Devices for recording brain activity of a subject include a first arm shaped to extend along a subject's head, the first arm having a first aperture that allows access to the subject's head. A sensor assembly of the device has multi-directional adjustability in orientation. The sensor assembly includes a shell configured for multi-directional rotation; a sleeve inside the shell; an elastic element attaching a first end of the sleeve to an interior end of the shell; and a sensor removably inserted into the sleeve, with a contact surface of the sensor facing the subject's head. The device also includes a housing that contains an energy source and operational components for the sensor assembly.