Moving magnetoencephalography towards real-world applications with a wearable system.

Imaging human brain function with techniques such as magnetoencephalography typically requires a subject to perform tasks while their head remains still within a restrictive scanner. This artificial environment makes the technique inaccessible to many people, and limits the experimental questions that can be addressed. For example, it has been difficult to apply neuroimaging to investigation of the neural substrates of cognitive development in babies and children, or to study processes in adults that require unconstrained head movement (such as spatial navigation). Here we describe a magnetoencephalography system that can be worn like a helmet, allowing free and natural movement during scanning. This is possible owing to the integration of quantum sensors, which do not rely on superconducting technology, with a system for nulling background magnetic fields. We demonstrate human electrophysiological measurement at millisecond resolution while subjects make natural movements, including head nodding, stretching, drinking and playing a ball game. Our results compare well to those of the current state-of-the-art, even when subjects make large head movements. The system opens up new possibilities for scanning any subject or patient group, with myriad applications such as characterization of the neurodevelopmental connectome, imaging subjects moving naturally in a virtual environment and investigating the pathophysiology of movement disorders.

Measurement of Frontal Midline Theta Oscillations using OPM-MEG.

Optically pumped magnetometers (OPMs) are an emerging lightweight and compact sensor that can measure magnetic fields generated by the human brain. OPMs enable construction of wearable magnetoencephalography (MEG) systems, which offer advantages over conventional instrumentation. However, when trying to measure signals at low frequency, higher levels of inherent sensor noise, magnetic interference and movement artefact introduce a significant challenge. Accurate characterisation of low frequency brain signals is important for neuroscientific, clinical, and paediatric MEG applications and consequently, demonstrating the viability of OPMs in this area is critical. Here, we undertake measurement of theta band (4-8 Hz) neural oscillations and contrast a newly developed 174 channel triaxial wearable OPM-MEG system with conventional (cryogenic-MEG) instrumentation. Our results show that visual steady state responses at 4 Hz, 6 Hz and 8 Hz can be recorded using OPM-MEG with a signal-to-noise ratio (SNR) that is not significantly different to conventional MEG. Moreover, we measure frontal midline theta oscillations during a 2-back working memory task, again demonstrating comparable SNR for both systems. We show that individual differences in both the amplitude and spatial signature of induced frontal-midline theta responses are maintained across systems. Finally, we show that our OPM-MEG results could not have been achieved without a triaxial sensor array, or the use of postprocessing techniques. Our results demonstrate the viability of OPMs for characterising theta oscillations and add weight to the argument that OPMs can replace cryogenic sensors as the fundamental building block of MEG systems.

Enabling ambulatory movement in wearable magnetoencephalography with matrix coil active magnetic shielding.

The ability to collect high-quality neuroimaging data during ambulatory participant movement would enable a wealth of neuroscientific paradigms. Wearable magnetoencephalography (MEG) based on optically pumped magnetometers (OPMs) has the potential to allow participant movement during a scan. However, the strict zero magnetic field requirement of OPMs means that systems must be operated inside a magnetically shielded room (MSR) and also require active shielding using electromagnetic coils to cancel residual fields and field changes (due to external sources and sensor movements) that would otherwise prevent accurate neuronal source reconstructions. Existing active shielding systems only compensate fields over small, fixed regions and do not allow ambulatory movement. Here we describe the matrix coil, a new type of active shielding system for OPM-MEG which is formed from 48 square unit coils arranged on two planes which can compensate magnetic fields in regions that can be flexibly placed between the planes. Through the integration of optical tracking with OPM data acquisition, field changes induced by participant movement are cancelled with low latency (25 ms). High-quality MEG source data were collected despite the presence of large (65 cm translations and 270° rotations) ambulatory participant movements.

Naturalistic Hyperscanning with Wearable Magnetoencephalography.

