The Cortical Processing of Sensorimotor Sequences is Disrupted in Writer's Cramp.
Evidence for pre-existing abnormalities in the sensory and motor systems has been previously reported in writer's cramp (WC). However, the processing of somatosensory information during motor planning has received little attention. We hypothesized that sensorimotor integration processes might be impaired partly due to a disruption in the parieto-premotor network. To test this assumption, we designed 2 nonwriting motor tasks in which subjects had to perform a 4-finger motor sequence either on the basis of sensory stimuli previously memorized (SM task) or freely generated (SG task). Brain activity was measured by combining event-related functional magnetic resonance imaging and coherency electroencephalography in 15 WC patients and 15 normal controls. The bold signal was decreased in patients in both tasks during sensory stimulation but not during movement execution. However, the EEG study showed that coherency was decreased in patients compared with controls, during the delay of the SM task and during the execution of the SG task, on both the whole network and for specific couples of electrodes. Overall, these results demonstrate an endophenotypic impairment in the synchronization of cortical areas within the parieto-premotor network during somatosensory processing and motor planning in WC patients.
Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.
N
N
Langbour
Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|Service de Neurophysiologie Clinique, Centre Hospitalier Universitaire de Bordeaux, 33076 Bordeaux, France.
V
V
Michel
Université de Bordeaux, INCIA, UMR 5287, F-33400 Talence, France.|CNRS, INCIA, UMR 5287, F-33400 Talence, France.
B
B
Dilharreguy
Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|Service de Neurophysiologie Clinique, Centre Hospitalier Universitaire de Bordeaux, 33076 Bordeaux, France.
D
D
Guehl
Université de Bordeaux, INCIA, UMR 5287, F-33400 Talence, France.|CNRS, INCIA, UMR 5287, F-33400 Talence, France.|Service de Médecine Nucléaire, Centre Hospitalier Universitaire de Bordeaux, 33076 Bordeaux, France.
M
M
Allard
Université de Bordeaux, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|CNRS, Institut des Maladies Neurodégénératives, UMR 5293, F-33000 Bordeaux, France.|Service de Neurophysiologie Clinique, Centre Hospitalier Universitaire de Bordeaux, 33076 Bordeaux, France.
P
P
Burbaud
D000328:Adult; D020821:Dystonic Disorders / Q000503:physiopathology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009068:Movement; D013003:Somatosensory Cortex / Q000503:physiopathology*
EEG coherency; fMRI; nonwriting task; sensorimotor integration; writer's cramp