Cortical adaptation in patients with MS: a cross-sectional functional MRI study of disease phenotypes.
BACKGROUND
Movement-associated cortical reorganisation is known to occur in multiple sclerosis (MS). We aimed to define the development of such cortical reorganisation by comparing data from patients with different disease phenotypes.


METHODS
We studied patients with different phenotypes of MS: 16 patients with a clinically isolated syndrome (CIS), 14 patients with relapsing-remitting MS (RRMS) and no disability, 15 patients with RRMS and mild clinical disability, and 12 patients with secondary progressive MS (SPMS). Patients did a simple motor task with their unimpaired dominant hand during MRI, which was compared across the phenotype groups.


RESULTS
Patients with a CIS activated more of the contralateral primary sensorimotor cortex than those with RRMS and no disability, whereas patients with RRMS and no disability activated more of the supplementary motor area than those with a CIS. Patients with RRMS and no disability activated more of the primary sensorimotor cortex, bilaterally, and more of the ipsilateral supplementary motor area than patients with RRMS and mild clinical disability. Conversely, patients with RRMS and mild clinical disability activated more of the contralateral secondary somatosensory cortex and inferior frontal gyrus, and the ipsilateral precuneus. Patients with RRMS and mild clinical disability activated more of the contralateral thalamus and of the ipsilateral secondary somatosensory cortex than those with SPMS. However, patients with SPMS activated more of the inferior frontal gyrus, bilaterally, the middle frontal gyrus, bilaterally, the contralateral precuneus, and the ipsilateral cingulate motor area and inferior parietal lobule.


CONCLUSIONS
Movement-associated cortical reorganisation in patients with MS seems to vary across individuals at different stages of disease. Our study suggests that early in the disease course more areas typically devoted to motor tasks are recruited. Then bilateral activation of these regions is seen, and late in the disease course, areas that healthy people recruit to do novel or complex tasks are activated.
Rocca
Maria A
MA
Neuroimaging Research Unit, University Ospedale San Raffaele, Milan, Italy.
Colombo
Bruno
B
Falini
Andrea
A
Ghezzi
Angelo
A
Martinelli
Vittorio
V
Scotti
Giuseppe
G
Comi
Giancarlo
G
Filippi
Massimo
M
D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D005385:Fingers / Q000502:physiology / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000473:pathology / Q000503:physiopathology; D009048:Motor Skills / Q000502:physiology; D009069:Movement Disorders / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D009103:Multiple Sclerosis / Q000150:complications / Q000503:physiopathology*; D009434:Neural Pathways / Q000473:pathology / Q000503:physiopathology; D009473:Neuronal Plasticity / Q000502:physiology*; D010641:Phenotype; D020127:Recovery of Function / Q000502:physiology