Perceptual organization and visual search processes during target detection task performance in schizophrenia, as revealed by fMRI

Background

Past studies of perceptual organization in schizophrenia have demonstrated impairments binding fragmented stimulus components into unified representations. ERP and fMRI data indicate that even under conditions of adequate behavioral task performance, significant and meaningful changes in cortical and subcortical activation are present. Here, we examined, using fMRI, activation differences on a visual task wherein feature grouping was a precursor to the formation of distinct groups in the service of target location and identification.

Method

Fourteen schizophrenia patients and 16 healthy controls completed a target detection task with 2 conditions: one in which target-distractor grouping facilitates detection (the Isolated condition) and one in which it hinders detection (the Embedded condition). Stimuli were blocked by condition. Accuracy and RT data were obtained in addition to fMRI data.

Results

Patients and controls did not differ significantly in accuracy or RT in either condition. Within this context, controls demonstrated greater recruitment of brain regions involved in visual-spatial processing, and the groups differed in activity in areas known to support visual search, visual analysis, decision making and response generation.

Conclusion

These findings are consistent with past data indicating reduced processing of stimulus organization, and the subsequent use of inefficient visual search strategies, even under conditions when behavioral performance is at a high level and matches that of healthy controls.     

Un tremblement d’attitude révélant une maladie de Huntington

Introduction

Initial manifestations of Huntington's disease (HD) are varied and chorea is not always the first motor symptom.

Case report

We report the case of a 44-year-old woman, with a family history of HD, who presented isolated head and upper limbs tremor for 4 years. Genetic testing confirmed the diagnosis of HD and no cause of secondary postural tremor was found. Propanolol was introduced with success.

Conclusion

This kind of presentation is unusual and has mostly been reported in the juvenile form of HD.     

The effect of decreased visual acuity on control of posture

Objectives

The goal of this study was to investigate the effect of visual acuity on the anticipatory (APAs) and compensatory (CPAs) components of postural control.

Methods

Ten individuals participated in the experiments involving perturbations induced by a pendulum while their visual acuity was altered. The different visual acuity conditions were no glasses, blurred vision induced by wearing glasses with positive or negative lenses, and no vision. EMG activity of trunk and leg muscles and ground reaction forces were recorded during the typical anticipatory and compensatory periods.

Results

In the no vision condition the subjects did not generate APAs, which resulted in the largest displacements of the center of pressure (COP) after the perturbation (p < 0.01). In all other visual conditions APAs were present showing a distal to proximal order of muscle activation. The subjects wearing positive glasses showed earlier and larger anticipatory EMGs than subjects wearing negative glasses or no glasses at all.

Conclusions

The study outcome revealed that changes in visual acuity induced by wearing differently powered eye glasses alter the generation APAs and as a consequence, affect the compensatory components of postural control.

Significance

The observed changes in APAs and CPAs in conditions with blurred vision induced by positive and negative glasses suggest the importance of using glasses with an appropriate power. This outcome should be taken into consideration in balance rehabilitation of individuals wearing glasses.     

Differences in audiovisual integration, as measured by McGurk phenomenon, among adult and adolescent patients with schizophrenia and age-matched healthy control groups

Background

McGurk effect is a perceptual phenomenon that reflects the integration of visual and auditory information during speech perception. Using McGurk effect, the authors examined the audiovisual integration in adolescents and adults with schizophrenia as compared with healthy volunteers.

Sampling and Methods

Thirty hospitalized patients with schizophrenia and 20 age-matched healthy controls were examined for perception of ambiguous audiovisual stimuli.

Results

The mean of McGurk-positive responses was significantly lower in adolescent patients with schizophrenia than in healthy adolescents (3.13 ± 2.09 vs 5.60 ± 0.7, respectively; t = 3.591, P = .001). The McGurk-positive responses were significantly higher in healthy adolescents than in healthy adults (5.60 ± 0.7 vs 3.60 ± 1.43, respectively; t = 3.974, P = .001). No significant difference in McGurk-positive responses was found between adults with schizophrenia and healthy adult individuals, or between adolescent and adults with schizophrenia. Duration of schizophrenia, soft sign status, type of symptoms, and type of antipsychotic medication showed no influence on the audiovisual integration ability.

