Abstract: In a medical electroencephalographic EEG system, a hat is placed on the head of the patient. The hat contains a plurality of electrodes conforming to the hat. A circuit board having a low-noise integrated circuit amplifiers may be mounted thereon. In one embodiment each of the electrodes has a number of flexible and elastic fingers, for example 2-16 gum rubber fingers, having a conductive tip at the end of each finger, or flexible fingers made entirely of conductive material. In another embodiment the multi-contact electrode uses fingers which are rigid and connected to a spring-loaded plate. The tips contact the patient's scalp, without conductive gel or liquid, to provide a redundancy of contacts.