Overall, we found that noninvasive HFB detection is not only possible at sites where the skull hasn’t fully developed, but sufficiently robust to enable systematic investigation of early cognitive development!

Thanks to my co-authors, as well as to the Dynamic Brain Lab for their support! 🙂

At the single-baby level, the same wake > sleep effects were detected with 60% reliability using as few as 50 seconds of data per state. Although this reliability is lower than the 90% group-level reliability, 60% is higher than reliabilities seen in other developmental scalp EEG studies.

We found that when varying both the number of trials and babies included in group analyses, the reliability of the wake > sleep effect stabilized at ~90% at around 25 seconds of data per state, with as few as 10 babies (see panels A and C) and even fewer babies for occipital channels (see panel D)!

At the group level, we found that HFB power was greater in wake versus sleep states in midline and central channels near fontanelles, as well as occipital channels over thin skull. This was replicated 9/10 times (90% reliability) using as little as 25 seconds of data per state!

We analyzed scalp EEG data from 18 babies during wake and sleep states (5-second trials). Past intracranial work has shown that HFB is greater in wake vs. sleep states, so to see whether we could detect this signal in babies, we compared HFB power between these two states. 😴👶

iEEG electrode implantation is extremely rare in babies because they have fontanelles (see pink regions in image) and thin skull. However, scalp EEG channels over these regions may be able to detect HFB since they are closer to brain tissue, allowing for less signal drop off!

HFB indexes local brain activity and is predominantly studied invasively using iEEG. This signal is tricky to detect with scalp EEG because it is attenuated as it passes through skull.

HFB has been studied across development, but to our knowledge, not in babies - why not?