Conclusions

(I) Age effect: It seems that the audiovisual integrative function increases from childhood to adolescence and decreases from adolescence to early adulthood. (II) Schizophrenia: Audiovisual integration is poor in adolescent and adult patients with schizophrenia. Thus, it seems that schizophrenia is associated with early and persistent impairment in the development of the audiovisual integration ability. (III) Reliance on visual cue stimuli: Although several previous investigations concluded that patients with schizophrenia rely less on visual cue stimuli than healthy controls, our data suggest that this is true only for specific types of visual cue stimuli.     

Hepatitis C virus seropositivity and TNF superfamily receptors: sCD40, sFas - the new putative determinants of endothelial dysfunction in haemodialysis patients

Introduction

Hepatitis C virus (HCV) infection occurs frequently among haemodialysis (HD) patients and increases the risk of atherosclerosis. CD40 and Fas belong to tumor necrosis factor receptor (TNFR) superfamily, which play a role in hepatocyte apoptosis during HCV infection. The aim of the present study was to determine whether anti-HCV-seropositivity constitutes an additional risk factor for endothelial dysfunction in HD patients, and whether sCD40 and sFas could be associated with endothelial dysfunction.

Materials and methods

A total of 69 stable HD patients and 28 healthy controls were included in this study. Patients were divided into anti-HCV-seropositive (HCV[+], n = 18) and anti-HCV- seronegative (HCV[-], n = 51). The plasma endothelial markers: von Willebrand factor (vWF), thrombomodulin (TM), soluble adhesion molecules - sICAM-1, sVCAM-1 and TNFRs were assayed.

Results

HD patients showed a significant increase in the levels of TM, sVCAM-1, sCD40 and sFas compared to controls, and all these parameters were higher in HCV[+] than in HCV[-] patients. sICAM-1 concentrations were higher in the HCV[+] group compared to controls and the HCV[-] group. vWF levels were higher in HD patients than in the controls, however there was no difference in this parameter between HCV[+] and HCV[-] group. The anti-HCV-seropositivity and sCD40 were determined as an independent variables of TM, whereas anti-HCV-seropositivity and sFas were found as independent determinants of sICAM-1 and sVCAM-1 levels.

Conclusions

This study showed that anti-HCV-seropositivity and TNF superfamily receptors: sCD40 and sFas are the novel determinants of the increased plasma endothelial dysfunction markers in haemodialysis patients.     

Illness representations are associated with fluid nonadherence among hemodialysis patients

Objective

Patients with end-stage renal disease are required to limit fluid and salt intake. We examined illness representations [common-sense model (CSM)] among a sample of hemodialysis (HD) patients, investigating whether fluid-adherent patients held illness representations different from those of nonadherent patients. We also explored the utility of illness perceptions in predicting fluid nonadherence after controlling for clinical parameters, including residual renal function (KRU).

Methods

Illness perceptions were assessed [Revised Illness Perception Questionnaire (IPQ-R)] in 99 HD patients. Clinical parameters were collected and averaged over a 3-month period prior to and including the month of IPQ-R assessment. Depression scores, functional status, and comorbidity were also collected. Fluid nonadherence was defined using interdialytic weight gain (IDWG) and dry weight (ideal weight). Patients in the upper quartile of percent weight gain were defined as nonadherent (IDWG≥3.21% dry weight).

Results

Nonadherent patients had timeline perceptions significantly lower than those of adherent patients. Logistic regression models were computed in order to identify predictors of fluid nonadherence. After several demographic and clinical variables, including age, gender, and KRU, had been controlled for, lower consequence perceptions predicted nonadherence.

Conclusions

Illness representations appear to predict fluid nonadherence among HD patients. Extending the CSM to investigate specific perceptions surrounding treatment behaviors may be useful and merits attention in this setting.     

