Effect of age related macular degeneration on the Eger macular stressometer photostress recovery time

Aim: To assess the repeatability of Eger macular stressometer (EMS) measures of photostress recovery and determine their association with other measures of visual function. Methods: EMS photostress recovery time was measured in 90 patients with bilateral exudative age related macular degeneration (AMD), 19 with bilateral atrophic AMD and 47 with both forms of the condition (mean age 79 (SD 13) years). Measurements were made on two occasions separated by 1 year. Intrasession repeatability was assessed by repeating the measures after a 10 minute recovery period at the first visit. Distance visual acuity was measured with a logMAR chart, near visual acuity with a MNRead chart at 25 cm, contrast sensitivity with a Pelli-Robson chart, and the presence of central visual disturbance assessed with an Amsler grid. A questionnaire was used to assess self reported difficulties with glare recovery. Results: The average EMS recovery time was 11.0 (SD 8.9) seconds, decreasing by 1.6 (5.2) seconds on repeated measurement (p0.05). EMS photostress recovery time did not predict those whose vision decreased over the following year compared with those among whom it remained stable. Conclusions: The EMS test is not a useful tool in determining the severity or progression of AMD

Guidelines for the recording and evaluation of pharmaco-EEG data in man: the International Pharmaco-EEG Society (IPEG)

The International Pharmaco-EEG Society (IPEG) presents updated guidelines summarising the requirements for the recording and computerised evaluation of pharmaco-EEG data in man. Since the publication of the first pharmaco-EEG guidelines in 1982, technical and data processing methods have advanced steadily, thus enhancing data quality and expanding the palette of tools available to investigate the action of drugs on the central nervous system (CNS), determine the pharmacokinetic and pharmacodynamic properties of novel therapeutics and evaluate the CNS penetration or toxicity of compounds. However, a review of the literature reveals inconsistent operating procedures from one study to another. While this fact does not invalidate results per se, the lack of standardisation constitutes a regrettable shortcoming, especially in the context of drug development programmes. Moreover, this shortcoming hampers reliable comparisons between outcomes of studies from different laboratories and hence also prevents pooling of data which is a requirement for sufficiently powering the validation of novel analytical algorithms and EEG-based biomarkers. The present updated guidelines reflect the consensus of a global panel of EEG experts and are intended to assist investigators using pharmaco-EEG in clinical research, by providing clear and concise recommendations and thereby enabling standardisation of methodology and facilitating comparability of data across laboratories

Mapping depression in schizophrenia: A functional magnetic resonance imaging study

Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. Depressive symptoms are common in schizophrenia, often left untreated, and associated with a high relapse rate, suicidal ideation, increased mortality, reduced social adjustment and poor quality of life. The neural mechanisms underlying depression in psychosis are poorly understood. Given reports of altered brain response to negative facial affect in depressive disorders, we examined brain response to emotive facial expressions in relation to levels of depression in people with psychosis. Seventy outpatients (final N = 63) and 20 healthy participants underwent functional magnetic resonance imaging during an implicit affect processing task involving presentation of facial expressions of fear, anger, happiness as well as neutral expressions and a (no face) control condition. All patients completed Beck Depression Inventory (BDI-II) and had their symptoms assessed on the Positive and Negative Syndrome Scale (PANSS). In patients, depression (BDI-II) scores associated positively with activation of the left thalamus, extending to the putamen-globus pallidus, insula, inferior-middle frontal and para-post-pre-central gyri during fearful expressions. Furthermore, patients with moderate-to-severe depression had significantly higher activity in these brain regions during fearful expressions relative to patients with no, minimal, or mild depression and healthy participants. The study provides first evidence of enhanced brain response to fearful facial expressions, which signal an uncertain source of threat in the environment, in patients with psychosis and a high level of self-reported depression

Incidence of ocular complications in patients with multibacillary leprosy after completion of a 2 year course of multidrug therapy

