Embodiments of a shielded sensor headset including a plurality of electrodes are generally described herein. In some embodiments a sensor headset can include electrodes, traces, and connection terminals printed on a first side of a flexible insulating substrate; and a shield plane printed on a second side of the flexible insulating substrate, the shield plane providing protection against interference. In some embodiments a sensor headset can include a first and a second assembly each having a plurality of electrodes, the first and second assemblies being configured to mate such that the electrodes comply with the 10-20 standard for EEG electrode placement. In some embodiments a sensor headset can include a dual-layer foam reservoir disposed above individual electrodes. An inner layer of the dual-layer foam reservoir can be in contact with an electrode, include a conductive gel, and form a cavity for receiving additional gel through a perforation in the electrode.