In vitro study of the anticoagulant effects of edoxaban and its effect on thrombin generation in comparison to fondaparinux

Introduction

Edoxaban, an oral direct factor Xa (FXa) inhibitor, is in Phase III development for prevention and treatment of thromboembolic disorders. Fondaparinux is an approved indirect FXa inhibitor. This study compared the effects of edoxaban and fondaparinux on thrombin generation (TG) using the calibrated automated thrombogram (CAT). Secondary objectives included evaluation of edoxaban and inhibition of coagulation parameters (prothrombin time [PT], activated partial thromboplastin time [aPTT]), anti-FXa activity and clotting times.

Materials and Methods

Pooled citrated platelet-poor plasma from healthy subjects was spiked with edoxaban (0.02-3.65 μM) or fondaparinux (0.15-1.18 μM). Parameters of TG were calculated using Thrombinoscope™ software. PT ratios and aPTT were measured in the presence of different thromboplastin reagents. Exogenous anti-FXa was measured using Rotachrom HBPM (Stago) and a specific assay developed for direct FXa inhibitors (Hyphen BioMed).

Results

Edoxaban exhibited a 3-fold greater concentration-dependent effect than fondaparinux across TG parameters (except endogenous thrombin potential). Edoxaban also produced a concentration-dependent prolongation of PT ratio and aPTT. The magnitude of concentration-dependent increase was related to thromboplastin reagent. In contrast to edoxaban, fondaparinux was inactive on these clotting tests. Linear correlations were observed between plasma concentration of edoxaban and anti-FXa activity and results of clotting time assays.

Conclusions

TG evaluation by the CAT method, coagulation tests, and anti-FXa and clotting assays demonstrated concentration-dependent effects of edoxaban. The PT and aPTT prolongation are reagent dependent; correction of PT ratio by international normalized ratio does not reduce variability in response. The greater effect of edoxaban vs. fondaparinux may be related to the broader activity of direct FXa inhibitors compared with indirect FXa inhibitors.     

An evaluation of illness, treatment perceptions, and depression in hospital- vs. home-based dialysis modalities

Objectives

Depressive symptoms are common among patients with end-stage renal disease (ESRD). In order to better understand what factors influence these symptoms, we examined the impact of illness and treatment cognitions on emotional adjustment and the influence of dialysis modality (hospital- vs. home-based dialysis) on this relationship.

Methods

A cross-sectional sample of 145 ESRD patients on four different dialysis modalities [hospital hemodialysis (HD), n=52; home HD, n=25; continuous ambulatory peritoneal dialysis (CAPD), n=45; automated PD (APD), n=23] completed the Illness Perceptions Questionnaire, the Illness Effects Questionnaire, the Treatment Effects Questionnaire, and the Beck Depression Inventory. Measures of ESRD severity/comorbidity and biochemistry were also collected.

Results

Perceptions of treatment disruptiveness and attributions to poor medical care were significantly greater in CAPD. Home-based treatments were not found to confer an emotional adjustment advantage compared to hospital HD. There were marked differences across home-based modalities, with n=22 (44.4%) CAPD meeting the clinical cutoff of depression (≧16) vs. n=6 (26.1%) in APD and n=2 (8%) in home HD. After adjusting for case-mix differences, the mean levels of depressed mood remained significantly higher in CAPD patients compared to APD and home HD (P<.01). On multiple regression analysis, 42.5% of the variance in depression was explained by the End-Stage Renal Severity Index, dialysis modality, perceived treatment disruptiveness, and beliefs about illness consequences and the extent to which the illness could be controlled.

Conclusion

The findings suggest that the benefits of self-care are not uniformly manifested across dialysis modalities and that patients' cognitions are important determinants of depressed mood with implications for future research and clinical practice.     

Visuo-motor integration in humans: Cortical patterns of response lateralisation and functional connectivity

Purpose

We assessed response and functional connectivity patterns of different parts of the visual and motor cortices during visuo-motor integration with particular focus on the intraparietal sulcus (IPS).

