Change in upper limb function in people with multiple sclerosis treated with nabiximols: a quantitative kinematic pilot study

Objectives: Nabiximols represents an increasingly employed add-on treatment option for spasticity in people with multiple sclerosis (PwMS) who either were unresponsive or reported excessive adverse reactions to other therapies. While several studies performed in the last decade demonstrated its effectiveness, safety, and tolerability, few quantitative data are available on the impact on motor dysfunctions. In this open-label, not concurrently controlled study, we aimed to assess the impact of a 4-week treatment with nabiximols on upper limb functionality. Methods: Thirteen PwMS (9 female, 4 male) with moderate-severe spasticity underwent a combination of clinical tests (i.e., Box and Block, BBT and Nine-Hole Peg test, 9HPT) and instrumental kinematic analysis of the "hand to mouth" (HTM) movement by means of optical motion capture system. Results: After the treatment, improvements in gross and fine dexterity were found (BBT + 3 blocks/min, 9HPT - 2.9 s, p < 0.05 for both cases). The kinematic analysis indicated that HTM movement was faster (1.69 vs. 1.83 s, p = 0.05), smoother, and more stable. A significant reduction of the severity of spasticity, as indicated by the 0-10 numerical rating scale (4.2 vs. 6.3, p < 0.001), was also observed. Conclusion: The findings from the present pilot study suggest that a 4-week treatment with nabiximols ameliorates the spasticity symptoms and the overall motor function of upper limb in PwMS with moderate-severe spasticity. The use of quantitative techniques for human movement analysis may provide valuable information about changes originated by the treatment in realistic upper limb motor tasks involved in activities of daily living.