Figure 4

Acquisition of EEG and respiration from inside the ear canal. (a) Stability of the electrode-skin interface over the course of 8 hours, for 5 subjects¹³. (b) ASSR response measured from the ear, M1 and Cz scalp locations. (c) SSVEP response measured from the ear, M1 and Cz locations. (d) Visual evoked potential measured with the earpiece¹³. (e) Alpha rhythm recorded from the ear electrodes, 30 s into the trial subject closed their eyes. (f,g) (Top and Middle) Spectrograms of acoustic signals measured by the two microphones (inward- and wall-facing) integrated within the earpiece when the subject was asked to breath at 16 and 28 breaths per minute, respectively. (f,g) (Bottom) Breathing signals extracted from the associated spectrograms. (h) EEG signals from scalp and ear canal during the N2 stage of sleep. (i) EEG signals from scalp and ear canal when the subject was awake, but with eyes closed.