Methods

Brain activity was measured during a visuo-motor task in 14 subjects using event-related fMRI. During central fixation, a blue or red target embedded in an array of grey distractors was presented for 250 ms in either the left or right visual hemifield. After a delay, the subjects were prompted to press the upper or lower response button for targets in the upper and lower hemifield with the left or right thumb for blue and red targets, respectively. The fMRI responses were evaluated for different regions of interests (ROIs), and the functional connectivity of the IPS subregions with these ROIs was quantified.

Results

In an anterior IPS region and a region in the anterior premotor cortex, presumably the frontal eye fields (FEF), visually driven responses were dominant contralateral to both visual stimulus and effector. Thus, the anterior IPS combines, in contrast to the posterior IPS and the occipital cortex, response properties of cortex activated by visual input and by motor output. Further, functional connectivity with the motor areas was stronger for the anterior than for the posterior IPS regions.

Discussion

Anterior IPS and FEF appear to be of major relevance for relating visual and effector information during visuo-motor integration. Patient studies with the devised paradigm are expected to uncover the impact of pathophysiologies and plasticity on the observed cortical lateralisation patterns.     

Cognitive behavioral therapy versus paroxetine in the treatment of hypochondriasis: An 18-month naturalistic follow-up

Background

The present maintenance study investigated whether the reduction in hypochondriacal complaints after initial treatment with CBT or paroxetine sustained during a follow-up period and whether psychiatric severity at pretest predicted the course of hypochondriacal symptoms.

Method

A naturalistic follow-up period of 18 months after a 16-week RCT consisting of 33 patients initially allocated to a CBT condition and 29 patients to a paroxetine condition. The main outcome measure was the Whiteley Index.

Results

The initial treatment effect of CBT and paroxetine sustained during the follow-up period. No significant differences between CBT and paroxetine were found. Treatment course could not be predicted by psychiatric comorbidity.

Conclusion

CBT and paroxetine are both effective treatments for hypochondriasis in the long term.     

Chronic viral hepatitis C, oxidative stress and the coagulation/fibrinolysis system in haemodialysis patients

Introduction

The aim of the present study was to establish whether the presence of chronic viral hepatitis (PVH) could be implicated in the elevation of oxidative stress (SOX) and haemostasis system in haemodialysis (HD) patients.

Matherials and methods

In HD patients with and without PVH and in controls we compared the markers of: coagulation pathway- tissue factor (TF) and its inhibitor (TFPI), prothrombin fragment F _1 + 2 (F _1 + 2); fibrinolysis: tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA) and its soluble receptor (suPAR), plasminogen activator inhibitor 1 (PAI-1), plasmin/antiplasmin complexes (PAP); and a marker of SOX - Cu/Zn superoxide dismutase (Cu/Zn SOD) levels.

Results

Patients, particularly those with PVH, showed a significant increase in the markers of the coagulation, fibrinolysis and oxidative status as compared to controls. All parameters of coagulation/fibrinolysis system were directly associated with the PVH and Cu/Zn SOD levels, and there was a relationship between the PVH and Cu/Zn SOD levels. Multivariable analysis showed that PVH and increased SOX were identified as independent variables significantly associated with the disturbances of coagulation/fibrinolysis system in these patients.

Conclusions

We concluded that PVH is a novel determinant of the increased oxidative stress as well as the disturbances of coagulation/fibrinolysis system in haemodialysis patients.     

Mobile phone emission modulates event-related desynchronization of alpha rhythms and cognitive-motor performance in healthy humans

Objectives

It has been shown that electromagnetic fields of Global System for Mobile Communications phone (GSM-EMFs) affect human brain rhythms ( [Vecchio et al., 2007] and [Vecchio et al., 2010]), but it is not yet clear whether these effects are related to alterations of cognitive functions.

