Recently, a new kind of sensor applicable in magnetoencephalography (MEG) has been presented: a solid-state yttrium-iron garnet magnetometer (YIGM). The feasibility of yttrium-iron garnet magnetometers (YIGMs) was demonstrated in an alpha-rhythm registration experiment. In this paper, we propose the analysis of lead-field matrices for different possible multi-channel on-scalp sensor layouts using YIGMs with respect to information theory. Real noise levels of the new sensor were used to compute signal-to-noise ratio (SNR) and total information capacity (TiC), and compared with corresponding metrics that can be obtained with well-established MEG systems based on superconducting quantum interference devices (SQUIDs) and optically pumped magnetometers (OPMs). The results showed that due to YIGMs’ proximity to the subject’s scalp, they outperform SQUIDs and OPMs at their respective noise levels in terms of SNR and TiC. However, the current noise levels of YIGM sensors are unfortunately insufficient for constructing a multichannel YIG-MEG system. This simulation study provides insight into the direction for further development of YIGM sensors to create a multi-channel MEG system, namely, by decreasing the noise levels of sensors.

This paper addresses several critical aspects of using optically pumped magnetometers (OPMs), focusing on both metrological issues and the enhancement of signal quality. We present a quantitative methodology for OPM measurements standardization and quality evaluation, which is crucial in biomedical applications like magnetoencephalography (MEG). Additionally, we introduce a novel, cost-effective portable active magnetic shielding system - digital adaptive suppression system (DASS) – that represents a significant advancement over traditional analog active shielding. Through comprehensive experimental research, we evaluate first-and third-generation commercial OPMs from QuSpin Inc. in two distinct magnetic environments. Our results demonstrate that the DASS ensures optimal and reliable OPM performance, even in noisy urban settings, surpassing the effectiveness of conventional analog shielding. These findings highlight the need for advanced magnetic shielding solutions to enhance the accuracy and reproducibility of OPM measurements.

Recently, a new kind of sensor applicable in magnetoencephalography (MEG) has been presented: a solid-state yttrium-iron garnet magnetometer (YIGM). The feasibility of YIGM was proved in alpha-rhythm registration experiment. In the current paper, we propose the analysis of lead-field matrices for different possible YIGM multichannel on-scalp sensor layouts with respect to the information theory. We use real noise level of the new sensor to compute signal power, signal-to-noise ration (SNR) and total information capacity, and compare them with corresponding metrics that can be obtained with well-established MEG systems: based on superconducting quantum interference devices (SQUIDs) and optically-pumped magnetometers (OPMs). This simulation study is aimed to shed some light on the direction for further development of YIGM sensor, namely creation of multi-channel YIG-MEG.

This paper addresses several critical aspects of using optically pumped magnetometers (OPMs), focusing on both metrological issues and the enhancement of signal quality. We present a quantitative methodology for OPM measurements standardization and quality evaluation, which is crucial in biomedical applications like magnetoencephalography (MEG). Additionally, we introduce a novel, cost-effective portable active magnetic shielding system – digital adaptive suppression system (DASS) – that represents a significant advancement over traditional analog active shielding. Through comprehensive experimental research, we evaluate first- and third-generation commercial OPMs from QuSpin Inc. in two distinct magnetic environments. Our results demonstrate that the DASS ensures optimal and reliable OPM performance, even in noisy urban settings, surpassing the effectiveness of conventional analog shielding. These findings highlight the need for advanced magnetic shielding solutions to enhance the accuracy and reproducibility of OPM measurements.