Κυριακή, 20 Ιανουαρίου 2019

Early demise of twins in a cohort of stillbirths and second trimester miscarriages

Twins, particularly monochorionic (MC) pairs, are at increased risk for fetal death. Whereas previous work has sought to understand the mechanisms for this increased mortality, most studies analyze viable twin pregnancies or liveborn twin cohorts. In the Wisconsin Stillbirth Service Program cohort of 3,137 stillbirths and second trimester miscarriages, we identified 175 twin pregnancies for a twinning rate of 56/1,000, which is approximately double the general population. The excess of twins among miscarriages and stillbirths was attributable to MC pairs as the incidence of dizygotic (DZ) twinning was not increased compared to livebirth data. The leading causes of fetal demise among twins were twin–twin transfusion, acardia, and twin–twin disruption. Maternal causes of death, primarily premature rupture of membranes, were moderately increased in both MC and DZ twins relative to singletons. Although deceased twins were smaller than expected for viable twins at comparable gestational ages, placenta weights of deceased MC pairs were large compared to combined fetal weight, which indicates placental inefficiency likely due to vascular shunting. Co‐twin survival was much lower for MC than for DZ pairs. Therefore, earlier diagnosis and treatment of MC twinning complications may decrease prenatal mortality.



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Next Steps for Measures of Physical Activity During Pregnancy



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Free Cortisol Is a More Accurate Marker for Adrenal Function and Does Not Correlate with Renal Function in Cirrhosis

Abstract

Background

The accuracy of diagnosis and clinical implications of the hepatoadrenal syndrome, as currently diagnosed using total cortisol, remain to be validated.

Aim

The aim of this study was to assess adrenal function using free cortisol in stable cirrhosis and study the potential implications of any abnormalities for renal and/or cardiac function.

Methods

Sixty-one stable consecutively enrolled patients with cirrhosis underwent assessment of adrenal function using the low-dose short Synacthen test, renal function by 51Cr-EDTA glomerular filtration rate (GFR), and cardiac function by two-dimensional echocardiography.

Results

Eleven patients (18%) had total peak cortisol (PC) < 500 nmol/L, but no patient had free PC < 33 nmol/L indicating that diagnosis of AI using total cortisol is not confirmed using free cortisol. Free cortisol did not correlate with GFR or parameters of cardiac function. Patients with higher Child–Pugh class had progressively lower free cortisol. Patients with low GFR < 60 mL/min (N = 22) had more frequently grade II–III diastolic dysfunction (66.7% vs. 17.6%; p = 0.005) and had higher Child–Pugh and MELD score compared to those with normal GFR.

Conclusions

Diagnosis of AI using total cortisol is not confirmed using free cortisol and is thus considered unreliable in cirrhosis. Free cortisol is not associated with renal or cardiac dysfunction. Lower free cortisol in more advanced stages of liver disease might be secondary to decreased synthesis due to lower cholesterol levels. Irrespective of free cortisol, parameters of cardiac dysfunction are associated with renal impairment supporting the cardio–renal hypothesis.



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Characteristics of Intestinal Myoelectrical and Motor Activities in Diet-Induced Obese Rats: Obesity and Motility

Abstract

Background

Gastrointestinal motility has been reported to be altered in obesity. However, it is unknown whether intestinal myoelectrical activity (IMA) is also changed in obesity.

Aims

The aim of this study was to characterize intestinal myoelectrical and motility activities in the fasting state, during feeding, and postprandial state after various test meals in diet-induced obese (DIO) rats in comparison with regular rats.

Methods

IMA was recorded in the fasting, feeding, and postprandial states in DIO and regular rats. Regular laboratory chow, high-fat solid food, and high-fat liquid food were used to test IMA responses to different meals.

Results

(1) The intestinal slow waves in the DIO rats were not different from those in normal rats in the fasting or postprandial state. Neither intestinal transit nor the number of intestinal contractions per minute was altered in DIO rats although gastric emptying was accelerated. (2) Both DIO rats and normal rats showed altered IMA during the first minute of feeding (cephalic stimulation). (3) The intestinal slow waves in both DIO rats and regular rats were impaired slightly but significantly after intake of a high-fat meal.

Conclusions

Our study demonstrates that intestinal myoelectrical activity is not altered in DIO rats and its postprandial responses to various meals are not altered either. High-fat meals induce intestinal dysrhythmia but do not have a chronic impact on intestinal slow waves in DIO rats.



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A 12-Week Maintenance Therapy with a New Prepared Viscous Budesonide in Pediatric Eosinophilic Esophagitis

Abstract

Background

A new prepared oral viscous budesonide (PVB) has been effective in inducing clinical and histological remission in pediatric eosinophilic esophagitis (EoE).

