An artificial neural-network approach to identify motor hotspot for upper-limb based on electroencephalography: a proof-of-concept study

Abstract Background To apply transcranial electrical stimulation (tES) to the motor cortex, motor hotspots are generally identified using motor evoked potentials by transcranial magnetic stimulation (TMS). The objective of this study is to validate the feasibility of a novel electroencephalography (EEG)-based motor-hotspot-identification approach using a machine learning technique as a potential alternative to TMS. Methods EEG data were measured using 63 channels from thirty subjects as they performed a simple finger tapping task. Power spectral densities of the EEG data were extracted from six frequency bands (delta, theta, alpha, beta, gamma, and full) and were independently used to train and test an artificial neural network for motor hotspot identification. The 3D coordinate information of individual motor hotspots identified by TMS were quantitatively compared with those estimated by our EEG-based motor-hotspot-identification approach to assess its feasibility. Results The minimum mean error distance between the motor hotspot locations identified by TMS and our proposed motor-hotspot-identification approach was 0.22 ± 0.03cm, demonstrating the proof-of-concept of our proposed EEG-based approach. A mean error distance of 1.32 ± 0.15cm was measured when using only nine channels attached to the middle of the motor cortex, showing the possibility of practically using the proposed motor-hotspot-identification approach based on a relatively small number of EEG channels. Conclusion We demonstrated the feasibility of our novel EEG-based motor-hotspot-identification method. It is expected that our approach can be used as an alternative to TMS for motor hotspot identification. In particular, its usability would significantly increase when using a recently developed portable tES device integrated with an EEG device

Soft, curved electrode systems capable of integration on the auricle as a persistent brain–computer interface

Recent advances in electrodes for noninvasive recording of electroencephalograms expand opportunities collecting such data for diagnosis of neurological disorders and brain–computer interfaces. Existing technologies, however, cannot be used effectively in continuous, uninterrupted modes for more than a few days due to irritation and irreversible degradation in the electrical and mechanical properties of the skin interface. Here we introduce a soft, foldable collection of electrodes in open, fractal mesh geometries that can mount directly and chronically on the complex surface topology of the auricle and the mastoid, to provide high-fidelity and long-term capture of electroencephalograms in ways that avoid any significant thermal, electrical, or mechanical loading of the skin. Experimental and computational studies establish the fundamental aspects of the bending and stretching mechanics that enable this type of intimate integration on the highly irregular and textured surfaces of the auricle. Cell level tests and thermal imaging studies establish the biocompatibility and wearability of such systems, with examples of high-quality measurements over periods of 2 wk with devices that remain mounted throughout daily activities including vigorous exercise, swimming, sleeping, and bathing. Demonstrations include a text speller with a steady-state visually evoked potential-based brain–computer interface and elicitation of an event-related potential (P300 wave)

Influence of B1 Inhomogeneity on Pharmacokinetic Modeling of Dynamic Contrast-Enhanced MRI: A Simulation Study

Objective: To simulate the B1-inhomogeneity-induced variation of pharmacokinetic parameters on DCE-MRI. Materials and Methods: B1-inhomogeneity-induced flip angle (FA) variation was estimated in a phantom study. Monte Carlo simulation was performed to assess the FA-deviation-induced measurement error of the pre-contrast R1, contrast-enhancement ratio, Gd concentration, and two-compartment pharmacokinetic parameters (Ktrans, ve and vp). Results: B1-inhomogeneity resulted in -23% ~ 5% fluctuations (95% confidence interval (CI) of % error) of FA. The 95% CIs of FA-dependent % errors in the gray matter and blood were as follows: -16.7% - 61.8% and -16.7% - 61.8% for the pre-contrast R1, -1.0% - 0.3% and -5.2% - 1.3% for the contrast-enhancement ratio, and -14.2% - 58.1% and -14.1% - 57.8% for the Gd concentration, respectively. These resulted in -43.1% - 48.4% error for Ktrans, -32.3% - 48.6% error for the ve, and -43.2% - 48.6% error for vp. The pre-contrast R1 was more vulnerable to FA error than the contrast-enhancement ratio, and was therefore a significant cause of the Gd-concentration error. For example, a -10% FA error led to a 23.6% deviation in the pre-contrast R1, -0.4% in the contrast-enhancement ratio, and 23.6% in the Gd concentration. In a simulated condition with a 3% FA error in a target lesion and a -10% FA error in a feeding vessel, the % errors of the pharmacokinetic parameters were -23.7% for Ktrans, -23.7% for ve, and -23.7% for vp. Conclusion: Even a small degree of B1-inhomogeneity can cause a significant error in the measurement of pharmacokinetic parameters on DCE-MRI, while the vulnerability of the pre-contrast R1 calculations to FA deviations is a significant cause of the miscalculation.ope

