Comparison of psychophysical and evoked potential methods in the detection of visual deficits in multiple sclerosis.
We compared the diagnostic sensitivity of traditional visual tests such as the Snellen-test and pattern reversal VEPs with psychophysical and electrophysiological tests involving motion processing and psychophysical tests of contrast processing in detecting visual deficits in a group of MS patients. A total of 30 patients with a definite diagnosis of MS and 22 age-matched controls selected from a pool of healthy volunteers participated in this study. Visual evoked potentials elicited by reversing checkerboards and moving random dot patterns (motion-onset VEPs) were recorded. The recognition of motion-defined forms (motion-defined letter test, MDL-test) and of contrast reduced optotypes was measured psychophysically. Of 30 patients, 29 showed deficits in at least one of the tests applied. The highest detection rate was obtained for a simple psychophysical test, the MDL-test, which revealed abnormalities in 80% of the patients. This is about 12% more than pattern VEPs could detect. Conversely, abnormalities in motion-onset VEPs were found in only 16% of the patients. Our results show that by adding a simple psychophysical test of form-from-motion analysis our capability to demonstrate an involvement of the visual system in MS patients may be promoted considerably.
Herbst
H
H
Department of Neurology, University of Tübingen, Germany.
Ketabi
A
A
Thier
P
P
Dichgans
J
J
D000328:Adult; D001921:Brain / Q000503:physiopathology; D001931:Brain Mapping; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000503:physiopathology*; D010775:Photic Stimulation; D014786:Vision Disorders / Q000503:physiopathology*