Evaluating sub-clinical cognitive dysfunction and event-related potentials (P300) in clinically isolated syndrome

Objective  This study investigated the presence of sub-clinical cognitive dysfunction in patients with clinically isolated syndrome (CIS) and the abnormalities of cognitive event-related potentials (ERPs). Methods  Subclinical cognitive dysfunction was assessed in 20 patients with CIS and in 20 healthy controls. Results  Patients had impairments in verbal learning and long-term memory, evaluating attention, executive function and visuospatial skills, in decreasing order of frequency. SDLT and SIT were the most, and COWAT and BNT were the least affected tests. The N200 and P200 latencies were prolonged, and N100, N200 and P200 amplitudes were reduced in the patients relative to the controls, from the Fz, Cz and Pz electrode positions (p<0.05). Conclusion  Detailed cognitive testing is valuable in determining subclinical cognitive dysfunction in CIS patients. ERP abnormalities as well as abnormalities in detailed cognitivetesting in patients with CIS are helpful in the diagnosis of sub-clinical cognitive dysfunction.