The evolution of human cognitive function is reliant on complex social interactions which form the behavioural foundation of who we are. These social capacities are subject to dramatic change in disease and injury; yet their supporting neural substrates remain poorly understood. Hyperscanning employs functional neuroimaging to simultaneously assess brain activity in two individuals and offers the best means to understand the neural basis of social interaction. However, present technologies are limited, either by poor performance (low spatial/temporal precision) or an unnatural scanning environment (claustrophobic scanners, with interactions via video). Here, we describe hyperscanning using wearable magnetoencephalography (MEG) based on optically pumped magnetometers (OPMs). We demonstrate our approach by simultaneously measuring brain activity in two subjects undertaking two separate tasks-an interactive touching task and a ball game. Despite large and unpredictable subject motion, sensorimotor brain activity was delineated clearly, and the correlation of the envelope of neuronal oscillations between the two subjects was demonstrated. Our results show that unlike existing modalities, OPM-MEG combines high-fidelity data acquisition and a naturalistic setting and thus presents significant potential to investigate neural correlates of social interaction.

Evaluating the Impact of Pharmacist Dual Verification of Anticancer Therapy in the Modern Era.

Background: Pharmacist order verification is a critical step in ensuring medication safety for patients. While the second pharmacist verification (SPV) before dispensing anticancer therapies has been a longstanding practice, its continued necessity in the context of modern electronic health systems lacks robust evidence. Objective: This study aimed to assess the frequency of interventions performed by a second pharmacist to determine the ongoing effectiveness of the SPV process. Methods: This retrospective chart review was conducted at the Mayo Clinic, encompassing all anticancer therapy orders that necessitated an SPV. The study period extended from January 1, 2019, to June 30, 2021, and included inpatient and outpatient anticancer orders. The quantification and reporting of alterations made to discrete order fields subsequent to initial pharmacist verification of clinical significance were performed, utilizing the total number of anticancer therapy orders as the denominator. Results: Approximately 300 000 anticancer therapy orders were screened for inclusion criteria and 2.6% (N = 7634) of orders were modified on the SPV. Most changes were in the categories of rate (N = 1962), order start time (N = 1219), and pharmacy communication note (N = 777). Dosing changes greater than 10% accounted for 0.03% (N = 99) of the orders, with 10 anticancer therapies responsible for more than 50% of these changes. Conclusion and relevance: This study represents the largest report on the impact of SPV in a modern era. Our results suggest the SPV may be valuable for a small proportion of chemotherapy orders but raises questions about the necessity for broad application of this practice.

Triaxial detection of the neuromagnetic field using optically-pumped magnetometry: feasibility and application in children.

Optically-pumped magnetometers (OPMs) are an established alternative to superconducting sensors for magnetoencephalography (MEG), offering significant advantages including flexibility to accommodate any head size, uniform coverage, free movement during scanning, better data quality and lower cost. However, OPM sensor technology remains under development; there is flexibility regarding OPM design and it is not yet clear which variant will prove most effective for MEG. Most OPM-MEG implementations have either used single-axis (equivalent to conventional MEG) or dual-axis magnetic field measurements. Here we demonstrate use of a triaxial OPM formulation, able to characterise the full 3D neuromagnetic field vector. We show that this novel sensor is able to characterise magnetic fields with high accuracy and sensitivity that matches conventional (dual-axis) OPMs. We show practicality via measurement of biomagnetic fields from both the heart and the brain. Using simulations, we demonstrate how triaxial measurement offers improved cortical coverage, especially in infants. Finally, we introduce a new 3D-printed child-friendly OPM-helmet and demonstrate feasibility of triaxial measurement in a five-year-old. In sum, the data presented demonstrate that triaxial OPMs offer a significant improvement over dual-axis variants and are likely to become the sensor of choice for future MEG systems, particularly for deployment in paediatric populations.

Using OPM-MEG in contrasting magnetic environments.

Magnetoencephalography (MEG) has been revolutionised by optically pumped magnetometers (OPMs). "OPM-MEG" offers higher sensitivity, better spatial resolution, and lower cost than conventional instrumentation based on superconducting quantum interference devices (SQUIDs). Moreover, because OPMs are small, lightweight, and portable they offer the possibility of lifespan compliance and (with control of background field) motion robustness, dramatically expanding the range of MEG applications. However, OPM-MEG remains nascent technology; it places stringent requirements on magnetic shielding, and whilst a number of viable systems exist, most are custom made and there have been no cross-site investigations showing the reliability of data. In this paper, we undertake the first cross-site OPM-MEG comparison, using near identical commercial systems scanning the same participant. The two sites are deliberately contrasting, with different magnetic environments: a "green field" campus university site with an OPM-optimised shielded room (low interference) and a city centre hospital site with a "standard" (non-optimised) MSR (higher interference). We show that despite a 20-fold difference in background field, and a 30-fold difference in low frequency interference, using dynamic field control and software-based suppression of interference we can generate comparable noise floors at both sites. In human data recorded during a visuo-motor task and a face processing paradigm, we were able to generate similar data, with source localisation showing that brain regions could be pinpointed with just ∼10 mm spatial discrepancy and temporal correlations of > 80%. Overall, our study demonstrates that, with appropriate field control, OPM-MEG systems can be sited even in city centre hospital locations. The methods presented pave the way for wider deployment of OPM-MEG.

