Sensitivity studies and optimization of arrangements of optically pumped magnetometers in simulated magnetoencephalography

Abstract

Purpose The purpose of this paper is to present a simulation study using a model of a new optically pumped magnetometer sensor for application in the field of magnetoencephalography. The effects of sensor distance and orientation on the measurement information and the sensitivity to neuronal sources are investigated. Further, this paper uses a combinatorial optimization approach for sensor placement to measure spontaneous activity in the region of the occipital cortex. Design/methodology/approach This paper studies the effects of sensor distance and orientation on sensitivity to cortical sources and measurement information. A three-compartment model of the head, using the boundary element method, is applied. For sensor setup optimization, a combinatorial optimization scheme is developed. Findings The sensor distance to sources considerably affects the sensitivity and the retrieved information. A specific arrangement of four sensors for measuring spontaneous activity over the occipital part of the head is optimized by effectively avoiding position conflicts. Research limitations/implications Individual head models, as well as more detailed noise and signal models, will increase the significance for specific-use cases in future studies. Originality/value Effects of sensor distance and orientation are specifically evaluated for a new optically pumped magnetometer. A discrete optimization scheme for sensor optimization is introduced. The presented methodology is applicable for other sensor characterization and optimization problems. The findings contribute significantly to the development of new sensors.

Optimal design of on‐scalp electromagnetic sensor arrays for brain source localisation

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“…Even more, this approach seems better suited for practical applications in which the number of sensors available at any moment may vary due to technological glitches, as we have personally experienced with state‐of‐the‐art OPMs. The use of a more thorough methodology, such as combinatorial multilevel optimisation (Eichardt et al, 2019), is planned for future development.…”

“…All these perturbations are likely to increase the CRB metrics and consequently worth exploring in more detail. What is more, although this noise model is widely adopted and accepted, it is an idealised version of the real noise found in OPMs (and sensors in general), and therefore more work is needed to represent noise depending on the sensor technology (Eichardt et al, 2019; Oelsner et al, 2019). Second, we utilised the point electrode and sensor models, which are generally adopted in E/MEG, and in OPM research in particular (Duque‐Munoz et al, 2019; Hill et al, 2020; Pfeiffer et al, 2018).…”

Transcranial ultrasonic propagation and enhanced brain imaging exploiting the focusing effect of the skull

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