Head-mounted physiological signal monitoring system, devices and methods

A physiological signal monitoring system comprising:

• at least two dry surface electrophysiological electrodes each comprising a lower surface adapted to contact the subject's skin, each electrode comprising a plurality of low aspect ratio surface features on the lower surface;
• an earpiece adapted to be worn in or around at least one ear of a subject and comprising at least one soundspeaker at least one of the at least two dry surface electrophysiological electrodes being adapted to be attached to or integrated into the earpiece;
• a smartphone or smartwatch comprising one or more sensors, at least one processor, and a user interface, the one or more sensors not being of the at least two dry electrophysiological electrodes and being adapted for measurement of physiological signals from a subject and/or environmental signals from the subject's surroundings, the at least one processor adapted to at least obtain, amplify, and filter signals from the dry electrode(s);
• the processor or a second electronic component comprising an algorithm adapted to process the amplified and filtered signals to produce one or more electrophysiological signals, and the processor or second electronic component being further adapted to measure a physiological signal from the subject using the one or more sensors of the smartphone or smartwatch substantially simultaneously with the measuring of the signals using the dry electrodes.