Gradient Field Detection Using Interference of Stimulated Microwave Optical Sidebands.

We demonstrate that stimulated microwave optical sideband generation using parametric frequency conversion can be utilized as a powerful technique for coherent state detection in atomic physics experiments. The technique has advantages over traditional absorption or polarization rotation-based measurements and enables the isolation of signal photons from probe photons. We outline a theoretical framework that accurately models sideband generation using a density matrix formalism. Using this technique, we demonstrate a novel intrinsic magnetic gradiometer that detects magnetic gradient fields between two spatially separated vapor cells by measuring the frequency of the beat note between sidebands generated within each cell. The sidebands are produced with high efficiency using parametric frequency conversion of a probe beam interacting with ^{87}Rb atoms in a coherent superposition of magnetically sensitive hyperfine ground states. Interference between the sidebands generates a low-frequency beat note whose frequency is determined by the magnetic field gradient between the two vapor cells. In contrast to traditional gradiometers the intermediate step of measuring the magnetic field experienced by the two vapor cells is unnecessary. We show that this technique can be readily implemented in a practical device by demonstrating a compact magnetic gradiometer sensor head with a sensitivity of 25 fT/cm/sqrt[Hz] with a 4.4 cm baseline, while operating in a noisy laboratory environment unshielded from Earth's field.

Abemaciclib: The First FDA-Approved CDK4/6 Inhibitor for the Adjuvant Treatment of HR+ HER2- Early Breast Cancer.

OBJECTIVE: To review the new indication of cyclin-dependent kinase (CDK4/6) inhibitor abemaciclib for the adjuvant treatment of hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (HER2-), axillary lymph node (LN) positive early breast cancer (EBC) at high risk of recurrence and a Ki-67 ≥20%. DATA SOURCES: A literature search was performed through PubMed, ClinicalTrials.gov, and Food and Drug Administration (FDA) website (February 1, 2018, to December 23, 2021) to identify relevant information. STUDY SELECTION AND DATA EXTRACTION: Human and animal studies related to pharmacology, pharmacokinetics, efficacy, and safety of abemaciclib were identified. DATA SYNTHESIS: Addition of abemaciclib to standard of care endocrine therapy (ET) for patients with high-risk clinicopathologic features and Ki-67 ≥20% demonstrated 30% reduction in the risk of developing invasive disease and distant recurrence. At 15.5 months, abemaciclib + ET demonstrated a significant improvement in invasive disease-free survival (IDFS) vs ET alone (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.60-0.93, P = 0.01). At 27 months, IDFS benefit was maintained (HR, 0.70; 95% CI, 0.59-0.82, P < 0.0001). Diarrhea occurred in more than 80% of patients in the abemaciclib arm. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: This review describes the clinical applicability of adjuvant abemaciclib for patients with HR+, HER2- EBC at high risk for recurrence. CONCLUSION: Adjuvant abemaciclib significantly reduces the risk for early development of invasive disease and distant recurrence in patients with HR+, HER2- node positive EBC. Longer follow-up is needed to determine the impact of adjuvant abemaciclib on late disease recurrence and survival outcomes.

Coworkers are more likely than patients to transmit SARS-CoV-2 infection to healthcare personnel.

