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The main hypotheses of the project were that (1) early MS patients (disease duration >=3 months and <=5 years, EDSS score <=2.5) would present emotional impairment, as demonstrated using a task assessing decision making (Iowa Gambling Task [IGT]) and two questionnaires measuring behavioral symptoms (Dysexecutive questionnaire [DEX], Iowa Scale of Personality Change [ISPC]); (2) these emotional alterations might impair social and familial functioning, as measured by the London Handicap Scale and a self-report of general health status (SEP-59), independently from the occurrence of fatigue. We tested a cohort of 109 patients with definite MS and 56 with possible MS (117 women and 48 men, mean age 35.4 years) at inclusion, and compared their performances to those of a control group composed of 50 healthy volunteers (35 women and 15 men, mean age 32.2). For the baseline analysis, we disposed of a follow-up period of 15 months for all MS patients. At this time point, 53 patients had had a relapse, including 17 having possible MS at inclusion who thus evolved to definite MS. Eighty-two patients (71 with definite MS) were also reassessed longitudinally >=2 years after inclusion with the same testing, to measure changes in emotional impairment. At baseline, the performances in the IGT were comparable in confirmed MS patients, possible MS patients and controls for a learning index measuring the ability to evolve in the process of decision making (p=0.7). The comparison of the relapsing patients with those who remained clinically stable throughout the study allowed us to find a difference in the learning index (p=0.02), that remained a trend after adjustment for age, gender, and education, (p=0.06). Finally, cognitive, behavioral, fatigue, handicap or QoL scores were surprisingly not associated with the IGT learning index. At retest, a significant decline in the learning index of the IGT was observed from baseline (p=0.005), MS patients learning slower to avoid disadvantageous decks at retest. In the opposite, neither the prevalence of cognitive impairment, nor behavioral, handicap and QoL scores showed a significant change. In conclusion, the ability in decision making in our cohort of patients was not different from controls’ at baseline but it had decreased significantly at retest. Unexpectedly, the performances in the IGT were not associated with more general emotional and behavioral factors. Considering our results, it seems clear that MS patients are affected by mild changes in the cognitive (Simioni et al., 2007) and behavioral (Souza Lima et al., 2007) fields early in the course of the disease. However, decision making difficulties may develop later and independently from cognitive and behavioral ones.
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