Method and apparatus for objective electrophysiological assessment of visual function

An apparatusus for analysing at least one multifocal visual evoked potential response of at least two subjects, the at least one visual evoked potential response being induced by any mode of multifocal stimulation, wherein the stimulation mode is adapted to simultaneously stimulate different parts of the visual field of an eye of the subject such that different parts of the visual field are stimulated with random sequences of different timing or character, the apparatus comprising:

• (a) electrodes placed on the scalp or in contact with the eye of each subject configured to simultaneously record (A) the at least one visual evoked potential responses from each of the different parts of the visual field of the eye and (B) the subject's overall spontaneous brain activity levels;
• and
• (b) a computer configured to:
• (bi) identify, for each subject, the alpha rhythm component in the subject's overall spontaneous brain activity levels,
• (bii) remove, for each subject, the alpha rhythm component from the subject's overall spontaneous brain activity levels;
• (biii) calculate, for each subject, a corresponding scaling factor, the scaling factor being derived from the subject's overall spontaneous brain activity levels from which the component of alpha rhythm is identified and removed;
• and
• (biv) scale, for each subject, each subject's visual evoked potential response using said each subject's scaling factor such that the variability of the visual evoked potential responses induced by the multifocal stimulation between the at least two subjects is minimised.