An earpiece having two electroencephalogram (EEG) sensors 4 on the upper surface 7 of a component casing 3. The casing houses a battery 6, a power connector 2, a wireless communications module 1, and a bone transducer 5. The device delivers sound to the middle ear via the bone transducer, and measures an EEG signal derived from the user. The two EEG electrodes touch the skin in front of or around the ear of the user.