Aims

To evaluate the efficacy of a 12-week maintenance therapy on clinical, endoscopic, and histological remission using half of the dose used in the induction therapy.

Methods

We prospectively enrolled pediatric patients with active EoE. After 12 weeks of induction therapy with PVB (< 150 cm: 2 mg/day; ≥ 150 cm: 4 mg/day) patients received a maintenance dose of half of the dose used in the induction therapy (1 mg or 2 mg) for another 12 weeks. A 12-week follow-up was then performed in all patients after the end of therapy. Endoscopy was performed at weeks 0, 12, 24, and 36. Symptoms, endoscopy, and histology scores were also calculated. Serum cortisol was evaluated during the treatment period.

Results

We enrolled 20 children (15 males; median age 10 years; range 4–17). After the 12-week induction therapy 18 patients (90%) were in remission, with a significant decrease in the median peak of eosinophil count/HPF as well as a marked reduction in clinical, endoscopic, and histological scores (p < 0.01). At the end of the maintenance therapy (week 24), 17 patients (85%) were still in remission, while there were only 9 at week 36 (45%). No significant changes in cortisol levels were observed during the study period.

Conclusions

The 12-week maintenance treatment with the half the dose of PVB was effective in sustaining remission at week 24; however, no reduction in the rate of relapse after suspension of treatment occurred.



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Healthcare Providers Underestimate Patients’ Glucocorticoid Use in Crohn’s Disease

Abstract

Background

One of the therapy goals for Crohn's disease (CD) is glucocorticoid-free remission. Studies have shown care setting-specific variations in inflammatory bowel disease (IBD) management.

Aims

The principal objective of this study was to assess concordance between patient-reported and physician-reported outcomes in two different care settings (IBD centers and community practices).

Methods

Data of overall and long-term (≥ 3 months) glucocorticoid, immunosuppressant, and biologics use in participants ≥ 18 years old with a confirmed diagnosis of CD were collected. HCPs were grouped by IBD centers and community practices. Quality of life (using EuroQol 5D [EQ-5D]) and work/activity days lost were assessed. Agreement between patients' and HCPs' responses to survey questions was tested using kappa statistics.

Results

Data from 812 patients were examined. Significantly more patients versus HCPs reported oral glucocorticoid use (25.9% vs. 20.8%, κ = 0.735, P < 0.0001). Long-term use of oral glucocorticoids was similar for patients versus HCPs (67.7% vs. 63.8%, κ = 0.598, P = 0.53). Immunosuppressant use was 52.4% vs. 51.1% (κ = 0.784) and biologics use was 49.5% vs. 47.0% (κ = 0.909) for patients vs. HCPs. Patients and HCPs reported greater rates of symptom improvement with vs without biologic therapy (patients: 33.3% vs 16.8%; HCPs: 29.3% vs 13.5%, both P < 0.001). Patients with versus without routine follow-up were less likely to be treated with long-term glucocorticoid monotherapy (10.3% vs. 20.7%, P < 0.01) and had fewer lost work/activity days (5 vs. 8 days, P < 0.05).

Conclusions

Patients reported more oral glucocorticoid use than physicians thought. Routine follow-up and higher rates of biologic use are associated with improvement in disease symptoms and general health among patients with CD.



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Fragility of Life: Recurrent Intestinal Perforation Due to Vascular Ehlers–Danlos Syndrome



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Adherence to Two Large-Bore Intravenous Lines in Acute Gastrointestinal Bleeding Is Low

Abstract

Background

While the available literature recommends placement of two large-bore intravenous (2LBIV) lines in every patient presenting with acute GIB, the adherence and impact of this recommendation have never before been reported.

Aims

We designed a quality improvement project to assess whether the patients presenting to our institution with acute GIB have appropriate intravenous (IV) access or not.

Methods

We conducted a prospective, observational study, of all patients presenting to our emergency department with overt GIB over a 2-month period. Data analysis was performed, and based on the results, an intervention plan was developed and executed. Post-intervention data collection was done over a 3-month period. Our interventions included physician and nursing education, placing posters in the emergency department, and creation of an order set in the electronic medical record system.

Results

A total of 46 patients were in the pre-intervention group, and 71 patients were in the post-intervention group. The presence of 2LBIV lines in the pre-intervention group was only 19.5%, which improved to 36.6% in the post-intervention group (p = 0.049). Factors associated with placement of 2LBIV lines were being in the post-intervention group and admission to the intensive care unit.