A Validation Study of the Korean Version of SPAN

Purpose: The SPAN, which is acronym standing for its four components: Startle, Physiological arousal, Anger, and Numbness, is a short post-traumatic stress disorder (PTSD) screening scale. This study sought to develop and validate a Korean version of the SPAN (SPAN-K). Materials and Methods: Ninety-three PTSD patients (PTSD group), 73 patients with non-psychotic psychiatric disorders (psychiatric control group), and 88 healthy participants (normal control group) were recruited for this study. Participants completed a variety of psychiatric assessments including the SPAN-K, the Davidson Trauma Scale (DTS), the Clinician-Administered PTSD Scale (CAPS), and the State-Trait Anxiety Inventory (STAI). Results: Cronbach's alpha and test-retest reliability values for the SPAN-K were both 0.80. Mean SPAN-K scores were 10.06 for the PTSD group, 4.94 for the psychiatric control group, and 1.42 for the normal control group. With respect to concurrent validity, correlation coefficients were 0.87 for SPAN-K vs. CAPS total scores (p<0.001) and 0.86 for SPAN-K vs. DTS scores (p<0.001). Additionally, correlation coefficients were 0.31 and 0.42 for SPAN-K vs. STAI-S and STAI-T, respectively. Receiver operating characteristic analysis of SPAN-K showed good diagnostic accuracy with an area under the curve (AUC) of 0.87. The SPAN-K showed the highest efficiency at a cutoff score of 7, with a sensitivity of 0.83, a specificity of 0.81, positive predictive value (PPV) of 0.88, and negative predictive value (NPV) of 0.73. Conclusion: These results suggest that the SPAN-K had good psychometric properties and may be a useful instrument for rapid screening of PTSD patients.This study was supported by a grant of the Korean Academy of Anxiety Disorders, Korean Neuropsychiatric Association, and Korean Research Foundation (2006-2005152), Republic of Korea

Clinical outcomes of balloon-occluded retrograde transvenous obliteration for the treatment of gastric variceal hemorrhage in Korean patients with liver cirrhosis: a retrospective multicenter study

Background/AimsThis study evaluated the clinical outcomes of balloon-occluded retrograde transvenous obliteration (BRTO) for the treatment of hemorrhage from gastric varices (GV) in Korean patients with liver cirrhosis (LC).MethodsWe retrospectively analyzed data from 183 LC patients who underwent BRTO for GV bleeding in 6 university-based hospitals between January 2001 and December 2010.ResultsOf the 183 enrolled patients, 49 patients had Child-Pugh (CP) class A LC, 105 had CP class B, and 30 had CP class C at the time of BRTO. BRTO was successfully performed in 177 patients (96.7%). Procedure-related complications (e.g., pulmonary thromboembolism and renal infarction) occurred in eight patients (4.4%). Among 151 patients who underwent follow-up examinations of GV, 79 patients (52.3%) achieved eradication of GV, and 110 patients (72.8%) exhibited marked shrinkage of the treated GV to grade 0 or I. Meanwhile, new-appearance or aggravation of esophageal varices (EV) occurred in 54 out of 136 patients who underwent follow-up endoscopy (41.2%). During the 36.0±29.2 months (mean±SD) of follow-up, 39 patients rebled (hemorrhage from GV in 7, EV in 18, nonvariceal origin in 4, and unknown in 10 patients). The estimated 3-year rebleeding-free rate was 74.8%, and multivariate analysis showed that CP class C was associated with rebleeding (odds ratio, 2.404; 95% confidence-interval, 1.013-5.704; P=0.047).ConclusionsBRTO can be performed safely and effectively for the treatment of GV bleeding. However, aggravation of EV or bleeding from EV is not uncommon after BRTO; thus, periodic endoscopy to follow-up of EV with or without prophylactic treatment might be necessary in LC patients undergoing BRTO

