Functional Magnetic Resonance Imaging Of The Brain Before And After Botulinum Toxin Treatment Of Spasmodic Torticollis

ObjectiveCompare the difference of cerebral activation patterns between patients with cervical dystonia (CD) and healthy controls during complex finger movements, and observe the brain activation change caused by peripheral botulinum toxin injection by functional magnetic resonance imaging (fMRI) to investigate the pathophysiological mechanism of CD and the effect of botulinum toxin at central nervous system level.MethodA fMRI block design with complex finger movements was introduced and14patients with cervical dystonia as well as the age and gender matched controls were scanned with signa3.0T MRI scanner (GE). Patients were scanned before and4weeks after the treatment of botulinum toxin, and evaluated with TWSTRS (Toronto Western Spasmodic Torticollis Rating Scale) by examinant as well. The image data were analyzed with software SPM8, MRIcroN, AAL, etc. For average activation maps within group a one sample t-test was used, for between group contrasts (CD patients vs. controls) a two sample t-test was used. And for correlation analysis between activation pattern alteration of pre/post treatment and TWSTRS score change a one sample t-test was used.Result1. An overall reduced extent of activation in patients with cervical dystonia was demonstrated compared to healthy controls, especially in ipsilateral putamen, prefrontal cortex and contralateral somatosensory cortex to the direction of the head deviation. And greater magnitude of activation in ipsilateral precuneus was documented with statistic significance (P<0.005, unc.).2.At the time point of4weeks after botulinum toxin treatment patients showed no evident difference with healthy controls except for the higher activation in contralateral precuneus to the direction of the head deviation (P<0.005, unc.).3.There was a positive correlation between cerebral activation pattern change in some areas (ipsilateral primary somatosensory cortex, premotor cortex, supplementary motor cortex, insula as well as contralateral middle temporal cortex and bilateral Hippocampus/parahippocampa to the direction of the head deviation) and TWSTRS score decrease (P<0.001,unc.).Conclusion1. There are widespread abnormalities in cerebral and subcerebral activation pattern between patients with cervical dystonia and healthy controls provoked by complex finger movements. The pathophysiological mechanism may associate with dysfunction of sensorymotor integration.2. Patients with cervical dystonia showing less activated putamen during normal hand movements possibly suggests a basic pre-dystonic state for affected body parts before its clinical symptoms appear.3. For patients with cervical dystonia Botulinum toxin fulfills its subsequent central effect by reorganizing and normalizing the cerebral cortex.