Smell loss associated with SARS-CoV-2 is not clinically different from other viruses: a multicenter cohort study

BACKGROUND

Although the COVID-19 pandemic has increased the prevalence of cases with olfactory loss, other respiratory viruses can also cause this condition. We aimed to compare the prevalence of acute SARS-CoV-2 infection and other respiratory viruses in patients with sudden smell loss, and to assess the impact of SARS-CoV-2 viral load and co-infection on olfactory symptoms.

METHODS

Patients with sudden smell loss were recruited in a multicenter prospective cohort study in 15 hospitals in Brazil. Clinical questionnaire, Connecticut Chemosensory Clinical Research Center (CCCRC) olfactory test and nasopharyngeal swab to perform a PCR-based respiratory viral panel were collected at first visit (day 0) and 30 and 60 days after recruitment.

RESULTS

188 of 213 patients presented positive test result for SARS-CoV-2, among which 65 were co-infected with other respiratory viruses (e.g., rhinovirus, enterovirus, and parainfluenza). 25 had negative test results for SARS-CoV-2. Patients in both SARSCoV-2 and non-SARS-CoV-2 groups had objective anosmia (less than 2 points according to the psychophysical olfactory CCCRC) at day 0, with no significant difference between them. Both groups had significant smell scores improvement after 30 and 60 days, with no difference between them. Co-infection with other respiratory viruses, and SARS-CoV-2 viral load did not impact olfactory scores.

CONCLUSION

Patients with sudden smell loss associated with SARS-CoV-2 and other respiratory viruses had similar presentation, with most participants initiating with anosmia, and total or near total recovery after 60 days. SARS-CoV-2 viral load and co-infections with other respiratory viruses were not associated with poorer olfactory outcomes.

One out of ten independent components shows flipped polarity with poorer data quality: EEG database study

Independent component analysis (ICA) is widely used today for scalp-recorded EEG analysis. One of the limitations of ICA-based analysis is polarity indeterminacy. It is not easy to find detailed documentations that explains engineering solutions of how the polarity indeterminacy is addressed in a given implementation. We investigated how it is implemented in the case of EEGLAB and also the relation between the outcome of the polarity determination and classification of independent components (ICs) in terms of the estimated nature of the sources (brain, muscle, eye, etc.) using an open database of n = 212 EEG dataset of resting state recordings. We found that (1) about 91% of ICs showed positive-dominant IC scalp topographies; (2) positive-dominant ICs were more associated with brain-originated signals; (3) positive-dominant ICs showed more radial (peaked at 10-30 degrees deviations from the radial axis) dipolar projection pattern with less residual variance from fitting the equivalent current dipole. In conclusion, using the EEGLAB's default ICA algorithm, one out of 10 ICs results in flipping its polarity to negative, which is associated with non-radial dipole orientation with higher residual variance. Thus, we determined EEGLAB biases toward positive polarity in decomposing high-quality brain ICs.

Stimulus Design for Visual Evoked Potential Based Brain-Computer Interfaces

Visual stimuli design plays an important role in brain-computer interfaces (BCIs) based on visual evoked potentials (VEPs). Variations in stimulus parameters have been shown to affect both decoding accuracy and subjective perception experience, implying the need for a trade-off in design. In this study, we comprehensively and systematically compared various combinations of amplitude contrast and spectral content parameters in the stimulus design to quantify their impact on decoding performance and subject comfort. Specifically, three parameters were investigated: 1) contrast level, 2) temporal pattern (periodic steady-state or pseudo-random code-modulated), and 3) frequency range. We collected electroencephalogram (EEG) data and subjective perception ratings from ten subjects and evaluated the decoding accuracy and subject comfort rating for different combinations of the stimulus parameters. Our results indicate that while high-frequency steady-state VEP (SSVEP) stimuli were rated the most comfortable, they also had the lowest decoding accuracy. Conversely, low-frequency SSVEP stimuli were rated the least comfortable but had the highest decoding accuracy. Standard and high-frequency M-sequence code-modulated VEPs (c-VEPs) produced intermediates between the two. We observed a consistent trade-off relationship between decoding accuracy and subjective comfort level across all parameters. Based on our findings, we offer c-VEP as a preferable stimulus for achieving reliable decoding accuracy while maintaining a reasonable level of comfortability.

New evidence for the Ontong Java Nui hypothesis

The formation of the Ontong Java Nui super oceanic plateau (OJN), which is based on the model that the submarine Ontong Java Plateau (OJP), Manihiki Plateau (MP), and Hikurangi Plateau (HP) were once its contiguous fragments, could have been the largest globally consequential volcanic event in Earth's history. This OJN hypothesis has been debated given the paucity of evidence, for example, the differences in crustal thickness, the compositional gap between MP and OJP basalts and the apparent older age of both plateaus relative to HP remain unresolved. Here we investigate the geochemical and ⁴⁰Ar-³⁹Ar ages of dredged rocks recovered from the OJP's eastern margin. Volcanic rocks having compositions that match the low-Ti MP basalts are reported for the first time on the OJP and new ~ 96-116 Ma and 67-68 Ma ⁴⁰Ar-³⁹Ar age data bridge the temporal gap between OJP and HP. These results provide new evidence for the Ontong Java Nui hypothesis and a framework for an integrated tectonomagmatic evolution of the OJP, MP, and HP. The isotopic data imply four mantle components in the source of OJN that are also expressed in present-day Pacific hotspots sources, indicating origin from (and longevity of) the Pacific Large Low Shear-wave Velocity Province.

