults with HF-ASD and 11 age-matched normal controls (NC) participated in this study. Visual ERPs were recorded using 128-channel EEG. The P1 and P300 were recorded in response to target stimuli. Visual mismatch negativity (vMMN) potentials were obtained by subtracting responses to standard from those to deviant stimuli. Behaviorally, individuals with HF-ASD showed faster target detection than NCs. However, vMMN amplitude and latency were the same between the two groups. In contrast, P1 and P300 amplitudes were significantly decreased in HF-ASD compared with NCs. In addition, P300 latency was significantly delayed in HF-ASD. Individuals with HF-ASD exhibit altered visual information processing. Intact bottom-up attention (vMMN) may contribute to their superior simple visual task performance in spite of abnormal low-level (P1) and top-down (P300) visual information processing.

Reversible posterior leukoencephalopathy syndrome in childhood: report of nine cases and review of the literature

Reversible posterior leukoencephalopathy syndrome (RPLS) is recently described disorder with typical radiological findings in the posterior regions of the cerebral hemisphere and cerebellum. Its clinical symptoms include headache, decreased alertness, mental abnormalities, such as confusion, diminished spontaneity of speech, and changed behavior ranging from drowsiness to stupor, seizures, vomiting and abnormalities of visual perception like cortical blindness. RPLS is caused by various heterogeneous factors, the commonest being hypertension, followed by non-hypertensive causes such as eclampsia, renal diseases and immunosuppressive therapy. We presented nine patients with RPLS who had primary diagnoses such as acute post-streptococcal glomerulonephritis, idiopathic hypertension, the performing of intravenous immunoglobulin for infection with crescentic glomerulonephritis, erythrocyte transfusion for severe iron deficiency, L: -asparaginase treatment for acute lymphoblastic leukemia and performing of granulocyte-colony stimulating factor for ulcerative colitis due to neutropenia. Early recognition of RPLS as complication during different diseases and therapy in childhood may facilitate precise diagnosis and appropriate treatment.

Fear of heights: cognitive performance and postural control

Fear of heights, or acrophobia, is one of the most frequent subtypes of specific phobia frequently associated to depression and other anxiety disorders. Previous evidence suggests a correlation between acrophobia and abnormalities in balance control, particularly involving the use of visual information to keep postural stability. This study investigates the hypotheses that (1) abnormalities in balance control are more frequent in individuals with acrophobia even when not exposed to heights, that (2) acrophobic symptoms are associated to abnormalities in visual perception of movement; and that (3) individuals with acrophobia are more sensitive to balance-cognition interactions. Thirty-one individuals with specific phobia of heights and thirty one non-phobic controls were compared using dynamic posturography and a manual tracking task. Acrophobics had poorer performance in both tasks, especially when carried out simultaneously. Previously described interference between posture control and cognitive activity seems to play a major role in these individuals. The presence of physiologic abnormalities is compatible with the hypothesis of a non-associative acquisition of fear of heights, i.e., not associated to previous traumatic events or other learning experiences. Clinically, this preliminary study corroborates the hypothesis that vestibular physical therapy can be particularly useful in treating individuals with fear of heights.

Reversible Posterior Leukoencephalopathy Syndrome Caused by Bevacizumab: Report of a Case

Reversible posterior leukoencephalopathy syndrome (RPLS) was first described by Hinchey et al. and is characterized by the presence of posterior white matter lesions predominantly bilaterally in the parieto-occipital regions on brain magnetic resonance imaging (MRI). The most common clinical symptoms are headache, vomiting, agitation, altered alertness, and behavior that ranges from drowsiness to stupor, abnormalities of visual perception, and epileptic seizures. Various causative factors have been described and include hypertension, renal diseases, chemotherapeutic drugs, and immunosuppressive drugs. The mechanism of the syndrome is probably a braincapillary leak syndrome related to hypertension, fluid retention, and possibly the cytotoxic effects of drugs on the vascular endothelium. Recently Glusker et al. and Ozcan et al. described the first two cases of RPLS occurring during treatment with bevacizumab, an antibody against the vascular endothelial growth factor (VEGF). We present a case history of severe bevacizumab-induced RPLS that illustrates the need for adherence to guidelines regarding control of blood pressure.