Risk factors of postoperative complications after radical cystectomy with continent or conduit urinary diversion in Armenia

To estimate the surgical volume and the incidence of in-hospital complications of RC in Armenia from 2005 to 2012, and to investigate potential risk factors of complications. The study utilized a retrospective chart review in a cohort of patients who had RC followed by either continent or conduit urinary diversion in all hospitals of Armenia from 2005 to 2012. A detailed chart review was conducted abstracting information on baseline demographic and clinical characteristics, surgical procedural details, postoperative management and in-hospital complications. Multivariable logistic regression analysis was applied to estimate the independent risk factors for developing ‘any postoperative complication’. The total study sample included 273 patients (mean age = 58.5 years, 93.4 % men). Overall, 28.9 % (n = 79) of patients had at least one in-hospital complication. The hospital mortality rate was 4.8 % (n = 13). The most frequent types of complications were wound-related (10.3 %), gastrointestinal (9.2 %) and infectious (7.0 %). The ischemic heart disease (OR = 3.3, 95 % CI 1.5–7.4), perioperative transfusion (OR = 2.0, 1.1–3.6), glucose level [OR = 0.71 (0.63–0.95)], and hospital type (OR = 2.3, 95 % CI 1.1–4.7) were independent predictors of postoperative complications. The rate of RC complications in Armenia was similar to those observed in other countries. Future prospective studies should evaluate the effect of RC complications on long-term outcomes and costs in Armenia. Policy recommendations should address the issues regarding surgeon training and hospital volume to decrease the risk of RC complications

Improving visual sensitivity with subthreshold transcranial magnetic stimulation

We probed for improvement of visual sensitivity in human participants using transcranial magnetic stimulation (TMS). Stimulation of visual cortex can induce an illusory visual percept known as a phosphene. It is known that TMS, delivered at intensities above the threshold to induce phosphenes, impairs the detection of visual stimuli. We investigated how the detection of a simple visual stimulus is affected by TMS applied to visual cortex at or below the phosphene threshold. Participants performed the detection task while the contrast of the visual stimulus was varied from trial to trial according to an adaptive staircase procedure. Detection of the stimulus was enhanced when a single pulse of TMS was delivered to the contralateral visual cortex 100 or 120 ms after stimulus onset at intensities just below the phosphene threshold. No improvement in visual sensitivity was observed when TMS was applied to the visual cortex in the opposite hemisphere (ipsilateral to the visual stimulus). We conclude that TMS-induced neuronal activity can sum with stimulus-evoked activity to augment visual perception

Wired for Her Face? Male Attentional Bias for Female Faces

Under conditions of inattention or deficits in orienting attention, special classes of stimuli (e.g. faces, bodies) are more likely to be perceived than other stimuli. This suggests that biologically salient visual stimuli automatically recruit attention, even when they are task-irrelevant or ignored. Here we report results from a behavioral experiment with female and male subjects and two magnetoencephalography (MEG) experiments with male subjects only, in which we investigated attentional capture with face and hand stimuli. In both the behavioral and MEG experiments, subjects were required to count the number of gender-specific targets from either face or hand categories within a block of stimuli. In the behavioral experiment, we found that male subjects were significantly more accurate in response to female than male face target blocks. There was no corresponding effect found in response to hand target blocks. Female subjects did not show a gender-based difference in response to face or hand target blocks. MEG results indicated that the male subjects’ responses to face stimuli in primary visual cortex (V1) and the face-selective part of the fusiform gyrus (FG) were reduced when male face stimuli were not relevant to the task, whereas female faces maintained a strong response in these areas in both task-relevant and task-irrelevant conditions. These results suggest that within the male brain, female face stimuli are more resilient to suppression than male faces, once attention is drawn to the part of the visual field where the face appears

Accurate and Rapid Estimation of Phosphene Thresholds (REPT)

To calibrate the intensity of transcranial magnetic stimulation (TMS) at the occipital pole, the phosphene threshold is used as a measure of cortical excitability. The phosphene threshold (PT) refers to the intensity of magnetic stimulation that induces illusory flashes of light (phosphenes) on a proportion of trials. The existing PT estimation procedures lack the accuracy and mathematical rigour of modern threshold estimation methods. We present an improved and automatic procedure for estimating the PT which is based on the well-established Ψ Bayesian adaptive staircase approach. To validate the new procedure, we compared it with another commonly used procedure for estimating the PT. We found that our procedure is more accurate, reliable, and rapid when compared with an existing PT measurement procedure. The new procedure is implemented in Matlab and works automatically with the Magstim Rapid2 stimulator using a convenient graphical user interface. The Matlab program is freely available for download

Attentional capture of emotional static and dynamic hand gestures and faces : the effect of valence in a novel stroop-based paradigm