Revisiting Polarity Indeterminacy of ICA-Decomposed ERPs and Scalp Topographies

We propose an alternative method to align the polarities of independent components (ICs) for group-level IC cluster analysis. Current methods are presently limited in how indeterminacy of IC polarities is handled, as when multiplying a weight matrix to a time-series IC activation, the result from 1 × 1 and - 1 × - 1 are indistinguishable. We first clarify the EEGLAB's default solution and define it as the iterative correlation maximization as it maximizes the within-cluster correlations of the IC scalp topographies to the cluster mean. We then propose the covariance maximization method, which determines the polarity of ICs based on the sign of the largest eigenvalue of covariance matrix. We compared the two methods on datasets from a published visual event-related potential (ERP) study. The results were similar when both methods were applied to the IC scalp topographies. However, when the proposed method was applied to IC ERPs, the number of clusters that showed significant ERP amplitudes increased from 5 to 9 out of 9 due to minimization of within-cluster ERP amplitude cancellation. Our study confirm covariance maximization provides an alternative solution to post-ICA group-level analysis that can maximize sensitivity of IC ERPs.

Novel Moving Steady-State Visual Evoked Potential Stimulus to Assess Afferent and Efferent Dysfunction in Multiple Sclerosis

Afferent and efferent visual dysfunction are prominent features of multiple sclerosis (MS). Visual outcomes have been shown to be robust biomarkers of the overall disease state. Unfortunately, precise measurement of afferent and efferent function is typically limited to tertiary care facilities, which have the equipment and analytical capacity to make these measurements, and even then, only a few centers can accurately quantify both afferent and efferent dysfunction. These measurements are currently unavailable in acute care facilities (ER, hospital floors). We aimed to develop a moving multifocal steady-state visual evoked potential (mfSSVEP) stimulus to simultaneously assess afferent and efferent dysfunction in MS for application on a mobile platform. The brain-computer interface (BCI) platform consists of a head-mounted virtual-reality headset with electroencephalogram (EEG) and electrooculogram (EOG) sensors. To evaluate the platform, we recruited consecutive patients who met the 2017 MS McDonald diagnostic criteria and healthy controls for a pilot cross-sectional study. Nine MS patients (mean age 32.7 years, SD 4.33) and ten healthy controls (24.9 years, SD 7.2) completed the research protocol. The afferent measures based on mfSSVEPs showed a significant difference between the groups (signal-to-noise ratio of mfSSVEPs for controls: 2.50 ± 0.72 vs. MS: 2.04 ± 0.47) after controlling for age (p = 0.049). In addition, the moving stimulus successfully induced smooth pursuit movement that can be measured by the EOG signals. There was a trend for worse smooth pursuit tracking in cases vs. controls, but this did not reach nominal statistical significance in this small pilot sample. This study introduces a novel moving mfSSVEP stimulus for a BCI platform to evaluate neurologic visual function. The moving stimulus showed a reliable capability to assess both afferent and efferent visual functions simultaneously.

Clinical characteristics and treatment outcomes of carbapenem-resistant Enterobacterales infections in Japan

OBJECTIVES

The dissemination of difficult-to-treat carbapenem-resistant Enterobacterales (CRE) is of great concern. We clarified the risk factors underlying CRE infection mortality in Japan.

METHODS

We conducted a retrospective, multicentre, observational cohort study of patients with CRE infections at 28 university hospitals from September 2014 to December 2016, using the Japanese National Surveillance criteria. Clinical information, including patient background, type of infection, antibiotic treatment, and treatment outcome, was collected. The carbapenemase genotype was determined using PCR sequencing. Multivariate analysis was performed to identify the risk factors for 28-day mortality.

RESULTS

Among the 179 patients enrolled, 65 patients (36.3%) had bloodstream infections, with 37 (20.7%) infections occurring due to carbapenemase-producing Enterobacterales (CPE); all carbapenemases were of IMP-type (IMP-1: 32, IMP-6: 5). Two-thirds of CPE were identified as Enterobacter cloacae complex. Combination therapy was administered only in 46 patients (25.7%), and the 28-day mortality rate was 14.3%. Univariate analysis showed that solid metastatic cancer, Charlson Comorbidity Index ≥3, bloodstream infection, pneumonia, or empyema, central venous catheters, mechanical ventilation, and prior use of quinolones were significant risk factors for mortality. Multivariate analysis revealed that mechanical ventilation (OR: 6.71 [1.42-31.6], P = 0.016), solid metastatic cancers (OR: 5.63 [1.38-23.0], P = 0.016), and bloodstream infections (OR: 3.49 [1.02-12.0], P = 0.046) were independent risk factors for 28-day mortality.

CONCLUSION

The significant risk factors for 28-day mortality in patients with CRE infections in Japan are mechanical ventilation, solid metastatic cancers, and bloodstream infections.

Differences in the sequence of PlcR transcriptional regulator binding site affect sphingomyelinase production in Bacillus cereus

Bacillus cereus is an opportunistic pathogen that often causes severe infections such as bacteremia, with sphingomyelinase (SMase) being a crucial virulence factor. Although many strains of B. cereus carry the SMase gene, they are classified as SMase-producing and non-producing strains. The reason for different SMase production among B. cereus strains remains unknown. In this study, we investigated the relationship between SMase and the PlcR transcriptional regulation system to clarify the mechanism leading to varied SMase production among B. cereus strains. We analyzed the sequence of the PlcR box, which is a transcriptional regulator binding site, located at the promoter region of SMase and phosphatidylcholine-specific phospholipase C. Based on differences in the PlcR box sequences, we classified the B. cereus strains into three groups (I, II, and III). SMase expression and activity were hardly detected in Group III strains. In Group I strains, SMase activity and its expression were maximal at the onset of the stationary phase and decreased during the stationary phase, whereas those were maintained during the stationary phase in Group II stains. On injection of B. cereus strains into mice or incubation with macrophages for phagocytosis assay, the SMase-producing Group I and II strains showed higher pathogenicity than Group III strains. These findings suggest that PlcR box sequence in B. cereus affects the production of SMase, which may provide important clinical information for the detection of highly pathogenic B. cereus strains. This article is protected by copyright. All rights reserved.

