A Basis for Evoked Potential Assessment of Certain Visual Functions.
Abstract
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 1981
- Accession Number
- ADA102884
Entities
People
- David Regan
Organizations
- Dalhousie University