title: A Functional Magnetic Resonance Imaging Study of Head Movements in Cervical Dystonia.
abstract: Cervical dystonia (CD) is a neurological disorder characterized by abnormal movements and postures of the head. The brain regions responsible for these abnormal movements are not well understood, because most imaging techniques for assessing regional brain activity cannot be used when the head is moving. Recently, we mapped brain activation in healthy individuals using functional magnetic resonance imaging during isometric head rotation, when muscle contractions occur without actual head movements. In the current study, we used the same methods to explore the neural substrates for head movements in subjects with CD who had predominantly rotational abnormalities (torticollis). Isometric wrist extension was examined for comparison. Electromyography of neck and hand muscles ensured compliance with tasks during scanning, and any head motion was measured and corrected. Data were analyzed in three steps. First, we conducted within-group analyses to examine task-related activation patterns separately in subjects with CD and in healthy controls. Next, we directly compared task-related activation patterns between participants with CD and controls. Finally, considering that the abnormal head movements in CD occur in a consistently patterned direction for each individual, we conducted exploratory analyses that involved normalizing data according to the direction of rotational CD. The between-group comparisons failed to reveal any significant differences, but the normalization procedure in subjects with CD revealed that isometric head rotation in the direction of dystonic head rotation was associated with more activation in the ipsilateral anterior cerebellum, whereas isometric head rotation in the opposite direction was associated with more activity in sensorimotor cortex. These findings suggest that the cerebellum contributes to abnormal head rotation in CD, whereas regions in the cerebral cortex are involved in opposing the involuntary movements.
authors.affiliation: Department of Neurology, Emory University , Atlanta, GA , USA.
authors.forename: Cecília N
authors.initials: CN
authors.lastname: Prudente
authors.affiliation: Department of Neurology, Emory University , Atlanta, GA , USA.
authors.forename: Randall
authors.initials: R
authors.lastname: Stilla
authors.affiliation: Department of Neurology, Emory University , Atlanta, GA , USA.
authors.forename: Shivangi
authors.initials: S
authors.lastname: Singh
authors.affiliation: Department of Neurology, Emory University, Atlanta, GA, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA.
authors.forename: Cathrin
authors.initials: C
authors.lastname: Buetefisch
authors.affiliation: Department of Neurology, Emory University, Atlanta, GA, USA; Atlanta Parkinson's Consortium Center, Atlanta VAMC, Decatur, GA, USA.
authors.forename: Marian
authors.initials: M
authors.lastname: Evatt
authors.affiliation: Department of Neurology, Emory University , Atlanta, GA , USA.
authors.forename: Stewart A
authors.initials: SA
authors.lastname: Factor
authors.affiliation: Department of Neurology, Emory University , Atlanta, GA , USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Freeman
authors.affiliation: Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University , Atlanta, GA , USA.
authors.forename: Xiaoping Philip
authors.initials: XP
authors.lastname: Hu
authors.affiliation: Department of Neurology, Emory University, Atlanta, GA, USA; Department of Pharmacology, Emory University, Atlanta, GA, USA.
authors.forename: Ellen J
authors.initials: EJ
authors.lastname: Hess
authors.affiliation: Department of Neurology, Emory University, Atlanta, GA, USA; Department of Rehabilitation Medicine, Emory University, Atlanta, GA, USA; Department of Psychology, Emory University, Atlanta, USA; Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VAMC, Decatur, GA, USA.
authors.forename: K
authors.initials: K
authors.lastname: Sathian
authors.affiliation: Department of Neurology, Emory University, Atlanta, GA, USA; Department of Human Genetics, Emory University, Atlanta, GA, USA; Department of Pediatrics, Emory University, Atlanta, GA, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Jinnah
keywords: cerebellum; cervical dystonia; fMRI; head movements; isometric; spasmodic torticollis