Online Adaptation Boosts SSVEP-Based BCI Performance

OBJECTIVE

A user-friendly steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) prefers no calibration for its target recognition algorithm, however, the existing calibration-free schemes perform still far behind their calibration-based counterparts. To tackle this issue, learning online from the subject's unlabeled data is investigated as a potential approach to boost the performance of the calibration-free SSVEP-based BCIs.

METHODS

An online adaptation scheme is developed to tune the spatial filters using the online unlabeled data from previous trials, and then developing the online adaptive canonical correlation analysis (OACCA) method.

RESULTS

A simulation study on two public SSVEP datasets (Dataset I and II) with a total of 105 subjects demonstrated that the proposed online adaptation scheme can boost the CCA's averaged information transfer rate (ITR) from 94.60 to 158.87 bits/min in Dataset I and from 85.80 to 123.91 bits/min in Dataset II. Furthermore, in our online experiment it boosted the CCA's ITR from 55.81 bits/min to 95.73 bits/min. More importantly, this online adaptation scheme can be easily combined with any spatial filtering-based algorithms to achieve online learning.

CONCLUSION

By online adaptation, the proposed OACCA performed much better than the calibration-free CCA, and comparable to the calibration-based algorithms.

SIGNIFICANCE

This work provides a general way for the SSVEP-based BCIs to learn online from unlabeled data and thus avoid calibration.

Source decomposition of the frontocentral auditory steady-state gamma band response in schizophrenia patients and healthy subjects

AIM

Gamma-band auditory steady-state response (ASSR) is a neurophysiologic index that is increasingly used as a translational biomarker in the development of treatments of neuropsychiatric disorders. While gamma-band ASSR is generated by distributed networks of highly interactive temporal and frontal cortical sources, the majority of human gamma-band ASSR studies using electroencephalography (EEG) highlight activity from only a single frontocentral scalp site, Fz, where responses tend to be largest and reductions in schizophrenia patients are most evident. However, no previous study has characterized the relative source contributions to Fz, which is a necessary step to improve the concordance of preclinical and clinical EEG studies.

METHODS

A novel method to back-project the contributions of independent cortical source components was applied to assess the independent sources and their proportional contributions to Fz as well as source-resolved responses in 432 schizophrenia patients and 294 healthy subjects.

RESULTS

Independent contributions of gamma-band ASSR to Fz were detected from orbitofrontal, bilateral superior/middle/inferior temporal, bilateral middle frontal, and posterior cingulate gyri in both groups. In contrast to expectations, the groups showed comparable source contribution weight to gamma-band ASSR at Fz. While gamma-band ASSR reductions at Fz were present in schizophrenia patients consistent with previous studies, no group differences in individual source-level responses to Fz were detected.

CONCLUSION

Small differences in multiple independent sources summate to produce scalp-level differences at Fz. The identification of independent source contributions to a single scalp sensor represents a promising methodology for measuring dissociable and homologous biomarker targets in future translational studies.

Usefulness and Safety of Remote Continuous Glucose Monitoring for a Severe COVID-19 Patient with Diabetes

Diabetes is associated with mortality and severity of coronavirus disease (COVID-19). Protecting against infection in health care workers at high risk of COVID-19 is critical. This report investigates the usefulness and safety of remote continuous glucose monitoring (CGM) in a patient with diabetes and severe interstitial pneumonia caused by the coronavirus disease. The Dexcom G4 Platinum CGM system^® was used to monitor blood glucose (BG) levels from outside the patient's isolation room. Continuous insulin infusion rates and boluses were determined based on the patient's BG levels. Real-time CGM made it possible to track BG trends and prevent dramatic variations in BG, although the rate of insulin infusion changed dynamic. Furthermore, the need for health care workers to enter the isolation room was minimized because the Dexcom G4 Platinum CGM system can evaluate from a distance of up to 6.0 m.

Boosting template-based SSVEP decoding by cross-domain transfer learning

OBJECTIVE

This study aims to establish a generalized transfer-learning framework for boosting the performance of steady-state visual evoked potential(SSVEP)-based brain-computer interfaces (BCIs) by leveraging cross-domain data transferring.

APPROACH

We enhanced the state-of-the-art template-based SSVEP decoding through incorporating a least-squares transformation (LST)-based transfer learning to leverage calibration data across multiple domains (sessions, subjects, and EEG montages).

MAIN RESULTS

Study results verified the efficacy of LST in obviating the variability of SSVEPs when transferring existing data across domains. Furthermore, the LST-based method achieved significantly higher SSVEP-decoding accuracy than the standard task-related component analysis (TRCA)-based method and the non-LST naive transfer-learning method.

SIGNIFICANCE

This study demonstrated the capability of the LST-based transfer learning to leverage existing data across subjects and/or devices with an in-depth investigation of its rationale and behavior in various circumstances. The proposed framework significantly improved the SSVEP decoding accuracy over the standard TRCA approach when calibration data are limited. Its performance in calibration reduction could facilitate plug-and-play SSVEP-based BCIs and further practical applications.