Conclusion

The relatively simple and cost-effective intervention of placing 2LBIV lines is not often executed. We suggest that specific mention of 2LBIV placement in guidelines from national gastroenterology societies might improve compliance in this aspect.



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Expression of Demethylase Genes, FTO and ALKBH1 , Is Associated with Prognosis of Gastric Cancer

Abstract

Background

Reversible N6-methyladenosine (m6A) modifications in messenger RNAs can be categorized under the field of "RNA epigenetics." However, the potential role of m6A-related genes in gastric cancer (GC) prognosis has not been systematically researched.

Aims

This study was aimed at providing insights into the prognostic role of m6A-related gene expression, at both mRNA and protein levels.

Methods

Kaplan–Meier (KM) plotter database and The Cancer Genome Atlas (TCGA) database were used to explore the prognostic significance of individual m6A-related genes in overall survival (OS) and progression-free survival at the mRNA level. For independent validation, the protein level of genes significantly associated with prognosis in both databases was further detected in 450 paired GC and corresponding adjacent non-tumor tissues using tissue microarray (TMA)-based immunohistochemistry (IHC). The relationship between the FTO and ALKBH1 expression and the clinicopathological characteristics was explored.

Results

Among nine m6A-related genes, aberrantly high mRNA expression of FTO and ALKBH1 was associated with poor OS in the KM and TCGA cohorts. However, the TMA-IHC indicated that protein expression of FTO and ALKBH1 was markedly downregulated in GC tissues. A lower protein level of ALKBH1 was closely correlated with larger tumor sizes (≥ 5 cm) and more advanced TNM stages, while lower FTO protein expression was associated with shorter OS in GC patients.

Conclusions

Aberrant expression of demethylase genes, FTO and ALKBH1, has a distinct prognostic value in GC patients, indicating that FTO and ALKBH1 may play vital roles in GC progression and metastasis.



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Pre-transplant ALBI Grade 3 Is Associated with Increased Mortality After Liver Transplantation

Abstract

Background

Although MELD score is a reliable tool for estimating mortality in the waiting list, criteria for preoperative prediction of survival after liver transplantation (LT) are lacking. ALBI score was validated as a prognostic marker for hepatocellular carcinoma patients undergoing transarterial chemoembolization, hepatic resection, and sorafenib treatment but not for LT outcomes yet. This study aimed to evaluate ALBI score as a prognostic factor in LT.

Methods

This is a single-center analysis of patients undergoing LT between October 2001 and June 2017. Primary endpoint was overall post-LT mortality. Secondary endpoint was 90-day mortality.

Results

Of all 301 patients included in this study, 185 (61.5%) were males. The median age was 54.1 ± 11.3 years. Univariate and multivariate analysis revealed that ALBI grade 3 (HR 1.836, 95% CI 1.154–2.921, p = 0.010), low serum albumin (HR 0.628, 95% CI 0.441–0.893, p = 0.010), black race (HR 2.431, 95% CI 1.160–5.092, p = 0.019), and elevated body mass index (HR 1.061, 95% CI 1.022–1.102, p = 0.002) all were associated with decreased overall survival following LT. Patients with both ALBI grade 3 (n = 25) and calculated MELD score ≥ 25 had the lowest overall survival (p < 0.001).

Discussion

ALBI grade 3 was related to lower post-LT survival and can be utilized as a tool for risk stratification in LT.



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Investigating dynamic functional network patterns after propofol-induced loss of consciousness

Publication date: March 2019

Source: Clinical Neurophysiology, Volume 130, Issue 3

Author(s): Yun Zhang, Chunshu Wang, Yubo Wang, Fei Yan, Qiang Wang, Liyu Huang

Abstract
Objective

We investigated the changes of dynamic brain functional network from awaken state to the anesthesia level suitable for surgery.

Methods

60-channel EEG data of 22 subjects are acquired at wakefulness, light anesthesia and deep anesthesia. The activity of 68 cortical regions are obtained by using EEG source imaging. Sliding window analysis is employed to obtain a dynamic sequence of brain functional network. K-means clustering algorithm is then employed to identify the common brain functional network patterns.

Results

Five common brain functional network patterns were identified across all conscious levels. The occurrence of each meta-stable network pattern was associated with the level of anesthesia. A transition functional network pattern was found to transfer to the anesthesia dominating or wakefulness dominating network pattern depending on the conscious level. Furthermore, a functional network pattern persisted during both wakefulness and anesthesia is found to be supported by the anatomical connectivity.

Conclusions

Dynamic changes of brain functional network exist in both awaken and anesthesia state.

