Study of episodic memory in multiple sclerosis using the California Verbal Learning Test: the data favour altered encoding.

Introduction. Alteration of episodic memory is one of the main cognitive deficits observed in MS patients. Patients and methods. We studied episodic memory in a group of 71 MS patients (37 RR, 34 SP) with the California Verbal Learning test (CVLT). Direct scores and calculated indices from CVLT performances were analyzed in comparison with controls. Results. We observed a deficit of episodic memory in 69 p.cent of patients. This deficit was related to an alteration of encoding and retrieval processes. Despite SP-MS patients performances were constantly lower than those of RR-MS patients no significant difference was observed between the two groups. Significant correlation between the disease duration and CVLT performances were observed for the whole group but not for RR- or SP-MS groups separately, indicating that duration is more important than the phase of the disease in the worsening of memory deficit.