Head-mountable apparatus for measuring magnetic brain response to auditory stimuli is disclosed. The apparatus comprises a first case adapted to be mounted on the head on the right auditory cortex, wherein the first case houses a first set of optically pumped magnetometers for measuring magnetic brain response to auditory stimuli. The apparatus also comprises a second case adapted to be mounted on the head on the left auditory cortex, wherein the second case houses a second set of optically pumped magnetometers for measuring magnetic brain response to auditory stimuli. Finally, the apparatus comprises at least one output interface for transmitting measurement data from the apparatus.
