Figure 4

Profiles of psychophysiological findings for the four clusters. [⊙ = target stimuli; ○ = standard stimuli] Collectively, these findings suggest that the relapsing-remitting course of MS appears to form a more homogenous group of patients in this disease while the benign course of MS forms a more heterogeneous group in terms of altered cognitive processing. Thus, RRMS patients appear to have a relatively preserved behavioural performance with mild/moderate abnormalities of early-latency ERP components and moderate/severe impairment for P3 latency. However, our findings also show that some RRMS patients may develop important cognitive disturbances during typical relapsing-remitting stages of the disease. On the other hand, BMS patients tended to demonstrate a high heterogeneity according to their psychophysiological abnormalities. Thus, BMS patients clustered into Cluster 2 without signs of cognitive impairment and into Cluster 3 with moderate cognitive disturbances. Furthermore, BMS patients even fell into outlier cases with more severe abnormalities.