Relationship between apathy and cognitive dysfunctions in multiple sclerosis: A 4-year prospective longitudinal study

•Apathy is frequent in MS and associated with more severe executive dysfunctions.•Higher level of apathy at baseline predicts the cognitive decline at 4-year follow-up.•Apathy represents an early neurobehavioral marker of the dysexecutive syndrome in MS.•Apathy may be considered a potential target of interventions for delaying clinical decline in MS.