Download or read book A Basis for Evoked Potential Assessment of Certain Visual Functions written by David Regan and published by . This book was released on 1981 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evoked potential recording is a technique for recording electrical brain responses from scalp electrodes so as to assess human visual functions objectively. This report describes two evoked potential stimulators and methods for testing visual acuity and visual contrast sensitivity. These two electronic devices enable true contrast responses to be distinguished from responses to changes in local light intensity. This is achieved by dissociating the direction of contrast change from the direction of intensity change. The devices also allow different stimuli to be randomly interleaved under computer control. This procedure improves measurement accuracy by combining interleaving (to combat slow changes of the evoked potential with time) with signal averaging (to combat the unfavourable signal-to-noise ratio). Pattern and contrast evoked potentials are similar to those generated by the relatively inflexible optical technique, and the major EP component to pattern appearance is shown to be a true pattern response of the human visual pathway. (Author).