Discovery of ONO-8590580: A novel, potent and selective GABAA α5 negative allosteric modulator for the treatment of cognitive disorders

The identification and SAR development of a series of negative allosteric modulators of the GABA_A α5 receptor is described. This novel series of compounds was optimised to provide analogues with high GABA_A α5 binding affinity, high α5 negative allosteric modulatory activity, good functional subtype selectivity and low microsomal turnover, culminating in identification of ONO-8590580.

Statistically Optimized Spatial Filtering in Decoding Steady-State Visual Evoked Potentials Based on Task-Related Component Analysis

Task-related component analysis (TRCA) has been the most effective spatial filtering method in implementing high-speed brain-computer interfaces (BCIs) based on steady-state visual evoked potentials (SSVEPs). TRCA is a data-driven method, in which spatial filters are optimized to maximize inter-trial covariance of time-locked electroencephalographic (EEG) data, formulated as a generalized eigenvalue problem. Although multiple eigenvectors can be obtained by TRCA, the traditional TRCA-based SSVEP detection considered only one that corresponds to the largest eigenvalue to reduce its computational cost. This study proposes using multiple eigen-vectors to classify SSVEPs. Specifically, this study integrates a task consistency test, which statistically identifies whether the component reconstructed by each eigenvector is task-related or not, with the TRCA-based SSVEP detection method. The proposed method was evaluated by using a 12-class SSVEP dataset recorded from 10 subjects. The study results indicated that the task consistency test usually identified and suggested more than one eigenvectors (i.e., spatial filters). Further, the use of additional spatial filters significantly improved the classification accuracy of the TRCA-based SSVEP detection.

Questionable Classification Accuracy Reported in "Designing a Sum of Squared Correlations Framework for Enhancing SSVEP-Based BCIs"

This commentary presents a replication study to verify the effectiveness of a sum of squared correlations (SSCOR)-based steady-state visual evoked potentials (SSVEPs) decoding method proposed by Kumar et al.. We implemented the SSCOR-based method in accordance with their descriptions and estimated its classification accuracy using a benchmark SSVEP dataset with cross validation. Our results showed significantly lower classification accuracy compared with the ones reported in Kumar et al.'s study. We further investigated the sources of performance discrepancy by simulating data leakage between training and test datasets. The classification performance of the simulation was remarkably similar to those reported by Kumar et al.. We, therefore, question the validity of evaluation and conclusions drawn in Kumar et al.'s study.

Functional Analysis of PTH1R Variants Found in Primary Failure of Eruption

Although many variants of the parathyroid hormone 1 receptor (PTH1R) gene are known to be associated with primary failure of eruption (PFE), the mechanisms underlying the link remains poorly understood. We here performed functional analyses of PTH1R variants reported in PFE patients-namely, 356C>T (P119L), 395C>T (P132L), 439C>T (R147C), and 1148G>A (R383Q)-using HeLa cells with a lentiviral vector-mediated genetic modification. Two particular variants, P119L and P132L, had severe reduction in a level of N-linked glycosylation when compared with wild-type PTH1R, whereas the other 2 showed modest alteration. PTH1R having P119L or P132L showed marked decrease in the affinity to PTH_1-34, which likely led to severely impaired cAMP accumulation upon stimulation in cells expressing these mutants, highlighting the importance of these 2 amino acid residues for ligand-mediated proper functioning of PTH1R. To further gain insights into PTH1R functions, we established the induced pluripotent stem cell (iPSC) lines from a patient with PFE and the heterozygous P132L mutation. When differentiated into osteoblastic-lineage cells, PFE-iPSCs showed no abnormality in mineralization. The mRNA expression of RUNX2, SP7, and BGLAP, the osteoblastic differentiation-related genes, and that of PTH1R were augmented in both PFE-iPSC-derived cells and control iPSC-derived cells in the presence of bone morphogenetic protein 2. Also, active vitamin D₃ induced the expression of RANKL, a major key factor for osteoclastogenesis, equally in osteoblastic cells derived from control and PFE-iPSCs. In sharp contrast, exposure to PTH_1-34 resulted in no induction of RANKL mRNA expression in the cells expressing P132L variant PTH1R, consistent with the idea that a type of heterozygous PTH1R gene mutation would spoil PTH-dependent response in osteoblasts. Collectively, this study demonstrates a link between PFE-associated genetic alteration and causative functional impairment of PTH1R, as well as a utility of iPSC-based disease modeling for future elucidation of pathogenesis in genetic disorders, including PFE.

[A Case of Aortic Graft Infection Due to Listeria monocytogenes Detected by Microarray-Based, Multiplexed, Automated Molecular Diagnosis System]

A 80-year-old man was transferred to our hospital for hemoptysis caused by erosion(perforation) of thoracic aortic stent graft infection into the airway. Blood cultures on admission detected Gram-positive rods, and a microarray-based, multiplexed, automated molecular diagnosis instrument (Verigene® system) identified Listeria spp. Although Listeria monocytogenes is rare organism of stent graft infection, we were able to start appropriate antibiotic therapy on the second hospital day due to rapid identification of bacteria. Verigene® system is considered to be useful in severe infectious diseases including stent graft infections, even if the causative organism is rare.

Robustness analysis of decoding SSVEPs in humans with head movements using a moving visual flicker

OBJECTIVE

The emergence of mobile electroencephalogram (EEG) platforms have expanded the use cases of brain-computer interfaces (BCIs) from laboratory-oriented experiments to our daily life. In challenging situations where humans' natural behaviors such as head movements are unrestrained, various artifacts could deteriorate the performance of BCI applications. This paper explored the effect of muscular artifacts generated by participants' head movements on the signal characteristics and classification performance of steady-state visual evoked potentials (SSVEPs).

