title: Lateral interactions and speed of information processing in highly functioning multiple sclerosis patients.
abstract: Visual impairment is a common feature of multiple sclerosis. The aim of this study was to investigate lateral interactions in the visual cortex of highly functioning patients with multiple sclerosis and to compare that with basic visual and neuropsychologic functions. Twenty-two young, visually unimpaired multiple sclerosis patients with minimal symptoms (Expanded Disability Status Scale <2) and 30 healthy controls subjects participated in the study. Lateral interactions were investigated with the flanker task, during which participants were asked to detect the orientation of a low-contrast Gabor patch (vertical or horizontal), flanked with 2 collinear or orthogonal Gabor patches. Stimulus exposure time was 40, 60, 80, and 100 ms. Digit span forward/backward, digit symbol, verbal fluency, and California Verbal Learning Test procedures were used for background neuropsychologic assessment. Results revealed that patients with multiple sclerosis showed intact visual contrast sensitivity and neuropsychologic functions, whereas orientation detection in the orthogonal condition was significantly impaired. At 40-ms exposure time, collinear flankers facilitated the orientation detection performance of the patients resulting in normal performance. In conclusion, the detection of briefly presented, low-contrast visual stimuli was selectively impaired in multiple sclerosis. Lateral interactions between target and flankers robustly facilitated target detection in the patient group.
authors.affiliation: Department of Neurology, Faculty of Medicine, Albert Szent-Györgyi Medical and Pharmaceutical Center, Szeged, Hungary.
authors.forename: Helga
authors.initials: H
authors.lastname: Nagy
authors.forename: Krisztina
authors.initials: K
authors.lastname: Bencsik
authors.forename: Cecília
authors.initials: C
authors.lastname: Rajda
authors.forename: Krisztina
authors.initials: K
authors.lastname: Benedek
authors.forename: Márta
authors.initials: M
authors.lastname: Janáky
authors.forename: Sándor
authors.initials: S
authors.lastname: Beniczky
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Kéri
authors.forename: László
authors.initials: L
authors.lastname: Vécsei
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003071:Cognition / Q000502:physiology; D005260:Female; D005364:Field Dependence-Independence; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000503:physiopathology*; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D012016:Reference Values; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013850:Thinking / Q000502:physiology*