Significance

These findings suggest that dynamic brain functional network analysis plays a critical role in decoding the mechanism of general anesthesia. The obtained five metastable network patterns may be employed for monitoring the depth of anesthesia.



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Monaural 40-Hz auditory steady-state magnetic responses can be useful for identifying epileptic focus in mesial temporal lobe epilepsy

Publication date: March 2019

Source: Clinical Neurophysiology, Volume 130, Issue 3

Author(s): Teppei Matsubara, Katsuya Ogata, Naruhito Hironaga, Taira Uehara, Takako Mitsudo, Hiroshi Shigeto, Toshihiko Maekawa, Shozo Tobimatsu

Abstract
Objective

Patients with mesial temporal lobe epilepsy (mTLE) often exhibit central auditory processing (CAP) dysfunction. Monaural 40-Hz auditory steady-state magnetic responses (ASSRs) were recorded to explore the pathophysiology of mTLE.

Methods

Eighteen left mTLE patients, 11 right mTLE patients and 16 healthy controls (HCs) were examined. Monaural clicks were presented at a rate of 40 Hz. Phase-locking factor (PLF) and power values were analyzed within bilateral Heschl's gyri.

Results

Monaural 40-Hz ASSR demonstrated temporal frequency dynamics in both PLF and power data. Symmetrical hemispheric contralaterality was revealed in HCs. However, predominant contralaterality was absent in mTLE patients. Specifically, right mTLE patients exhibited a lack of contralaterality in response to left ear but not right ear stimulation, and vice versa in left mTLE patients.

Conclusion

This is the first study to use monaural 40-Hz ASSR with unilateral mTLE patients to clarify the relationship between CAP and epileptic focus. CAP dysfunction was characterized by a lack of contralaterality corresponding to epileptic focus.

Significance

Monaural 40-Hz ASSR can provide useful information for localizing epileptic focus in mTLE patients.



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Force decline after low and high intensity contractions in persons with multiple sclerosis

Publication date: March 2019

Source: Clinical Neurophysiology, Volume 130, Issue 3

Author(s): Deborah Severijns, Koen Cuypers, Raf Meesen, Peter Feys, Inge Zijdewind

Abstract
Objective

Force decline during strong contractions is dominated by changes in the periphery whereas during weaker contraction changes in voluntary activation become more important. We compared force decline and contributing factors in persons with multiple sclerosis (PwMS) during low and high intensity contractions.

Methods

Index finger abduction force, force evoked by electrical stimulation of the ulnar nerve at rest (RTw), and during MVCs were investigated in 19 PwMS and 19 controls. Participants performed contractions in sets of six contractions (7 s-on, 3 s-off) at 25% or 80% MVC. After each set, a 5 s-MVC was performed with superimposed nerve stimulation followed by RTw. Contractions were repeated until MVC dropped below 80% of initial MVC.

Results

Low compared to high intensity contractions caused a greater decline in voluntary activation and a smaller decline in RTw. Compared to controls, PwMS accomplished equal sets of contractions but showed a smaller decline in RTw. Female PwMS showed poorer voluntary activation. The number of low intensity contractions was associated with sense of fatigue in PwMS.

Conclusion

Although, no difference in fatigability was observed, the mechanism contributing to force decline differed between PwMS and controls during submaximal contractions.

Significance

During weak contractions, fatigue and fatigability are associated in PwMS.



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Nerve ultrasound as a diagnostic tool for sensory neuronopathy in spinocerebellar ataxia syndrome

Publication date: Available online 19 January 2019

Source: Clinical Neurophysiology

Author(s): Ruth Leadbetter, Mark Weatherall, Luciana Pelosi

Abstract
Objective

The objective was to assess if nerve ultrasound has a role in diagnosing sensory neuronopathy in spinocerebellar ataxia syndrome (SCA) by examining if proposed diagnostic cut-off criteria of ultrasound in sensory neuronopathy caused by cerebellar ataxia neuropathy vestibular areflexia syndrome (CANVAS) were also discriminatory for SCA-related sensory neuronopathy.

Methods

Optimal diagnostic cut-off criteria for nerve size measured by diagnostic ultrasound were developed in 14 patients with CANVAS and 42 healthy controls using six peripheral nerve sites; and logistic regression and receiver operating characteristic (ROC) curves. These proposed cut-off values were tested in seven patients with spinocerebellar ataxia type 2 (SCA2) patients with sensory neuronopathy.

Results

Ultrasound of upper limb nerves was highly accurate in differentiating between CANVAS

and healthy controls with areas under the ROC curves between 0.97 and 0.99. Optimal

cut-off measurements from the CANVAS patients also accurately diagnosed sensory

neuronopathy in all patients with SCA2.

