Upper motor neuron evaluation in multiple sclerosis patients treated with Sativex.

BACKGROUND

Spasticity in multiple sclerosis (MS) results from an imbalance of inputs from descending pathways to the spinal motor circuits, as well as from a damage of the corticospinal tract (CST).

OBJECTIVES

To assess CST impairment in MS patients with and without spasticity and to evaluate its evolution under Sativex treatment.

METHODS

Ten MS patients with spasticity ("cases") underwent clinical (EDSS, 9-hole Peg, Ashworth scale, Timed 25-Foot Walk, and NRS for spasticity), MRI (CST fractional anisotropy [FA]), and electrophysiological (central motor conduction time [CMCT] and H/M ratio) evaluations at baseline and after 12 months. We selected 20 MS patients without spasticity as control group at baseline.

RESULTS

At baseline, cases showed a lower CST FA (0.492±0.045 vs 0.543±0.047; P=.01) and a higher CMCT (P=.001) compared to the control group. No correlations were found between clinical, electrophysiological, and MRI features. After 12 months, cases showed a decrease in non-prevalent degree of impairment (PDI) side FA (0.502±0.023 vs 0.516±0.033; P=.01) without differences for electrophysiological features compared to baseline. Treatment with Sativex resulted in a reduction of NRS for spasticity (P=.01).

CONCLUSIONS

We confirm the presence of CST impairment in MS patients with spasticity. We did not identify structural/electrophysiological correlates that could explain Sativex clinical effect.