Paced visual serial addition test in multiple sclerosis

The paced auditory serial addition test (PASAT), a subtest of the multiple sclerosis functional composite score (MSFC), is increasingly used in the evaluation of cognitive function in multiple sclerosis (MS). While patient acceptance for the PASAT is low, its visual version, the paced visual serial addition test (PVSAT), is perceived to be better tolerated. The aim of this study was to investigate the interchangeability of PVSAT and PASAT in the evaluation of cognitive function in MS. Twenty-one normal controls and 50 patients with clinically definite MS were tested with PASAT and PVSAT. Both for PASAT and PVSAT, 3 and 2-second versions of two parallel test forms were used. In the PVSAT, the PASAT stimuli were shown on a computer screen. Patients were also tested with the other two MSFC subtests, i.e. the nine-hole pegboard test and timed 25-foot walk test, to calculate MSFC scores. PASAT-3 correlated highly with both PVSAT-3 and PVSAT-2. MSFC-v scores calculated with PVSAT-2 and PVSAT-3 values correlated highly with MSFC scores calculated with PASAT-3 results. The results suggest that the PVSAT can be used as an alternative for the PASAT in the MSFC.