Effects of intermittent theta burst stimulation on spasticity in post-stroke patients

Abstract

Objectives: Spasticity is a common cause of long-term disability in post-stroke hemiplegic patients. We investigated whether intermittent theta burst stimulation (iTBS) could reduce upper-limb spasticity after a stroke.Methods: Fifteen stroke patients were recruited for a double-blind sham-controlled cross-over design study. Over a 1-week period, they received a single session of both iTBS and sham stimulation, in random order, on the motor hotspot of the flexor carpi radialis muscle (FCR) of the affected hemisphere. One day prior to this session, we assessed patients using the following measures: modified Ashworth scale (MAS), modified Tardieu scale (MTS), H-wave/M-wave amplitude ratio (H/M), peak torque (PT), peak torque angle (PTA), work, and electromyographic activity (EMG) of the FCR. We made these same assessments at four other time points relative to stimulation: (1) immediately before, (2) just after, (3) 30 min after, and (4) 1 week after stimulation.Results: No parameters showed any significant difference between the one-day-before-stimulation and the immediately-before-stimulation measurement times. Repeated measures analysis of variance revealed a significant interaction between TIME and INTERVENTION on the MAS, MTS, PT, PTA, and rectified integrated EMG (p<0.05), indicating these parameters were significantly improved iTBS compared with sham stimulation. However, H/M and work were not affected. The MAS and MTS measures were improved for at least 30 min after iTBS, but other parameters improved significantly only immediately after iTBS (p<0.05).Conclusion: The application of iTBS on the affected hemisphere may be helpful in transiently reducing spasticity after a stroke.