Patterns of cognitive impairment in secondary progressive stable phase of multiple sclerosis: correlations with MRI findings.

Cognitive impairment is commonly described in multiple sclerosis (MS), but conflicting results have been reported about its pattern by previous studies focused on heterogeneous patient groups. The aim of this study was to investigate the cognitive skills of a homogeneous group of secondary progressive MS patients, and to examine the relationship of this impairment to MRI parameters. Forty-four MS patients underwent a series of neuropsychological tests devised to explore the main cognitive domains, and T1- and T2-weighted brain MRI. Results showed the presence of deficits of attention, memory, planning abilities, problem-solving and conceptual reasoning (frontal functions) in a subgroup of MS patients. Correlations between the performance in some 'frontal' tests and the extent of frontal lobe MRI lesional area were present, but rather unspecific, the same performance being also correlated with the nonfrontal lesional area. These findings suggest that in MS, overall macroscopic and microscopic brain damage is more important than the corresponding focal brain disease, even in determining deficits of selective cognitive domains.