Artemis 123: development of a whole-head infant and young child MEG system

Abstract

Background: A major motivation in designing the new infant and child magnetoencephalography (MEG) system described in this manuscript is the premise that electrophysiological signatures (resting activity and evoked responses) may serve as biomarkers of neurodevelopmental disorders, with neuronal abnormalities in conditions such as autism spectrum disorder (ASD) potentially detectable early in development. Whole-head MEG systems are generally optimized/sized for adults. Since magnetic field produced by neuronal currents decreases as a function of distance2 and infants and young children have smaller head sizes (and thus increased brain-to-sensor distance), whole-head adult MEG systems do not provide optimal signal-to-noise in younger individuals. This spurred development of a whole-head infant and young child MEG system – Artemis 123.Methods:In addition to describing the design of the Artemis 123, the focus of this manuscript is the use of Artemis 123 to obtain auditory evoked neuromagnetic recordings and resting-state data in young children. Data were collected from a 14-month-old female, an 18-month-old female, and a 48-month-old male. Phantom data are also provided to show localization accuracy.Results:Examination of Artemis 123 auditory data showed generalizability and reproducibility, with auditory responses observed in all participants. The auditory MEG measures were also found to be manipulable, exhibiting sensitivity to tone frequency. Furthermore, there appeared to be a predictable sensitivity of evoked components to development, with latencies decreasing with age. Examination of resting-state data showed characteristic oscillatory activity. Finally, phantom data showed that dipole sources could be localized with an error less than 0.5 cm.Conclusions:Artemis 123 allows efficient recording of high-quality whole-head MEG in infants four years and younger. Future work will involve examining the feasibility of obtaining somatosensory and visual recordings in similar-age children as well as obtaining recordings from younger infants. Thus, the Artemis 123 offers the promise of detecting earlier diagnostic signatures in such neurodevelopmental disorders.

Advanced neuroimaging and its role in predicting neurodevelopmental outcomes in very preterm infants

“…One likely development will be the use of combined advanced MRI, genomic/epigenetic biomarkers and sophisticated pattern classification techniques to make personalized predictions for high-risk infants a reality (Figure 4). Newer developments in infant magnetoencephalography 91 and bedside monitoring tools (e.g., high-density EEG and near infrared spectroscopy) 92,93 may also yield novel complementary biomarkers. Such advances will facilitate targeted early intervention therapies and novel neuroprotective interventions to enable improved developmental outcomes.…”

Magnetoencephalography in the study of children with autism spectrum disorder

“…As shown in Figures and , after the development of the custom child‐sized MEG in 2010, researchers could focus on brain activity in young children (e.g., 3–7 years old), which had been the missing link in brain‐developmental neurophysiological data. Furthermore, in 2014, a novel whole‐head infant MEG system was developed . This system was optimized for children 3 years of age and younger, allowing the helmet to be placed closer to the underlying neuronal sources even in infants.…”

“…Furthermore, in 2014, a novel whole-head infant MEG system was developed. 57 This system was optimized for children 3 years of age and younger, allowing the helmet to be placed closer to the underlying neuronal sources even in infants. Now, the time has come to use whole-head MEG systems in humans of all ages for developmental brain research.…”

Short-range connections in the developmental connectome during typical and atypical brain maturation

“…Specific MEG systems tailored for infant brain has also been recently established (e.g. Roberts et al, 2014; Edgar et al, 2015; Okada et al, 2016). …”