APPROACH

A moving visual flicker was employed to induce not only SSVEPs but also horizontal and vertical head movements at controlled speeds, leading to acquiring EEG signals with intensity-manipulated muscular artifacts. To properly induce neck muscular activities, a laser light was attached to participants' heads to give visual feedback; the laser light indicates the direction of the head independently from eye movements. The visual stimulus was also modulated by four distinct frequencies (10, 11, 12, and 13 Hz). The amplitude and signal-to-noise ratio (SNR) were estimated to quantify the effects of head movements on the signal characteristics of the elicited SSVEPs. The frequency identification accuracy was also estimated by using well-established decoding algorithms including calibration-free and fully-calibrated approaches.

MAIN RESULTS

The amplitude and SNR of SSVEPs tended to deteriorate when the participants moved their heads, and this tendency was significantly stronger in the vertical head movements than in the horizontal movements. The frequency identification accuracy also deteriorated in proportion to the speed of head movements. Importantly, the accuracy was significantly higher than its chance-level regardless of the level of artifact contamination and algorithms.

SIGNIFICANCE

The results suggested the feasibility of decoding SSVEPs in humans freely moving their head directions, facilitating the real-world applications of mobile BCIs.

Semi-simulation Experiments for Quantifying the Performance of SSVEP-based BCI after Reducing Artifacts from Trapezius Muscles

Muscular artifacts often contaminate electroencephalograms (EEGs) and deteriorate the performance of brain-computer interfaces (BCIs). Although many artifact reduction techniques are available, most of the studies have focused on their reduction ability (i.e. reconstruction errors), and it has been missing to evaluate their effect on the performance of BCIs. This study aims at evaluating the performance of a state-of-the-art muscular artifact reduction technique on a scenario of a steady-state visual evoked potentials (SSVEPs)based BCI. The performance was evaluated based on a semisimulation setting using a benchmark dataset of SSVEPs artificially contaminated by muscular artifacts acquired from the trapezius. Our results showed that combining the artifact reduction method and the classification algorithm based on the task-related component analysis gained improved classification accuracy. Interestingly, the artifact reduction setting minimizing the reconstruction errors, i.e. elaborately recovering the true EEG waveforms, was inconsistent to the one maximizing the classification performance. The results suggest that artifact reduction methods should be tuned so as to tomaximize performance of BCIs.

Evaluating the Performance of Non-Hair SSVEP-Based BCIs Featuring Template-Based Decoding Methods

Our previous study has demonstrated the feasibility of employing non-hair-bearing electrodes to build a Steadystate Visual Evoked Potential (SSVEP)-based Brain-Computer Interface (BCI) system, relaxing technical barriers in preparation time and offering an ease-of-use apparatus. The signal quality of the SSVEPs and the resultant performance of the non-hair BCI, however, did not close upon those reported in the state-of-the-art BCI studies based on the electroencephalogram (EEG) measured from the occipital regions. Recently, advanced decoding algorithms such as task-related component analysis have made a breakthrough in enhancing the signal quality of the occipital SSVEPs and the performance of SSVEP-based BCIs in a well-controlled laboratory environment. However, it remains unclear if the advanced decoding algorithms can extract highfidelity SSVEPs from the non-hair EEG and enhance the practicality of non-hair BCIs in real-world environments. This study aims to quantitatively evaluate whether, and if so, to what extent the non-hair BCIs can leverage the state-of-art decoding algorithms. Eleven healthy individuals participated in a 5-target SSVEP BCI experiment. A high-density EEG cap recorded SSVEPs from both hair-covered and non-hair-bearing regions. By evaluating and demonstrating the accessibility of nonhair-bearing behind-ear signals, our assessment characterized constraints on data length, trial numbers, channels, and their relationships with the decoding algorithms, providing practical guidelines to optimize SSVEP-based BCI systems in real-life applications.

Transferring Shared Responses Across Electrode Montages for Facilitating Calibration in High-Speed Brain Spellers

Recent studies have shown that using the user's average steady-state visual evoked responses (SSVEPs) as the template to template-matching methods could significantly improve the accuracy and speed of the SSVEP-based brain- computer interface (BCI). However, collecting the pilot data for each individual can be time-consuming. To resolve this practical issue, this study aims to explore the feasibility of leveraging pre- recorded datasets from the same users by transferring common electroencephalogram (EEG) responses across different sessions with the same or different electrode montages. The proposed method employs spatial filtering techniques including response averaging, canonical correlation analysis (CCA), and task- related component analysis (TRCA) to project scalp EEG recordings onto a shared response domain. The transferability was evaluated by using 40-class SSVEPs recorded from eight subjects with nine electrodes on two different days. Three subsets of electrode montages were selected to simulate different scenarios such as identical, partly overlapped, and non-overlapped electrode placements across two sessions. The target identification accuracy of the proposed methods with transferred training data significantly outperformed a conventional training-free algorithm. The result suggests training data required in the BCI speller could be transferred from different EEG montages and/or headsets.

Facilitating Calibration in High-Speed BCI Spellers via Leveraging Cross-Device Shared Latent Responses

OBJECTIVE

This paper proposes a novel device-to-device transfer-learning algorithm for reducing the calibration cost in a steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) speller by leveraging electroencephalographic (EEG) data previously acquired by different EEG systems.