Task-irrelevant static emotional faces, pictures, and words are known to involuntarily receive or capture attention. Hand gestures, similar to faces, are biological stimuli that are often used to express emotion. This thesis examines attentional capture using static emotional hand gestures and dynamic emotional hand gestures and faces. The component processes model of emotion predicts that either positive or negative stimuli that are appraised as relevant will capture attention for further and deeper processing. Attentional capture and the resulting competition for resources to process emotional stimuli can cause interference with an ongoing implicit cognitive task. In a series of experiments, participants identified the gender of hand or face stimuli while neutral, positive, and negative valence of stimuli was manipulated. It was hypothesised that interference resulting from attentional capture would lead to greater gender identification accuracy for static neutral hand gestures than for static positive or negative hand gestures. Neutral and emotional static faces were used as comparison stimuli. The hypothesis was tested in six experiments using a novel Stroop-based experimental paradigm, specifically devised for future implementation in Magnetoencephalography (MEG) environment. Stimulus items were presented to the peripheral visual field in one of four quadrants for 100 ms (Experiments 1 and 4), 200 ms (Experiment 2), and 300 ms (Experiment 3) each, in trials of eight items with an inter-stimulus interval (ISI) that varied from 1800 to 2300 ms. As hypothesised, accuracy of identifying neutral hand gestures was significantly greater than accuracy of identifying gender of positive or negative hand gestures. The hypothesis was also supported for the case of negative faces but not for positive faces. The lack of an effect in response to positive faces is possibly due to the valence ambiguity of neutral faces capturing attention and interfering with gender identification. Experiment 5 examined attentional capture using emotional static hand gestures and faces presented to the central visual field. Only positive hand gestures and positive faces captured attention in this experiment. Experiment 6 tested two hypotheses using dynamic stimuli presented in the peripheral visual field for 300 ms. The hypothesis that greater gender identification accuracy would be found for neutral hand gestures/faces than for positive or negative hand gestures/faces was supported for positive hand gestures and negative faces, but not for negative hand gestures and positive faces. A second hypothesis was that greater attentional capture and resulting interference from dynamic stimuli would lead to poorer gender identification accuracy for emotional dynamic stimuli than for emotional static stimuli. The results of Experiment 6 did not support this hypothesis. These six experiments demonstrate that both static and dynamic positive and negative hand gestures and dynamic negative faces capture attention and interfere with an ongoing cognitive task when presented to the peripheral visual field. The experiments also demonstrate that static positive hand gestures and static positive faces capture attention when presented to the central visual field. Moreover, the novel Stroop-based experimental design appears to be a useful method for studying attentional capture using emotional pictorial stimuli and has already been implemented in a companion MEG experiment. A model explaining attentional capture and interference using emotional stimuli is proposed, based on the component processes model of emotion. In the model, the degree of attention recruited during the primary appraisal is proportional to the degree of interference with an implicit cognitive task

Reliability of TMS phosphene threshold estimation: toward a standardized protocol

Phosphenes induced by transcranial magnetic stimulation (TMS) are a subjectively described visual phenomenon employed in basic and clinical research as index of the excitability of retinotopically organized areas in the brain. Objective: Phosphene threshold estimation is a preliminary step in many TMS experiments in visual cognition for setting the appropriate level of TMS doses; however, the lack of a direct comparison of the available methods for phosphene threshold estimation leaves unsolved the reliability of those methods in setting TMS doses. The present work aims at fulfilling this gap. Methods: We compared the most common methods for phosphene threshold calculation, namely the Method of Constant Stimuli (MOCS), the Modified Binary Search (MOBS) and the Rapid Estimation of Phosphene Threshold (REPT). In two experiments we tested the reliability of PT estimation under each of the three methods, considering the day of administration, participants' expertise in phosphene perception and the sensitivity of each method to the initial values used for the threshold calculation. Results: We found that MOCS and REPT have comparable reliability when estimating phosphene thresholds, while MOBS estimations appear less stable. Conclusions: Based on our results, researchers and clinicians can estimate phosphene threshold according to MOCS or REPT equally reliably, depending on their specific investigation goals. We suggest several important factors for consideration when calculating phosphene thresholds and describe strategies to adopt in experimental procedures.M.R. was supported by Juan de la Cierva postdoctoral fellowship (JCI-2012-12335) from the Spanish Government

Brain-stimulation induced blindsight: unconscious vision or response bias?

