A head-gear 1 (e.g. hat or cap) incorporates flexible substrate 3, which may be metal or copper-clad, and has electrical circuitry 4, 4A within or on its surface, including electrodes 5 monitoring e.g. electro-encephalography (EEG) signals. In use, the flexible circuit 3 conforms to the users head. The headwear 1 may comprise receptacles, such as pockets or pouches, which may permanently or removably retain the substrate via e.g. stitching, hooks and loops, zips or straps. Apertures 2 may then be positioned in register with electrodes 5. An anterior 12 and posterior portion 15 may be dimensioned to extend between the users nasion and inion. Together with branches 13 (possibly releasable via electrical connectors), this may allow positioning of electrodes in register with positions of the 10-20 system, and/or monitoring of the motor or visual cortex respectively. The headgear may provide a brain-computer interface (BCI) which is discrete, unobtrusive and adaptable.