Conclusions

Upper limb ultrasound is a sensitive tool for detecting sensory neuronopathy in

established cases of CANVAS and SCA2.

Significance

Ultrasound could aid the diagnosis of sensory neuronopathy in spinocerebellar ataxias.



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Nerve ultrasound in dorsal root ganglion disorders: smaller nerves lead to bigger insights

Publication date: Available online 19 January 2019

Source: Clinical Neurophysiology

Author(s): Nens van Alfen



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Clinical utility and prospective of TMS–EEG

Publication date: Available online 19 January 2019

Source: Clinical Neurophysiology

Author(s): Sara Tremblay, Nigel C. Rogasch, Isabella Premoli, Daniel M. Blumberger, Silvia Casarotto, Robert Chen, Vincenzo Di Lazzaro, Faranak Farzan, Fabio Ferrarelli, Paul B. Fitzgerald, Jeanette Hui, Risto J. Ilmoniemi, Vasilios K. Kimiskidis, Dimitris Kugiumtzis, Pantelis Lioumis, Alvaro Pascual-Leone, Maria Concetta Pellicciari, Tarek Rajji, Gregor Thut, Reza Zomorrodi

Abstract

Concurrent transcranial magnetic stimulation and electroencephalography (TMS–EEG) has emerged as a powerful tool to non-invasively probe brain circuits in humans, allowing for the assessment of several cortical properties such as excitability and connectivity. Over the past decade, this technique has been applied to various clinical populations, enabling the characterization and development of potential TMS–EEG predictors and markers of treatments and of the pathophysiology of brain disorders. The objective of this article is to present a comprehensive review of studies that have used TMS–EEG in clinical populations and to discuss potential clinical applications. To provide a technical and theoretical framework, we first give an overview of TMS–EEG methodology and discuss the current state of knowledge regarding the use of TMS–EEG to assess excitability, inhibition, plasticity and connectivity following neuromodulatory techniques in the healthy brain. We then review the insights afforded by TMS–EEG into the pathophysiology and predictors of treatment response in psychiatric and neurological conditions, before presenting recommendations for how to address some of the salient challenges faced in clinical TMS–EEG research. Finally, we conclude by presenting future directions in line with the tremendous potential of TMS–EEG as a clinical tool.



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Three-dimensional amplitude characteristics of masseter motor units and representativeness of extracted motor unit samples

Publication date: Available online 19 January 2019

Source: Clinical Neurophysiology

Author(s): Bernd Georg Lapatki, Ulrike Eiglsperger, Hans Jürgen Schindler, Johanna Radeke, Ales Holobar, Johannes Petrus van Dijk

Abstract
Objective

This study aimed to characterize amplitude topographies for masseter motor units (MUs) three-dimensionally, and to assess whether high-density surface electromyography (HDsEMG) is able to detect MU samples that represent the masseter's entire MU pool.

Methods

Ten healthy adult volunteers participated in the study, which combined three EMG techniques. A HDsEMG grid covering the entire masseter, and intramuscular fine-wire electrodes were used to obtain two independent MU samples for comparison. The MUs' amplitude profiles in the dimension of muscle depth were determined using scanning EMG. All data were recorded simultaneously during a low, constant contraction level controlled by 3D force feedback.

Results

The median medio-lateral diameter of 4.4 mm (range: 1.2–7.9 mm) for MUs detected by HDsEMG did not differ significantly (Mann-Whitney-U test, p=0.805) from that of 3.9 mm (0.6–8.6 mm) for MUs detected by fine-wire EMG. For individual subjects, the medio-lateral diameters of all HDsEMG-detected MUs spanned 70.5% (19.2–75.1%) of the masseter's thickness.

Conclusions

HDsEMG is able to examine small and large MUs from a great masseter proportion in one single measurement.

Significance

Clinical application of HDsEMG might contribute to a better understanding of neuromuscular adaptations in patients with temporomandibular disorders (TMD) and could allow for monitoring treatment effects.



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Assessing blink reflex circuits by three different afferent routes in Parkinson’s disease

Publication date: Available online 19 January 2019

Source: Clinical Neurophysiology

Author(s): David Weise, Clemens Pargac, Johann Otto Pelz, Jost-Julian Rumpf, Christopher Fricke, Joseph Classen

Abstract
Objective

Degeneration of nuclei of the brainstem, especially parts of the vagal nuclei complex and the reticular formation, in Parkinson's disease (PD) may in part be responsible for nonmotor signs like obstipation, cardiac dysfunction and rapid eye movement sleep behavior disorder (RBD). The aim of the study was to establish a new blink reflex (BR) variant involving the vagal nuclei complex and the reticular formation and to investigate BR comprehensively using 3 different afferent routes in PD.