METHODS

The transferring is done by projecting the scalp-channel EEG signals onto a shared latent domain across devices. Three spatial filtering techniques, including channel averaging, canonical correlation analysis (CCA), and task-related component analysis (TRCA), were employed to extract the shared responses from different devices. The transferred data were integrated into a template-matching-based algorithm to detect SSVEPs. To evaluate its transferability, this paper conducted two sessions of simulated online BCI experiments with ten subjects using 40 visual stimuli modulated by joint frequency-phase coding method. In each session, two different EEG devices were used: first, the Quick-30 system (Cognionics, Inc.) with dry electrodes, and second, the ActiveTwo system (BioSemi, Inc.) with wet electrodes.

RESULTS

The proposed method with CCA- and TRCA-based spatial filters achieved significantly higher classification accuracy compared with the calibration-free standard CCA-based method.

CONCLUSION

This paper validated the feasibility and effectiveness of the proposed method in implementing calibration-free SSVEP-based BCIs.

SIGNIFICANCE

The proposed method has great potentials to enhance practicability and usability of real-world SSVEP-based BCI applications by leveraging user-specific data recorded in previous sessions even with different EEG systems and montages.

EEG-Based Brain-Computer Interfaces

Brain-computer interfaces (BCIs) provide a direct communication channel between human brain and output devices. Due to advantages such as non-invasiveness, ease of use, and low cost, electroencephalography (EEG) is the most popular method for current BCIs. This chapter gives an overview of the current EEG-based BCIs for the main purpose of communication and control. This chapter first provides a taxonomy of the EEG-based BCI systems by categorizing them into three major groups: (1) BCIs based on event-related potentials (ERPs), (2) BCIs based on sensorimotor rhythms, and (3) hybrid BCIs. Next, this chapter describes challenges and potential solutions in developing practical BCI systems toward high communication speed, convenient system use, and low user variation. Then this chapter briefly reviews both medical and non-medical applications of current BCIs. Finally, this chapter concludes with a summary of current stage and future perspectives of the EEG-based BCI technology.

Cathepsin K inhibitor causes changes in crystallinity and crystal structure of newly-formed mandibular bone in rats

Cathepsin K inhibitors are new drugs with the potential for the treatment of osteoporosis because they sustain bony remodelling better than bone resorption inhibitors such as bisphosphonates. The treatment of osteoporosis with inhibitors of bony resorption is associated with osteonecrosis of the jaw, as the deterioration in bony quality that they induce is thought to be one of its causes. The quality of bone is delineated by structural and material characteristics (which include the degree and quality of mineralisation, and depends on the content of proteoglycan and the structural integrity of the bony collagen).^1,2 Animal and clinical studies have shown that cathepsin K inhibitors improve the mineral density and structural characteristics of bone, but their effect on the rest remains unknown. We therefore hypothesised that these inhibitors will affect the material characteristics of newly-formed mandibular bone. To verify our hypothesis, we used Raman microspectroscopy to examine such bone in rats that were given a cathepsin K inhibitor, and found unusual crystallinity and an increased substitution of carbonate (CO₃^2-) in its crystal structure.

Correction to "Correlated Component Analysis for Enhancing the Performance of SSVEP-Based Brain-Computer Interface"

In the above paper [1], a method has been proposed to use the correlated component analysis (CORCA) to learn spatial filters with multiple blocks of individual training data for steady-state visual evoked potential (SSVEP)-based brain-computer interface (BCI) scenario. In order to evaluate the performance of CORCA, the task-related component analysis (TRCA)-based method was used as a baseline method [2]. For a fair and convincing comparison, the MATLAB codes on the website (https://github.com/mnakanishi/TRCA-SSVEP) for implementing TRCA method provided by Dr. Masaki Nakanishi, the first author of [2], were used to take the role of the TRCA method. At that time, the proposed CORCA-based method outperforms the TRCA-based method [1].

A dynamic stopping method for improving performance of steady-state visual evoked potential based brain-computer interfaces

The performance of steady-state visual evoked potential (SSVEP)-based brain-computer interfaces (BCIs) has been drastically improved in the past few years. In conventional SSVEP-based BCIs, the speed of a selection is fixed towards high performance based on preliminary offline analysis. However, due to inter-trial variability, the optimal selection time to achieve sufficient accuracy is different for each trial. To optimize the performance of SSVEP-based BCIs, this study proposed a dynamic stopping method that can adaptively determine a selection time in each trial by applying a threshold to the probability of detecting a target. A 12-class SSVEP dataset recorded from 10 subjects was used to evaluate the performance of the proposed method. Compared to the conventional method with a fixed selection time towards the highest accuracy, the proposed method could significantly reduce the averaged selection time (0.84±0.39 s vs. 1.44±0.63 s, p<;0.05) with comparable accuracy (99.44±1.57 % vs. 99.55±1.22 %). As a result, the simulated online information transfer rate (ITR) with the dynamic stopping method achieved a significant improvement compared to the conventional method (125.30±21.55 bits/min vs. 92.75±23.77 bits/min). These results suggest that the proposed dynamic stopping method is effective for improving the performance of SSVEP-based BCI systems.

