A Novel, Robust, and Portable Platform for Magnetoencephalography using Optically Pumped Magnetometers.

Magnetoencephalography (MEG) measures brain function via assessment of magnetic fields generated by neural currents. Conventional MEG uses superconducting sensors, which place significant limitations on performance, practicality, and deployment; however, the field has been revolutionised in recent years by the introduction of optically-pumped-magnetometers (OPMs). OPMs enable measurement of the MEG signal without cryogenics, and consequently the conception of 'OPM-MEG' systems which ostensibly allow increased sensitivity and resolution, lifespan compliance, free subject movement, and lower cost. However, OPM-MEG remains in its infancy with limitations on both sensor and system design. Here, we report a new OPM-MEG design with miniaturised and integrated electronic control, a high level of portability, and improved sensor dynamic range (arguably the biggest limitation of existing instrumentation). We show that this system produces equivalent measures when compared to an established instrument; specifically, when measuring task-induced beta-band, gamma-band and evoked neuro-electrical responses, source localisations from the two systems were highly comparable and temporal correlation was >0.7 at the individual level and >0.9 for groups. Using an electromagnetic phantom, we demonstrate improved dynamic range by running the system in background fields up to 8 nT. We show that the system is effective in gathering data during free movement (including a sitting-to-standing paradigm) and that it is compatible with simultaneous electroencephalography (EEG - the clinical standard). Finally, we demonstrate portability by moving the system between two laboratories. Overall, our new system is shown to be a significant step forward for OPM-MEG technology and offers an attractive platform for next generation functional medical imaging.

The neurodevelopmental trajectory of beta band oscillations: an OPM-MEG study.

Neural oscillations mediate the coordination of activity within and between brain networks, supporting cognition and behaviour. How these processes develop throughout childhood is not only an important neuroscientific question but could also shed light on the mechanisms underlying neurological and psychiatric disorders. However, measuring the neurodevelopmental trajectory of oscillations has been hampered by confounds from instrumentation. In this paper, we investigate the suitability of a disruptive new imaging platform - Optically Pumped Magnetometer-based magnetoencephalography (OPM-MEG) - to study oscillations during brain development. We show how a unique 192-channel OPM-MEG device, which is adaptable to head size and robust to participant movement, can be used to collect high-fidelity electrophysiological data in individuals aged between 2 and 34 years. Data were collected during a somatosensory task, and we measured both stimulus-induced modulation of beta oscillations in sensory cortex, and whole-brain connectivity, showing that both modulate significantly with age. Moreover, we show that pan-spectral bursts of electrophysiological activity drive task-induced beta modulation, and that their probability of occurrence and spectral content change with age. Our results offer new insights into the developmental trajectory of beta oscillations and provide clear evidence that OPM-MEG is an ideal platform for studying electrophysiology in neurodevelopment.

Challenges in international health financing and implications for the new pandemic fund.

BACKGROUND: The failures of the international COVID-19 response highlighted key gaps in pandemic preparedness and response (PPR). The G20 and WHO have called for additional funding of $10.5 billion per year to adequately strengthen the global PPR architecture. In response to these calls, in 2022 the World Bank announced the launch of a new Financial Intermediary Fund (The Pandemic Fund) to catalyse this additional funding. However, there is considerable unclarity regarding the governance makeup and financial modalities of the Pandemic Fund, and divergence of opinion about whether the Fund has been successfully designed to respond to key challenges in global health financing. METHODS/RESULTS: The article outlines eight challenges associated with global health financing instruments and development aid for health within the global health literature. These include misaligned aid allocation; accountability; multistakeholder representation and participation; country ownership; donor coherency and fragmentation; transparency; power dynamics, and; anti-corruption. Using available information about the Pandemic Fund, the article positions the Pandemic Fund against these challenges to determine in what ways the financing instrument recognizes, addresses, partially addresses, or ignores them. The assessment argues that although the Pandemic Fund has adopted a few measures to recognise and address some of the challenges, overall, the Pandemic Fund has unclear policies in response to most of the challenges while leaving many unaddressed. CONCLUSION: It remains unclear how the Pandemic Fund is explicitly addressing challenges widely recognized in the global health financing literature. Moreover, there is evidence that the Pandemic Fund might be exacerbating these global financing challenges, thus raising questions about its potential efficacy, suitability, and chances of success. In response, this article offers four sets of policy recommendations for how the Pandemic Fund and the PPR financing architecture might respond more effectively to the identified challenges.

The Dynamics of Power Flow From the Global Health Financing Comment on "Power Dynamics Among Health Professionals in Nigeria: A Case Study of the Global Fund Policy Process".

This article agrees with Lassa et al that biomedical paradigms and medical professionals are a dominating force within the policy dynamics of the Global Fund to Fight AIDS, Tuberculosis and Malaria (GFATM) and that there needs to be greater community involvement in how global health initiatives (GHIs) are adopted, designed, implemented and evaluated. However, we argue that many of the conditions identified are entrenched and perpetuated by how GHIs are financed and the financing modalities employed in Development Aid for Health (DAH), particularly in low resource settings. As a result, the dynamics of power not only flow from traditionally entrenched epistemic authorities but are disproportionally sustained by global health financing modalities that favour particular GHIs over others. As we argue, these DAH modalities can exert forms of power with problematic effects on policy-making.

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.

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.

A 90-channel triaxial magnetoencephalography system using optically pumped magnetometers.

