  A normative electrographic activity map could be a powerful resource to
understand normal brain function and identify abnormal activity. Here, we
present a normative brain map using scalp EEG in terms of relative band power.
In this exploratory study we investigate its temporal stability, its similarity
to other imaging modalities, and explore a potential clinical application.
  We constructed scalp EEG normative maps of brain dynamics from 17 healthy
controls using source-localised resting-state scalp recordings. We then
correlated these maps with those acquired from MEG and intracranial EEG to
investigate their similarity. Lastly, we use the normative maps to lateralise
abnormal regions in epilepsy.
  Spatial patterns of band powers were broadly consistent with previous
literature and stable across recordings. Scalp EEG normative maps were most
similar to other modalities in the alpha band, and relatively similar across
most bands. Towards a clinical application in epilepsy, we found abnormal
temporal regions ipsilateral to the epileptogenic hemisphere.
  Scalp EEG relative band power normative maps are spatially stable across
time, in keeping with MEG and intracranial EEG results. Normative mapping is
feasible and may be potentially clinically useful in epilepsy. Future studies
with larger sample sizes and high-density EEG are now required for validation.
