ATTENTION RELATED PERFORMANCE IN 2 COGNITIVELY DIFFERENT SUBGROUPS OFPATIENTS WITH MULTIPLE-SCLEROSIS

To evaluate the underlying mechanisms of cognitive decline in multiple sclerosis, two clinically and demographically matched multiple sclero sis groups differing in cognitive status were assessed with attention related tasks. In addition to the attention tests recommended by the C ognitive Function Study Group of the American National Multiple Sclero sis Society, a test of sustained attention was used to evaluate the ro le of possible fatigue on cognitive performance. The cognitively mildl y deteriorated group was slower than the cognitively preserved group a nd the controls on all tests of attention. The mildly deteriorated gro up did not, however, consistently differ from the other groups in the error scores of the attention tests. The preserved group exhibited slo wness at the end of the visual vigilance test, but no deficits were fo und on the other attention related tests in this group. It is suggeste d that dissociable kinds of processing slowness are the origin of the deficits found on the attention tests in the two multiple sclerosis gr oups. Our preserved group exhibited signs of motor and fatigue related slowness, whereas the mildly deteriorated group also had extensive co gnitive slowness. As sensitive indicators of cognitive slowness, atten tional tests should be included in evaluation of the cognitive status of patients with multiple sclerosis.