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Examples of in-ear EEG mounts. On the left is seen a single earplug (right ear), on the right is seen a right earplug in ear.

Ear-EEG is a method for measuring dynamics of brain activity through the minute voltage changes observable on the skin, typically by placing electrodes on the scalp. In ear-EEG, the electrodes are exclusively placed in or around the outer ear.


Ear-EEG was first described in "A1 US patent US20070112277 A1",[1] though other mentions are "B1 EP patent EP2448477 B1"[2] and "Auditory evoked responses from Ear-EEG recordings".[3]

Demonstration of multiple cEEGrids on dummy heads

Dry-contact electrode ear-EEG[edit]

Dry-contact electrode ear-EEG is a method in which no gel is applied between the electrode and the skin.[4] Dry-contact electrode ear-EEG have been used to perform high-density ear-EEG recordings, which enable mapping of the brain response on a topographic 3D map of the ear (Ear-topographies).[5]

When using dry-contact electrodes, the interface between the skin and the electrodes are mainly defined by the electrochemical properties of the electrode material, the mechanical design of the electrode, the surface properties of the electrode, and how the electrode is retained against the skin. The electronic instrumentation must also be carefully designed to accommodate dry-contact electrodes.[6][7]

Sleep monitoring[edit]

Innovation Fund Denmark recently funded a large project on using ear-EEG for sleep monitoring, in a collaboration between industry and Aarhus University in Denmark.[8]


  1. ^ A1 US patent US20070112277 A1 
  2. ^ B1 EP patent EP2448477 B1 
  3. ^ Kidmose, Preben. Auditory evoked responses from Ear-EEG recordings. EMBC 2012. San Diego, Cal.
  4. ^ Kappel, Simon L.; Rank, Mike Lind; Toft, Hans Olaf; Andersen, Mikael; Kidmose, Preben (2018). "Dry-Contact Electrode Ear-EEG". IEEE Transactions on Biomedical Engineering. doi:10.1109/tbme.2018.2835778. ISSN 0018-9294.
  5. ^ Kappel, Simon L.; Kidmose, Preben (July 2017). "High-density ear-EEG". 2017 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE. doi:10.1109/embc.2017.8037338. ISBN 9781509028092.
  6. ^ Kappel, Simon L.; Kidmose, Preben (August 2015). "Study of impedance spectra for dry and wet EarEEG electrodes". 2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC). IEEE. doi:10.1109/embc.2015.7319063. ISBN 9781424492718.
  7. ^ Xiong Zhou; Qiang Li; Kilsgaard, Søren; Moradi, Farshad; Kappel, Simon L.; Kidmose, Preben (June 2016). "A wearable ear-EEG recording system based on dry-contact active electrodes". 2016 IEEE Symposium on VLSI Circuits (VLSI-Circuits). IEEE. doi:10.1109/vlsic.2016.7573559. ISBN 9781509006359.
  8. ^ "Øreprop skal aflæse søvnløses hjerneaktivitet". Innnovation Fund Denmark. Retrieved 4 January 2018.