Deviation maps
Authors: Pauline Amrouche, Raymundo Cassani
This tutorial introduces the implementation of the deviation maps process in Brainstorm, using the five subjects of the OMEGA tutorial as an illustration. Before proceeding, please complete the OMEGA tutorial as we will build on its results.
Introduction
Electrophysiology recordings have been explored to identify and describe abnormal activity patterns in patients with specific clinical phenotypes compared to healthy controls. Normative modelling helps define the healthy range of certain biomarkers and map individual differences at the single-subject level—a concept known as deviation maps.
Several studies have explored the potential of electrophysiology recordings to identify and describe abnormal activity patterns in patients with specific clinical phenotypes compared to healthy controls. Normative modelling has been used to define the healthy range of certain biomarkers and map individual differences at the single-subject level, a concept to which we refer as deviation maps. This approach has been applied in refractory epilepsy using scalp EEG [1] and in identifying new biomarkers for mild traumatic brain injury (mTBI) using MEG [2] for instance.
In this tutorial, we will create dummy deviation maps from the MEG spectral features of five subjects from the OMEGA tutorial. Four subjects will serve as the reference population, against which the fifth subject will be compared.
Preprocessing: extract spectral features