Functional cortical changes of the sensorimotor network are associated with clinical recovery in multiple sclerosis.
OBJECTIVE
To assess the early cortical changes following an acute motor relapse secondary to a pseudotumoral lesion in MS patients, the longitudinal cortical functional correlates of clinical recovery, and the evolution over time of cortical reorganization.


METHODS
FMRI during the performance of a simple motor task were obtained from 12 MS patients (after a clinical attack involving the motor system secondary to a pseudotumoral lesion) and 15 matched controls. In six patients and five controls, a longitudinal fMRI study was also performed.


RESULTS
In patients, at baseline, the primary sensorimotor cortex (SMC) of the ipsilateral (contralesional) hemisphere was significantly more active during task performance with the impaired than the unimpaired hand. During task performance with the unimpaired hand, the ipsilateral cerebellum and several motor areas in the contralateral hemisphere were significantly more active. Pseudotumoral lesion volume was correlated with activation of the primary SMC bilaterally (r = -0.86 and -0.85) and the nine-hole peg test score with activation of the primary SMC of the affected hemisphere (r = 0.88). A recovery of function of the primary SMC of the affected hemisphere was found in the four patients with clinical improvement. In the two patients without clinical recovery, there was a persistent recruitment of the primary SMC of the unaffected hemisphere.


CONCLUSIONS
Pseudotumoral MS lesions affecting the motor system can determine short-term cortical changes characterized by the recruitment of pathways in the unaffected hemisphere. The regain of function of motor areas of the affected hemisphere seems to be a critical factor for a favorable recovery.
Mezzapesa
Domenico M
DM
Neuroimaging Research Unit, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.
Rocca
Maria A
MA
Rodegher
Mariaemma
M
Comi
Giancarlo
G
Filippi
Massimo
M
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009103:Multiple Sclerosis / Q000473:pathology / Q000503:physiopathology*; D020127:Recovery of Function / Q000502:physiology*