Brain Advance Access originally published online on May 16, 2008
Brain 2008 131(6):1562-1573; doi:10.1093/brain/awn083
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The sensory and motor representation of synchronized oscillations in the globus pallidus in patients with primary dystonia
1Department of Physiology, Anatomy, and Genetics, University of Oxford, 2Department of Clinical Neuroscience, Faculty of Medicine, Imperial College London, 3Department of Neurosciences, Charing Cross Hospital, London, 4Department of Neurosurgery and 5Department of Neurology, John Radcliffe Hospital, Oxford, UK
Correspondence to: Dr Xuguang Liu, 10th floor, Laboratory Block, Charing Cross Hospital, Fulham Palace Road, London W6 8RF, UK E-mail: x.liu{at}ic.ac.uk
In 15 patients with primary dystonia (six cervical and nine generalized dystonias) who were treated with bilateral chronic pallidal stimulation, we investigated the sensorimotor modulation of the oscillatory local field potentials (LFPs) recorded from the pallidal electrodes. We correlated these with the surface electromyograms in the affected muscles. The effects of involuntary, passive and voluntary movement and muscle-tendon vibration on frequency ranges of 0–3 Hz, theta (3–8 Hz), alpha (8–12 Hz), low (12–20 Hz) and high beta (20–30 Hz), and low (30–60 Hz) and high gamma (60–90 Hz) power were recorded and compared between cervical and generalized dystonia groups. Significant decreases in LFP synchronization at 8–20 Hz occurred during the sensory modulation produced by voluntary or passive movement or vibration. Voluntary movement also caused increased gamma band activity (30–90 Hz). Dystonic involuntary muscle spasms were specifically associated with increased theta, alpha and low beta (3–18 Hz). Furthermore, the increase in the frequency range of 3–20 Hz correlated with the strength of the muscle spasms and preceded them by
320 ms. Differences in modulation of pallidal oscillation between cervical and generalized dystonias were also revealed. This study yields new insights into the pathophysiological mechanisms of primary dystonias and their treatment using pallidal deep brain stimulation.
Key Words: dystonia; deep brain stimulation; electromyograms; globus pallidus; oscillations
Abbreviations: BFMDRS, The Burke, Fahn and Marsden dystonia rating score; DBS, deep brain stimulation; ECoG, electrocorticogram; EMG, electromyogram; GPe, globus pallidus externus; GPi, globus pallidus internus; FFT, fast Fourier transform; LFPs, local field potentials; PSD, power spectrum density; TWSTRS, The Toronto Spasmodic Torticollis rating scale
Received October 25, 2007. Revised February 12, 2008. Accepted April 11, 2008.