Aim: To evaluate the incidence of and risk factors for ocular complications in multibacillary (MB) leprosy patients following completion of 2 year, fixed duration, multidrug therapy (MDT). Methods: Biannual eye examinations were conducted prospectively on a cohort of MB patients who had completed MDT and followed up for 5 years. The incidence of ocular pathology was calculated as the number of events per person year of event free follow up of patients who did not have the specific finding before completion of MDT. Results: 278 patients had one or more follow up visits after completion of MDT. The incidence of lagophthalmos was 0.24%/patient year (95% CI 0.10% to 0.37%); corneal opacity, 5.35%/patient year (95% CI 4.27% to 6.70%); uveal involvement, 3.78%/patient year (95% CI 2.96% to 4.83%); and cataract that reduced vision to 6/18 or less, 2.4%/patient year (95% CI 1.77% to 3.26%). Overall, 5.65%/patient year (95% CI 4.51% to 7.09%) developed leprosy related ocular disease and 3.86%/patient year (95% CI 3.00% to 4.95%) developed leprosy related, potentially blinding ocular pathology during the period following MDT. Age and other disability also predicted incident eye disease. Conclusions: Every year, approximately 5.6% of patients with MB who have completed MDT can be expected to develop new ocular complications of leprosy, which often (3.9%) are potentially vision threatening. Because many of these complications cannot be detected without slit lamp examination, periodic monitoring, particularly of older patients and those with other disability, is recommended, in order to detect and treat ocular complications satisfactorily. I t is estimated that by the end of the year 2005, more than 14 million leprosy patients will have completed a standard course of anti-leprosy multidrug therapy (MDT). 1 Although the incidence of leprosy is declining in some areas, approximately half a million new patients are diagnosed with leprosy each year. Recent changes in the epidemiology of leprosy include a gradual shift in the proportion of the type of leprosy from the paucibacillary to the multibacillary (MB) form, as well as a shift to an older age at diagnosis of disease. 2 Improving health care and socioeconomic conditions predict increasing survival, with the fortunate result that there will be an ever increasing number of antimicrobially ''cured'' leprosy patients than ever existed in history. There is evidence that even after adequate treatment with MDT, a sizeable proportion of cured leprosy patients continue to manifest progressive impairment of nerve function. Although the pathophysiology of this process is not fully understood, it is thought to be related to continuing immunological reactions and slow evolution of pre-existing nerve damage. Ocular complications are frequently observed in newly diagnosed leprosy patients and in patients who are undergoing MDT. 7-9 However, little information exists on the incidence of ocular complications after completion of MDT in MB patients who have completed the recommended course of MDT. Knowledge of the risk and nature of ocular morbidity in leprosy patients after treatment with MDT is needed to prevent and/or manage such complications promptly and effectively in programmes worldwide. Such information potentially could identify risk factors that may be amenable to intervention and help prioritise groups for more active follow up. In our previous reports, we have described a cohort of newly diagnosed MB leprosy patients who were followed for ocular complications during 2 year fixed MDT. 8 10 These patients were followed up for a further 5 years. In this paper, we report information on ocular complications that were incident during the post-MDT period. MATERIAL AND METHODS All new clinically diagnosed MB patients starting on a 2 year MDT and living within the leprosy control area of the Schieffelin Leprosy Research and Training Centre in southern India were invited to participate. Recruitment began in 1991 and was completed in 1997. Consenting patients received a baseline ocular examination followed by biannual examinations during MDT and for a period of at least 5 years after completion of MDT. Based on sample size calculations taking into account possible losses to follow up resulting from migration and mortality, 301 MB leprosy patients were enrolled over a period of 6 years. Research methods and protocols were approved by the institutional review board of the Schieffelin Leprosy Research and Training Centre. All patients were examined and given treatment free of charge. At enrolment the following leprosy characteristics were recorded; the type of MB leprosy, based on the clinical classification of Ridley and Jopling 11 ; deformity grading of hands and legs, based on the WHO classification 12 ; the bacterial index, calculated from the results of the acid fast staining of smears from specific skin sites 13 ; presence or Abbreviations: LROP, leprosy related ocular pathology; MB, multibacillary; MDT, multidrug therapy; PBLROP, potentially blinding leprosy related ocular pathology 949 www.bjophthalmol.co

