A sensor array can be integrally defined in a fabric headgear. A gel distribution module can be connected to each sensor of the sensor array. Each module can include an outer part that is connectable to a second inner part so that the fabric of the headgear and sensor are between the inner and outer parts. Each module can be configured to facilitate the distribution of a gel onto a scalp of a patient and into contact with the sensor via actuation of an actuator of the module to permit rapid deployment of the gel at the sensor specific locations on the head of a patient. The gel can be distributed directly onto skin of the scalp even when the patient has hair at the sensor location. The sensor array can be positioned so that asymmetrical positioning of the sensors on a patient's head is detectable.