Early Cognitive Impairment in Multiple Sclerosis
Early Cognitive Impairment in Multiple Sclerosis
Cognitive impairment is one of the symptoms of Multiple Sclerosis (MS), and it may occur
 during the first years of the disease. It usually affects attention, information processing
 speed and short term memory. To date, the mechanisms of this specific symptom remain unclear
 (local or global inflammation, neurodegenerative processes).

 Magnetic Resonance Imaging (MRI) can be useful to understand the pathophysiology of cognitive
 impairment in MS. The investigators will combine conventional and non conventional MRI
 sequences to determine the respective role of white matter and grey matter injury and the
 cortical reorganization of neuronal networks.
Cognitive impairment in Multiple Sclerosis (MS) occurs in 50% of patients and has a major
 social impact. There is no clear correlation between cognitive dysfunction and disease
 duration and recent studies have pointed out that it may affects patients at the very early
 stages of the disease especially in tasks involving sustained attention, processing speed,
 working memory and executive function.

 Recent imaging and pathology studies have shown that MS affects white matter as well as grey
 matter. Unlike white matter lesion burden or distribution, grey matter atrophy has often been
 linked to cognitive impairment. Microscopic injury of Normally Appearing White Matter (NAWM)
 explored by non conventional MRI sequences has also been shown to be involved in
 pathophysiology of cognitive disorders.

 Nevertheless mechanisms of cognitive impairment remain unclear. The relationship between
 cortical injury and diffuse white matter tracts damage and their respective contribution to
 cognitive dysfunction affecting patients during the first years of the disease is still under
 investigation.

 This study aims at investigating structural and functional correlates of early cognitive
 impairment using multimodal MRI.

 Relapsing Remitting MS (RRMS) patients with disease duration of less than 5 years will be
 included. Patients with and without cognitive impairment will be compared to healthy
 controls. All subjects will perform a clinical and neuropsychological evaluation before the
 MRI examination.

 We will combine new available MRI techniques using a 3 Tesla magnet in order to evaluate
 precisely cortical and white matter tracts lesions in patients with cognitive MS. These
 techniques will include :

 -  3D T1 sequences to study cortical atrophy using VBM.

 -  Diffusion tensor imaging fibre tracking to study selected white matter tracts that may
 be involved in cognitive disorders, such as the thalamus-cortical or the
 striatum-cortical tracts connecting sub-cortical structures to the prefrontal cortex.

 -  Functional MRI sequences during a working memory task and during the resting state in
 order to describe functional networks and their possible reorganization in patients with
 or without cognitive impairment.
Inclusion Criteria:

 -  Relapsing remitting Multiple Sclerosis patients

 -  Age: 18-40 years

 -  Evolving between 3 and 5 years

 -  EDSS<5

 Exclusion Criteria:

 -  MRI exclusion criteria (metallic prothetic, pace maker etc)

 -  Renal failure due to Gadolinium injection

 -  Major depressive disorder