Despite the need for cognitive rehabilitation, there is a paucity of well-designed research studies to investigate treatment approaches or their effectiveness in MS. Most of published studies suffer from significant methodological flaws including small sample size, short follow-up periods, and lack of specific outcome criteria to determine improvement. O'Brien et al. (2008) recently reviewed 16 studies of cognitive rehabilitation designed to persons with MS and found only 4 class I studies and only one class I study of rehabilitation of attention deficits. Methodologically rigorous research is needed to confirm the preliminary results reported by these studies and determine the effectiveness and efficacy of cognitive rehabilitation interventions in attention deficits in MS. O'Brien et al. listed limitations found in previous studies that must be addressed in future studies. The present study was designed according to these recommendations. It is a randomized, controlled study, in parallel groups, evaluator blinded.

Number of participants: 25 RRMS patients in the active group, 25 RRMS patients in the control group and 25 healthy subjects.

The protocol will be proposed to RRMS patients AFFILIATED TO FRENCH SOCIAL SECURITY referred to the investigators center by practicing neurologists and fulfilling the inclusion criteria for screening.

Patients will be randomised between two groups. The active group (25 patients) will be treated by rehabilitation. Individual rehabilitation procedures will be focused on attention, executive functions and IPS. The program will be tailored to each patient cognitive status depending on the impairments identified during the initial assessment while maintaining a systematic work on attention and executive functions. A total of 50 sessions lasting one hour at a rate of 3 sessions per week for a total period of 4 months will be proposed. Patients randomized in the other group will participate to group session every week without specific cognitive rehabilitation. 25 healthy control subjects (group C), matched to patients for education, gender and age with patients of groups A/B will have the same evaluation procedures than patients.

Evaluation will be performed at baseline, after 4 months (end of treatment period) and after 8 months. Evaluation will include clinical testing, cognitive battery (paper/pencil and computer tests), cognitive ecological evaluation (Computer test of attention in a virtual reality environment and driving test on a driving simulator), questionnaires about daily life and MRI (fMRI and MRI). All patients and healthy subjects will undergo the fMRI protocol using a paradigm previously published by the investigators group (Bonnet et al., 2009): Go/No-go paradigm with increasing difficulty during four successive conditions (the Tonic Alertness task, Go/No-go (IG), reversal Go/No-go (RG), and complex Go/No-go (CG). In a previous study the investigators observed compensatory activation in MS patients as compared to healthy controls for the three first conditions and a saturation of compensatory processes for the more complex. In the present study, the investigators hypothesize that a similar pattern will occur at baseline and that cognitive rehabilitation will improve brain compensation at the fourth level of complexity.

: Multiple Sclerosis (MS) is the most frequent disabling neurological disease in young adults. Over the past two decades, cognitive impairment in MS has received increasing interest. Although for a long time described in MS text books, it has been underestimated until recently. It is now accepted as an important feature of MS with a high impact on working and social abilities. The cognitive disorders in MS are dominated by a slowdown in information processing speed (IPS), as well as disturbances of attention and memory. The nature of cognitive findings suggest that the impairments depend on the integrity of large-scale cortical integrative processes, which involve long-distance white matter projections which can be impaired due to diffuse demyelinating injury in patients with MS. At the early stages of MS there is increasing evidence that neuroplasticity, the ability of the brain to respond to various insults, allows adaptive reorganization of cognitive functions to limit impairment, despite widespread tissue damage. Recently, we showed that at the early stages of RRMS compensatory capacities are relatively maintained, especially in highly-educated patients suggesting that cognitive training might be useful. The requirement of cerebral compensatory mechanisms to perform the cognitive tests was postulated in MS patients on the basis of functional MRI (fMRI) studies. By using a go/no go task of increasing complexity in a fMRI study in RRMS patients, we observed that a limitation of this compensatory cerebral recruitment appears when the attentional solicitations reach a particular level of difficulty. We postulate that a cognitive training program may help to maintain these compensatory capacities. Therefore, we propose to evaluate the effect of the program on brain activation using a task with several levels of attention requirement (increased attention load) by using fMRI and to evaluate in parallel its clinical effect and its impact in daily activities.

Inclusion Criteria:

patients

• male or female relapsing remitting or secondary progressive or primary progressive Multiple sclerosis patients according to Polman et al. (2005),
• age 18-55; disease duration >6 months and ≤15 years,
• right handed,

Patients will be eligible for randomization (cognitive inclusion criterion) if they performed worse than :

• 2 scores <1 standard deviation (SD) on the scores evaluating information processing speed and attention (IPS-Attention) and 1 score <1DS on other tests assessing executive functions (EF) and working memory (WM).

or

• if they performed worse than 2 scores <1 SD on the 5 tests of information processing speed, attention and executive function (SDMT, Stroop and TMT battery GREFEX, and divided attention substests (TAP) and 1 score <1DS on other tests assessing information processing speed, and executive and attention functions (IPS / FAE) and working memory (WM).

healthy volunteers

• male or female,
• age 18-55 matched for age, gender and education
• Accepting to participate and signing the informed consent
• affiliated to french social security

Exclusion Criteria:

• existing other neurological or psychiatric disorder, visual, oculomotor, auditory and motor impairments precluding ability to perform computerized tasks and the driving simulator tasks,
• prior history of addictive behaviour,
• MS attack in the 2 months preceding the screening,
• corticosteroid pulse therapy within 2 months preceding screening,
• severe cognitive deficits or dementia (MMS<27), moderate to severe visuospatial incapacity (type IV or V at the Rey figure score < 28), moderate to severe depression (BDI >27),
• Participant without driving licence