OBJECTIVES: To compare the impact of occupational exposures to SARS-CoV-2 positive patients and SARS-CoV-2 positive coworkers, by comparing the frequency of occupational exposure incidents and the rate of healthcare personnel (HCP) who developed a positive PCR test for SARS-COV-2 after occupational exposure to the two different types of infectious individuals. METHODS: A retrospective analysis of all confirmed higher risk occupational exposure incidents that occurred in HCP from 20 March 2020 to 31 December 2020 at a large multisite US academic medical centre. Comparisons between groups for source type were performed using unpaired Student's t-test for continuous variables and the χ2 test for categorical variables, regression analysis was conducted to assess the associations between source type and risk of positive COVID-19 test after occupational exposure. RESULTS: In total, 2253 confirmed medium or high-risk occupational exposures occurred during the study period. 57% were exposures from coworker sources. Each source individual exposed a mean of 2.6 (95% CI 2.3 to 2.9) HCP; during postexposure surveillance, 4.5% of exposed HCP tested positive within 14 days. A coworker source on average exposed 2.2 (95% CI 2.01 to 2.4) other HCP and infected 0.14 (95% CI 0.1 to 0.17) HCP, while patient sources exposed a mean of 3.4 (95% CI 2.6 to 4.2) HCP but only infected 0.07 (95% CI 0.04 to 0.11) HCP. The multivariate analysis demonstrated that exposure to a coworker source carried a higher risk of testing positive compared with exposure to a patient source (OR 3.22; 95% CI 1.72 to 6.04). CONCLUSION: Occupational exposures to coworker sources were not only more frequent but also associated with triple the risk of developing COVID-19 infection, compared with exposures to patient sources.

Successful management of iliofemoral and visceral malperfusion syndrome in acute type A aortic dissection with endovascular revascularization followed by delayed proximal aortic repair.

Acute type A aortic dissection with malperfusion syndrome is associated with high mortality. Despite having no consensus-based guidelines, we believe the "endovascular-first" approach should be undertaken. This report describes the successful management of iliofemoral and visceral malperfusion syndrome with endovascular revascularization followed by delayed proximal aortic repair after acute type A aortic dissection.

A Tale of Two D-Dimers: Comparison of Two Assay Methods to Evaluate Deep Vein Thrombosis or Pulmonary Embolism.

BACKGROUND: D-dimer testing rules out deep vein thrombosis (DVT) and pulmonary embolism (PE) in low-risk emergency department (ED) patients. Most research has measured fibrin-equivalent units (FEUs), however, many laboratories measure D-dimer units (DDUs). OBJECTIVE: Our aim was to determine whether either DDU measurements or FEU measurements can rule out DVT/PE using traditional or age-related cutoff values. METHODS: We performed a de-identified multicenter retrospective evaluation of D-dimer in nonpregnant adult ED patients to evaluate for DVT/PE. DDUs were multiplied by 2 to determine equivalent FEUs prior to analysis. Sensitivity measurements for D-dimer were calculated for FEUs, DDUs, combined FEU/DDUs, and multiple age-adjusted values. RESULTS: We identified 47,088 ED patients with a D-dimer laboratory value (27,307 FEUs/19,781 DDUs) and 1623 DVT/PEs. The median combined FEU/DDU D-dimer was 400 ng/mL FEUs (interquartile range [IQR] 300-900 ng/mL FEUs) for patients without a DVT/PE vs 2530 ng/mL FEU (IQR 1094-6000 ng/mL FEUs) with a DVT/PE (p < 0.001), overall sensitivity of 87.3% (95% confidence interval [CI] 87.0-87.6%) and negative predictive value of 99.3% (95% CI 99.2-99.4%). Individually, FEUs performed better than DDUs, with sensitivities of 88.0% (95% CI 85.8-89.9%) and 86.1% (95% CI 83.1-88.7%), respectively; however, this difference was not statistically significant. Combined age-adjusted performance had a sensitivity of 90.3% (95% CI 88.3-92.0%); however, a new DDU-only age-adjusted criteria had the highest sensitivity of 91.1% (95% CI 87.9-93.6%). CONCLUSIONS: Our undifferentiated D-dimer measurements had a slightly lower sensitivity to rule out DVT/PE than reported previously. Our data support using either DDU or FEU measurements for all ages or when using various age-adjusted criteria to rule out DVT/PE.

Theoretical advantages of a triaxial optically pumped magnetometer magnetoencephalography system.

