28. Modulation of cerebral sensorimotor circuits during botulinum toxin treatment of cervical dystonia

Abstract

Objective Neurophysiological and lately also functional brain imaging studies in cervical dystonia (CD) patients indicate a disorder of sensorimotor integration within extensive cortico-subcortical brain networks. Intramuscular botulinum toxin type A (BoNT-A) application has a proven clinical effect on pathological muscle activation in CD but recently has also been shown to modulate sensorimotor networks. To clarify cervical dystonia pathophysiology through functional magnetic resonance imaging of sensorimotor network changes associated with first-time botulinum toxin treatment. Methods We have studied 12 BoNT-A naive CD patients using functional MRI during specific hand motor task performance. Clinical and imaging examinations were performed before the first BoNT-A application and subsequently 4 weeks after application, at the time of maximal clinical effect of BoNT-A. Clinical treatment response was evaluated with the Tsui score, functional MRI data were analyzed with a general linear model implemented in FSL software, treatment effects were tested in pair-wise linear contrasts. Results First BoNT-A injection, although it had a good clinical effect, did not lead to any significant changes in activation of cortex or basal ganglia in our group of CD patients. Discussions Within the context of previously described sensorimotor network hypoactivation during motor task performance in CD, our observed effect of no significant change in sensorimotor cortex activation would suggest the hypothesis that robust central changes develop after long-term regular BoNT-A treatment, although even the first BoNT-A application is clinically effective. Acknowledgment Research supported by Grant IGA MH CR NT13575.