Methods

In this cross-sectional observational study in 30 PD patients and 30 age and sex matched healthy controls, BR was elicited by stimulation of the auricular branch of the vagus nerve (ABVN) and compared to conventional BR variants evoked by the trigeminal and median nerve.

Results

BRs could be elicited reliably by stimulation of ABVN in both groups. In none of the three BR variants, latencies or amplitudes differed between PD patients and controls. In PD, BR parameters were not related to cognition or presence of RBD.

Conclusion

The present study did not provide evidence for malfunctioning of neural circuits subserving BRs elicited by three different afferents in PD.

Significance

Brainstem circuits mediating these BR variants may be spared from neurodegeneration in PD.



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Graham Harding, 1937–2018

Publication date: Available online 19 January 2019

Source: Clinical Neurophysiology

Author(s): Jonathan Cole



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Similarities and differences between the interictal epileptiform discharges of green-spikes and red-spikes zones of human neocortex

Publication date: Available online 19 January 2019

Source: Clinical Neurophysiology

Author(s): Ruggero Serafini

Abstract
Objective

This study looks for differences in the waveforms of interictal epileptiform discharges (IEDs) between cortices expressing only isolated discharges (green-spikes zones) vs those manifesting seizures (red-spikes zones): these can help to understand ictogenesis mechanisms and improve clinical decision in surgical epilepsy. Typical IEDs are triphasic, exhibiting in sequence: a negative-sharp-wave, a positive-baseline-shift and a negative-slow-wave. Negative-slow-waves are thought to reflect neurophysiological inhibition: their features at a focus' edge may reflect peripheral inhibition, a mechanism characterized in experimental models, curbing seizures' spread. This might be weakened in red-spikes.

Methods

A retrospective review of human intracranial EEGs was performed, comparing green- and red-spikes for their peripheral slow-waves' amplitudes. Green- and red-spikes were also compared also for the amplitudes of their negative-sharp-waves and positive-baseline-shifts, as well as for their spread pathways.

Results

Green-spikes exhibit more pronounced peripheral slow-waves than red-spikes. They also exhibit more pronounced positive-baseline-shifts, and more frequent propagation pathways' shifts.

Conclusions

Peripheral slow-waves' amplitudes correlate with seizures' suppression and may reflect neurophysiological peripheral inhibition.

Significance

This study suggests a novel approach to reading intracranial EEGs: amplitudes measures of IEDs waveforms are technically simple, may help identifying epileptogenic zones and indicate the spatial distribution of underlying ictogenesis mechanisms.



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Cutaneous silent periods – part 1: update on physiological mechanisms

Publication date: Available online 18 January 2019

Source: Clinical Neurophysiology

Author(s): Markus Kofler, A. Arturo Leis, Josep Valls-Solé

Abstract

Testing of exteroceptive electromyographic modulation of ongoing voluntary muscle activity is of interest in normal human physiology and in diagnostic clinical neurophysiology in normal and pathological conditions. The cutaneous silent period (CSP) is a robust and reproducible nociceptive EMG suppression, mediated at the spinal level by small-diameter A-delta afferents. This critical review surveys the literature on applied stimulation and recording techniques, physiological principles, involved fiber types, spinal circuitry, supraspinal modulation, neurotransmitters and pharmacology of CSPs. Understanding the principles of CSP testing is fundamental for a valid and thoughtful clinical application of CSPs (reviewed in part 2) (Kofler et al. 2019).



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Cutaneous silent periods – part 2: update on pathophysiology and clinical utility

Publication date: Available online 18 January 2019

Source: Clinical Neurophysiology

Author(s): Markus Kofler, A. Arturo Leis, Josep Valls-Solé

Abstract

Testing of exteroceptive electromyographic modulation of ongoing voluntary muscle activity is of increasing interest as a diagnostic tool in clinical neurophysiology. The cutaneous silent period (CSP) is a robust and reproducible nociceptive EMG suppression, mediated at the spinal level by small-diameter A-delta afferents. The techniques and physiological principles of CSP testing, which are a fundamental prerequisite for a valid and thoughtful clinical application, are reviewed separately in part 1 (Kofler et al. 2019). This comprehensive review surveys the literature on pathophysiological conditions in which CSPs have been reported, and aims at a critical overview on the clinical utility of CSP testing. The most useful clinical applications seem to be the functional diagnostics of intramedullary, in particular centromedullary, dysfunctions, and the assessment of small fiber neuropathies, in particular those affecting A-delta fibers. CSPs have in addition been studied in a variety of movement disorders and in neuropathic pain and other painful conditions, including fibromyalgia.



