Cognitive impairment predicts conversion to multiple sclerosis in clinically isolated syndromes

Abstract

Significant cognitive impairment has been found in 20-30% of patients with clinically isolated syndromes suggestive of multiple sclerosis. In this study we aimed to assess the prognostic value of the presence of cognitive impairment for the conversion to multiple sclerosis in patients with clinically isolated syndromes. All patients with clinically isolated syndromes consecutively referred to our centre since 2002 and who had been followed-up for at least one year underwent cognitive assessment through the Rao's Battery and the Stroop test. Possible predictors of conversion to clinically definite multiple sclerosis were evaluated through the Kaplan Meier curves and Cox regression analysis. A total of 56 patients (41 women; age 33.2 +/- 8.5 years; expanded disability scale score 1.2 +/- 0.7) were recruited. At baseline, 32 patients (57%) fulfilled McDonald's criteria for dissemination in space. During the follow-up (3.5 +/- 2.3 years), 26 patients (46%) converted to a diagnosis of multiple sclerosis. In particular, 64% of patients failing >or= 2 tests and 88% of patients failing >or= 3 tests converted to multiple sclerosis. In the Cox regression model, the failure of at least three tests (HR 3.3; 95% CI 1.4-8.1; p = 0.003) and the presence of McDonald's dissemination in space at baseline (HR 3.8; 95% CI 1.5-9.7; p = 0.005), were found to be predictors for conversion to multiple sclerosis. We conclude that cognitive impairment is detectable in a sizable proportion of patients with clinically isolated syndromes. In these subjects cognitive impairment has a prognostic value in predicting conversion to multiple sclerosis and may therefore play a role in therapeutic decision making.

How much radiologically isolated syndrome suggestive of multiple sclerosis is multiple sclerosis?

“…These cognitive changes are similar to those found in MS patients, but RIS subjects are usually less severely affected than MS ones 18 . This finding is in agreement with the early occurrence of cognitive impairment in MS and even its observation in CIS patients 23,24 . Although RIS and MS patients have striking similarities on their conventional MRI features, the use of quantitative MR indices has provided evidences of their differences, as well as an explanation for the lack of clinical expression in RIS subjects 25 .…”

The Montreal Cognitive Assessment (MoCA) in Multiple Sclerosis: Relation to Clinical Features

“…While those with more severe disease are at greatest risk [11,[13][14][15], all patients are vulnerable. Cognitive deficits are found even among patients with "benign" disease [16] as well as those at a very early disease stage (i.e., clinically isolated syndrome or CIS and radiologically isolated syndrome or RIS) [17,18].…”

Functional magnetic resonance imaging correlates of cognitive performance in patients with a clinically isolated syndrome suggestive of multiple sclerosis at presentation: an activation and connectivity study

“…A characterization of the cognitive profile of CIS patients as well as the mechanisms underlying the preservation of some cognitive functions in this condition might improve our understanding of the development of cognitive impairment in MS. Indeed, it has been recently demonstrated that cognitive deficits in CIS patients have a prognostic value to predict subsequent conversion to definite MS [8].…”