The optically pumped magnetometer (OPM) is a viable means to detect magnetic fields generated by human brain activity. Compared to conventional detectors (superconducting quantum interference devices) OPMs are small, lightweight, flexible, and operate without cryogenics. This has led to a step change in instrumentation for magnetoencephalography (MEG), enabling a "wearable" scanner platform, adaptable to fit any head size, able to acquire data whilst subjects move, and offering improved data quality. Although many studies have shown the efficacy of 'OPM-MEG', one relatively untapped advantage relates to improved array design. Specifically, OPMs enable the simultaneous measurement of magnetic field components along multiple axes (distinct from a single radial orientation, as used in most conventional MEG systems). This enables characterisation of the magnetic field vector at all sensors, affording extra information which has the potential to improve source reconstruction. Here, we conduct a theoretical analysis of the critical parameters that should be optimised for effective source reconstruction. We show that these parameters can be optimised by judicious array design incorporating triaxial MEG measurements. Using simulations, we demonstrate how a triaxial array offers a dramatic improvement on our ability to differentiate real brain activity from sources of magnetic interference (external to the brain). Further, a triaxial system is shown to offer a marked improvement in the elimination of artefact caused by head movement. Theoretical results are supplemented by an experimental recording demonstrating improved interference reduction. These findings offer new insights into how future OPM-MEG arrays can be designed with improved performance.

Measuring functional connectivity with wearable MEG.

Optically-pumped magnetometers (OPMs) offer the potential for a step change in magnetoencephalography (MEG) enabling wearable systems that provide improved data quality, accommodate any subject group, allow data capture during movement and potentially reduce cost. However, OPM-MEG is a nascent technology and, to realise its potential, it must be shown to facilitate key neuroscientific measurements, such as the characterisation of brain networks. Networks, and the connectivities that underlie them, have become a core area of neuroscientific investigation, and their importance is underscored by many demonstrations of their disruption in brain disorders. Consequently, a demonstration of network measurements using OPM-MEG would be a significant step forward. Here, we aimed to show that a wearable 50-channel OPM-MEG system enables characterisation of the electrophysiological connectome. To this end, we measured connectivity in the resting state and during a visuo-motor task, using both OPM-MEG and a state-of-the-art 275-channel cryogenic MEG device. Our results show that resting-state connectome matrices from OPM and cryogenic systems exhibit a high degree of similarity, with correlation values >70%. In addition, in task data, similar differences in connectivity between individuals (scanned multiple times) were observed in cryogenic and OPM-MEG data, again demonstrating the fidelity of the OPM-MEG device. This is the first demonstration of network connectivity measured using OPM-MEG, and results add weight to the argument that OPMs will ultimately supersede cryogenic sensors for MEG measurement.

Precision magnetic field modelling and control for wearable magnetoencephalography.

Optically-pumped magnetometers (OPMs) are highly sensitive, compact magnetic field sensors, which offer a viable alternative to cryogenic sensors (superconducting quantum interference devices - SQUIDs) for magnetoencephalography (MEG). With the promise of a wearable system that offers lifespan compliance, enables movement during scanning, and provides higher quality data, OPMs could drive a step change in MEG instrumentation. However, this potential can only be realised if background magnetic fields are appropriately controlled, via a combination of optimised passive magnetic screening (i.e. enclosing the system in layers of high-permeability materials), and electromagnetic coils to further null the remnant magnetic field. In this work, we show that even in an OPM-optimised passive shield with extremely low (<2 nT) remnant magnetic field, head movement generates significant artefacts in MEG data that manifest as low-frequency interference. To counter this effect we introduce a magnetic field mapping technique, in which the participant moves their head to sample the background magnetic field using a wearable sensor array; resulting data are compared to a model to derive coefficients representing three uniform magnetic field components and five magnetic field gradient components inside the passive shield. We show that this technique accurately reconstructs the magnitude of known magnetic fields. Moreover, by feeding the obtained coefficients into a bi-planar electromagnetic coil system, we were able to reduce the uniform magnetic field experienced by the array from a magnitude of 1.3±0.3 nT to 0.29±0.07 nT. Most importantly, we show that this field compensation generates a five-fold reduction in motion artefact at 0‒2 Hz, in a visual steady-state evoked response experiment using 6 Hz stimulation. We suggest that this technique could be used in future OPM-MEG experiments to improve the quality of data, especially in paradigms seeking to measure low-frequency oscillations, or in experiments where head movement is encouraged.

Mouth magnetoencephalography: A unique perspective on the human hippocampus.