Molecular alterations of newly formed mandibular bone caused by zoledronate

Bone quality is defined by structural and material characteristics. Most studies on the mandible have focused on the analysis of structural characteristics, with insufficient investigation of material characteristics. This study tested whether zoledronate affects the material characteristics of newly formed mandibular bone. Thirty-six female Wistar rats were assigned to three groups: sham-ovariectomized rats (SHAM, n=12), ovariectomized rats (OVX, n=12), and ovariectomized rats treated with zoledronate (ZOL, n=12). The left side of the mandibular ramus of all rats was drilled bicortically. Twenty-eight days after surgery, all surviving rats were euthanized and all mandibles were removed. Raman microspectroscopy was performed, and five spectra per specimen of newly formed mandibular bone were analysed. Compared with OVX rats, the mineral/matrix ratio in ZOL rats was significantly increased (5.43±1.88 vs. 7.86±2.05), while crystallinity (0.055±0.002 vs. 0.050±0.002), relative proteoglycan content (0.43±0.10 vs. 0.31±0.05), and collagen structural integrity (1.16±0.21 vs. 0.72±0.06) were significantly decreased. These changes in material characteristics may explain why rats that received zoledronate exhibited peculiar biological phenomena such as bisphosphonate-related osteonecrosis of the jaw.

Enhancing Detection of SSVEPs for a High-Speed Brain Speller Using Task-Related Component Analysis

OBJECTIVE

This study proposes and evaluates a novel data-driven spatial filtering approach for enhancing steady-state visual evoked potentials (SSVEPs) detection toward a high-speed brain-computer interface (BCI) speller.

METHODS

Task-related component analysis (TRCA), which can enhance reproducibility of SSVEPs across multiple trials, was employed to improve the signal-to-noise ratio (SNR) of SSVEP signals by removing background electroencephalographic (EEG) activities. An ensemble method was further developed to integrate TRCA filters corresponding to multiple stimulation frequencies. This study conducted a comparison of BCI performance between the proposed TRCA-based method and an extended canonical correlation analysis (CCA)-based method using a 40-class SSVEP dataset recorded from 12 subjects. An online BCI speller was further implemented using a cue-guided target selection task with 20 subjects and a free-spelling task with 10 of the subjects.

RESULTS

The offline comparison results indicate that the proposed TRCA-based approach can significantly improve the classification accuracy compared with the extended CCA-based method. Furthermore, the online BCI speller achieved averaged information transfer rates (ITRs) of 325.33 ± 38.17 bits/min with the cue-guided task and 198.67 ± 50.48 bits/min with the free-spelling task.

CONCLUSION

This study validated the efficiency of the proposed TRCA-based method in implementing a high-speed SSVEP-based BCI.

SIGNIFICANCE

The high-speed SSVEP-based BCIs using the TRCA method have great potential for various applications in communication and control.

Independent component analysis-based spatial filtering improves template-based SSVEP detection

This study proposes a new algorithm to detect steady-state visual evoked potentials (SSVEPs) based on a template-matching approach combined with independent component analysis (ICA)-based spatial filtering. In recent studies, the effectiveness of the template-based SSVEP detection has been demonstrated in a high-speed brain-computer interface (BCI). Since SSVEPs can be considered as electroencephalogram (EEG) signals generated from underlying brain sources independent from other activities and artifacts, ICA has great potential to enhance the signal-to-noise ratio (SNR) of SSVEPs by separating them from artifacts. This study proposes to apply the ICA-based spatial filters to test data and individual templates obtained by averaging training trials, and then to use the correlation coefficients between the filtered data and templates as features for SSVEP classification. This study applied the proposed method to a 40-class SSVEP dataset to evaluate its classification accuracy against those obtained by conventional canonical correlation analysis (CCA)- and extended CCA-based methods. The study results showed that the ICA-based method outperformed the other methods in terms of the classification accuracy. Furthermore, its computational time was comparable to the CCA-based method, and was much shorter than that of the extended CCA-based method.

Clonal structure in Ichthyobacterium seriolicida, the causative agent of bacterial haemolytic jaundice in yellowtail, Seriola quinqueradiata, inferred from molecular epidemiological analysis

Bacterial haemolytic jaundice caused by Ichthyobacterium seriolicida has been responsible for mortality in farmed yellowtail, Seriola quinqueradiata, in western Japan since the 1980s. In this study, polymorphic analysis of I. seriolicida was performed using three molecular methods: amplified fragment length polymorphism (AFLP) analysis, multilocus sequence typing (MLST) and multiple-locus variable-number tandem repeat analysis (MLVA). Twenty-eight isolates were analysed using AFLP, while 31 isolates were examined by MLST and MLVA. No polymorphisms were identified by AFLP analysis using EcoRI and MseI, or by MLST of internal fragments of eight housekeeping genes. However, MLVA revealed variation in repeat numbers of three elements, allowing separation of the isolates into 16 sequence types. The unweighted pair group method using arithmetic averages cluster analysis of the MLVA data identified four major clusters, and all isolates belonged to clonal complexes. It is likely that I. seriolicida populations share a common ancestor, which may be a recently introduced strain.