Magnetoencephalography (MEG) measures the small magnetic fields generated by current flow in neural networks, providing a noninvasive metric of brain function. MEG is well established as a powerful neuroscientific and clinical tool. However, current instrumentation is hampered by cumbersome cryogenic field-sensing technologies. In contrast, MEG using optically pumped magnetometers (OPM-MEG) employs small, lightweight, noncryogenic sensors that provide data with higher sensitivity and spatial resolution, a natural scanning environment (including participant movement), and adaptability to any age. However, OPM-MEG is new and the optimum way to design a system is unknown. Here, we construct a novel, 90-channel triaxial OPM-MEG system and use it to map motor function during a naturalistic handwriting task. Results show that high-precision magnetic field control reduced background fields to ∼200 pT, enabling free participant movement. Our triaxial array offered twice the total measured signal and better interference rejection compared to a conventional (single-axis) design. We mapped neural oscillatory activity to the sensorimotor network, demonstrating significant differences in motor network activity and connectivity for left-handed versus right-handed handwriting. Repeatability across scans showed that we can map electrophysiological activity with an accuracy ∼4 mm. Overall, our study introduces a novel triaxial OPM-MEG design and confirms its potential for high-performance functional neuroimaging.

The role of health systems for health security: a scoping review revealing the need for improved conceptual and practical linkages.

BACKGROUND: Practical links between health systems and health security are historically prevalent, but the conceptual links between these fields remain under explored, with little on health system strengthening. The need to address this gap gains relevance in light of the COVID-19 pandemic as it demonstrated a crucial relationship between health system capacities and effective health security response. Acknowledging the importance of developing stronger and more resilient health systems globally for health emergency preparedness, the WHO developed a Health Systems for Health Security framework that aims to promote a common understanding of what health systems for health security entails whilst identifying key capacities required. METHODS/ RESULTS: To further explore and analyse the conceptual and practical links between health systems and health security within the peer reviewed literature, a rapid scoping review was carried out to provide an overview of the type, extent and quantity of research available. Studies were included if they had been peer-reviewed and were published in English (seven databases 2000 to 2020). 343 articles were identified, of those 204 discussed health systems and health security (high and medium relevance), 101 discussed just health systems and 47 discussed only health security (low relevance). Within the high and medium relevance articles, several concepts emerged, including the prioritization of health security over health systems, the tendency to treat health security as exceptionalism focusing on acute health emergencies, and a conceptualisation of security as 'state security' not 'human security' or population health. CONCLUSION: Examples of literature exploring links between health systems and health security are provided. We also present recommendations for further research, offering several investments and/or programmes that could reliably lead to maximal gains from both a health system and a health security perspective, and why these should be explored further. This paper could help researchers and funders when deciding upon the scope, nature and design of future research in this area. Additionally, the paper legitimises the necessity of the Health Systems for Health Security framework, with the findings of this paper providing useful insights and evidentiary examples for effective implementation of the framework.

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.

Mapping buyer's clubs; what role do they play in achieving equitable access to medicines?

Buyer's clubs were first recognised during the HIV/AIDS pandemic in the 1980s and focussed on knowledge curation and distribution of treatments. In the past decade, there has been a resurgence of buyer's clubs, mostly focussed on hepatitis C treatment and PrEP. This paper aims to increase understanding of buyer's clubs and stimulate discussion on their role in achieving equitable access to medicines. Our proposed definition of a buyer's club is 'a community-led organisation or group which seeks to improve an individual's access to medication through knowledge sharing and/or distribution as its primary goal'. The logistical and relational infrastructures of buyer's clubs have been mapped out. Networks and communities are integral to buyer's clubs by facilitating practical aspects of buyer's clubs and creating a sense of community that serves as a foundation of trust. For a user to receive necessary medical support, doctors play a crucial role, yet, obtaining this support is difficult. Whilst buyer's clubs are estimated to have enabled thousands of people to access medicines, and they run the risk of perpetuating health inequities and injustices. They may have the potential to serve as a health activism tool to stimulate sustainable changes; however, this needs to be explored further.

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.

The Effectiveness of Enhanced Cognitive Behavioural Therapy (CBT-E): A Naturalistic Study within an Out-Patient Eating Disorder Service.

BACKGROUND: The effectiveness of enhanced cognitive behavioural Therapy (CBT-E) for adults with a range of eating disorder presentations within routine clinical settings has been examined in only two known published studies, neither of which included a follow-up assessment period. AIM: The current study aimed to evaluate the effectiveness of CBT-E within an out-patient eating disorder service in Brisbane, Queensland, Australia, and incorporated a follow-up assessment period of approximately 20 weeks post-treatment. METHOD: The study involved 114 adult females with a diagnosed eating disorder, who attended an average of 20-40 individual CBT-E sessions with a psychologist or a psychiatry registrar between 2009 and 2013. RESULTS: Of those who began treatment, 50% did not complete treatment, and the presence of psychosocial and environmental problems predicted drop-out. Amongst treatment completers, statistically and clinically significant improvements in eating disorder and general psychopathology were observed at post-treatment, which were generally maintained at the 20-week follow-up. Statistically significant improvements in eating disorder and general psychopathology were observed amongst the total sample. CONCLUSIONS: The findings, which were comparable to the previous Australian effectiveness study of CBT-E, indicate that CBT-E is an effective treatment for adults with all eating disorders within out-patient settings. Given the high attrition rate, however, minimizing drop-out appears to be an important consideration when implementing CBT-E within clinical settings.