Comparison between the therapeutic effects of robotic-assisted locomotor training and an anti-spastic medication on spasticity

We studied the effects of robotic-assisted locomotor (LOKOMAT) training or an anti-spastic medication (tizanidine) on neuromuscular abnormality associated with spasticity in persons with incomplete Spinal Cord Injury (SCI). Subjects were randomly divided to three groups: Lok, Tiz, and Cont. LOKOMAT training was performed 3 days/week for 4 weeks, with up to 45 minutes of training per session. Tizanidine (2mg) was administered (4\day), for 4 weeks. Subjects in Cont group received no intervention. The participants were evaluated before and after 4 weeks of training, and the effects of training on the intrinsic (muscular) and reflexive components of the neuromuscular properties were quantified over the ankle range-of-motion. A parallel-cascade system identification technique was used to determine the reflex and intrinsic stiffness of the ankle joint as a function of ankle position at each time point. The intercept and slope of the stiffness vs. joint angle curve were then calculated and tracked over the four-week period. The number of subjects that achieved the minimally important difference (MID) for the intercepts and slopes, and levels of changes were compared. Both Lokomat and tizanidine resulted in significant reduction in both intercept and slope of reflex and intrinsic stiffness. However, a higher proportion of subjects in Lok group achieved the MID for the reflex (>90%) and intrinsic (65-78%) parameters compared with Tiz group (up to 63% and 25% for reflex and intrinsic parameters, respectively). The levels of reduction were also higher in the Lok than the Tiz group. No one in the Cont group achieved the MID. Our findings demonstrate that LOKOMAT training can be more efficient in modifying neuromuscular abnormalities associated with spasticity than tizanidine.