Methods

Eleven healthy adults underwent two electroencephalographic (EEG) sessions separated by 1 week, following a cross-over, placebo-controlled, double-blind paradigm. In both sessions, they performed a visual go/no-go task before real exposure to GSM-EMFs or after a sham condition with no EMF exposure. In the GSM real session, temporal cortex was continuously exposed to GSM-EMFs for 45 min. In the sham session, the subjects were not aware that the EMFs had been switched off for the duration of the experiment. In the go/no-go task, a central fixation stimulus was followed by a green (50% of probability) or red visual stimulus. Subjects had to press the mouse button after the green stimuli (go trials). With reference to a baseline period, power decrease of low- (about 8-10 Hz) and high-frequency (about 10-12 Hz) alpha rhythms indexed the cortical activity.

Results

It was found less power decrease of widely distributed high-frequency alpha rhythms and faster reaction time to go stimuli in the post- than pre-exposure period of the GSM session. No effect was found in the sham session.

Conclusions

These results suggest that the peak amplitude of alpha ERD and the reaction time to the go stimuli are modulated by the effect of the GSM-EMFs on the cortical activity.

Significance

Exposure to GSM-EMFs for 45 min may enhance human cortical neural efficiency and simple cognitive-motor processes in healthy adults.     

Microsurgical management of tuberculum sellae meningiomas by the frontolateral approach: surgical technique and visual outcome

Objectives

The aim of this study was to evaluate visual outcome in patients with tuberculum sellae meningioma (TSM) treated microsurgically using the frontolateral or fronto-orbital approach and optic canal unroofing to resect tumor involvement of the optic canal.

Methods

Data from 67 patients with TSMs who underwent microsurgical treatment by a frontolateral approach (n = 44) or fronto-orbital approach (n = 23) between January 2002 and December 2008 were retrospectively collected and analyzed. Change in visual function was evaluated as the main outcome.

Results

Total tumor resection was achieved in 62 of 67 cases (92.4%). Postoperative, visual acuity was improved in 87 eyes (64.9%) and unchanged in 39 eyes (29.1%), and the optic nerve was therefore preserved in 126 of 134 eyes (94.0%). Visual field deficits were improved or stable in 65 eyes, no patient experienced worsening of vision in both eyes. There was no mortality in our series.

Conclusions

The frontolateral approach with microsurgical dissection of the Sylvian fissure provides quick access to TSMs, which can be resected safely and totally. Visual function is improved and neurological and ophthalmological morbidity is minimal. Optic nerve decompression by intradural clinoidectomy and optic canal unroofing is likely to increase the rate of reducing or eliminating preoperative visual symptoms.     

Effects of placebo interventions on gastric motility and general autonomic activity

Objective

The study aimed to investigate placebo effects on gastric motility and to examine possible autonomic mediating mechanisms.

Methods

Eighteen healthy volunteers received a placebo pill on three occasions together with the verbal suggestion that it would stimulate, relax, or not affect gastric activity. Electrogastrogram, electrocardiogram, and electrodermal activity recordings were conducted for 30 min prior to and following intervention.

Results

Dominant frequency of the gastric slow wave decreased in the stimulant condition, and increased in the relaxant condition, the difference among conditions being significant. No differential effects of the interventions on cardiac interbeat intervals, heart rate variability, and skin conductance levels were observed.

Conclusion

Stomach relaxant and stimulant placebo interventions modulated gastric motility independently from changes in general autonomic activity.     

Direct and indirect effects of the temperament and character on alexithymia: a pathway analysis with mood and anxiety

Objective

We aimed to assess the pathway from personality to alexithymia through mood and anxiety as mediators.

Method

Three hundred thirty-four subjects (130 male), whose psychiatric health was verified by Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Axis I disorders, completed the Toronto Alexithymia Scale-20 (TAS-20), the Temperament and Character Inventory, the State-Trait Anxiety Inventory (STAI), and the Center for Epidemiological Studies-Depression scale (CES-D). The schematic models for the pathway analysis from Temperament and Character Inventory (TCI) to TAS-20 scores were made.

