TMS-evoked twitches in the passive limb change direction according to muscle activation of the active limb

Abstract

s / Brain Stimulation 8 (2015) 326e342 330 The cerebellum may provide a therapeutic target for non-invasive stimulation in people with cervical dystonia (CD). This study assessed the effect of 10 sessions of intermittent theta-burst stimulation (iTBS) of the cerebellum on symptoms, quality of life and cortical neurophysiology. Fourteen participants (to date) were randomised into intermittent (n 1⁄4 7) or sham (n 1⁄4 7) TBS groups. TMS was used to elicit MEPs from upper trapezius muscles. Dystonia severity and quality of life were assessed using TWSTRS (primary outcome) and CDQ24 questionnaires, pre intervention (pre), after five (mid) and ten (post1) interventions. The CDQ24 was also assessed 4 (post2) and 12 (post3) weeks later. Questionnaire datawere analysed using non-parametric tests. The Mann-Whitney test revealed no difference between groups for the TWSTRS (all P > 0.66). Friedman test showed a reduction in the iTBS group (X2 (2) 1⁄4 8.86, P 1⁄4 0.012), but not in the sham group (X2 (2) 1⁄4 0.67, P 1⁄4 0.72). For TWSTRS pain subsection, there was a group difference at post1 (iTBS -2.93 0.74; sham TBS 0.053 0.94, P 1⁄4 0.046) and a reduction from baseline across time after iTBS (X2 (2) 1⁄4 8.67, P 1⁄4 0.013), but not sham TBS (X2 (2) 1⁄4 4.26, P 1⁄4 0.12). For CDQ-24, the groups differed at post3 (P 1⁄4 0.029) with a trend toward a group difference at post2 (P1⁄4 0.063). Therewas a difference from baseline across time for iTBS (X2 (4)1⁄4 11.14, P1⁄4 0.025), but not sham TBS (X2 (4)1⁄4 4.69, p1⁄4 0.32). MEPs were unaffected by iTBS or sham TBS (all P > 0.21). These preliminary results suggest iTBS may provide an effective intervention for people with CD, particularly for symptoms of pain and for quality of life.