Traditional magnetoencephalographic (MEG) brain imaging scanners consist of a rigid sensor array surrounding the head; this means that they are maximally sensitive to superficial brain structures. New technology based on optical pumping means that we can now consider more flexible and creative sensor placement. Here we explored the magnetic fields generated by a model of the human hippocampus not only across scalp but also at the roof of the mouth. We found that simulated hippocampal sources gave rise to dipolar field patterns with one scalp surface field extremum at the temporal lobe and a corresponding maximum or minimum at the roof of the mouth. We then constructed a fitted dental mould to accommodate an Optically Pumped Magnetometer (OPM). We collected data using a previously validated hippocampal-dependant task to test the empirical utility of a mouth-based sensor, with an accompanying array of left and right temporal lobe OPMs. We found that the mouth sensor showed the greatest task-related theta power change. We found that this sensor had a mild effect on the reconstructed power in the hippocampus (~10% change) but that coherence images between the mouth sensor and reconstructed source images showed a global maximum in the right hippocampus. We conclude that augmenting a scalp-based MEG array with sensors in the mouth shows unique promise for both basic scientists and clinicians interested in interrogating the hippocampus.

Assessment of pain, anxiety and depression, and quality of life after minimally invasive aortic surgery.

BACKGROUND: Minimally invasive cardiac surgery may reduce surgical trauma, diminish postoperative pain and improve quality of life (QOL). The aim of this study is to assess pain, hospital anxiety and depression scale (HADS), and QOL in patients undergoing minimally invasive aortic surgery. METHODS: This is a prospective, single-center cohort study of 24 consecutive patients undergoing upper ministernotomy aortic valve, aortic root, and concomitant aortic valve and ascending aorta replacement. Visual analog scale (VAS) pain scores and HADS and Short-Form-36 (SF-36) questionnaires were evaluated at preoperative baseline, during hospitalization, and at 1 and 3 months postoperatively. RESULTS: At discharge, the average VAS pain score was significantly lower than postoperative Day 1 (2.7 ± 0.4 vs. 6.5 ± 0.4; p ≤ .001). By 1 month, the pain scores were not significantly different from baseline (1.7 ± 0.4 vs. 1.0 ± 0.4; p = 1.000), and by 3 months, pain scores returned to baseline (1.0 ± 0.4; p = 1.000). HADS scores show that compared with preoperative baseline, average anxiety scores decreased by 1 month (3.1 ± 0.7 vs. 4.3 ± 0.6; p = 1.000) and decreased significantly by 3 months (1.8 ± 0.7 vs. 4.3 ± 0.6; p = .012). Additionally, depression scores were unchanged at 1 month (3.0 ± 0.4 vs. 3.1. ± 0.4; p = 1.000) and decreased by 3 months (1.3 ± 0.5 vs. 3.0 ± 0.4; p = .060). SF-36 scores revealed no changes in scores in 7 of 8 domains at 1 month and a significant increase in "physical functioning," "energy," and "general health" domains compared to preoperative baseline at 3 months. CONCLUSIONS: Following minimally invasive aortic surgery, VAS pain scores, HADS and scores in 7 of 8 SF-36 domains returned to preoperative baseline or improved compared to preoperative baseline at 1 month. At 3 months, scores in 3 of 8 SF-36 domains significantly improved compared to preoperative baseline. Larger studies are necessary for further investigation.

Transcatheter and ministernotomy aortic valve replacement after bioprosthetic valve failure.