A dissociation between visual awareness and visual discrimination is referred to as "blindsight". Blindsight results from loss of function of the primary visual cortex (V1) which can occur due to cerebrovascular accidents (i.e. stroke-related lesions). There are also numerous reports of similar, though reversible, effects on vision induced by transcranial Magnetic Stimulation (TMS) to early visual cortex. These effects point to V1 as the "gate" of visual awareness and have strong implications for understanding the neurological underpinnings of consciousness. It has been argued that evidence for the dissociation between awareness of, and responses to, visual stimuli can be a measurement artifact of the use of a high response criterion under yes-no measures of visual awareness when compared with the criterion free forced-choice responses. This difference between yes-no and forced-choice measures suggests that evidence for a dissociation may actually be normal near-threshold conscious vision. Here we describe three experiments that tested visual performance in normal subjects when their visual awareness was suppressed by applying TMS to the occipital pole. The nature of subjects' performance whilst undergoing occipital TMS was then verified by use of a psychophysical measure (d') that is independent of response criteria. This showed that there was no genuine dissociation in visual sensitivity measured by yes-no and forced-choice responses. These results highlight that evidence for visual sensitivity in the absence of awareness must be analysed using a bias-free psychophysical measure, such as d', In order to confirm whether or not visual performance is truly unconscious

Reliability of TMS phosphene threshold estimation: toward a standardized protocol

Background: Phosphenes induced by transcranial magnetic stimulation (TMS) are a subjectively described visual phenomenon employed in basic and clinical research as index of the excitability of retinotopically organized areas in the brain. Objective: Phosphene threshold estimation is a preliminary step in many TMS experiments in visual cognition for setting the appropriate level of TMS doses; however, the lack of a direct comparison of the available methods for phosphene threshold estimation leaves unsolved the reliability of those methods in setting TMS doses. The present work aims at fulfilling this gap. Methods: We compared the most common methods for phosphene threshold calculation, namely the Method of Constant Stimuli (MOCS), the Modified Binary Search (MOBS) and the Rapid Estimation of Phosphene Threshold (REPT). In two experiments we tested the reliability of PT estimation under each of the three methods, considering the day of administration, participants' expertise in phosphene perception and the sensitivity of each method to the initial values used for the threshold calculation. Results: We found that MOCS and REPT have comparable reliability when estimating phosphene thresholds, while MOBS estimations appear less stable. Conclusions: Based on our results, researchers and clinicians can estimate phosphene threshold according to MOCS or REPT equally reliably, depending on their specific investigation goals. We suggest several important factors for consideration when calculating phosphene thresholds and describe strategies to adopt in experimental procedures.M.R. was supported by Juan de la Cierva postdoctoral fellowship (JCI-2012-12335) from the Spanish Government

Risk factors of postoperative complications after radical cystectomy with continent or conduit urinary diversion in Armenia

Abstract To estimate the surgical volume and the incidence of in-hospital complications of RC in Armenia from 2005 to 2012, and to investigate potential risk factors of complications. The study utilized a retrospective chart review in a cohort of patients who had RC followed by either continent or conduit urinary diversion in all hospitals of Armenia from 2005 to 2012. A detailed chart review was conducted abstracting information on baseline demographic and clinical characteristics, surgical procedural details, postoperative management and in-hospital complications. Multivariable logistic regression analysis was applied to estimate the independent risk factors for developing ‘any postoperative complication’. The total study sample included 273 patients (mean age = 58.5 years, 93.4 % men). Overall, 28.9 % (n = 79) of patients had at least one in-hospital complication. The hospital mortality rate was 4.8 % (n = 13). The most frequent types of complications were wound-related (10.3 %), gastrointestinal (9.2 %) and infectious (7.0 %). The ischemic heart disease (OR = 3.3, 95 % CI 1.5–7.4), perioperative transfusion (OR = 2.0, 1.1–3.6), glucose level [OR = 0.71 (0.63–0.95)], and hospital type (OR = 2.3, 95 % CI 1.1–4.7) were independent predictors of postoperative complications. The rate of RC complications in Armenia was similar to those observed in other countries. Future prospective studies should evaluate the effect of RC complications on long-term outcomes and costs in Armenia. Policy recommendations should address the issues regarding surgeon training and hospital volume to decrease the risk of RC complications

The timing of face selectivity and attentional modulation in visual processing

Despite the complete imprint of a visual scene on the retina, the brain selects particular items for further processing. However, there is considerable debate about when and where the first attentional effects take hold in the cortex. We examined the timing of face specificity and attentional influences in the primary/secondary visual cortex (V1/V2) and in the fusiform gyrus (FG) in two experiments using magnetoencephalography (MEG). In experiment 1, using a passive viewing task, we identified three components in response to "Face," "Hand," and "Shoe" stimuli bilaterally in the FG: MFG100, MFG170, and MFG200-all showing a stronger preference for faces. The timing of these three activations of the FG is consistent with earlier studies claiming distinct stages of processing of visual stimuli in the first 300 ms. In experiment 2, subjects performed a gender-discrimination task on either faces or hands, drawing attention to only one of the two object categories. In addition to the previously identified three components in FG, here we found object-selective attentional enhancement first appearing in V1/V2 at around 170 ms, and then in FG at around 200 ms, i.e. concurrent with the third component. No attentional effects were evident on the first or second magnetoencephalography components. These findings may indicate that the visual input for an object is first encoded and matched to an attended "cue" object held in mind. When the attended and encoded objects match, a third stage involving attentive processing is enhanced