Results

Low reward dependence (RD), low self-directedness (S-D), and high cooperativeness (CO) had paths to TAS-20 total (P = .000, P = .000, and P = .042, respectively). S-D had also an indirect path via STAI-state to TAS total. On TAS-20 factor 1, low RD, low S-D, and high self-transcendence (ST) had direct effects (P = .004, P = .000, and P = .000, respectively). S-D had also an indirect path via STAI-state and (CES-D) on TAS-20 factor 1. On TAS factor 2, low novelty seeking (NS), high harm avoidance (HA), low RD, low S-D, and high cooperativeness (CO) had direct effects (P = .005, P = .011, P = .000, P = .000, and P = .004, respectively). On TAS-20 factor 3, low RD and S-D had direct effects (P = .002 and P = .000, respectively).

Conclusion

Current results suggest that although alexithymia is affected by the personality, state-dependent mood and anxiety may mediate the relationship between alexithymia and personality.     

Static and pulsatile intracranial pressure in idiopathic intracranial hypertension

Objective

The aim of this observational study was to characterize the static and pulsatile intracranial pressure (ICP) in conservatively (medically) treated idiopathic intracranial hypertension (IIH) patients in need of shunt surgery, and also in patients with chronic daily headache (CDH) without visual disturbances.

Methods

The material includes 14 IIH patients and 7 CDH patients in whom ICP was monitored continuously over-night. Static ICP was characterized by mean ICP, pulsatile ICP was characterized by the wave amplitude, rise time, and rise time coefficient.

Results

In the IIH group all 14 had headache and visual disturbances. Mean ICP was high (>15 mmHg) in only 7 patients (50%), while mean ICP wave amplitude was high (≥4 mmHg) in all 14 (100%). All IIH patients were shunted and improved clinically thereafter (i.e., relief from visual disturbances and/or headache). None in the CDH group had high mean ICP or mean ICP wave amplitude, and none were shunted.

Conclusions

In this cohort of 14 conservatively treated IIH patients with lasting and shunt-responsive headache and visual disturbances, the mean ICP wave amplitude was elevated (≥4 mmHg) in all patients despite normal mean ICP (<15 mmHg) in 7 patients (all but one on medication). Therefore, the pulsatile ICP may be more relevant than the static ICP in the diagnostic setting for patients with IIH. Further prospective standardized approaches are warranted.     

Contextual control of audiovisual integration in low‐level sensory cortices

Potential sources of multisensory influences on low‐level sensory cortices include direct projections from sensory cortices of different modalities, as well as more indirect feedback inputs from higher order multisensory cortical regions. These multiple architectures may be functionally complementary, but the exact roles and inter‐relationships of the circuits are unknown. Using a fully balanced context manipulation, we tested the hypotheses that: (1) feedforward and lateral pathways subserve speed functions, such as detecting peripheral stimuli. Multisensory integration effects in this context are predicted in peripheral fields of low‐level sensory cortices. (2) Slower feedback pathways underpin accuracy functions, such as object discrimination. Integration effects in this context are predicted in higher‐order association cortices and central/foveal fields of low‐level sensory cortex. We used functional magnetic resonance imaging to compare the effects of central versus peripheral stimulation on audiovisual integration, while varying speed and accuracy requirements for behavioral responses. We found that interactions of task demands and stimulus eccentricity in low‐level sensory cortices are more complex than would be predicted by a simple dichotomy such as our hypothesized peripheral/speed and foveal/accuracy functions. Additionally, our findings point to individual differences in integration that may be related to skills and strategy. Overall, our findings suggest that instead of using fixed, specialized pathways, the exact circuits and mechanisms that are used for low‐level multisensory integration are much more flexible and contingent upon both individual and contextual factors than previously assumed. Hum Brain Mapp 35:2394–2411, 2014. © 2013 Wiley Periodicals, Inc .     

Cognitive deficits in patients with chronic fatigue syndrome compared to those with major depressive disorder and healthy controls

Object

Chronic fatigue syndrome (CFS) patients report usually cognitive complaints. They also have frequently comorbid depression that can be considered a possible explanation for their cognitive dysfunction. We evaluated the cognitive performance of patients with CFS in comparison with a control group of healthy volunteers and a group of patients with MDD.