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Linking invasive and noninvasive neuromodulation techniques to study network properties of the brain

Publication date: Available online 18 January 2019

Source: Clinical Neurophysiology

Author(s): Andreas Horn, Andrea A. Kühn



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Impaired prefrontal cortex-thalamus pathway in intractable temporal lobe epilepsy with aberrant executive control function: MRI evidence

Publication date: Available online 18 January 2019

Source: Clinical Neurophysiology

Author(s): Chao Zhang, Haiyan Zhang, Kai Xu, Hongyu Yang, Chang Liu, Tao Yu, Nan Chen, Kuncheng Li

Abstract
Objectives

This study aimed to assess structural and functional connectivity alterations of the prefrontal cortex (PFC)-thalamus axis in individuals with unilateral intractable temporal lobe epilepsy (TLE) showing executive control function (ECF) impairment and to explore the potential mechanism.

Methods

Thirty-eight individuals with intractable left TLE and twenty-nine healthy controls (HCs) were recruited for diffusion tensor imaging (DTI) and resting-state fMRI (rs-fMRI) scanning. According to the ECF state, patients were assigned to normal and impaired ECF groups. Functional connectivity (FC) and probabilistic diffusion tractography of the PFC- thalamus pathway were assessed. The general linear model (GLM) was employed for comparing fiber number (FN) and FC between groups. Pearson correlation analysis of FC, FN and ECF test scores was performed.

Results

FC and FN of left DLPFC-thalamus pathway were significantly increased in the impaired ECF group compared with the normal ECF and HC groups. However, FC and FN were not correlated with ECF score.

Conclusions

These findings indicated increased connectivity between DLPFC and the ipsilateral thalamus might reflect nonfunctional nerve remodeling along the seizure pathway.

Significance

The present findings suggest that the DLPFC-thalamus pathway may be an important structure for exploring the mechanisms of TLE with ECF dysfunction.



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Scotopic multifocal visual evoked potentials

Publication date: Available online 31 December 2018

Source: Clinical Neurophysiology

Author(s): D. Muranyi, F. Kramer, A. Herbik, M.B. Hoffmann

Abstract
Objective

To investigate the scope of scotopic multifocal visual evoked potentials (mfVEPS) for the assessment of scotopic visual fields.

Methods

Pattern-reversal mfVEP for photopic (mfVEPP) and scotopic conditions (mfVEPS; 0.003 cd/m2) were recorded from 36 visual field locations of a circular checkerboard pattern (25° radius) in 9 participants with normal vision. MfVEPP were recorded with a conventional central fixation cross, mfVEPS were recorded (i) with (mfVEPS+) and (ii) without (mfVEPS-) an additional fixation aid. Latency shifts were determined using cross-correlations, mfVEP magnitudes were analysed in an eccentricity dependent manner using signal-to-noise ratios (SNRs).

Results

In comparison to mfVEPP, mfVEPS- and mfVEPS+ were delayed by 101 ms and 97 ms, respectively, and had smaller signal-to-noise-ratios (SNR). Both mfVEPS were reduced down to noise level in the center and also severely reduced for the most peripheral stimulus eccentricity used. The visual-field-coverage for the paracentral eccentricities of mfVEPS+ and mfVEPS- was 76% and 65% [4°-9°], respectively, and 79% and 66% [9°-16°].

Conclusions

MfVEPS were delayed compared to mfVEPP and demonstrated the expected central response drop-out typical for scotopic vision.

Significance

MfVEPS may hold promise of an objective, spatially resolved visual field test which motivates testing it in patients with diseases affecting scotopic vision.



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Exploration of autonomic activity in narcolepsy: The riddle remains unsolved

Publication date: Available online 27 December 2018

Source: Clinical Neurophysiology

Author(s): Alessandro Silvani



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Focal hole versus screw stimulation to prevent false negative results in detecting pedicle breaches during spinal instrumentation

Publication date: Available online 26 December 2018

Source: Clinical Neurophysiology

Author(s): Walter Troni, Carlo Alberto Benech, Rosa Perez, Stefano Tealdi, Maurizio Berardino, Franco Benech

Abstract
Objective

We describe a stimulus-evoked EMG approach to minimize false negative results in detecting pedicle breaches during lumbosacral spinal instrumentation.

Methods

In 36 patients receiving 176 lumbosacral pedicle screws, EMG threshold to nerve root activation was determined using a focal probe inserted into the pilot hole at a depth, customized to the individual patients, suitable to position the stimulating tip at the point closest to the tested nerve root. Threshold to screw stimulation was also determined.

