Evidence for enhanced functional activity of cervical cord in relapsing multiple sclerosis

Functional MRI (fMRI) was used to assess proprioceptive‐associated cervical cord activity in 24 relapsing multiple sclerosis (MS) patients and 10 controls. Cord and brain conventional and diffusion tensor (DT) MRI were also acquired. fMRI was performed using a block design during a proprioceptive stimulation consisting of a passive flexion‐extension of the right upper limb. Cord lesion number, cross‐sectional area, mean diffusivity (MD) and fractional anisotropy (FA), whole brain and left corticospinal tract lesion volume (LV), gray matter (GM) MD, and normal‐appearing white matter (NAWM) MD and FA were calculated. MS patients had higher average cord fMRI signal changes than controls (3.4% vs. 2.7%, P = 0.03). Compared to controls, MS patients also had a higher average signal change in the anterior section of the right cord at C5 (P = 0.005) and left cord at C5–C6 (P = 0.03), whereas no difference was found in the other cord sections. Cord average signal change correlated significantly with cord FA and brain left corticospinal tract LV, GM‐MD, and NAWM‐FA. This study shows an abnormal pattern of activations in the cervical cord of MS patients following proprioceptive stimulation. Cord fMRI changes might have a role in limiting the clinical consequences of MS associated with irreversible tissue damage. Magn Reson Med 59:1035–1042, 2008. © 2008 Wiley‐Liss, Inc.