Migraine aura: retracting particle-like waves in weakly susceptible cortex

Cortical spreading depression (SD) has been suggested to underlie migraine aura. Despite a precise match in speed, the spatio-temporal patterns of SD and aura symptoms on the cortical surface ordinarily differ in aspects of size and shape. We show that this mismatch is reconciled by utilizing that both pattern types bifurcate from an instability point of generic reaction-diffusion models. To classify these spatio-temporal pattern we suggest a susceptibility scale having the value [sigma]=1 at the instability point. We predict that human cortex is only weakly susceptible to SD ([sigma]<1), and support this prediction by directly matching visual aura symptoms with anatomical landmarks using fMRI retinotopic mapping. We discuss the increased dynamical repertoire of cortical tissue close to [sigma]=1, in particular, the resulting implications on migraine pharmacology that is hitherto tested in the regime ([sigma]>>1), and potentially silent aura occurring below a second bifurcation point at [sigma]=0 on the susceptible scale

Psychoanalytic sociology and the traumas of history: Alexander Mitscherlich between the disciplines

This article examines the way aspects of recent history were excluded in key studies emerging from psychoanalytic social psychology of the mid-twentieth century. It draws on work by Erikson, Marcuse and Fromm, but focuses in particular on Alexander Mitscherlich. Mitscherlich, a social psychologist associated with the later Frankfurt school, was also the most important psychoanalytic figure in postwar Germany. This makes his work significant for tracing ways in which historical experience of the war and Nazism was filtered out of psychosocial narratives in this period, in favour of more structural analyses of the dynamics of social authority. Mitscherlich?s 1967 work The Inability to Mourn, co-authored with Margarete Mitscherlich, is often cited as the point at which the ?missing? historical experience flooded back into psychoanalytic accounts of society. I argue that this landmark publication doesn?t hail the shift towards the psychoanalysis of historical experience with which it is often associated. These more sociological writers of the mid-century were writing before the impact of several trends occurring in the 1980s-90s which decisively shifted psychoanalytic attention away from the investigation of social authority and towards a focus on historical trauma. Ultimately this is also a narrative about the transformations which occur when psychoanalysis moves across disciplines

Spatio-Temporal Brain Mapping of Motion-Onset VEPs Combined with fMRI and Retinotopic Maps

Neuroimaging studies have identified several motion-sensitive visual areas in the human brain, but the time course of their activation cannot be measured with these techniques. In the present study, we combined electrophysiological and neuroimaging methods (including retinotopic brain mapping) to determine the spatio-temporal profile of motion-onset visual evoked potentials for slow and fast motion stimuli and to localize its neural generators. We found that cortical activity initiates in the primary visual area (V1) for slow stimuli, peaking 100 ms after the onset of motion. Subsequently, activity in the mid-temporal motion-sensitive areas, MT+, peaked at 120 ms, followed by peaks in activity in the more dorsal area, V3A, at 160 ms and the lateral occipital complex at 180 ms. Approximately 250 ms after stimulus onset, activity fast motion stimuli was predominant in area V6 along the parieto-occipital sulcus. Finally, at 350 ms (100 ms after the motion offset) brain activity was visible again in area V1. For fast motion stimuli, the spatio-temporal brain pattern was similar, except that the first activity was detected at 70 ms in area MT+. Comparing functional magnetic resonance data for slow vs. fast motion, we found signs of slow-fast motion stimulus topography along the posterior brain in at least three cortical regions (MT+, V3A and LOR)

Charles Bonnet Syndrome:Evidence for a Generative Model in the Cortex?

Several theories propose that the cortex implements an internal model to explain, predict, and learn about sensory data, but the nature of this model is unclear. One condition that could be highly informative here is Charles Bonnet syndrome (CBS), where loss of vision leads to complex, vivid visual hallucinations of objects, people, and whole scenes. CBS could be taken as indication that there is a generative model in the brain, specifically one that can synthesise rich, consistent visual representations even in the absence of actual visual input. The processes that lead to CBS are poorly understood. Here, we argue that a model recently introduced in machine learning, the deep Boltzmann machine (DBM), could capture the relevant aspects of (hypothetical) generative processing in the cortex. The DBM carries both the semantics of a probabilistic generative model and of a neural network. The latter allows us to model a concrete neural mechanism that could underlie CBS, namely, homeostatic regulation of neuronal activity. We show that homeostatic plasticity could serve to make the learnt internal model robust against e.g. degradation of sensory input, but overcompensate in the case of CBS, leading to hallucinations. We demonstrate how a wide range of features of CBS can be explained in the model and suggest a potential role for the neuromodulator acetylcholine. This work constitutes the first concrete computational model of CBS and the first application of the DBM as a model in computational neuroscience. Our results lend further credence to the hypothesis of a generative model in the brain