Stim1 Regulates Enamel Mineralization and Ameloblast Modulation

Loss-of-function mutations in the Ca²⁺ release-activated Ca²⁺ channel genes ORAI1 and STIM1 abolish store-operated Ca²⁺ entry (SOCE) and result in ectodermal dysplasia with amelogenesis imperfecta. However, because of the limited availability of patient tissue, analyses of enamel mineralization or possible changes in ameloblast function or morphology have not been possible. Here, we generated mice with ectodermal tissue-specific deletion of Stim1 ( Stim1 cKO [conditional knockout]), Stim2 ( Stim2 cKO), and Stim1 and Stim2 ( Stim1/2 cKO) and analyzed their enamel phenotypes as compared with those of control ( Stim1/2^fl/fl) animals. Ablation of Stim1 and Stim1/2 but not Stim2 expression resulted in chalky enamel and severe attrition at the incisor tips and molar cusps. Stim1 and Stim1/2 cKO, but not Stim2 cKO, demonstrated inferior enamel mineralization with impaired structural integrity, whereas the shape of the teeth and enamel thickness appeared to be normal in all animals. The gene expression levels of the enamel matrix proteins Amelx and Ambn and the enamel matrix proteases Mmp20 and Klk4 were not altered by the abrogation of SOCE in Stim1/2 cKO mice. The morphology of ameloblasts during the secretory and maturation stages was not significantly altered in either the incisors or molars of the cKO animals. However, in Stim1 and Stim1/2 cKO incisors, the alternating modulation of maturation-stage ameloblasts between the smooth- and ruffle-ended cell types continued beyond the regular cycle and extended to the areas corresponding to the zone of postmodulation ameloblasts in the teeth of control animals. These results indicate that SOCE is essential for proper enamel mineralization, in which Stim1 plays a critical role during the maturation process.

Detecting Glaucoma With a Portable Brain-Computer Interface for Objective Assessment of Visual Function Loss

Importance

The current assessment of visual field loss in diseases such as glaucoma is affected by the subjectivity of patient responses and the lack of portability of standard perimeters.

Objective

To describe the development and initial validation of a portable brain-computer interface (BCI) for objectively assessing visual function loss.

Design, Setting, and Participants

This case-control study involved 62 eyes of 33 patients with glaucoma and 30 eyes of 17 healthy participants. Glaucoma was diagnosed based on a masked grading of optic disc stereophotographs. All participants underwent testing with a BCI device and standard automated perimetry (SAP) within 3 months. The BCI device integrates wearable, wireless, dry electroencephalogram and electrooculogram systems and a cellphone-based head-mounted display to enable the detection of multifocal steady state visual-evoked potentials associated with visual field stimulation. The performances of global and sectoral multifocal steady state visual-evoked potentials metrics to discriminate glaucomatous from healthy eyes were compared with global and sectoral SAP parameters. The repeatability of the BCI device measurements was assessed by collecting results of repeated testing in 20 eyes of 10 participants with glaucoma for 3 sessions of measurements separated by weekly intervals.

Main Outcomes and Measures

Receiver operating characteristic curves summarizing diagnostic accuracy. Intraclass correlation coefficients and coefficients of variation for assessing repeatability.

Results

Among the 33 participants with glaucoma, 19 (58%) were white, 12 (36%) were black, and 2 (6%) were Asian, while among the 17 participants with healthy eyes, 9 (53%) were white, 8 (47%) were black, and none were Asian. The receiver operating characteristic curve area for the global BCI multifocal steady state visual-evoked potentials parameter was 0.92 (95% CI, 0.86-0.96), which was larger than for SAP mean deviation (area under the curve, 0.81; 95% CI, 0.72-0.90), SAP mean sensitivity (area under the curve, 0.80; 95% CI, 0.69-0.88; P = .03), and SAP pattern standard deviation (area under the curve, 0.77; 95% CI, 0.66-0.87; P = .01). No statistically significant differences were seen for the sectoral measurements between the BCI and SAP. Intraclass coefficients for global and sectoral parameters ranged from 0.74 to 0.92, and mean coefficients of variation ranged from 3.03% to 7.45%.

Conclusions and Relevance

The BCI device may be useful for assessing the electrical brain responses associated with visual field stimulation. The device discriminated eyes with glaucomatous neuropathy from healthy eyes in a clinically based setting. Further studies should investigate the feasibility of the BCI device for home-based testing as well as for detecting visual function loss over time.

[Selection of Laboratory Procedures to Detect Toxigenic by the 2-Step Method]

The 2-step method is an algorithm to detect toxigenic Clostridium difficile. We herein compared the sensitivities and specificities of an enzyme immunoassay (toxin A/B-EIA), toxigenic culture (TC-EIA), Loop-Mediated Isothermal Amplification assay (LAMP), and Xpert C. difficile (Xpert) with the detection of the toxin B gene by a polymerase chain reaction (PCR). The results obtained showed that the sensitivities and specificities of toxin A/B-EIA, Xpert, TC-EIA, and LAMP were 30 and 100%, 87.2 and 100%, 97.5 and 89.7%, and 95 and 100%, respectively. We also evaluated the turnaround time (TAT) and cost of toxigenic C. difficile detection. Our hospital TAT for toxin A/B-EIA and TC-EIA are 37 min and 5 days, respectively. We estimated the TAT of Xpert, LAMP, and PCR to be 105 min, 5 days, and 6 days, respectively. On the other hand, the cost to detect toxigenic C. difficile increased in the order of TC-EIA, LAMP, Xpert, and PCR. We have never experienced outbreak of Clostridium difficile infection (CDI) in our hospital, and there is less the number of CDI than other place. So we selected TC-EIA that is good sensitivity and low cost per specimen. Hereafter it'll be necessary to solve a problem it takes time, because we have to respond to outbreak of CDI quickly if it happens.

Correlation between temperature variations of static and dynamic properties in glass-forming liquids

Detailed analysis of the static structure factor S(Q) in several glass-forming liquids reveals that the temperature variations of the width of the main diffraction peak ΔQ(T) correlate with the fragility of these liquids. This observation suggests a direct connection between rather subtle structural changes and sharp slowing down of structural relaxation in glass-forming liquids. We show that this observation can be rationalized using the Adam-Gibbs approach, through a connection between temperature variations of structural correlation length, l_{c}∼2π/ΔQ, and the size of cooperatively rearranging regions.