Results

Mean EMG thresholds in 161 correctly fashioned pedicle instrumentations were 7.5 mA ± 2.46 after focal hole stimulation and 21.8 mA ± 6.8 after screw stimulation. Direct comparison between both thresholds in individual pedicles showed that screw stimulation was always biased by an unpredictable leakage of the stimulating current ranging from 10 to 90%. False negative results were never observed with hole stimulation but this was not true with screw stimulation.

Conclusions

Focal hole stimulation, unlike screw stimulation, approaches absolute EMG threshold as shown by the lower normal limit (2.6 mA; p < 0.05) that borders the upper limit of threshold to direct activation of the exposed root.

Significance

The technique provides an early warning of a possible pedicle breakthrough before insertion of the more harmful, larger and threaded screw.



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Exploring brain functions in autism spectrum disorder: A systematic review on functional near-infrared spectroscopy (fNIRS) studies

Publication date: Available online 19 January 2019

Source: International Journal of Psychophysiology

Author(s): Fen Zhang, Herbert Roeyers

Abstract

A growing body of research has investigated the functional development of the brain in autism spectrum disorder (ASD). Functional near-infrared spectroscopy (fNIRS) is increasingly being used in this respect. This method has several advantages over other functional neuroimaging techniques in studying brain functions in ASD, including portability, low cost, and availability in naturalistic settings. This article reviews thirty empirical studies, published in the past decade, that used fNIRS in individuals with ASD or in infants with a high risk of developing ASD. These studies investigated either brain activation using multiple tasks (e.g., face processing, joint attention and working memory) or functional organization under a resting-state condition in ASD. The majority of these studies reported atypical brain activation in the prefrontal cortex, inferior frontal gyrus, middle and superior temporal gyrus. Some studies revealed altered functional connectivity during resting-state, suggesting an inefficient information transfer between brain regions in ASD. Overall, the findings suggest that fNIRS is a promising tool to explore neurodevelopment in ASD from an early age.



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Visual presentation modality's superiority in the detection of concealed information: A comparison of the efficiencies of the P300-based Complex Trial Protocol in visual versus auditory modalities

Publication date: Available online 18 January 2019

Source: International Journal of Psychophysiology

Author(s): Huihui Zheng, J. Peter Rosenfeld, Xiaohong Deng, Yang Lu, Chao Xue, Ying Wang, Erhu Zhang, Gejun Yan, Dan Ouyang

Abstract

Some studies have shown a superiority of visual vs. auditory item presentation in the Complex Trial Protocol (CTP), which is a countermeasure-resistant version of the P300-based Concealed Information Test (CIT). But those studies used elaborately- rehearsed autobiographical information as stimuli, instead of incidentally-acquired crime-related information. Thus, the relative superiority of the visual as opposed to the auditory modality in detecting episodic crime-related information is still unknown. The present study also improved on the usual mock crime scenario by adding a mock disposal task between a mock theft and administration of a CTP test to increase stimulus saliency. In this CTP, the probe and the irrelevant items were presented visually or acoustically on alternating trials, while target and non-target stimuli were simultaneously presented in visual and auditory modalities. The results showed that the P300 amplitude differences of probe minus irrelevant items presented in the visual modality were significantly larger compared to the auditory modality, and the detection rate of the guilty participants was also significantly higher for the visual (14/16) versus auditory modality (5/16). These results suggest a superiority of visual vs. auditory presentation when a CTP is used to detect crime-related information in a mock crime scenario.



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ΒΟΗΘΗΜΑΤΑ ΑΚΟΗΣ,ΑΚΟΥΣΤΙΚΑ ΒΑΡΗΚΟΙΑΣ,ΕΝΙΣΧΥΤΕΣ ΑΚΟΗΣ

Οπισθωτιαία
Εφαρμόζονται πίσω από το αυτί και συνδέονται με το κατάλληλο εκμαγείο

Ενδοκαναλικά
Αθέατα,Είναι μικρότερα σε μέγεθος και εφαρμόζονται μέσα στον ακουστικό πόρο.

Καθαρή και διαυγή μετάδοση της φωνής των συνομιλούντων
Έξυπνη φραγή των θορύβων

Άριστη ποιοτική ενίσχυση και απόδοση του ήχου,εύκολα στη χρήση,άνετα στην εφαρμογή,όμορφα για καλύτερη αισθητική όσο αφορά το μέγεθος και την εξωτερική εμφάνιση,χωρίς καμμία ιδιαίτερη συντήρηση.

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