BACKGROUND: Transcatheter valve-in-valve implantation (TViV) and minimally invasive reoperative aortic valve replacement (MIrAVR) have rapidly increased as alternatives to conventional reoperative surgical AVR. This study reports a single-center experience of patients undergoing TViV and MIrAVR after bioprosthetic valve failure. METHODS: In this retrospective review between March 2009 and October 2018, 68 patients without reoperative full sternotomies, concomitant procedures, active endocarditis, and prior homografts or coronary artery bypass grafting underwent isolated AVR for degenerated aortic bioprostheses. Society of Thoracic Surgeons (STS) risk scores and age are reported as median (interquartile range [IQR]) and length of stay is reported as mean (standard deviation [SD]) due to their characteristics of the distribution. RESULTS: Forty-one (60.3%) patients underwent TViV, and 27 (39.7%) patients underwent MIrAVR. Median [IQR] STS risk scores were 5.7 [4.0-7.8] and 2.0 [1.5-3.4] for TViV and MIrAVR, respectively (p ≤ .001). The median [IQR] age for TViV patients was higher (78 [71-84] vs. 66 [53-72] years, p ≤ 0.001). More permanent pacemakers were implanted (22.2% vs. 9.8%) following MIrAVR. The MIrAVR group had a higher rate of atrial fibrillation (18.5% vs. 9.8%, p = .466). Average (SD) length of stay was less in TViV (5.3 days, SD: 3.4 vs. 8.6 days, SD: 7.4, p = .001). Survival at 1 year was not significantly different for TViV and MIrAVR (94.9% [95% confidence interval [CI]: 81.0%, 98.7%] and 86.9% [95% CI: 64.0%, 95.7%], respectively [p = .969]). CONCLUSIONS: Despite being at higher-risk, patients undergoing TViV had reduced rates of permanent pacemaker implantations and atrial fibrillation, and a shorter hospital stay as compared to MIrAVR. Survival at 1-year was similar between the two groups.

Multi-channel whole-head OPM-MEG: Helmet design and a comparison with a conventional system.

Magnetoencephalography (MEG) is a powerful technique for functional neuroimaging, offering a non-invasive window on brain electrophysiology. MEG systems have traditionally been based on cryogenic sensors which detect the small extracranial magnetic fields generated by synchronised current in neuronal assemblies, however, such systems have fundamental limitations. In recent years, non-cryogenic quantum-enabled sensors, called optically-pumped magnetometers (OPMs), in combination with novel techniques for accurate background magnetic field control, have promised to lift those restrictions offering an adaptable, motion-robust MEG system, with improved data quality, at reduced cost. However, OPM-MEG remains a nascent technology, and whilst viable systems exist, most employ small numbers of sensors sited above targeted brain regions. Here, building on previous work, we construct a wearable OPM-MEG system with 'whole-head' coverage based upon commercially available OPMs, and test its capabilities to measure alpha, beta and gamma oscillations. We design two methods for OPM mounting; a flexible (EEG-like) cap and rigid (additively-manufactured) helmet. Whilst both designs allow for high quality data to be collected, we argue that the rigid helmet offers a more robust option with significant advantages for reconstruction of field data into 3D images of changes in neuronal current. Using repeat measurements in two participants, we show signal detection for our device to be highly robust. Moreover, via application of source-space modelling, we show that, despite having 5 times fewer sensors, our system exhibits comparable performance to an established cryogenic MEG device. While significant challenges still remain, these developments provide further evidence that OPM-MEG is likely to facilitate a step change for functional neuroimaging.

Hand posture as localizing sign in adult focal epileptic seizures.

OBJECTIVE: The aim of this study was to identify specific ictal hand postures (HPs) as localizing signs of the epileptogenic zone (EZ) in patients with frontal or temporal lobe epilepsy. METHODS: In this study, we retrospectively analyzed ictal semiology of 489 temporal lobe or frontal lobe seizures recorded over a 6-year period at the Seizure Disorder Center at University of California, Los Angeles in the USA (45 patients) or at the C. Munari Epilepsy Surgery Center at Niguarda Hospital in Milan, Italy (34 patients). Our criterion for EZ localization was at least 2 years of seizure freedom after surgery. We analyzed presence and latency of ictal HP. We then examined whether specific initial HPs are predictive for EZ localization. RESULTS: We found that ictal HPs were present in 72.5% of patients with frontal and 54.5% of patients with temporal lobe seizures. We divided HPs into 6 classes depending on the reciprocal position of the fingers ("fist," "cup," "politician's fist," "pincer," "extended hand," "pointing"). We found a striking correlation between EZ localization and ictal HP. In particular, fist and pointing HPs are strongly predictive of frontal lobe EZ; cup, politician's fist, and pincer are strongly predictive of temporal lobe EZ. INTERPRETATION: Our study offers simple ictal signs that appear to clarify differential diagnosis of temporal versus frontal lobe EZ localization. These results are meant to be used as a novel complementary tool during presurgical evaluation for epilepsy. At the same time, they give us important insight into the neurophysiology of hand movements. ANN NEUROL 2019;86:793-800.