Patients and methods

Twenty-five patients with CFS, 25 patients with major depressive disorder (MDD), and 25 healthy control subjects were given standardized tests of attention, working memory, and verbal and visual episodic memory, and were also tested for effects related to lack of effort/simulation, suggestibility, and fatigue.

Results

Patients with CFS had slower phasic alertness, and also had impaired working, visual and verbal episodic memory compared to controls. They were, however, no more sensitive than the other groups to suggestibility or to fatigue induced during the cognitive session. Cognitive impairments in MDD patients were strongly associated with depression and subjective fatigue; in patients with CFS, there was a weaker correlation between cognition and depression (and no correlation with fatigue).

Conclusions

This study confirms the presence of an objective impairment in attention and memory in patients with CFS but with good mobilization of effort and without exaggerated suggestibility.     

Different effects of enoxaparin and unfractionated heparin on some thrombogenesis markers during hemodialysis: a cross-over study

Background

Unfractionated heparin (UFH) and low molecular weight heparin constitute fundamental anticoagulants during hemodialysis (HD). We aimed to investigate the effect of UFH and enoxaparin on plasma levels of prothrombin fragment 1 + 2 (PF 1 + 2) and thrombin/antithrombin complex (TAT) as markers of intravascular thrombogenesis during HD.

Methods

We enrolled 22 chronic HD patients, who were randomly assigned to either iv enoxaparin (n = 11) or UFH (n = 11) anticoagulation, and followed prospectively for 12 weeks before crossing over to the alternate therapy for further 12 weeks. Plasma levels of PF 1 + 2 and TAT were measured by immunoassay at the start, at 10 and 180 min of HD session after each period of evaluation.

Results

The baseline PF 1 + 2 and TAT levels were comparable under enoxaparin and UFH treatment. PF 1 + 2 significantly decreased during both UFH (χ² ANOVA = 9.82, P = 0.007) and enoxaparin (χ² ANOVA = 29.40, P < 10^− 6) anticoagulated HD, while over-HD TAT levels changes differed depending on the type of heparin. The switch from enoxaparin to UFH treatment was connected with a significantly higher PF 1 + 2 after 10 and 180 min as well as higher TAT concentration after 180 min of HD. Only during enoxaparin anticoagulated HD 34% PF 1 + 2 decrease and TAT levels after 180 min of HD was closely associated with heparin dosage.

Conclusion

Single bolus of enoxaparin ensures efficient and convenient anti-thrombotic protection during HD procedure. Enoxaparin mean dose of 0.67 mg/kg, which is generally lower than manufacturer's instructions, can be recommended for over-dialytic regular use.     

Interictal high frequency oscillations (HFOs) in patients with focal epilepsy and normal MRI

Objective

We aim to analysis the relationship between HFOs-generating regions and the seizure onset zone (SOZ) in epileptic patients without a visible lesion on MRI.

Methods

Intracerebral EEGs were recorded in 17 patients with intractable focal seizures and normal MRIs. The rates of interictal HFOs and spikes inside and outside the SOZ were analyzed as well as the specificity, sensitivity and accuracy of HFOs and spikes to determine the SOZ.

Results

The mean rate of spikes, ripples and fast ripples (FR) was higher in the SOZ than in the non-SOZ channels. In regard to the identification of the SOZ the sensitivity was 91% for spikes, 91% for ripples and 66% for FR, the specificity was 30% for spikes, 42% for ripples and 80% for FR, and the accuracy was 44% for spikes, 54% for ripples and 76% for FR.

Conclusions

The rates of spikes and HFOs were higher inside than outside the SOZ. However, HFOs are also more specific and accurate than spikes to delineate the SOZ.

Significance

Analysis of interictal HFOs during 5-10 min of sleep recording is a good tool to localize the SOZ in patients with epilepsy and normal MRI, and could potentially reduce the duration of chronic intracerebral EEG recordings.