“…An elegant solution to avoid placing electrodes on the head in locations where they are visible or difficult to apply, has been proposed in the form of a miniaturized EEG device placed in or around the ears, offering both a reliable and user-friendly alternative for full-scalp EEG (Mikkelsen, Kappel, Mandic, & Kidmose, 2015;Mikkelsen, Kidmose, & Hansen, 2017;Mikkelsen, Villadsen, Otto, & Kidmose, 2017;Pacharra, Debener, & Wascher, 2017). More specifically, several studies have reported progress towards using such ear-centered EEG devices for tracking the presence of different sleep stages (Looney, Goverdovsky, Rosenzwei, Morrell, & Mandic, 2016;Mikkelsen, Villadsen, et al, 2017;Stochholm, Mikkelsen, & Kidmose, 2016;Zibrandtsen, Kidmose, Otto, Ibsen, & Kjaer, 2016). These studies all showed promising results, but involved a limited number of participants and also restricted electrode positioning.…”