Efficacy and safety of entecavir plus carnitine complex (GODEX®) compared to entecavir monotherapy in patient with ALT elevated chronic hepatitis B: randomized, multicenter open-label trials. The GOAL study

Background/AimsCarnitine and vitamin complex (Godex®) is widely used in patients with chronic liver disease who show elevated liver enzyme in South Korea. The purpose of this study is to identify the efficacy and safety of carnitine from entecavir combination therapy in Alanine aminotransferase (ALT) elevated Chronic Hepatitis B (CHB) patients.Methods130 treatment-naïve patients with CHB were enrolled from 13 sites. The patients were randomly selected to the entecavir and the complex of entecavir and carnitine. The primary endpoint of the study is ALT normalization level after 12 months.ResultsAmong the 130 patients, 119 patients completed the study treatment. The ALT normalization at 3 months was 58.9% for the monotherapy and 95.2% for the combination therapy (P<0.0001). ALT normalization rate at 12 months was 85.7% for the monotherapy and 100% for the combination group (P=0.0019). The rate of less than HBV DNA 300 copies/mL at 12 months was not statistically significant (P=0.5318) 75.9% for the monotherapy, 70.7% for the combination and it was. Quantification of HBsAg level was not different from the monotherapy to combination at 12 months. Changes of ELISPOT value to evaluate the INF-γ secretion by HBsAg showed the increasing trend of combination therapy compare to mono-treatment.ConclusionsALT normalization rate was higher in carnitine complex combination group than entecavir group in CHB. Combination group was faster than entecavir mono-treatment group on ALT normalization rate. HBV DNA normalization rate and the serum HBV-DNA level were not changed by carnitine complex treatment

Phase II randomized trial of neoadjuvant metformin plus letrozole versus placebo plus letrozole for estrogen receptor positive postmenopausal breast cancer (METEOR)

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Abstract Background Neoadjuvant endocrine therapy with an aromatase inhibitor has shown efficacy comparable to that of neoadjuvant chemotherapy in patients with postmenopausal breast cancer. Preclinical and clinical studies have shown that the antidiabetic drug metformin has anti-tumor activity. This prospective, multicenter, phase II randomized, placebo controlled trial was designed to evaluate the direct anti-tumor effect of metformin in non-diabetic postmenopausal women with estrogen-receptor (ER) positive breast cancer. Methods/Design Patients meeting the inclusion criteria and providing written informed consent will be randomized to 24 weeks of neoadjuvant treatment with letrozole (2.5 mg/day) and either metformin (2000 mg/day) or placebo. Target accrual number is 104 patients per arm. The primary endpoint will be clinical response rate, as measured by calipers. Secondary endpoints include pathologic complete response rate, breast conserving rate, change in Ki67 expression, breast density change, and toxicity profile. Molecular assays will be performed using samples obtained before treatment, at week 4, and postoperatively. Discussion This study will provide direct evidence of the anti-tumor effect of metformin in non-diabetic, postmenopausal patients with ER-positive breast cancer. Trial registration ClinicalTrials.gov Identifier NCT0158936