The comparison of small-size rectangle and checkerboard stimulation for the evaluation of delayed visual evoked responses in patients suspected of multiple sclerosis.

The use of foveal small-size rectangle stimulation to elicit visual evoked responses was compared with VERs elicited by the standard checkerboard pattern. Foveal stimulation achieved a significantly better discrimination of optic nerve lesions in the early diagnosis of multiple sclerosis. Sources of misdiagnosis due to different neurological disorders are discussed.